List of articles (by subject) Mechanical Engineering

    • Open Access Article

      1 - Optimization The High Speed Machining of Hardened AISI 4140 Steel Using Vapor Deposited Cutting Tools (Wear and Roughness)
      Mehdi Jalali Azizpour Ata Fardaghaie
      In this study, the main cutting parameters of high speed machining (HSM) including cutting speed, feed rate, depth of cut as well as deposition method were optimized using genetic algorithm considering the average surface roughness (Ra) of work piece and flank wear (Vb) More
      In this study, the main cutting parameters of high speed machining (HSM) including cutting speed, feed rate, depth of cut as well as deposition method were optimized using genetic algorithm considering the average surface roughness (Ra) of work piece and flank wear (Vb) of CVD and PVD coated tool criteria in high speed turning of hardened AISI 4140 Steel. Standard L18 orthogonal array has been used for the design of experiment (DOE) applying Taguchi approach. Multiple linear regression model applying Minitab, was used to determine the relationship and interaction between machining parameters and outputs. For genetic algorithm(GA) optimization, the average was applied as a functional output of design of experiments. The results of GA for smaller- the better quality characterization shows the optimum roughness of 1.107 mm and optimum flank wear of 0.461mm. The confirmation tests were carried out in order to validate the response of predicted optimum condition. The results of validation test show a good agreement between obtained optimum condition and the results of genetic algorithm. The analysis of variance was used in order to obtain the contribution of each factor on the output statistically. ANOVA results indicated that the cutting speed and cut depth are the most effective factors on the flank wear by 37.02 and 27.80 percent contribution respectively. The most effective factors on surface roughness were feed rate and cutting speed by 82.49 and 10.50 percent contribution respectively. Stereoscopy and Scanning electron microscopy was used to evaluate the wear mechanism and topography of worn surface. Manuscript profile
    • Open Access Article

      2 - Genetic Algorithm and ANN for Estimation of SPIV of Micro Beams
      M. Heidari
      In this paper, the static pull-in instability (SPIV) of beam-type micro-electromechanical systems is theoretically investigated. Herein, modified strain gradient theory in conjunction with Euler–Bernoulli beam theory have been used for mathematical modeling of the More
      In this paper, the static pull-in instability (SPIV) of beam-type micro-electromechanical systems is theoretically investigated. Herein, modified strain gradient theory in conjunction with Euler–Bernoulli beam theory have been used for mathematical modeling of the size dependent instability of the micro beams. Considering the mid-plane stretching as the source of the nonlinearity in the beam behavior, a nonlinear size-dependent Euler-Bernoulli beam model is used based on a modified couple stress theory, capable of capturing the size effect. Two common beam-type systems including double-clamped and clamped-free cantilever have been investigated. By selecting a range of geometric parameters such as beam lengths, width, thickness, gaps and size effect, we identify the static pull-in instability voltage. Back propagation artificial neural network (ANN) with three functions have been used for modelling the static pull-in instability voltage of micro beam. Effect of the size dependency on the pull-in performance has been discussed for both micro-structures. The network has four inputs of length, width, gap and the ratio of height to scale parameter of beam as the independent process variables, and the output is static pull-in voltage of microbeam. The number of nodes in the hidden layer, learning ratio and momentum term are optimized using genetic algorithms (GAs). Numerical data, employed for training the network and capabilities of the model in predicting the pull-in instability behaviour has been verified. The output obtained from neural network model is compared with numerical results, and the amount of relative error has been calculated. Based on this verification error, it is shown that the back propagation neural network has the average error of 6.36% in predicting pull-in voltage of cantilever micro-beam. Resultant low relative error value of the ANN model indicates the usability of the BPN in this area. Manuscript profile
    • Open Access Article

      3 - Estimation of Surface Roughness in Turning by Considering the Cutting Tool Vibration, Cutting Force and Tool Wear
      A. Salimi A. Ebrahimpour M. Shalvandi E. Seidi
      Surfacequality along with the low production cost, play significant role in today’s manufacturing market. Quality of a product can be described by various parameters. One of the most important parameters affecting the product quality is surface roughness of the ma More
      Surfacequality along with the low production cost, play significant role in today’s manufacturing market. Quality of a product can be described by various parameters. One of the most important parameters affecting the product quality is surface roughness of the machined parts. Good surface finish not only assures quality, but also reduces the product cost. Before starting any machining process, surface finish is predictable using cutting parameters and estimation methods. Establishing a surface prediction system on a machine tool, avoids the need for secondary operation and leads to overall cost reduction. On the other hand, creating a surface estimation system in a machining plant, plays an important role in computer integrated manufacturing systems (CIMS). In this study, the effect of cutting parameters, cutting tool vibration, tool wear and cutting forces on surface roughness are analyzed by conducting experiments using different machining parameters, vibration and dynamometers sensors to register the amount of tool vibration amplitude and cutting force during the machining process. For this, a number of 63 tests are conducted using of different cutting parameters. To predict the surface quality for different parameters and sensor variables, an ANN model is designed and verified using the test results. The results confirm the model accuracy in which the R2 value of the tests was obtained as 0.99 comparing with each other. Manuscript profile
    • Open Access Article

      4 - An Experimental Investigation on Comparison of the Similar and Dissimilar Resistance Spot Welding of St12 and Galvanized Steel using Design of Experiments
      Mahmoud Moradi Hadi Abdollahi Ali Khorram
      In the present research, similar and dissimilar resistance spot welding (RSW) process of St12 and galvanized steel sheets with thickness of 0.9 mm was investigated. The experiments were carried out based on the statistical design of experiments (DOE) approach to investi More
      In the present research, similar and dissimilar resistance spot welding (RSW) process of St12 and galvanized steel sheets with thickness of 0.9 mm was investigated. The experiments were carried out based on the statistical design of experiments (DOE) approach to investigate the effect of RSW parameters on the welding quality, achieving the mathematical regression equations and predicting the new results. Welding time and electrode force were considered as the input process variables while the tensile-shear strength of the joints was considered as the process response. By comparing three RSW types, galvanized steel has the highest tensile-shear strength. Statistical analysis shows that tensile-shear strength is increased with increasing electrode force and welding time. Verification experiments for three types of RSW joints were carried out in order to analyse the obtained results via software. Good agreement between the verification tests and the optimization results revealed that the statistical modelling would be appropriate for RSW process. Welding time (T)  = 5 s and electrode force (P)  = 925 N, welding time (T) = 5 s and electrode force (P) = 1100 N and welding time (T) = 3 s and electrode force (P) = 925 N were obtained as the optimum settings for similar RSW of St12, dissimilar RSW of St12 to galvanized steel and similar RSW of galvanized steel, respectively. Manuscript profile
    • Open Access Article

      5 - Experimental Study on Magnetic Abrasive Honing of Inner Surface of Tube AISI304
      Hamzeh Shahrajabian Masoud Farahnakian Payam Saraeian
      To overcome the limitation of honing process, the present work proposes magnetic abrasive honing (MAH) process whereby abrasive stones are replaced by magnetic abrasives. This process is combination of magnetic abrasive finishing (MAF) and honing. MAF which is one of th More
      To overcome the limitation of honing process, the present work proposes magnetic abrasive honing (MAH) process whereby abrasive stones are replaced by magnetic abrasives. This process is combination of magnetic abrasive finishing (MAF) and honing. MAF which is one of the finishing processes can improve the quality of workpiece surface with various geometries, removing the chips in micrometer scale by magnetic field forces. This study set to apply longitudinal vibration to the tube workpiece in MAF process; hence, this process is called MAH. The effects of rotary speed of workpiece, cross-hatch angle, and mesh number were investigated on the surface roughness of AISI 304. Magnetic abrasives were combination of SiC particles as abrasives and iron particles as ferromagnetic particles in lubricant of SAE 40 oil. The results revealed that the longitudinal movement of workpiece is effective on MAH, as the surface roughness decreased with increasing the cross-hatch angle. Surface roughness decreased with increase of rotary and mesh number. The major changes in surface roughness (58%) were obtained in cross-hatch angle of 45º rotary speed of 800 rpm and mesh size of 400. The microscopic picture showed that three-body wear mechanism is dominant for fine grits. Manuscript profile
    • Open Access Article

      6 - Corrosion Behavior Characterization of the Nugget Zone in Copper/Brass Metals of Dissimilar Friction Stir Welded Lap Joints
      kamran amini Farhad Gharavi
      The electrochemical behavior of the weld nugget zone (WNZ) in copper-brass plates was studied in this paper. These plates were welded by the friction stir lap welding method in 1M NaCl solution at low heating input (450 rpm-25 mm/min ) and high heating input (710 rpm-16 More
      The electrochemical behavior of the weld nugget zone (WNZ) in copper-brass plates was studied in this paper. These plates were welded by the friction stir lap welding method in 1M NaCl solution at low heating input (450 rpm-25 mm/min ) and high heating input (710 rpm-16 mm/min) by using the electrochemical impedance spectroscopy (EIS) and Tafel polarization at ambient temperature. The morphology of nugget zone corroded surfaces was analyzed by SEM (scanning electron microscopy) technique. The welding process appeared to decrease the corrosion resistance of the welded nugget regions through increasing the welding heat input. The results from EIS measurements presented the welded joints of NZ which showed higher and lower values respectively than brass and copper. Due to changing of microstructural of weld nugget zone during welding process, the Icorr of nugget zone enhances with increasing welding heat input. In fact, the surface corrosion morphology analysis revealed that the surface of welded sample by high heating input was shielded with a roughly porous corrosion layer rather than the surface of the welded sample at low heating input Manuscript profile
    • Open Access Article

      7 - Qualification of Propeller by Experimental and Analytical Methods
      K. Siva Prasad S. Murthy Bellala
      The paper focuses on static and dynamic analysis of propeller blade made of Aluminium-24345 material. The solid model of propeller blade and propeller are developed in CATIA V5 R20. By using this model, propeller blade was manufactured using 3-Axis CNC milling machine b More
      The paper focuses on static and dynamic analysis of propeller blade made of Aluminium-24345 material. The solid model of propeller blade and propeller are developed in CATIA V5 R20. By using this model, propeller blade was manufactured using 3-Axis CNC milling machine by adopting MASTERCAM software. Qualification tests were carried out on the propeller blade of an underwater vehicle for their strength and vibration. Impact Hammer Method is employed to measure the vibration-damping properties of Propeller blade. Computational Fluid Dynamics (CFD) analysis is carried out to analyze the contours of static pressure on the 5-Blade propeller and the forces, moments acting on the propeller. Finite element analysis (FEA) of the blade was carried in ANSYS 15.0. Static, modal, harmonic analysis was carried out on analysis software for the modeled propeller blade and Factor of Safety was determined to qualify the propeller.Deformation of the propeller blade is measured using Coordinate Measuring Machine (CMM). Manuscript profile
    • Open Access Article

      8 - Forecasting Operational Parameters of a Solar Space Heating System using a Novel Multistage Artificial Neural Network
      Farnaz Jamadi Behnam Jamali
      In this study, several operational parameters of a solar energy system are predicted through using a multistage ANN model. To achieve the best design of this model, three different back-propagation learning algorithms, i.e. Levenberg-Marquardt (LM), Pola-Riber Conjugate More
      In this study, several operational parameters of a solar energy system are predicted through using a multistage ANN model. To achieve the best design of this model, three different back-propagation learning algorithms, i.e. Levenberg-Marquardt (LM), Pola-Riber Conjugate Gradient (CGP) and the Scaled Conjugate Gradient (SCG) are utilized. Further, to validate the ANN results, some experimental tests have been done in winter 2016 on a solar space heating system (SSHS) equipped with a parabolic trough collector (PTC). In the proposed model, ANN comprises three consecutive stages, while the outputs of each one are considered to be the inputs of the next. Results show that the maximum error rate in Stages 1, 2, and 3 has occurred in the LM algorithm with respectively 10, 6, and 10 neurons. Moreover, the best obtained determination coefficient of all stages belongs to the total system efficiency and has the value 0.999934 for LM-10. As a result, the multistage ANN model can simply forecast operational parameters of the solar energy systems with high accuracy. Manuscript profile
    • Open Access Article

      9 - Investigating the Tribological Behavior of Diesel-biodiesel Blends with Nanoparticle Additives under Short-term Tests
      Hossein Khorshidnia Alireza Shirneshan
      The addition of nanoparticles to lubricant is effective for the reduction of wear and friction in the mechanical system. In this research, the effects of additions of copper oxide nanoparticle nanoparticles on lubrication behavior of biodiesel-diesel fuel blends were in More
      The addition of nanoparticles to lubricant is effective for the reduction of wear and friction in the mechanical system. In this research, the effects of additions of copper oxide nanoparticle nanoparticles on lubrication behavior of biodiesel-diesel fuel blends were investigated by using a four-ball tester. Three fuel blends with the addition of 0, 25, 50 and 75 ppm nanoparticle were tested in steady-state conditions at four different rotational speed of 600, 1200 and 1500 rev/min. the results showed that the friction coefficient decreases with the increase in nanoparticles up to 50 ppm because of filling the friction surface with the nanoparticles and replacement of sliding friction with the rolling effect in the contact zone. On the other hand, the FC was enhanced significantly with 75 ppm nanoparticle addition in fuel blends B10 and B20. However, the results showed that the lubrication of fuel blend B50 with the 75 ppm nanoparticle is better than that of other fuel blends in the same situation. Moreover, it was found that with an increase in biodiesel concentration the friction coefficient was reduced due to free fatty acids, monoglycerides, and diglycerides as the components of biodiesel. Manuscript profile
    • Open Access Article

      10 - Synthesis of B4C - Nano TiB2 Composite Nano Powder by the Chemical Precipitation Method
      M. Saeedi Heydari H. R. Baharvandi
      The aim of this research is to determine the proper concentration of Titanium Tetra IsoPropoxide (TTIP) and select the right temperature and time of calcinations for the synthesis of B4C-nano TiB2 composite Nano powder by the chemical precipitation method. For this purp More
      The aim of this research is to determine the proper concentration of Titanium Tetra IsoPropoxide (TTIP) and select the right temperature and time of calcinations for the synthesis of B4C-nano TiB2 composite Nano powder by the chemical precipitation method. For this purpose, first, solutions with TTIP molar concentrations of 0.1, 0.05 and 0.03 were prepared and the optimal molar concentration of TTIP was determined to be 0.05. Then, a diluted solution of distilled water and TTIP was mixed with Isopropanol Alcohol containing B4C micropowder. In this mixture, Titanium Hydroxide nanoparticles were initially synthesized and then, to convert the Ti(OH)4 to TiB2, the above mixture were calcined in a furnace, under Argon atmosphere. The calcination process was carried out at temperatures of 750, 1000 and 1250 ºC. It was observed that the most suitable temperature for the formation of the TiB2 phase is 1250 ºC and that the lower temperatures only lead to the formation of the TiO2 phase. It was also observed that, at the calcination temperature of 1250 ºC, the most appropriate time duration for the conversion of Ti(OH)4 nanoparticles to TiB2 nanoparticles is 30 minutes, during which B4C-nano TiB2 composite Nano powders form, with most of the TiB2 particle sizes being in the range of 30-60 nm. Manuscript profile
    • Open Access Article

      11 - Evaluating the Effect of Operating Conditions on Temperature Variation Rate of Inner Walls and Inside Inflated Air of Pneumatic Tires
      Moslem Namjoo Hossein Golbakhshi Farhad Khoshnam Ahmad Soleimani
      For rolling pneumatic tires, the thermal induced effects are mainly resulted from visco-elastic behaviour of rubber parts and dissipation of stores strain energy during the cyclic deformations. It is noted that the operating conditions crucially contribute to the rubber More
      For rolling pneumatic tires, the thermal induced effects are mainly resulted from visco-elastic behaviour of rubber parts and dissipation of stores strain energy during the cyclic deformations. It is noted that the operating conditions crucially contribute to the rubber hysteresis effect and temperature development in a rolling tire. In current study, an elaborated 3D FE model is worked up for simulating the certain inflation pressure, loading and velocity conditions for a specified radial tire. Special emphasis is given to transient temperature distribution of interior walls and tire cavities as critical zones. Compared with the experimental tests, the current study gives satisfactory results for time rate of change in temperature of tire walls and inside inflated air. Manuscript profile
    • Open Access Article

      12 - Picard Iteration Method to Kinetic Analysis of Thermal Inactivation of Enzyme as Applied in Biotechnology
      A. Olurotimi Adeleye M. Gbeminiyi Sobamowo
      In this work, Picard iteration method is used to obtain analytical expressions for the prediction of molar concentration of native and denatured jack bean urease (EC 3.5.1.5) through the three-reaction steps kinetic model of thermal inactivation of the urease. The obtai More
      In this work, Picard iteration method is used to obtain analytical expressions for the prediction of molar concentration of native and denatured jack bean urease (EC 3.5.1.5) through the three-reaction steps kinetic model of thermal inactivation of the urease. The obtained solutions are used to study the kinetics of thermal inactivation of the enzyme as applied in biotechnology. The analytical solutions are verified with numerical solutions using Runge –Kutta with shooting method and good agreements are established between the solutions. From the parametric studies using the iterative method, the molar concentration of native enzyme decreases as the time increases while the molar concentration of the denatured enzyme increases as the time increases. The time taken to reach the maximum value of the molar concentration of native enzyme is the same as the time taken to reach the minimum value of the molar concentration of the denature enzyme. The information given in this theoretical investigation will assist in the kinetic analysis of the experimental results over handling rate constants and molar concentrations. Manuscript profile
    • Open Access Article

      13 - Evaluating the Effects of Overload and Welding Residual Stress in Fatigue Crack Propagation
      Ali Moarefzadeh Shahram Shahrooi Mehdi Jalali Azizpour
      In this paper, a suitable method is presented to predicate fatigue crack propagation for cyclic loading with overload in residual stresses field resulted by weld. For this, first effective stress intensity factor (SIF) and effective cycle ratio (R) are introduced as fun More
      In this paper, a suitable method is presented to predicate fatigue crack propagation for cyclic loading with overload in residual stresses field resulted by weld. For this, first effective stress intensity factor (SIF) and effective cycle ratio (R) are introduced as function depending on SIFs resulted by external load, weld residual stress and overload. Weight function is applied to calculate SIF resulted by weld residual stress. Also, a method is introduced to determine overload SIF and overload stress ratio. Then fatigue crack propagation equation is modified for our purpose. In other words, a simple and efficient method is presented in this paper for predicting fatigue crack propagation rate in welded joints when the overload is happen. Finally for evaluating this modified equation, experimental methods are applied. Test samples were M(T) geometry made of aluminum alloy with a longitudinal weld by the Gas Tungsten arc welding process. Modified equation has a good agreement with the experimental model presented in this field. Manuscript profile
    • Open Access Article

      14 - Modelling of Non-Uniform Piezoelectric Micro-Cantilever in Different Environments
      Mitra Taghizade A. H. Korayem M. H. Korayem
      In recent years, Atomic Force Microscopy (AFM) has been known as a powerful and efficient tool for surface imaging in different environment. To enhance image quality and more precise prediction of Micro-cantilever (MC) behaviour, accuracy in the MC modeling and simulati More
      In recent years, Atomic Force Microscopy (AFM) has been known as a powerful and efficient tool for surface imaging in different environment. To enhance image quality and more precise prediction of Micro-cantilever (MC) behaviour, accuracy in the MC modeling and simulation and detecting the MC sensitivity to geometric parameters has great importance. To model the vibration motion of the AFM non-uniform piezoelectric MC, Timoshenko beam theory is used in order to consider the effect of shear effect in air and liquid environment. In addition, the effect of the forces imposed by the ambient and sample surface is considered. Frequency response has been studied in the air and different liquid environments and the obtained results have been compared with experiential results as well as with results obtained from Euler-Bernoulli beam theory that is reflective of higher precision exercised in the modeling in respect to Euler-Bernoulli beam theory. Efast statistical method, which is found efficient and quick in the survey of linear and nonlinear models and takes the inter-parameter coupling effect into consideration besides calculating the sensitivities unique to each of the factors, has been applied in order to analyse the geometrical parameters’ effects on the MC natural frequencies in the air and water environments. Manuscript profile
    • Open Access Article

      15 - A New Robust Strategy to Improve the Transient Dynamic of a Vehicle
      Mohammad Amin Saeedi
      In this paper for handling improvement and lateral stability increment of a four-wheeled vehicle a new robust active control system is proposed. First, to establish an accurate model of the vehicle, a fourteen-degrees-of-freedom nonlinear dynamic model is developed. Nex More
      In this paper for handling improvement and lateral stability increment of a four-wheeled vehicle a new robust active control system is proposed. First, to establish an accurate model of the vehicle, a fourteen-degrees-of-freedom nonlinear dynamic model is developed. Next to control the lateral motion and yawing motion of the vehicle a new active steering control system designed based on a simplified two-degrees-of-freedom dynamic model. The main reason of using the active steering controller is to track the desired values of the yaw rate and lateral velocity. Also, sliding mode control method is used to design the control system. A complete stability analysis based on the Lyapunov theory is presented to guarantee closed-loop stability. Simulation results show that the controller improves the vehicle’s maneuverability, especially during severe double lane change maneuver in which intense instability occurs. More investigations demonstrate that the proposed control system can considerably improve vehicle maneuverability and path tracking under uncertainties. Manuscript profile
    • Open Access Article

      16 - Determination of Local Constitutive Properties of Aluminum using Digital Image Correlation: A Comparative Study Between Uniform Stress and Virtual Fields
      Ali Shahmirzaloo Mohammadreza Farahani
      A proper understanding of material mechanical properties is important in designing and modelling of components. As a part of a study on the structural integrity, the Digital Image Correlation technique was used to obtain the full-field strain distribution during a tensi More
      A proper understanding of material mechanical properties is important in designing and modelling of components. As a part of a study on the structural integrity, the Digital Image Correlation technique was used to obtain the full-field strain distribution during a tensile test of the specimens. The displacement maps were analyzed using Matlab scripts to compute local stress-strain variations. Consequently the local proof stress values were extracted. In this study, the local extraction of the elastic and plastic properties of Al6061 alloy has been carried out using both the uniform stress method and the virtual fields method involving digital image correlation technique. In uniform stress methodology, full range stress–strain curves are obtained using the whole field strain measurement using Digital Image Correlation. The parameters investigated are Young's modulus, Poisson's ratio, yield strength, strain hardening exponent and strength coefficient. Recently, the virtual fields method is gaining a lot of popularity in domain characterization as it is robust, accurate and faster. Young's modulus, Poisson's ratio, yield strength, strength coefficient and strain hardening exponent are the parameters extracted using both uniform stress method and virtual fields method. The parameter variation obtained by both uniform stress method and the virtual fields method compares very well. Due to various advantages associated with virtual fields method, it is generally recommended for material mechanical properties extraction. Manuscript profile
    • Open Access Article

      17 - Ultrasonic Assisted Drilling of Bone
      Vahid Khademi Javad Akbari Farzam Farahmand
      Ultrasonic Assisted Drilling (USD) is new technique to drill difficult to machine materials. In this method, tool or workpiece vibrates with amplitude of few microns in addition to conventional drill bite rotation. In this experimental research, the bone was drilled bot More
      Ultrasonic Assisted Drilling (USD) is new technique to drill difficult to machine materials. In this method, tool or workpiece vibrates with amplitude of few microns in addition to conventional drill bite rotation. In this experimental research, the bone was drilled both conventionally and using UAD, then the thrust was measured in two methods at feed rates of 50, 75 and 125 mm/s and 500, 710 and 1000 RPMs. The results show that USD method causes the thrust force decreases considerably in compare whit conventional drilling. The maximum temperature is less in USD at low RPMs. Manuscript profile
    • Open Access Article

      18 - Minimizing Thermal Residual Stresses in Ceramic Matrix Composite by BSG-Starcraft Radius PSO
      Y.J. Xu E. Padayodi S. A. Bahrani D. Chamoret
      To achieve an excellent thermal-mechanical performance of CMCs, it is necessary to analyze and design the thickness of the multi-layered interphases for an optimized TRS distribution. An optimization was performed with a new version of the particle swarm optimization, t More
      To achieve an excellent thermal-mechanical performance of CMCs, it is necessary to analyze and design the thickness of the multi-layered interphases for an optimized TRS distribution. An optimization was performed with a new version of the particle swarm optimization, the BSG-Starcraft Radius PSO linked to a finite element software. Manuscript profile
    • Open Access Article

      19 - Predicting Strip Tearing in Cold Rolling Tandem Mill using Neural Network
      A. Haghani A. R. Khoogar F. Kumarci
      Strip tearing during cold rolling process has always been considered among the main concerns for steel companies. Several works have been done so far regarding the examination of the issue. In this paper, experimental data from cold rolling tandem mill is used for detec More
      Strip tearing during cold rolling process has always been considered among the main concerns for steel companies. Several works have been done so far regarding the examination of the issue. In this paper, experimental data from cold rolling tandem mill is used for detecting strip tearing. Sensors are placed across the cold rolling tandem mill. They receive information on parameters (such as angular velocity of the rolls, voltage and the electrical current of electrical motors driving rolls, roll gap, and strip tension force between rolls) directly from the cold rolling tandem mill and save as files. The information included two modes: perfect rolling and ruptured rolling. A neural network was designed by means of MATLAB software and, then, trained using the information from files. Finally, the neural network was examined by new data. It was concluded that neural network has high accuracy in distinguishing between perfect and defected rolling. Manuscript profile
    • Open Access Article

      20 - Geometrical Effects of Duct on the Entropy Generation in the Laminar Forced Convection Separated Flow
      Nasrin Aminzadeh Shima Sotoodehnia Meysam Atashafrooz
      In this research paper, irreversibility analysis of laminar forced convection flow in a duct with variable cross-section are numerically studied. Two-dimensional Cartesian coordinate system is used to solve the set of governing equations and also the blocked-off method More
      In this research paper, irreversibility analysis of laminar forced convection flow in a duct with variable cross-section are numerically studied. Two-dimensional Cartesian coordinate system is used to solve the set of governing equations and also the blocked-off method is considered for simulation of the inclined surfaces. To obtain the velocity and temperature fields, the basic equations are numerically solved using the finite volume method and SIMPLE algorithm. To determine the flow irreversibility, the entropy generation number is calculated according to the thermodynamic second law. The geometrical effects of duct on the distributions of streamlines, friction coefficient, Nusselt number, entropy generation, and Bejan number are presented with details. The results show that the duct heights and inclination angle of surfaces have great effects on the flow irreversibility and the hydrodynamics and thermal behaviours. Also, comparison of the present numerical results with the available data published in the open literature shows an excellent consistency. Manuscript profile
    • Open Access Article

      21 - Exact Vibration and Buckling Solution of Levy Type Initially Stressed Rectangular Thin Plates
      Ali Akbar Neyestanak Ali lotfi
      This paper has focused on vibration and buckling of thin rectangular plates when at least two opposite sides are simply supported condition and subjected to axial and biaxial initially stresses. Analysis is based on exact solution method, without further usage of any ap More
      This paper has focused on vibration and buckling of thin rectangular plates when at least two opposite sides are simply supported condition and subjected to axial and biaxial initially stresses. Analysis is based on exact solution method, without further usage of any approximate method. First analytic techniques are used to discuss the free vibrations of plate. Then, natural frequencies and critical buckling loads are calculated. It is believed that in the present work, the exact closed form characteristic equations and their associated eigenfunctions for the considered six case are obtained for the first time. Manuscript profile
    • Open Access Article

      22 - Sensitivity Analysis for Optimal Design of Multibody Systems with Clearance Joint
      Saeed Ebrahimi Esmaeil Salahshoor Saeed Nouri
      This paper deals with the sensitivity analysis and optimization of system parameters for a classical slider-crank mechanism as a multibody system which includes a clearance between the joints of coupler and slider. Due to the nonlinearity involved in the dynamics of cle More
      This paper deals with the sensitivity analysis and optimization of system parameters for a classical slider-crank mechanism as a multibody system which includes a clearance between the joints of coupler and slider. Due to the nonlinearity involved in the dynamics of clearance joints, the base reaction force, exerted on the base from the crank, changes roughly and does not vary as smooth as the case of the mechanism with ideal joint. Variation of the base reaction force can be a measure of the undesired vibrations induced due to the effect of clearance joint. After deriving the equations of motion and modeling the clearance, the direct differentiation method is used to conduct a local sensitivity analysis to assess the sensitivity measure of the base reaction force on some kinematic and contact parameters. The results show that the reaction force is more sensitive to the variation of link lengths and link masses compared to the variation of contact surface characteristics such as Young’s modulus, restitution coefficient and contact generalized stiffness in most parts of the motion cycle. On the other hand, the sensitivity of the base reaction force to the clearance size is very higher than its sensitivity to the above-mentioned kinematic and contact properties. Finally, based on the results of the sensitivity analysis, an optimization procedure is used to reduce the amount of the maximum base reaction force by choosing the optimized link lengths. Manuscript profile
    • Open Access Article

      23 - Thermo-Elastic and Time-Dependent Creep Evolution Behaviour of Ferritic Steel Rotating Disks using Theta Projection Concept
      H. Daghigh V. Daghigh
      In this article, thermo-elastic and creep evolution behaviour of ferritic steel rotating disks with variable thickness are investigated. Four thickness profiles of uniform, convex, concave and linear are considered for the disk geometry. The material creep constitutive More
      In this article, thermo-elastic and creep evolution behaviour of ferritic steel rotating disks with variable thickness are investigated. Four thickness profiles of uniform, convex, concave and linear are considered for the disk geometry. The material creep constitutive model is defined by the Θ projection concept, based on the experimental results existing in the literature. Loading applied is due to the inertial body force caused by the rotation and a constant temperature field throughout the disk. To achieve history of stresses and displacements, a numerical procedure using finite difference and Prandtl-Reuss relations is used. Stress and deformation histories are calculated using successive elastic solution method. In order to verify the solution approach, both composite and aluminum rotating disks were taken into account and the thermo-elastic and time-dependent creep behaviours for composite as well as the former for aluminum were obtained. Results from the current study were found to be in very good agreement with those available from literature in the area. It was shown that convex thickness profile disks display the least creep displacement, creep effective and circumferential stresses. Additionally, constant and concave thickness profiles were positively correlated with time while for linear and convex ones, it was found to have an inverse trend. Manuscript profile
    • Open Access Article

      24 - Modeling and Design of a Disk-Type Furrow Opener’s Coulter Its Mechanical Analysis and Study for No-Till Machinery (Combination and Bertini)
      J. Ghezavati M. Abbasgholipour B. Mohammadi Alasti A. Shirneshan A. Shadkam
      No-till practices play an important role in decreasing production costs, increasing soil organic matter content, improving soil structure and removing unwanted environmental impacts. However, due to a lack of access to proper machinery for direct seeding in unplowed lan More
      No-till practices play an important role in decreasing production costs, increasing soil organic matter content, improving soil structure and removing unwanted environmental impacts. However, due to a lack of access to proper machinery for direct seeding in unplowed lands, such practices have failed to produce successful results since they are incapable of providing sufficient contact between soil and seeds. Introducing a machine that can plant seeds and fertilizer at two different depths in hard (unplowed) soils covered with last season’s crop residues can be the first step towards pilot no-till initiatives. This step can finally lead to the promotion of this practice in the potential areas. In this study, different components of a disk furrow opener were optimally designed in Solid Works modelling software. ANSYS was used to analyze this furrow opener and its three main related components. Finally, the coulter’s stress was determined using the von Mises criterion. The result showed that the minimum coulter stress was 1985.5Pa throughout the plane and its maximum belonged to the holes inside the hub with 1.0819x107Pa. The safety factor of the initial coulter was 17.85, while that of the optimally designed coulter was 25. Manuscript profile
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      25 - Exergy Analysis for Heat Pipe over a Permeable Vertical Thin Cylinder In a Porous Medium
      Mehdi Asghari Cirus Aghanajafi
      Today heat pipes are widely used by the designers in industries such as air conditioning and heat transformers for optimizing energy consumption. Existence of a permeable cylinder at the beginning and ending part of the heat pipe was considered on the basis of two assum More
      Today heat pipes are widely used by the designers in industries such as air conditioning and heat transformers for optimizing energy consumption. Existence of a permeable cylinder at the beginning and ending part of the heat pipe was considered on the basis of two assumptions for surface temperature of the cylinder and the mainstream velocity at the outer edge of the boundary layer vary linearly with the axial distance x from the leading edge. In this paper solution has been presented analytically with introduction of mixed convection parameter and coefficient of porosity . Various forms of flow were examined and the optimum state for minimum entropy generation was suggested. Manuscript profile
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      26 - Stress and Displacement Analysis of First Molar Hollow Tooth during Dental Filling Operation using Three-Dimensional Finite Element Method
      M. R. Karamooz-Ravari B. Shahriari E. Seyfali
      the amount of rotten tooth that is come out of teeth is an important issue in dental filling because of its effects on strength of teeth. The main goal of this study is to determine a criterion for the amount of rotten tooth which can be brought out. To do so, first, a More
      the amount of rotten tooth that is come out of teeth is an important issue in dental filling because of its effects on strength of teeth. The main goal of this study is to determine a criterion for the amount of rotten tooth which can be brought out. To do so, first, a three-dimensional finite element model of the complex shape of Right First Molar Mandibular has been established. Then, cylindrical holes with different values of height and diameter (diameter of holes from 3 mm to 8 mm and height of 3 mm to 5.9 mm) is created on the cusp of the tooth. A uniform pressure (from 10 Pa to 10 kPa) is applied around the tooth resembling the belt which is utilized in reality. According to the obtained displacement and stress contours, the diameter of tooth hole can be increased up to 7 mm for pressures under 10 Pa while for higher pressures, the diameter of tooth hole can just be increased up to 6 mm. In addition, due to sudden increase in stress at a pressure of 10 kPa, increasing the value of pressure to higher values is not recommended. Manuscript profile
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      27 - Investigation and Optimization of EDM Milling and its Comparison with Die Sink EDM
      Mahmoud Moradi Reza AbbasiRad Majid Ghoreishi Hadi Abdollahi Majid Rostami
      In this study EDM milling process parameters of AISI H13, have been investigated by using Response Surface Methodology (RSM). Current (16-32A), pulse-on time (100-700 µs) and depth of cut (1-3mm) were considered as independent variables, while surface roughness, t More
      In this study EDM milling process parameters of AISI H13, have been investigated by using Response Surface Methodology (RSM). Current (16-32A), pulse-on time (100-700 µs) and depth of cut (1-3mm) were considered as independent variables, while surface roughness, tool wear ratio (TWR), and material removal rate (MRR) as process output responses. Results reveal that increases in the current and decreases in pulse-on time cause more MRR and more TWR and depth of cutting has no significant effect on them. Minimum surface roughness, minimum TWR and maximum MRR were considered as optimization criteria. Verification experiments were carried out in order to analyze the results via software. Optimized settings were used for EDM Milling and die sink EDM experiments to compare the results. The results indicate that using EDM milling has considerable economic savings than die sink EDM, better surface roughness, and higher MRR. Manuscript profile
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      28 - Design of Full Metal CNG Cylinders for Vehicle
      Mehdi Zohour
      In this paper, first design and analysis history of full metal CNG cylinders for vehicle are investigated. Next with respect to the CNG worldwide standards, a full metal type cylinder is designed and analysed. Then the numerical analysis results and practical results ar More
      In this paper, first design and analysis history of full metal CNG cylinders for vehicle are investigated. Next with respect to the CNG worldwide standards, a full metal type cylinder is designed and analysed. Then the numerical analysis results and practical results are compared, and the correctness of the investigation is verified. In the end, the most suitable alloy with respect to the dimensions for the purpose of manufacturing of such cylinders is suggested. Manuscript profile
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      29 - Drag-Reduction Characteristics in Air Flow over the Iced Surface at Re>104
      MohamadMehdi Hemmasian Manouchehr Rad
      This paper studied the mathematical method of flow with regard to two-Phase boundary layer that created over the iced surface. Based on experimental results, skin drag over the iced surface compared with this force that compute with slip condition. Based on this results More
      This paper studied the mathematical method of flow with regard to two-Phase boundary layer that created over the iced surface. Based on experimental results, skin drag over the iced surface compared with this force that compute with slip condition. Based on this results, for iced surface Blasius equation solving at non-slip condition, can replace with solving the Blasius equation with slip condition. The results are quir acceptable except at small region at the beginning of plate. Manuscript profile
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      30 - Numerical Studies of Laminar Natural Convection in a Square Cavity with Orthogonal Grid Mesh by Finite Volume Method
      MohammadReza Safaiy Sayed Reza Saleh Marjan Goudarzi
      In this work a numerical study of thermal and fluid dynamics behavior of natural air convection in a square cavity in a laminar flow is presented, by finite volume method. The square cavity has two walls heated with different temperatures and two isolated walls. The num More
      In this work a numerical study of thermal and fluid dynamics behavior of natural air convection in a square cavity in a laminar flow is presented, by finite volume method. The square cavity has two walls heated with different temperatures and two isolated walls. The numerical simulation is made up of several Rayleigh numbers to . Flow and isotherm lines are presented and analyzed. The numerical results presented in this work can be used by researchers who work in the natural convection problem. Manuscript profile
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      31 - An Investigation in the Deformation Zone of the ECAE Process by the Upper Bound Theorem
      MohamadJavad Mirnia Caren Abrinia Abbas Rastgoo
      In the present paper, the deformation zone of the ECAE (Equal Channel Angular Extrusion) process was investigated using the upper bound theorem. For this purpose, the shape of the streamlines in the deformation zone was assumed to be cubic Bezier curves. Then, the force More
      In the present paper, the deformation zone of the ECAE (Equal Channel Angular Extrusion) process was investigated using the upper bound theorem. For this purpose, the shape of the streamlines in the deformation zone was assumed to be cubic Bezier curves. Then, the force required for the ECAE process was optimized with regard to the parameters defining the shape of streamlines by the upper bound theorem. By using of these streamlines, equivalent stain induced through one pass of the ECAE was calculated and the shape of the dead metal zone was determined. The influence of different friction conditions on the deformation field was studied. The force applied through the process was determined by optimizing an upper bound solution and was compared with other works including experimental and theoretical data. Also using this comparison, it was seen that the difference between the theoretical and experimental value for the force was reduced in the present method. Manuscript profile
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      32 - Two Dimensional Simulation of Laminar Flow Around Two Bodies in Relative Motion
      sahar noori F. Mahdavi S.M.H. Karimian
      In this paper an efficient dual time implicit approach is used to solve viscous laminar flow around two bodies with general motion. Therefore, the grid includes a background grid and two sets of grids around the moving bodies. Rotational and translational motions of two More
      In this paper an efficient dual time implicit approach is used to solve viscous laminar flow around two bodies with general motion. Therefore, the grid includes a background grid and two sets of grids around the moving bodies. Rotational and translational motions of two bodies are managed separately in this grid arrangement. In this work the overset concept for hybrid grid is used and flow variables are interpolated with a simple method. The unsteady two dimensional Navier-Stokes equations are discretized using an implicit dual time stepping method. To accelerate convergence, the local pseudo-time stepping and implicit residual averaging are applied. To evaluate the present method, moving cases including rotational and translational motions are solved and the results are compared with experimental and numerical data. Manuscript profile
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      33 - Three Dimensional Free Vibration of FGM Circular Plates Using Semi-Analytical Method
      MohamadMehdi Najafzadeh Payman Shoghi
      In this research three-dimensional free vibration analysis of functionally graded circular plate with various boundary conditions is achieved. A semi-analytical method, which makes use of the state space method and the one-dimensional differential quadrature method, is More
      In this research three-dimensional free vibration analysis of functionally graded circular plate with various boundary conditions is achieved. A semi-analytical method, which makes use of the state space method and the one-dimensional differential quadrature method, is used to obtain the vibration frequencies and dynamic responses of circular plates. Numerical results are given to demonstrate the accuracy and superiority of the presented method. The numerical results are compared with the existing numerical solutions and good agreement is displayed .Using the semi-analytical method, the analytical solution in the thickness direction is given and an effective approximate solution in the radial direction is obtained by selecting fewer discrete points. Manuscript profile
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      34 - Finite Element Analysis of Self Destruction Mechanism in a Mechanical Controller
      Kourosh Hasanpour Mehdi Massah Mehrdad Poursina Mehdi Salmani
      In this study, dynamic behavior of a controller's Self Destruction mechanism has been simulated using 3D-FEM in Adams software and investigated. This paper has been concentrated on high acceleration controller's projectiles. This controller is mechanical and has been pl More
      In this study, dynamic behavior of a controller's Self Destruction mechanism has been simulated using 3D-FEM in Adams software and investigated. This paper has been concentrated on high acceleration controller's projectiles. This controller is mechanical and has been placed in top of the projectile. The goal of this study is to investigate the destruction mechanism operation i.e. movement of pin and balls to up and returning back. Also, the time and angular velocity for beginning of these movements which are important in this mechanism are studied. Finally, the simulated phenomena have been compared with available data qualitatively. This comparison confirms validity of the simulation. Manuscript profile
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      35 - Simulation of Mode I Strain Energy Release Rate for Rectangular Laminated Composite Plate Using a Simple Finite Element Model
      Mahmoud Shokrieh Mohsen Ghajar
      In this paper the critical strain energy release rate for T300/913 carbon-epoxy laminated composites has been studied using ANSYS finite element software based on virtual crack closure technique (VCCT). Compact Tension (CT) specimen has been used for numerical analyses More
      In this paper the critical strain energy release rate for T300/913 carbon-epoxy laminated composites has been studied using ANSYS finite element software based on virtual crack closure technique (VCCT). Compact Tension (CT) specimen has been used for numerical analyses and the geometrical dimensions have been extracted from the existing references. The results obtained from the finite element analysis are compared with the existing experimental results in literature. There is good agreement between the critical energy release rate obtained from finite element analysis and the experimental results. Accuracy and simplicity of presented model make it appropriate for predicting the experimental results and improving experimental techniques. The innovation of the present research is the simplicity of the model for simulation of the critical strain energy release rate of the laminated composites. Manuscript profile
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      36 - Investigating the Effect of Different Boundary Conditions on the Identification of a Cavity Inside Solid Bodies
      Mahmud Khodadad Mohsen DashtiArdakani
      The effect of boundary conditions on the solution of the inverse problem of identifying the geometry and location of a cavity inside an elastic solid body using displacement measurements obtained from a tension test is investigated. The boundary elements method (BEM) co More
      The effect of boundary conditions on the solution of the inverse problem of identifying the geometry and location of a cavity inside an elastic solid body using displacement measurements obtained from a tension test is investigated. The boundary elements method (BEM) coupled with the genetic algorithm (GA) and the conjugate gradient method (CGM) are implemented in this identification problem. A fitness function which is defined as the squared differences betweenthe computed and measured displacements is minimized. The best initial guess of the unknown shape and location of the cavity is found by the GA, then this initial guess is used by the CGM to achieve convergence. The imposed boundary conditions, i.e. geometrical constrain and specified tractions are kept constant during all iterations. Certainly changes in the boundary conditions can be effective in the correct identification of the shape and location of the cavity. In this study the effect of different boundary conditions on the convergence is investigated and the best and the most suitable boundary conditions which results in the faster and more accurate convergence are found. Manuscript profile
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      37 - Analytical Solution and Simulation of Flexible Joint in Thrust Vector Control System under Bending
      Ebrahim Harirbafan MOhsen Mohseni Shakib AliAkbar Karimi Mojtaba Heydari
      Flexible joint has the most critical role in Thrust Vector Control (TVC) solid fuel rockets. In this paper, a new analytic method for calculation of stiffness of spherical Elastomer-Metal joint by the theory of linear elasticity and Velasof Kantorowicz analytic method i More
      Flexible joint has the most critical role in Thrust Vector Control (TVC) solid fuel rockets. In this paper, a new analytic method for calculation of stiffness of spherical Elastomer-Metal joint by the theory of linear elasticity and Velasof Kantorowicz analytic method is developed. Velasof Kantorowicz analytic method is based on cross displacement which is driven from bending equation. Then flexible joint is simulated by ABAQUS code under bending load when thrust vector angle is critical (i.e. 15 degrees). Seven different configurations of metal and rubber layers are considered. In each configuration, required bending is determined when thrust vector is 15 degrees and maximum stress is calculated. Based on these results best selection of elastomer material and stiffness is proposed. Finally, the results of analytical and those of simulation are compared which show good agreement. This comparison shows that the derived formula predicts stresses precisely. Manuscript profile
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      38 - Experimental and Numerical Analysis of Bevel Gear Forge Method and Comparing it with Machining Method
      Saeed Beheshtian MohamadAli Sadeghi Darush Javabvar
      The purpose of this research is to analyze the bevel gear forge process with finite element method by means of Super forge software and to compare it with the experimental results. Also a comparison between the microstructure of machining gears and forge gears after app More
      The purpose of this research is to analyze the bevel gear forge process with finite element method by means of Super forge software and to compare it with the experimental results. Also a comparison between the microstructure of machining gears and forge gears after applying heat treatment on them is done. After committing the metallography experiments, we observe that the microstructure of forged gears has tinier martensites with short distances in gears surface, but machining gear has greater martensites with long distances.The obtained results show that the method of pieces production just before applying the heat treatment process will have a high effectiveness on the microstructure. Also, increasing in billet diameter that results billte’s heigh deduction, will cause pressure tonnage increasing. The obtained results of the simulation process show at the end of this paper. Manuscript profile
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      39 - Application of Different Hill’s Yield Criteria to Predict Limit Strains for Aerospace Titanium and Aluminum Sheet Alloys
      Milad Janbakhsh S. M. R. Loghmanian Faramarz Djavanroodi
      More recently, Titanium and aluminum alloys are gaining more interests to be implemented in hydro-forming applications. It is necessary to predict forming limits for these sheet alloys. Forming limits play an important role in metal forming processes. Forming limit diag More
      More recently, Titanium and aluminum alloys are gaining more interests to be implemented in hydro-forming applications. It is necessary to predict forming limits for these sheet alloys. Forming limits play an important role in metal forming processes. Forming limit diagrams, present the limit strains for various linear strain paths. In other hand, forming limit curve (FLC), illustrates localized formability for sheet metals under proportional loadings and are known as a powerful tool for trouble-shooting in sheet metal forming processes. In this study, mechanical properties of Ti-6Al-4V titanium sheets, AA7075-T6 and AA2024-T3 aluminum sheets are investigated through the uni-axial tensile test. Anisotropy coefficients as well as work-hardening exponent resulted from tensile test were used to theoretically prediction and numerical simulations of limit strains. For the theoretical prediction of the forming limit curves, several constitutive models were implemented. Several Hill’s yield criteria combined with Swift equation and empirical equation proposed by NADDRG were accomplished to predict the FLDs. Results showed that calculated numerical results are in good agreement with the predicted theoretical data when Hill93-Swift is the instability criteria used. Manuscript profile
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      40 - Optimization, Controller and Observer Design of a Reconfigurable Mobile Robot Using Genetic Algorithm and Neural Network
      Davoud Naderi Soheil Ganjefar Mohamad Mosadeghzad
      In this research optimal reconfiguration strategy of the improved SRR reconfigurable mobile robot based on Force-Angle stability measure has been designed using Genetic algorithm. Path tracking nonlinear controller which keeps robot’s maximum stability has been de More
      In this research optimal reconfiguration strategy of the improved SRR reconfigurable mobile robot based on Force-Angle stability measure has been designed using Genetic algorithm. Path tracking nonlinear controller which keeps robot’s maximum stability has been designed and simulated in MATLAB. Motion equations of the robot have been derived in parametric form by means of Newton- Euler, Lagrange and Kane dynamic methods using MATLAB symbolic toolbox. The robot has been simulated using ADAMS software for optimization evaluation. Path and velocity of the vehicle and end-effector and the terrain function below vehicle’s wheels have been already defined. Reconfigurable mobile robots increase their stability in rough terrain by static or dynamic reconfiguration or by means of mass-center quasi-static transportation or dynamical reconfiguration during motion. Extendable Newton-Euler, Lagrange and Kane dynamic methods algorithms to other kinds of robots have been designed for dynamic modeling of improved SRR reconfigurable mobile. Spatial complex dynamic equations of improved SRR have been derived in parametric form by means of those dynamic methods using MATLAB symbolic toolbox. Furthermore, the robot has been simulated using ADAMS software for evaluation of dynamic model. Manuscript profile
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      41 - An Analytical Study on Elastic Flange Wrinkling of Circular Plates in Deep Drawing Process
      Farzad Moayyedian Mehran Kadkhodayan
      Based on two-dimensional plane stress and bifurcation functional from Hill's general theory in polar coordinate the critical condition for elastic wrinkling of the flange of a circular blank ( the wave number in the flange and wrinkled area) during the deep-drawing proc More
      Based on two-dimensional plane stress and bifurcation functional from Hill's general theory in polar coordinate the critical condition for elastic wrinkling of the flange of a circular blank ( the wave number in the flange and wrinkled area) during the deep-drawing process are obtained analyticaly to improve the previous given results. In this analytical study, the elastic limitation of the material is also considered and to derive the bifurcation functional, the small and large deflection theoris are used and their results are compared to each other. The main advantage of the current research is obtainting an explicit solution and using the large deflection theory to detemine the critical conditions at onset of wrinkling. Manuscript profile
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      42 - Maximizing First Natural Frequency Of 2D Structures Using Bee Colony Optimization (BCO) and fuzzy logic
      esmail delfani ahmad delfani a ghoddosian
      Nowadays, different methods are used to solve optimization problems which ,one of the newest is BCO method that are inspired by the nature and derived from the social life of bees of these methods can be noted that BCO is derived from the social life of bees. We use in More
      Nowadays, different methods are used to solve optimization problems which ,one of the newest is BCO method that are inspired by the nature and derived from the social life of bees of these methods can be noted that BCO is derived from the social life of bees. We use in this paper fuzzy logic for bee‟s decision stage. at the end, we solve two different problem that have already been solved by ESO (Evolution Structural Optimization ) and BESO (Bi direction Evolution Structural Optimization ) methods. In this paper we indicate BCO is able to achieve better solutions and this method is quite proper even for constrained problems. Manuscript profile
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      43 - Application of Imperialist Competitive Algorithm to optimization problems arising in welding process
      Hossein Towsyfyan Seyed Adnan Adnani Salehi R. Rashidian
      The Imperialist Competitive Algorithm (ICA) that was recently introduced has shown its good performance in optimization problems. This algorithm is inspired by competition mechanism among Imperialists and colonies, in contrast to evolutionary algorithms. This paper pres More
      The Imperialist Competitive Algorithm (ICA) that was recently introduced has shown its good performance in optimization problems. This algorithm is inspired by competition mechanism among Imperialists and colonies, in contrast to evolutionary algorithms. This paper presents optimization of bead geometry in welding process using of ICA. Therefore, two case studies from literature are presented to show the effectiveness of the proposed algorithm. ICA has demonstrated excellent capabilities such as simplicity, accuracy, faster convergence and better global optimum achievement. The results of ICA were finally compared with the Genetic Algorithm (GA). The outcome shows the success of ICA in optimizing the weld bead geometry. Manuscript profile
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      44 - Bending Properties of Date Palm Fiber and Jute Fiber Reinforced Polymeric Composite
      Mahmoud Asadzadeh s.mohamad reza khalili reza eslami farsani siamak rafizadeh
      In this research work, the effects of natural fibers such as date palm fiber (DF) and jute fiber (JF) on bending properties of polypropylene (PP)/ ethylene–propylene–diene–monomer (EPDM) thermoplastic elastomers are investigated. For this purpose, the date palm and jute More
      In this research work, the effects of natural fibers such as date palm fiber (DF) and jute fiber (JF) on bending properties of polypropylene (PP)/ ethylene–propylene–diene–monomer (EPDM) thermoplastic elastomers are investigated. For this purpose, the date palm and jute fibers at five levels of fiber weight fractions (0, 5, 10, 20 and 30 wt. %) are utilized during composite fabrication. Maleic anhydride grafted to polypropylene (MAPP) is used as coupling agent to increase the interfacial adhesion between the polymer and the fibers. Results show that by adding fiber to the matrix, the bending properties are increased, but elongation at break is decreased. Manuscript profile
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      45 - Energy Absorption by Thin-Walled Tubes with various Thicknesses in Rectangular and Square Sections under Different Quasi-Static Conditions: Experimental and Numerical Studies
      K. Hoseini Safari Y. Mohammadi Sajjad Dehghanpour
      Impact is one of the most important subjects which always have been considered in mechanical science. Nature of impact is such that which makes its control a hard task. Therefore it is required to adopt a safe and secure mechanism for transferring the impact to other vu More
      Impact is one of the most important subjects which always have been considered in mechanical science. Nature of impact is such that which makes its control a hard task. Therefore it is required to adopt a safe and secure mechanism for transferring the impact to other vulnerable parts of a structure, when it is necessary. One of the best methods of absorbing impact energy is using Thin-walled tubes, where the tubes collapse under impact by absorbing energy, while this prevents the damage to other parts. Purpose of the present study is to survey the deformation and energy absorption of tubes with different type of cross section (rectangular or square) and with similar volumes, height, mean cross section, and material under different speed loading. Lateral loading of tubes are quasi-static type and in addition to the numerical analysis, also experimental experiment has been performed to evaluate the accuracy of the results. Results from the survey indicates that at the same conditions which mentioned above, samples with square cross sections, absorb more energy compared to rectangular cross sections; also by increasing the loading speed and thickness, the energy absorption would be more.. Manuscript profile
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      46 - Reducing stress concentration factor around a hole on a plate by piezoelectric patch
      Sa'id Golabi Javad Jafari Fesharaki
      Using piezoelectric patches the stress concentration around a hole on a plate under tension is reduced and controlled. To attain the reduction in stress two placements for piezoelectric patches is investigated. The first location is top/bottom of the hole with compressi More
      Using piezoelectric patches the stress concentration around a hole on a plate under tension is reduced and controlled. To attain the reduction in stress two placements for piezoelectric patches is investigated. The first location is top/bottom of the hole with compression induced strain and the second is left/right of the hole with tension induced strains to control the stress flow. The result for two above condition is presented for host plate and piezoelectric patches and by comparing the results the advantages of locating the piezoelectric patches to control the stress flow in the host plate is investigated. The results show that locating the piezoelectric patches at left/right of the hole, to control the stress flow and stress concentration is more effective than locating them at the top/bottom of the hole. Manuscript profile
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      47 - Thermodynamic Analysis of a Modified Two-Stage Trans-Critical CO2 Refrigeration Cycle with Multi Inter-Cooling System
      Ahmad Reza Rahmati Ali Gheibi
      Performance of a two-stage multi-inter-cooling trans-critical CO2 refrigeration cycle containing internal heat exchanger, two intercoolers, ejector, and separator, has been analyzed after modification. In the present study, an internal heat exchanger has been included w More
      Performance of a two-stage multi-inter-cooling trans-critical CO2 refrigeration cycle containing internal heat exchanger, two intercoolers, ejector, and separator, has been analyzed after modification. In the present study, an internal heat exchanger has been included within this cycle for possible improvement in its cooling performance. The impacts of operational parameters such as gas cooler and evaporator temperatures and gas-cooler pressure, on cycle performance have been investigated. Results are validated against those available in the literature. Comparisons of the results show that there is excellent agreement between them. Obtained results showed that modified cycle improved the maximum coefficient of performance (COP max), by 20.58% compared to the internal heat exchanger two-stage TRCC cycle and 23.2% compared to multi-inter-cooling two-stage TRCC cycle with ejector expansion device. Also, the total exergy destruction rate of the improved cycle is between its rates of two original cycles. Manuscript profile
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      48 - Optimization of the Forging Process of a Gas Turbine Blade using the Finite Element Analysis and Response Surface Method
      V. Alimirzaloo F. R. Biglari
      Forging of gas turbine blades needs a close control of the process parameters. These parameters require a suitable optimization method to achieve the best process conditions. This paper presents a hybrid method for the optimization of the forging process of an aerofoil More
      Forging of gas turbine blades needs a close control of the process parameters. These parameters require a suitable optimization method to achieve the best process conditions. This paper presents a hybrid method for the optimization of the forging process of an aerofoil blade. Forging process of the aerofoil blade was simulated using 3-dimentional finite element method. Preform shape and die parting-line angle are optimized in order to minimize the volume of the unfilled die cavity, material waste, and forging forces. The overall optimization scheme used in this research work includes a multi-objective approach that is a combination of response surface and finite element methods. The results show that the proposed optimization approach accrued to decrease the flash volume and the forging force of the aerofoil forging process. Therefore the proposed algorithm is a suitable method for the optimization of the gas turbine blade forging processes. Manuscript profile
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      49 - An Experimental Study of Energy Charging and Discharging in a PCM Thermal Storage
      Hamid Jahedi Amlashi
      In this work, a thermal energy storage system was designed and equipped with measuring instruments to study heat transfer characteristics and energy storage and release. In this system, a cubic container which is made of plexiglass was filled with dodecanoic acid as a p More
      In this work, a thermal energy storage system was designed and equipped with measuring instruments to study heat transfer characteristics and energy storage and release. In this system, a cubic container which is made of plexiglass was filled with dodecanoic acid as a phase change material. In order to transfer heat to the storage container, a constant temperature heat exchanger was designed and mounted on the side of the container. Several experimental tests were conducted for both the melting process (energy charging) and solidification process (energy discharging) with setting the temperature at 60 and 70 degrees of Celsius for the former experiments and 15 and 10 degrees of Celsius for the latter ones. Result indicated that the maximum amount of stored energy was 209 kJ/kg in the charging process. Furthermore, the charging process time was reduced, at most, by 42% and the absorbed energy was increased 9% when the temperature of heat exchanger was increased 10°C. Also the discharging process time was decreased 9% as the temperature of heat exchanger reduced by 5°C. Manuscript profile
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      50 - Laminar Mixed Convection Flow in a Shallow Two-Sided Lid-Driven Rectangular Enclosure
      Arash Karimipour Behzad Ghasemi
      A numerical investigation of laminar mixed convection heat transfer in a shallow two-sided lid driven rectangular enclosure of aspect ratio 5, (AR=5) is executed. The natural convection effect is sustained by subjecting the bottom wall to a higher temperature than its t More
      A numerical investigation of laminar mixed convection heat transfer in a shallow two-sided lid driven rectangular enclosure of aspect ratio 5, (AR=5) is executed. The natural convection effect is sustained by subjecting the bottom wall to a higher temperature than its top counterpart. In addition, the two horizontal walls of the enclosure are moving in different directions and the two vertical walls of the enclosure are kept insulate. Discretization of the governing equations is achieved through a finite volume scheme. Fluid flow and heat transfer characteristics are examined in the domain of the Richardson number and Grashof number as and while the bottom side of enclosure is moving in two different horizontal directions. The working fluid is assigned a Prandtl number of 0.7, 10 and 100 throughout this investigation. Temporal variations of streamlines, isotherms, and Nusselt number are presented in this investigation for various pertinent dimensionless groups. Manuscript profile
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      51 - Finite Element Simulation of Pulsating Hydroforming of Tube in Box-Shaped Die
      Mohsen Lohmousavi K.I Mori Mohamad Bakhshi Mahmoud Farzin Sayed Jamal Hoseinipour
      In recent years, the hydroforming due to reduction in weight and increase in strength of automotive parts has attracted attention of the automotive industry. Thus, the knowledge of the process to produce parts with desired quality and accuracy has been growing. One of t More
      In recent years, the hydroforming due to reduction in weight and increase in strength of automotive parts has attracted attention of the automotive industry. Thus, the knowledge of the process to produce parts with desired quality and accuracy has been growing. One of the effective methods in improving the formability in the hydroforming is known as pulsating hydroforming. However, the reason of improvement of formability in pulsating hydroforming is still unclear for the closed-die hydroforming of tubes. In this study, the pulsating hydroforming of tube with box die was simulated by the finite element method to examine the effect of pulsating pressure on improvement of formability. In addition, the calculated results are compared with experimental results and it is shown that the improvement of the formability occurs before contact of the tube and die in expansion zone of the tube. Thus, it can be obtained from the results, that the main reason of improvement of the formability is due to the deformation behavior before start of contact of the tube and die. Manuscript profile
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      52 - Genetic Algorithm Application in Guided Rockets
      AliReza Rezaei
      A gyroscope is a device for measuring or maintaining orientation, based on the principles of conservation of angular momentum. The device is a spinning wheel or disk whose axle is free to take any orientation. This orientation changes much less in response to a given ex More
      A gyroscope is a device for measuring or maintaining orientation, based on the principles of conservation of angular momentum. The device is a spinning wheel or disk whose axle is free to take any orientation. This orientation changes much less in response to a given external torque than it would without the large angular momentum associated with the gyroscope's high rate of spin. Since external torque is minimized by mounting the device in gimbals, its orientation remains nearly fixed, regardless of any motion of the platform on which it is mounted. A new method of optimization, particle swarm optimization (PSO), is able to accomplish the same goal as GA optimization in a new and faster way. The purpose of this paper is to investigate the foundations and performance of the two algorithms when applied to solve of gyroscope equation. Manuscript profile
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      53 - Design and Manufacturing Electrochemical Jet Turning Machine and Investigation of its Effective Parameters
      Amin Mirahamadi Nader Sharafi
      The applications of electrochemical machining are increasing because of increasing requests of industries for materials with high strengh and high hardness. Regular ECM uses a tool with spicified profile shape that is similar to final shape of workpiece. In this reasear More
      The applications of electrochemical machining are increasing because of increasing requests of industries for materials with high strengh and high hardness. Regular ECM uses a tool with spicified profile shape that is similar to final shape of workpiece. In this reasearch a nozzle that delivers electrolyte to the machining gap is used for machining cylinderical workpieces. By moving the electrochemical jet on the rotating workpiece the desired profile will be shaped on it. Using high voltage and big machining gap is the most important difference between this methode and other conventional ECM mehods. Manuscript profile
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      54 - The Finite Element Method and Genetic Algorithm Approaches on Shape Optimization of Prosthesis According to Fatigue Behavior
      Ramin Meshabadi Sayad Haji Mohamadi Amir Kazemi
      The Finite Element Method (FEM) is one of advanced methods in modeling of solid mechanics used in the design and analyzing of prosthesis in the human body. One of the important factors in designing a femur (the linkage between basin and knee) which is under complicated More
      The Finite Element Method (FEM) is one of advanced methods in modeling of solid mechanics used in the design and analyzing of prosthesis in the human body. One of the important factors in designing a femur (the linkage between basin and knee) which is under complicated stresses is to minimize the amount of the stress in the components of the prosthesis due to the body weight. In this research the authors have used prosthesis of two different substances to investigate the affect of the materials in the fatigue analyze. The other important factor is to apply a suitable linkage between prosthesis and bone called cement in order to prevent the slip of stem shape in the femur. In finite element analyze we have used contact elements for modeling the surfaces in contact. For the contact surface of stem shape and femur we have considered three cases: Bonded, slippage with the coefficient of friction 0, 0.22. We have used Genetic Algorithms (GA) method to optimize the shape of prosthesis. The results have been compared with the results presented by Charnley which shows an improvement in the shape of prosthesis. The optimized angle is about 132 degrees. Manuscript profile
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      55 - Effect of Methanol Concentration and Channel Depth on Performance of Direct Methanol Fuel Cell
      Ebrahim Alizadeh Kourosh Sedighi Mousa Farhadi Mohsen Shakeri
      Effect of methanol concentration and channel depth of bipolar plates on the performance of single direct methanol fuel cell was investigated experimentally. The membrane used in this experiment was Nafion117. Dimension of the single cell were 10cm 10 cm. Methanol concen More
      Effect of methanol concentration and channel depth of bipolar plates on the performance of single direct methanol fuel cell was investigated experimentally. The membrane used in this experiment was Nafion117. Dimension of the single cell were 10cm 10 cm. Methanol concentrations of 0.50, 1.0, 1.5, 2.0, 3.0 molar were used. Channel depth of the bipolar plates were chosen to be 1.0, 1.5, 2.0 mm, and in order to investigate the effect of channel depth, anode channel depth and cathode depth were changed simultaneously. Optimized methanol concentration for the single cell were 0.5-1.5 molar. Based on different experiments, as channel depth is decreased, mass transfer is improved and removal of carbone dioxide takes place easier. The results indicate that the best channel depth for this kind of single cell is 1.0 mm. Manuscript profile
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      56 - Analysis of Stresses in Tapered Rectangular Utility Pole
      Kondapalli Siva Prasad Chinthada Mankanteswar Rao
      Power transmission is generally carried out through electric cables supported by transmission pole (Utility pole) of various materials and cross sections. However, their utilization depends on climatic conditions and external loads acting on them. The forces comprise of More
      Power transmission is generally carried out through electric cables supported by transmission pole (Utility pole) of various materials and cross sections. However, their utilization depends on climatic conditions and external loads acting on them. The forces comprise of wind pressure, tension in conductors and seismic vibrations due to earthquakes. These loads induce various stresses in the pole like bending, shear, crushing etc. There is a necessity for investigation of these stresses in the existing utility pole subjected to the loads acting on them. The objective of the paper is to study the stresses developed in the tapered rectangular utility pole made of Steel Reinforced Concrete material which is 8m in total length. The work includes the calculation of stresses in the existing poles made of three grades of concrete (namely M40, M45, and M50), four different load cases of pre stressing (zero or no pre-stress, with a pre-stress of 50%, 60%, and 75% of maximum allowable strength of steel reinforcement), under the effect of 185 kmph wind velocity. Theoretical and FEA of stresses were carried out and the results were compared. The 3D solid modelling of pole is carried out using SOLIDWORKS and imported into ANSYS 15.0 for calculation of stresses. It is observed that in either cases of RCC and PSCC, the stresses developed in the concrete cause failure of the pole. However, in case of PSCC, the stresses causing failure are less compared to RCC and may have longer life. Manuscript profile
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      57 - Preform and Process Design of Ti-6Al-4V Compressor Blade using Equipotential Lines and 3D FE Simulation
      M. Soleimanzadeh M.M. Fallah
      Forging is one of the most important processes for production of titanium parts. Selection and evolution of forging parameters such as the forging preforms, part and die temperatures and strain rate are of great importance to achieve optimal process. In this work, a com More
      Forging is one of the most important processes for production of titanium parts. Selection and evolution of forging parameters such as the forging preforms, part and die temperatures and strain rate are of great importance to achieve optimal process. In this work, a comprehensive study on the near net hot forging of a Ti-6Al-4V compressor blade is performed through designing several preforms and simulating the process in several die and preform temperatures. The Equipotential lines method is used for the optimal design of preforms and Johnson-Cook constitutive model is used for 3D FE simulations and the criteria for selecting the parameters was the material temperature during the process that is necessary for achieving desired properties of Ti-6Al-4V parts. According to the results, performing the isothermal forging process in increased speeds could lead to increasing the temperature over the β-transus and improper mechanical properties development. So, finding a proper die and preform temperature is necessarily accomplished in this work. According to results the appropriate temperatures for performing the process using modified 0.1v preform and ram speed of 1mm/s were 1050˚C and 450˚C for the preform and die respectively. Manuscript profile
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      58 - Expert System Approach for Optimization of Design and Manufacturing Process for Rotary Ultrasonic Machining
      Morteza Sadegh Amalnik
      An expert system for evaluating rotary ultrasonic machining, in concurrent engineering environment and based on object oriented techniques, is developed. The design specification is obtained through a feature based approach. Different classes of design features are inte More
      An expert system for evaluating rotary ultrasonic machining, in concurrent engineering environment and based on object oriented techniques, is developed. The design specification is obtained through a feature based approach. Different classes of design features are interactively acquired. The attributes of different hard and brittle materials like glass, composite, stone and ceramic as work piece materials are stored in database. The system is also linked with tool material and machine databases. For each design feature, information is needed in manufacturing, such as machining cycle time, and cost, penetration rate, and efficiency are estimated by the expert system. Software system such as expert system based on object oriented technique is used to develop the expert system. The system links with a feature based CAD system in order to extract design data. The expert system provides useful information such as machining cycle time and cost, penetration rate, efficiency of machining of the selected design feature for product designers and advises of manufacturing engineers to select optimum machining parameters. In order to test the validity of the system, results of expert system is compared with the results of experimental rotary ultrasonic machining. Manuscript profile
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      59 - Dynamic Analysis of AFM in Air and Liquid Environments Considering Linear and Non-linear Interaction Forces by Timoshenko Beam Model
      P. Maleki Moghadam Abyaneh M.H. Korayem B. Manafi M. Damircheli
      The atomic force microscopy of the cantilever beam frequency response behaviour in the liquid environment is different in comparison with air environment. In this paper, the dynamic analysis of AFM in the air and liquid environments is carried out in consideration of li More
      The atomic force microscopy of the cantilever beam frequency response behaviour in the liquid environment is different in comparison with air environment. In this paper, the dynamic analysis of AFM in the air and liquid environments is carried out in consideration of linear and non-linear interaction forces and also the effect of geometrical parameters such as length, width, height; and inclined angle on the vibrating motion of the rectangular cantilever is investigated. A rectangular cantilever based on the Timoshenko theory is simulated in ADAMS software and more accurate results are obtained by considering the probe tip and the angular location of cantilever at simulation. At the end of the cantilever, a silicone probe is considered where the applied forces on it are approximated using two tangential and vertical springs. The vibrational simulation of cantilever at two states is carried out with regard to linear and non-linear interaction forces. The amplitude and resonance frequency of the simulated cantilever based on Timoshenko theory are different from obtained results of Euler-Bernoulli theory due to the effect of shear deformation and rotary moment in Timoshenko theory. Therefore, the Timoshenko theory has better accuracy in comparison with Euler theory. Many chemical and biological processes occur instantly; therefore the use of cantilevers with small length for improving the imaging speed at the tapping mode and in the liquid environment is essential. Eventually short cantilever that is modeled based on the Timoshenko theory may produce more accurate results. This paper is aimed to demonstrate that the amplitude and resonance frequency of vibration in the liquid environment is different from amplitude and frequency of vibration in the air environment due to the damping coeficient and added mass of liquid. Manuscript profile
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      60 - Study of Composite Pressure Vessel CNG with Nonmetal Liner Under Low Velocity Impact
      Abbas Vafaeisefat Mohammad Tafazoli Harandi
      Composite pressure vessel CNG made of epoxy – carbon material with nonmetal liner is 60% lighter than aluminum vessel under the same conditions. One of the important parameters in the pressure vessels design is their resistance against impact and prevention of exp More
      Composite pressure vessel CNG made of epoxy – carbon material with nonmetal liner is 60% lighter than aluminum vessel under the same conditions. One of the important parameters in the pressure vessels design is their resistance against impact and prevention of explosion. In this paper, the effects of low velocity impact on composite pressure vessel are investigated using FE analysis. The vessel reactions under velocity impact with different velocity, impact angle, and ply angle are studied based on Chang-Chang composite failure criterion. Finally, the effect of gas pressure inside the vessel before and after impact are analyzed. Manuscript profile
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      61 - Machining Parameters Optimization of Self – Rotating Turing Tools Via Taguchi Method
      Hosein Esmaeili Ahmad Afsari Payam Saraeiyan
      At this study, after designing and manufacturing a rotary tool, its machining parameters and their effects on surface roughness of aluminum alloy of Al99 which is one of the most consumable alloys in aerospace industry, is studied and optimized. First, the rotary tool i More
      At this study, after designing and manufacturing a rotary tool, its machining parameters and their effects on surface roughness of aluminum alloy of Al99 which is one of the most consumable alloys in aerospace industry, is studied and optimized. First, the rotary tool is designed and manufactred. Then according to Taguchi method, the experiments have been designed to record surface roughness, machining temperature and exerted forces on the tool. In order to evaluate optimum condition of the experiment results, MINITAB and Genetic Programming (GP) have been implemented to obtain the best regression; then for obtaining the optimum condition of machining, the results of running Genetic Programming has been used. In the end optimum machining parameters to achieve the best surface quality is presented. Manuscript profile
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      62 - Experimental study of the characteristics of the wake and drag coefficient changes of a car model in unsteady flow
      V. Barzanooni A.B. Khoshnevis
      In this study, changes in velocity, turbulence intensity and drag coefficient in the wake of a notch-back car modelling steady and unsteady flow is measured and evaluated. The blow open circuit wind tunnel is used to simulate fluid flow. Turbulence intensity and nominal More
      In this study, changes in velocity, turbulence intensity and drag coefficient in the wake of a notch-back car modelling steady and unsteady flow is measured and evaluated. The blow open circuit wind tunnel is used to simulate fluid flow. Turbulence intensity and nominal maximum speed of the device is measured to be 0.01% and 30m/s, respectively. The speed has been continuously increased by an invertercausing changes in rotational speed of the electromotor. In the near location to the model, the results showed three different regimes in the velocity profile of the model’s wake. With increasing distance from the model and with increasing the speed, three regimes in the wake are close to each other. Drag coefficient for several velocities is measured, where the result shows that decreasing in drag coefficient is proportional with increasing velocity. In addition, the changing trends of higher order velocity of parameters like flatness and skewedness are depicted. Manuscript profile
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      63 - Numerical Simulation of Fluid-Structure Interaction and its Application in Impact of Low-Velocity Projectiles with Water Surface
      N. Khazraiyan N. Dashtian Gerami M. Damircheli
      In this article, finite element method and ALE formulation were used to numerically simulate impact of low-velocity specific projectiles with water surface. For the simulation, Ls-Dyna finite element code was used. Material models which were used to express behavior of More
      In this article, finite element method and ALE formulation were used to numerically simulate impact of low-velocity specific projectiles with water surface. For the simulation, Ls-Dyna finite element code was used. Material models which were used to express behavior of air and water included Null material model. For the projectile, plastic-kinematics material model was applied. Mie-Gruneisen equation of state was also attributed to air and water. First, the results were validated by analyzing the impact of metallic cylinder with water surface and then impact of a mine as a low-velocity projectile was simulated. Among major outputs were force and pressure applied to the projectile, velocity and acceleration variations upon entering water, stress-strain variations and variations of water surface in various steps of analysis. The results showed that impact of structure with fluid can be modeled using finite element model with high accuracy in terms of quality and quantity. Manuscript profile
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      64 - Numerical Simulation of Laminar and Turbulent Mixed Convection in Rectangular Enclosure with Hot upper Moving Wall
      MohammadReza Safaiy HamidReza Goshayeshi
      Mixed convection is a fundamentally significant heat transfer mechanism that occurs in selection industrial and technological applications. In this study, first the laminar mixed convection inside rectangular enclosure with moving wall and Aspect Ratio=10 is modeled and More
      Mixed convection is a fundamentally significant heat transfer mechanism that occurs in selection industrial and technological applications. In this study, first the laminar mixed convection inside rectangular enclosure with moving wall and Aspect Ratio=10 is modeled and then the results are compared with other investigate. After showing varity of results, the investigation is continued with turbulent flow using RNG and standard . The results indicate that the turbulence intensity depends on the position. For example, in vertical walls and boundary layer, the flow is laminar and it is in the center of enclosure turbulent. Manuscript profile
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      65 - Dynamic Load Carrying Capacity of Spatial Cable Suspended Robot: Sliding Mode Control Approach
      Moharam Habibnejad korayem M. Jalali H. Tourajizadeh
      This paper proposes a control strategy for a cable-suspended robot based on sliding mode approach (SMC) which is faced to external disturbances and parametric uncertainties. This control algorithm is based on Lyapunov technique which is able to provide the stability of More
      This paper proposes a control strategy for a cable-suspended robot based on sliding mode approach (SMC) which is faced to external disturbances and parametric uncertainties. This control algorithm is based on Lyapunov technique which is able to provide the stability of the end-effecter during tracking a desired path with an acceptable precision. The main contribution of the paper is to calculate the Dynamic Load Carrying Capacity (DLCC) of a spatial cable robot while tracking a desired trajectory based on SMC algorithm. In finale, the efficiency of the proposed method is illustrated by performing some simulation studies on the ICaSbot (IUST Cable Suspended Robot) which supports 6 DOFs using six cables. Simulation and experimental results confirm the validity of the authors’ claim corresponding to the accurate tracking capability of the proposed control, its robustness and its capability toward DLCC calculation. Manuscript profile
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      66 - Stability of Shear-Thickening and Shear-Thinning Fluids in Narrow Gap between Rotating Cylinders
      Nariman Ashrafi Khorasani Habibollah KarimiHaghighi
      The effect of weak shear Thickening and shear thinning on the stability of the Taylor-Couette flow is explored for a Carreau-Bird fluid in the narrow-gap limit. The Galerkin projection method is used to derive a low-order dynamical system from the conservation of mass a More
      The effect of weak shear Thickening and shear thinning on the stability of the Taylor-Couette flow is explored for a Carreau-Bird fluid in the narrow-gap limit. The Galerkin projection method is used to derive a low-order dynamical system from the conservation of mass and momentum equations. In comparison with the Newtonian system, the present equations include additional nonlinear coupling in the velocity components through the viscosity. Similar to Newtonian fluids, there is an exchange of stability between the Couette and Taylor vortex flows. The results indicate that with increasing shear-thickening effect, the flow turns into unsteady state at higher Taylor numbers. In contrast, with increasing the shear-thinning effect the flow turns into unsteady state at lower Taylor numbers. Moreover, the results are in accordance to the other present research results. Manuscript profile
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      67 - Optimization of Composite Rotor Blade Using Merged Genetic Algorithm and Finite Element Method
      Davood Taherifar Sayed Mohsen MohseniShakib Mehdi Shahabi
      In this paper, an optimization method for both weight and displacement of composite blades is presented. In order to hold issues such as aerodynamics and acoustic unchanged, airfoil shape during optimization process remained constant. To achieve the ultimate goal, only More
      In this paper, an optimization method for both weight and displacement of composite blades is presented. In order to hold issues such as aerodynamics and acoustic unchanged, airfoil shape during optimization process remained constant. To achieve the ultimate goal, only blade lamination was changed. In order to achieve minimum weight for each part of the structure, the lowest layers are forecasted according to the required strength. Hence, the blade is divided into different parts. In optimization process, while focusing on weight and displacement reduction, layers integration must be assured. For desired performance, during optimization process, mass center location must be placed ahead of the aerodynamic center of blade. Weight reduction is in contrast to the displacement changes, and reduction in each of them would lead to an increase to the other. In optimization process, any changes in lamination of each part would influence the performance of the other parts. Therefore, in this paper, by making changes in genetic algorithm and defining appropriate objective function, design variables and other constraints, all of the above requirements are satisfied. Meanwhile, the natural frequencies of the optimized blade structure were in an acceptable range. Results and performance of the optimized blade are quite acceptable in comparison to the ordinary blades. Manuscript profile
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      68 - Machine Tool Design Optimization of High Resolution Parallel Hexapod in Cartesian Workspace
      Mir Amin Hosseini HamidReza Mohammadi Daniali
      In the research, six degrees of freedom Hexapod parallel machine tool is studied and investigated. Jacobian matrix is developed by cinematic relations differentiation and using weighted coefficient method, dimensional analysis operation is carried out on Jacobian matrix More
      In the research, six degrees of freedom Hexapod parallel machine tool is studied and investigated. Jacobian matrix is developed by cinematic relations differentiation and using weighted coefficient method, dimensional analysis operation is carried out on Jacobian matrix. Geometric parameters of Cartesian robot workspace are optimized, considering a minimum allowable rotation about three axes, and implementing Genetic Algorithm in MATLAB software workspace. For the manipulator workspace, isotropy indices, minimum and maximum singular values are calculated. The optimization operation has lead to two different designs of manipulators, namely the isotropic design, and high resolution Cartesian workspace. Manuscript profile
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      69 - Investigating the Effects of Expansion Equal Channel Angular Extrusion (Exp-ECAE) on Dynamic Behavior of AA7075 Aluminum Alloy
      J. Shahbazi Karami S. Sepahi-Boroujeni Mohsen Khodsetan
      Expansion equal channel angular extrusion (Exp-ECAE) is a severe plastic deformation (SPD) operation for processing bulk materials. In the current study, AA7075 Al was SPD-processed by expansion equal channel angular extrusion (Ex-ECAE) at various temperatures and ram v More
      Expansion equal channel angular extrusion (Exp-ECAE) is a severe plastic deformation (SPD) operation for processing bulk materials. In the current study, AA7075 Al was SPD-processed by expansion equal channel angular extrusion (Ex-ECAE) at various temperatures and ram velocities. Then, using split Hopkinson pressure bar (SHPB), the severely deformed products were compressed at room temperature and strain rates of 0.1~3000 s-1. Both the strain rate sensitivity (SRS) and the apparent activation volume (AAV) were determined for all deformed samples. The results revealed that the Ex-ECAE operation has noticeably increased the SRS. The tensile strength at a strain rate of 3000 s-1 was 6 times increased by conducting Ex-ECAE at 100 °C and with a ram velocity of 7 mm/min. Ex-ECAE was also capable of considerably decreasing the AAV. The results showed the yield stress of both the Exp-ECAE and the annealed samples increased with increasing the strain rate. Also, the results showed that after the Exp-ECAE process, the AAV reached to 6.3 b3 from the initial values of 118.5 b3 in the annealed state. Manuscript profile
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      70 - Performance Improvement of Solar Stills via Experimental Investigation
      Hitesh Panchal P. K. Shah
      Abstract: There is always a need to increase a distillate output of Solar still. If plates will be used inside solar still then distillate output of solar still are expected to increase. Hence, an experimental study is conducted to improve distillate output of basin sol More
      Abstract: There is always a need to increase a distillate output of Solar still. If plates will be used inside solar still then distillate output of solar still are expected to increase. Hence, an experimental study is conducted to improve distillate output of basin solar stills by increasing the effective surface area with the help of different plates. For the purpose of experiment, three solar stills are developed by locally available materials. The first solar still is a conventional type, the second is made of Aluminium plate while the third one is from Galvenized Iron plate. Performance of solar stills having aluminium plate and Galvenized iron plate is tested and compared with conventional solar still under the same climate conditions of Mehsana, Gujarat. The three solar stills are tested at two situations:  still at same water depth (40 mm) and stills having same quantity of brackish water (30 L & 40 L). Results indicate that, distillate output of solar still having aluminium plate is higher than conventional solar still and solar still having Galvenized iron plate. moreover, it is found that the average distillate output of water increases up to 45 % and 15 % of conventional solar still with respect to solar stills having aluminium plate and Galvenized iron plate respectively Manuscript profile
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      71 - Effects of Non-linear Suspension on Hunting and Critical Velocity of Railway Wheelset
      ardeshir karami mohammadi nasim ale ali
      In this paper the effects of non-linearity of suspension on dynamic behavior of a railway wheelset has been studied. This wheelset has four degrees of freedom that with two constraints it has reduced to two degrees of freedom. Vermeulen-Johnson theory has been used to c More
      In this paper the effects of non-linearity of suspension on dynamic behavior of a railway wheelset has been studied. This wheelset has four degrees of freedom that with two constraints it has reduced to two degrees of freedom. Vermeulen-Johnson theory has been used to calculate contact forces between wheel and rail. In this study the creep coefficients have considered constant. Any linearization has not been used for obtaining motion equations. Lateral suspension for these wheelset is dry friction which has been modeled by using Kolesch theory. Runge-kutta method has been used for solving these equations and results have presented to obtain limit cycles due to hunting behavior of wheelset. Manuscript profile
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      72 - The Influence of EDM Parameters in Finishing Stage on Surface Quality Using Artificial Neural Network
      saeid amini
      In this work, the influence of different EDM parameters (pulse current, pulse voltage, pulse on-time , pulse off-time) in finishing stage on  the surface roughness (Ra)  as a result of application copper electrode to a workpiece( cold work steel  DIN1.2379)  has been in More
      In this work, the influence of different EDM parameters (pulse current, pulse voltage, pulse on-time , pulse off-time) in finishing stage on  the surface roughness (Ra)  as a result of application copper electrode to a workpiece( cold work steel  DIN1.2379)  has been investigated. Design of the experiment was chosen as full factorial. Statistical analysis has been done and artificial neural network has been used to choose proper machining parameters and to reach certain surface roughness. The experiment results indicated a good performance of proposed method in optimization of such a complex and non-linear problems. Manuscript profile
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      73 - Design, Manufacture and Environmental Tests of Battery Pack for Spacecraft Freights
      Hossein Bolandi Moharram Ghahremani Darvish Masoud Hasanian
      The satellite battery pack is one of the important and vital parts that are required conducting special design with multiple capabilities. Some parameters like the minimum weight, lack of outgassing of parts, avoiding from short- circuit in batteries inside battery pack More
      The satellite battery pack is one of the important and vital parts that are required conducting special design with multiple capabilities. Some parameters like the minimum weight, lack of outgassing of parts, avoiding from short- circuit in batteries inside battery pack, the possibility for making series connection in batteries, and prevention from destroying battery pack structure caused by vibrations due to displacement of missile upon launching of a satellite are included in some requirements for design and manufacture of satellite battery pack where in the present essay we will study on design and manufacture of battery pack structure by considering the above- mentioned requirements in mind. In order to determine the authenticity of design and manufacture of battery pack in real conditions for launching and vacuum conditions, several environmental test of thoroughness such as Thermal Vacuum Testing and Vibration Tests have been carried out on the manufactured structure so the results of batteries performance will be purposed within these tests. The results obtained from environmental test conducted on satellite battery pack structure suggest the fully successful and innovative achievement in design and manufacture of battery pack structure. Manuscript profile
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      74 - A Novel Study of Penetration ‎into Concrete Targets by Ogive ‎Nose Projectiles
      Ahmad Khoogar Mohamad Mohades Khodadad Vahedi
      In design of defense structures, concrete are often used to provide protection against incidental dynamic loadings such as the impact of a steel projectile. In the present study, a new analytical model is proposed to predict penetration depth into concrete targets by og More
      In design of defense structures, concrete are often used to provide protection against incidental dynamic loadings such as the impact of a steel projectile. In the present study, a new analytical model is proposed to predict penetration depth into concrete targets by ogive nose projectile. Hence, to ­ develop the model and simulate penetration of high velocity ogive-shape nose steel projectiles into concrete targets, several tests has been simulated numerically with the Ls-Dyna finite element code. The results show good agreement with the analytical analyses and experimental results from other researchers. Manuscript profile
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      75 - Study of Skin Friction in Channels by Lattice Boltzmann Method
      Ahad Zarghami Negar Ahmadi
      A finite volume-lattice Boltzmann algorithm is applied to study skin friction behaviour in different channel flows. For this purpose, cell centred scheme is adapted to discretize the Boltzmann equation and consistent boundary conditions are also addressed, which resulte More
      A finite volume-lattice Boltzmann algorithm is applied to study skin friction behaviour in different channel flows. For this purpose, cell centred scheme is adapted to discretize the Boltzmann equation and consistent boundary conditions are also addressed, which resulted in a wider domain of stability. A simulation of flow in a two dimensional channels with different geometries are carried out. The results are compared with the valid previous results in which favourable agreement was observed. The results showed that skin friction in plane Poiseuille flow converged to 24/Re, but skin friction distribution in suddenly enlarged channels regain symmetry after some distance downstream of the expansion plane. Manuscript profile
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      76 - Obtain the Optimum Parameters for Cutting Hard and Tough Material (Hardox Steel) by Abrasive Water Jet Cutting Process
      sayed hadi nourian Mehdi Zohoor mostafa salehi
      Abstract: Nowadays, the non-traditional processes such as “LASER, EDM and AWJ” used for cutting high thickness sheet metal. Hardox is hard and tough steel alloy and it has many industrialize applications. One best process to cut the Hardox is abrasive water jet (AWJ) cu More
      Abstract: Nowadays, the non-traditional processes such as “LASER, EDM and AWJ” used for cutting high thickness sheet metal. Hardox is hard and tough steel alloy and it has many industrialize applications. One best process to cut the Hardox is abrasive water jet (AWJ) cutting.  It can cuts complex shape with high quality and accurate tolerance.  AWJ cutting offers certain unique benefits such as negligible heat affected zone, high degree of manoeuvrability in cutting process and less machining force exertion.  In this research work, first, the effective cutting process “AWJ” parameters were identified.  Then, to determine optimum Hardox cutting parameters, some experimental tests were undergone.  Finally, the experimental results were analysed using “ANOVA” technique in order to determine regression equations for achieving optimum parameters to set-up equipment for Hardox steel cutting. Manuscript profile
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      77 - Exergy Analysis of a Trigeneration System Driven by Aninternal Combustion Engine with Asteam Ejector Refrigeration System
      mohammad najafi K. Javaherdeh B. Liravinia
      The present study analizes a trigeneration system based on an internal combustion engine and a steam ejector refrigeration system from an energy point of view.
      The present study analizes a trigeneration system based on an internal combustion engine and a steam ejector refrigeration system from an energy point of view. Manuscript profile
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      78 - Experimental Study on Surface Roughness and Flatness in Lapping of AISI 52100 Steel
      Masoud Farahnakian H. ُُShahrajabian
      Lapping is one of the most important polishing processes which can be used to fabricate flat and smooth surfaces. In this paper, the effect of lapping characteristics and mesh number of abrasive particles are studied on the surface roughness and flatness for the machini More
      Lapping is one of the most important polishing processes which can be used to fabricate flat and smooth surfaces. In this paper, the effect of lapping characteristics and mesh number of abrasive particles are studied on the surface roughness and flatness for the machining of hardened AISI 52100 rings. The most significant lapping characteristics are pressure, lap plate speed and time. Scanning electron microscopy and optical microscopy are used to investigate micro cracks and surface textures. Results showed that surface roughness increased by rising the lapping pressure and plate speed. Also, reduction of the lapping time and mesh number of abrasive particles led to lower surface roughness. Application of lapping process decreased the flatness to 1.2 µm and surface roughness (Ra) from 0.58 to 0.051 µm. The lapping pressure was a significant factor on the surface roughness; and the lapping time was a significant factor on flatness. However, surface roughness increased with rising of mesh number and lapping time, and increased with decreasing the lapping pressure. The minimum surface roughness was 0.051 μm which was obtained in lapping pressure of 7 kPa, lapping speed of 0.164 m/s, time of 15 min and mesh number of 600.The flatness decreased with lapping speed, and reduced with increasing the pressure, mesh number and lapping time. Manuscript profile
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      79 - Comparison of performances of air standard Atkinson, Diesel and Otto cycles with constant specific heats
      Alireza Hajipour
      In this paper, the effects of input temperature and compression ratio on the net output work and efficiency of the air standard cycles, i.e. Atkinson cycle, Diesel cycle and Otto cycle are analyzed. We assumed that the compression and power processes are adiabatic and r More
      In this paper, the effects of input temperature and compression ratio on the net output work and efficiency of the air standard cycles, i.e. Atkinson cycle, Diesel cycle and Otto cycle are analyzed. We assumed that the compression and power processes are adiabatic and reversible and any convective, conductive and radiative heat transfer to cylinder wall during the heat rejection process may be ignored. We compared efficiency of these cycles with constant maximum temperature of each cycle. The results of this comparison may provide guidance for performance evaluation and improvement of practical internal combustion engines. Manuscript profile
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      80 - Design and Optimization of Metal Matrix Composite (MMC’S) Spur Gear
      Purushottam Karthik Janaswamy Rohith Sai Tunuguntla Sai Praneeth Singu
      Gears are one of the most critical components in power transmission system of an automobile and also many rotating machinery. Many studies have been conducted on optimum gear design. The main objective is to design different aluminium metal matrix composite spur gears b More
      Gears are one of the most critical components in power transmission system of an automobile and also many rotating machinery. Many studies have been conducted on optimum gear design. The main objective is to design different aluminium metal matrix composite spur gears before and after optimization. Aluminium metal matrix material composites are preferred mostly due to their low density. Also the high specific mechanical properties make these alloys one of the most interesting material alternatives for the manufacture of lightweight parts for many types of vehicles. With wear resistance and strength equal to cast iron, 67% lower density and three times thermal conductivity, aluminium MMC alloys are ideal materials for the manufacture of lightweight automotive and other commercial parts. In the present work materials considered are Al 6061-T6, Al 6106-T6, Al 7075-T651, and Al 7050-T7451. Finite Element Analysis is performed on different spur gears using above materials and the results will be compared. Manuscript profile
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      81 - Development of Process Model for Optimal Selection of Process Parameters for Geometric Tolerances and Surface Roughness in Stereolithography
      Chockalingam Kunjan Jawahar N. Chandrasekhar U. Praveen J. Karthic M.
      The accuracy of stereolithography (SL) product is vital for meeting the intended functional applications. The parameters like layer thickness, hatch spacing, hatch overcure contribute significantly to the accuracy of the SL parts. In this paper an attempt has been made More
      The accuracy of stereolithography (SL) product is vital for meeting the intended functional applications. The parameters like layer thickness, hatch spacing, hatch overcure contribute significantly to the accuracy of the SL parts. In this paper an attempt has been made to identify the process parameters that influences on the accuracy of the parts made with CIBA TOOL 5530 and optimize the process parameters. A standard test specimen is designed for this study. A process model between the geometric tolerance (parallelism, perpendicularity, angularity, radius fillet), surface roughness and the above mentioned process parameters (layer thickness, hatch spacing, hatch overcure) have been developed. It is found that parallelism, perpendicularity, angularity, radius fillet and surface roughness are influenced significantly by hatch spacing, layer thickness, hatch overcure, hatch spacing and layer thickness respectively. The percentage deviation between the experimental and process model values have also been calculated to validate the developed process model. Manuscript profile
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      82 - Experimental Investigation of Turbulence Promoters effect on Characteristics of Wake related to Linear Compressor Cascade
      amir khoshnevis Vahid Barzanooni Mohsen Vahidi
      In this paper, considering the importance of incoming flow turbulence intensity into combustion chamber, tripping wire effect on the flow wake has been experimentally investigated within a linear compressor cascade. To do this, two wires were implemented along each blad More
      In this paper, considering the importance of incoming flow turbulence intensity into combustion chamber, tripping wire effect on the flow wake has been experimentally investigated within a linear compressor cascade. To do this, two wires were implemented along each blade and their effects on average velocity, turbulence intensity and vortices frequencies at Reynolds number 45500 were accurately considered. To measure wake parameters, one–dimensional hot wire anemometer was used. It is found that turbulence promoters increased the maximum turbulence intensity in blades wake and also reduced corresponding frequency in maximum amplitude and the Strouhal number, consequently. Manuscript profile
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      83 - Design and Analysis of a New Dental Implant using Finite Element Method
      Sadegh Rahmati Hossein Kheirollahi Abbas Azari
      Dental implants restorations basically include four parts: implant, abutment, metal framework, and crown. In this common kind of restoration, crown is cemented to metal framework. However, in this research a novel method of design of dental implant is presented which in More
      Dental implants restorations basically include four parts: implant, abutment, metal framework, and crown. In this common kind of restoration, crown is cemented to metal framework. However, in this research a novel method of design of dental implant is presented which includes only two components: Integrated implant, and Crown. The new designed is based on an integrated implant which enables dentist to fit the crown by a snap-fit ring instantly. In order to carry out stress analysis, the finite element method (FEM) is applied on implant and bones to verify different loading conditions. The results of FEM are presented and proved to satisfy different loading conditions successfully. Manuscript profile
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      84 - A New Method for Measuring Perforated Surface by Coordinate Measuring Machine (CMM)
      MohammadMahdi Amiri
      Nowadays CMM machines are widely used in surface measurement and inspection. As inspection results from CMM machine are obtained by the means of measuring surfaces with direct contact, they are more precise than non-contact method (like optical measurement). However, CM More
      Nowadays CMM machines are widely used in surface measurement and inspection. As inspection results from CMM machine are obtained by the means of measuring surfaces with direct contact, they are more precise than non-contact method (like optical measurement). However, CMM machines give more reliable and accurate results rather than non-contact methods but also these results come with error when outer surface contains porosity spaces. This paper proposes a new method for measuring outer surface of porous objects. In this method the probe will be located above the porous area and doesn’t enter inside. The proposed strategy could be utilized whether CAD model of object is available or not. If CAD drawing of object exists, the probing stylus will not enter into the hole. On the other hand, if the CAD drawing doesn’t exist a perpendicular plane to the surface will be virtually modeled and by this normal plane the outer surface of the object will be estimated. In addition in this research an effort has been made to reduce dependence on CAD drawing. Manuscript profile
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      85 - Vibration Analysis of 2-PR(Pa)U- 2-PR(Pa)R New Parallel Mechanism
      Mehran Mahboubkhah Sajjad Pakzad Morteza Homayoun Sadeghi Mir Mohammad Ettefagh
      Parallel kinematic machines, are closed loop structures which have more accuracy, stiffness and ability to withstand high loads. In this paper the vibration equations of the new parallel mechanism, that has higher stiffness because of parallelogram system and fixed leng More
      Parallel kinematic machines, are closed loop structures which have more accuracy, stiffness and ability to withstand high loads. In this paper the vibration equations of the new parallel mechanism, that has higher stiffness because of parallelogram system and fixed length pods, have been derived by analytical approach. Whereas the proposed mechanism is applied as a machine tools, its vibrational behavior investigation has key impact factor. All the kinematic chains of the mechanism have been taken into consideration to achieve the coupled system of equations. To extract mechanism natural frequencies, modal analysis is carried out using three methods including analytical, finite element (FEM) and experimental method on parallel mechanism which has four degrees of freedom including three linear motion along the x, y and z axes and a rotary motion about x axis. Finally the natural frequencies and mode shapes obtained from analytical, experimental and FEM were compared. It is worth noting that all the frequencies obtained from three methods had little differences. Manuscript profile
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      86 - Determining Position and Orientation of 6R Robot using Image Processing
      Amin Habibnejad Korayem Ensieh Niyavarani Saeed Rafee Nekoo Moharam Habibnejad
      Stereo vision is one of the best image processing softwares to identify the environment of robot and allow its simultaneous process for providing three-dimensional measurement in an acceptable rate. On the one hand, vision measurement has simple structure and on the oth More
      Stereo vision is one of the best image processing softwares to identify the environment of robot and allow its simultaneous process for providing three-dimensional measurement in an acceptable rate. On the one hand, vision measurement has simple structure and on the other hand it is independent from active machine or robot. Appropriate software and efficient programming could improve the performance with same hardware (cameras). In this paper, stereo vision robot localization is used and the main code was developed in open source computer vision (Open CV) environment. The mathematical relationship between the three-dimensional reference coordinates and the local coordinates for entire system are presented. The vision system is an independent unit consists of two high definition (HD) cameras, set in a rotary base. The application of this measurement provides the position and orientation of 6R robot to verify its current measurement system. Stereo vision improved the speed of the image processing in comparison with image processing of MATLAB Toolbox that led to online monitoring of trajectory. Experimental tests of the proposed method express the capability of stereo vision in practical operations as a supervisory section. Manuscript profile
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      87 - Tool Wear Modeling in Drilling Process of AISI1020 and AISI8620 Using Genetic Programming
      Vahid Zakeri Mehrabad Vahid Pourmostaghimi
      In manufacturing industry, it has been acknowledged that tool wear prediction has an important role in higher quality of products and acceptable efficiency. Being an emerging area of research in recent years, drilling tool wear is an important factor which directly affe More
      In manufacturing industry, it has been acknowledged that tool wear prediction has an important role in higher quality of products and acceptable efficiency. Being an emerging area of research in recent years, drilling tool wear is an important factor which directly affects quality parameters of machined hole such as hole centring, roundness, burr formation and finished surface. In this paper, the genetic equation for prediction of drilling tool flank wear was developed using the experimentally measured wear values and genetic programming for two different materials, AISI1020 and AISI8620 steels. These equations could be used to compare the behaviour of wear in both mentioned materials and analyse the effect of materials characteristics on wear rate and wear pattern. The suggested equations have been shown to correspond well with experimental data obtained for flank wear when machining in various cutting conditions.The results of experiments and equations showed that properties of work material can affect drill bit flank wear drastically. It was concluded that greater toughness and strength of AISI8620, compared to AISI1020, lead to higher cutting stresses and temperatures, resulting more flank wear. Manuscript profile
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      88 - Experimental and Numerical Analysis of Titanium/HA FGM for Dental Implantation
      Sina Sazesh Aazam Ghassemi Reza Ebrahimi Mohammad Khodaei
      FGM dental implants are a very good alternative with respect to homogenous implants. In this study by focusing on mechanical property as one of the most important factors in implant design, the static behaviour of Ti/Nanostructure HA (hydroxyapatite) FGM dental implant More
      FGM dental implants are a very good alternative with respect to homogenous implants. In this study by focusing on mechanical property as one of the most important factors in implant design, the static behaviour of Ti/Nanostructure HA (hydroxyapatite) FGM dental implant has been fabricated and investigated experimentally and numerically. At the first step, the nanostructure hydroxyapatite powders were synthesized by natural origin. At the second step, the initial powders were cold compacted in order to fabricate Ti/HA FGM samples for 4 different volume fraction exponents (N=1/3, 2/3, 1, 2). Then the compacted powders have been sintered using a vacuum furnace, in which compressive strength of each particular sample was finally assessed. A three-dimensional geometrical model of FGM dental implant system and surrounding bone was created by using the macro programming language in ANSYS software and then finite element analysis under static forces was performed. Finally the experimental results strength tests were compared with numerical solutions. According to the results, the FGM dental implants made of Ti/HA under static forces were sufficiently safe. As a result, FGM sample with volume fraction exponent of N=2/3 was chosen as the best sample. Manuscript profile
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      89 - Design of Optimal PID, Fuzzy and New Fuzzy-PID Controller for CANSAT Carrier System Thrust Vector
      A. Kosari H. Jahanshahi A. A. Razavi
      In this paper, multi-objective optimization based on Genetic Algorithm is used to find the design variables of PID, fuzzy and new Fuzzy-PID controllers applying for a thrust vector control of CANSAT carrier system. Motion vector control is considered according to the dy More
      In this paper, multi-objective optimization based on Genetic Algorithm is used to find the design variables of PID, fuzzy and new Fuzzy-PID controllers applying for a thrust vector control of CANSAT carrier system. Motion vector control is considered according to the dynamic governing equation of the system which is derived using Newton’s method and defined mission in delivering payload into the specific height and flight path angle. The cost functions of the system are position error from the set point and deviation of the vector angle of carrier system with carrier body, where these cost functions must be minimized simultaneously. Results demonstrate that this new Fuzzy-PID controller is superior to other controllers which are exerted in the thrust vector control of a CANSAT carrier system. This Fuzzy-PID is capable of doing the mission with decrease in settling time and rise time with respect to the convenient minimized objective function values. Manuscript profile
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      90 - Modal and Aeroelastic Analysis of A High-Aspect-Ratio Wing with Large Deflection Capability
      R. Koohi H. Shahverdi H. Haddadpour
      This paper describes a modified structural dynamics model for aeroelastic analysis of high-aspect-ratio wings undergoing large deformation behavior. To gain this aim, a moderate deflection beam model is modified with some important large deflection terms and then couple More
      This paper describes a modified structural dynamics model for aeroelastic analysis of high-aspect-ratio wings undergoing large deformation behavior. To gain this aim, a moderate deflection beam model is modified with some important large deflection terms and then coupled with a state space unsteady aerodynamics model. Finite element method is used to discretize the equations of motion. A dynamic perturbation equation about a nonlinear static equilibrium is applied to determine the flutter boundary. The obtained results show good agreement in comparison with the other existing data such as high-altitude long-endurance (HALE) wing and Goland wing. It is found that the present aeroelastic tool have a good agreement in comparison with valid researches and also considering the effect of the geometric structural nonlinearity and higher order nonlinear terms on the flutter boundary determination is very significant. Manuscript profile
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      91 - Behavior Analysis of Cold Expanded-Bolt Clamped AL2024-T3 Plate
      M. Sayah Badkhor A. R. Naddaf Oskouei* H. Mohammadi Hooyeh F. Shirbakht
      For making rivet and bolt connections, making a hole is necessary. While basic S-N graph can be extracted from design documents, analysis of stress can be used for two different approaches. The first approach is the theoretical derivation of analytical relations with si More
      For making rivet and bolt connections, making a hole is necessary. While basic S-N graph can be extracted from design documents, analysis of stress can be used for two different approaches. The first approach is the theoretical derivation of analytical relations with simplified assumptions like planar stress or uniform bolt load distribution. The other one is the numerical simulation using robust codes like Abaqus software. By using these two approaches, residual stress distribution around the hole can be extracted in various conditions. In this experiment, an aluminium 2024-T3 plate with 3.2 mm thickness is considered. The stress analysis results and basic S-N graph were combined and discursive S-N graphs were obtained for different cold-expanded bolted holes. These graphs were compared with experimental data in several steps. First, the bolt fastening was considered. In the second step, cold expansion was considered and in the final step, the effects of fastening bolts and nuts and cold expansion was considered simultaneously. At last, a comparison between various steps was drawn. The results of this study showed that this new analytical method on distribution of residual stresses around cold expansion holes is as effectiveness as old methods. Manuscript profile
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      92 - Effects of Slip Boundaries on Mixed Convection of Al2O3-water Nanofluid in Microcavity
      A. R. Rahmati T. Azizi S. H. Mousavi A. Zarareh
      Due to the importance of the slip effect on modeling of microchannel and microcavity, numerical investigations have been introduced in this work for studying the mixed convection of Al2O3-water nanofluid in a square microcavity. Governing equations are discretized and s More
      Due to the importance of the slip effect on modeling of microchannel and microcavity, numerical investigations have been introduced in this work for studying the mixed convection of Al2O3-water nanofluid in a square microcavity. Governing equations are discretized and solved using the Finite Volume Method and SIMPLER algorithm. The Knudsen number is selected between 0.001 and 0.1 to consider slip velocity and the temperature jump boundary conditions in slip flow regime. In this study we investigate the influence of the Knudsen number on the average Nusselt number and heat transfer rate of Al2O3-water nanofluid. Results shows that the average Nusselt number is the function of Richardson number, Knudsen number and volume fraction of nanoparticles. Increasing the Richardson number, makes the forced convection less effective and leads in reduction of the Nusselt number. Hence, increasing the Knudsen number, leads to the temperature gradient reduction and reducing the average Nusselt number. As a result, the average Nusselt number could be enhanced up to 10.93% by using nanoparticles in the base fluid. Manuscript profile
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      93 - Effect of Processing Parameters on Properties of Friction Stir Welded Joints of Aluminium Alloys AA7075- T651 and AA6061-T6
      H. S. Patil Neelsai Sharma Kairav Patel Abhishek Patel Viral Patel Chetan Patil
      In the present investigation the mechanical behaviour of AA7075T651 and AA6061T6 aluminium alloys plates joined by friction stir welding (FSW) were evaluated. The effects of weld process parameter like tool rotation speed 650-1000 rpm and weld speed 30-40mm/min with squ More
      In the present investigation the mechanical behaviour of AA7075T651 and AA6061T6 aluminium alloys plates joined by friction stir welding (FSW) were evaluated. The effects of weld process parameter like tool rotation speed 650-1000 rpm and weld speed 30-40mm/min with square trapezoidal pin profile on mechanical properties were investigated. The welded joints were tested by means of by X-ray radiography, tensile, hardness and optical microscopy testing. The radiography revealed the presence of internal in FS welds and observed that increasing transverse speed increases the occurrence of weld defects. The hardness was found to be mixed effect with respect to tool rotations and transverse speed for similar FSW joints. But in dissimilar FSW joints, hardness decreases with increasing tool speed and weld speed and it was strongly affected by precipitate distribution. Difference in grain size and distribution was observed for different ranges of rotation and weld speed. Manuscript profile
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      94 - Effects of baffle on separated convection step flow of radiating gas in a duct
      Meysam Atashafrooz S. A. Gandjalikhan Nassab E. Sadat Behineh
      In this paper, the effects of baffle on thermal characteristics of combined convection-radiation heat transfer in laminar flow adjacent to an inclined backward facing step (BFS) in a horizontal duct are investigated. A baffle is mounted on the top wall of channel downst More
      In this paper, the effects of baffle on thermal characteristics of combined convection-radiation heat transfer in laminar flow adjacent to an inclined backward facing step (BFS) in a horizontal duct are investigated. A baffle is mounted on the top wall of channel downstream side of step. In this study, the fluid is treated as a gray, absorbing, emitting and scattering medium; therefore, in the energy equation besides the convective and conductive terms, radiation term is also presented. The radiative transfer equation (RTE) is solved numerically by the discrete ordinates method (DOM) to find the divergence of radiative heat flux distribution inside the radiating medium. The blocked off method is employed for both fluid mechanic and radiation problems to simulate the presence of both step and baffle. The effects of height, width and location of baffle in channel and also the effects of radiative parameters on the fluid flow and heat transfer are investigated by plotting the variations of streamlines, Nusselt number and mean bulk temperature along the flow. It is revealed that, baffle and radiative parameters have great influences on flow and the thermal behaviors of systems with combined convection-radiation heat transfer. Manuscript profile
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      95 - Multi-Stage Optimum Design for Composite Pressure Vessels
      Sadegh Rahmati Ali Khani
      In this paper, multi-stage optimum design of composite pressure vessels is presented. The design variables for composite vessels include the head shape, the winding angle, the layer thickness, the number of layers, and the stacking sequence. A parameter called modified More
      In this paper, multi-stage optimum design of composite pressure vessels is presented. The design variables for composite vessels include the head shape, the winding angle, the layer thickness, the number of layers, and the stacking sequence. A parameter called modified shape factor is introduced as an objective function. This parameter takes into account the effects of the internal pressure and volume, the vessel weight, and the composite material properties. The proposed algorithm uses genetic algorithm and finite element analysis to optimize the design parameters. As a few examples, this procedure is implemented on geodesic and ellipsoidal heads. The results show that for the given vessel conditions, the geodesic head shape with helical winding angle of nine degrees has the better performance. Manuscript profile
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      96 - Design of a Dynamically Balanced 2-DOF Planar Parallel Manipulator using Four-bar Legs
      Amin Poursafar Meisam Vahabi
      A mechanism is reactionless or dynamically balanced when there is no shaking force and shaking moment applied to the base during mechanism movement. The theory for designing reactionless 2 degree-of-freedom (DOF) planar parallel manipulator is discussed in this paper. T More
      A mechanism is reactionless or dynamically balanced when there is no shaking force and shaking moment applied to the base during mechanism movement. The theory for designing reactionless 2 degree-of-freedom (DOF) planar parallel manipulator is discussed in this paper. The legs of the manipulator are four-bar 2-DOF mechanisms with revolute joints. The dynamic balancing conditions of the manipulator are derived, considering that the time rate of the total linear and angular momentum have to be vanished. The dynamic balancing equations first are obtained and illustrated through a numerical example and finally verified by computer simulation using ADAMS software. Manuscript profile
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      97 - Investigation of Stresses in U-Shaped Metal Bellow Using EJMA Standards
      Kondapalli Siva Prasad Gudla Pavani
      Metal Bellows finds wide application in expansion joints, which are used in aerospace, chemical plants, power system, heat exchangers, automotive vehicle parts, piping system, petrochemical plant, refineries, etc. During service they are subjected to various stresses an More
      Metal Bellows finds wide application in expansion joints, which are used in aerospace, chemical plants, power system, heat exchangers, automotive vehicle parts, piping system, petrochemical plant, refineries, etc. During service they are subjected to various stresses and exposed to different environments, which leads to failure. Hence there is a need for proper design of metal bellow as per the application. The main objective of the paper is to evaluate the stresses generated in the metal bellow and the cycle life working at different working pressures. In this paper, the stresses are calculated using Expansion Joint Manufacturing Association (EJMA) standards and compared with the results obtained using ANYS software for two different materials namely Inconel 625 and Inconel 718 for the pressure values ranging from 20 to 40 bar. Manuscript profile
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      98 - Finite Volume Solutions of 2-D Steady Incompressible Navier-Stokes Equations in Driven Skewed Cavity Flow with Non-Orthogonal Grid Mesh
      MohammadReza Safaiy Sayed Reza Saleh Marjan Goudarzi
      The numerical method presented by Safaiy et al. [1] is reformulated with Finite Volume method in its most general form and tested on non-orthogonal flow problems. Navier-Stokes equations are solved for the solution of stream function and Vorticity. Numerical solutions o More
      The numerical method presented by Safaiy et al. [1] is reformulated with Finite Volume method in its most general form and tested on non-orthogonal flow problems. Navier-Stokes equations are solved for the solution of stream function and Vorticity. Numerical solutions of the driven skewed cavity flow, solved using a fine grid (513×513) mesh, are presented for Reynolds number of 100 and 1000 for skew angles ranging between . The results are compared with the numerical solutions found in the literature and also with analytical solutions as well. Manuscript profile
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      99 - Optimal Balancing of Spatial Suspended Cable Robot in Point-to-Point Motion using Indirect Approach
      Mojtaba Riyahi Vezvari Amin Nikoobin
      In this paper, a method based on the indirect solution of optimal control problem is presented to specify the optimal trajectory of spatially suspended cable robot in point to point motion with considering the counterweights. In fact, an optimal trajectory planning prob More
      In this paper, a method based on the indirect solution of optimal control problem is presented to specify the optimal trajectory of spatially suspended cable robot in point to point motion with considering the counterweights. In fact, an optimal trajectory planning problem is outlined in which states, controls and the values of counterweights must be calculated simultaneously in order to minimize the given performance index. The value of the pulley torques is considered for the performance index (objective function). Using the fundamental theorem of a calculus of variations, the necessary conditions for optimality of cable robot are achieved. For the three-cable spatial robot, a two-point boundary value problem is achieved which can be solved with bvp4c command in MATLAB. The obtained results show that optimal balancing in comparison with the unbalancing method can reduce the performance index significantly. Manuscript profile
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      100 - Natural Convection in an Inclined Partitioned Enclosure with Local Heat Source
      Parnian Safaei Behzad Ghasemi Amir Khorram
      In this paper, free convection in an inclined stepped chamber has been studied. One wall of this enclosure is kept cold and the opposite wall equipped with constant heat source. The remaining walls are maintained adiabatic. There is one adiabatic step on the bottom wall More
      In this paper, free convection in an inclined stepped chamber has been studied. One wall of this enclosure is kept cold and the opposite wall equipped with constant heat source. The remaining walls are maintained adiabatic. There is one adiabatic step on the bottom wall. The aim of the present study is to forecast the effect of Raleigh number, slope of enclosure, step dimension, and heat source position, on the stream field, temperature and heat transfer rate. In this regard, two dimensional equations of mass conservation, linear momentum and energy are solved by applying finite volume method and simple algorithm. Results indicate poor effect of enclosure slope, step height, and position of heat source in small Raleigh numbers, however in large Raleigh numbers significant effects on fluid and rate of heat transfer of enclosure are observed. Manuscript profile
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      101 - Investigation of Process Parameters on Hot Ring Rolling by Coupled Thermo-Mechanical 3D-FEA
      AmirHossein Gheisari MohammadReza Forouzan AbdolAli Maracy
      Hot rolling of a large ring of titanium alloy (LRT) is a highly nonlinear incremental forming process with coupled mechanical and thermal behaviors (MTBs) which significantly affect microstructure and properties of the ring. The feed rate of idle roll and the rotational More
      Hot rolling of a large ring of titanium alloy (LRT) is a highly nonlinear incremental forming process with coupled mechanical and thermal behaviors (MTBs) which significantly affect microstructure and properties of the ring. The feed rate of idle roll and the rotational speed of driver roll have major effects on ovality of the ring. In this paper, the effects of these parameters on the ovality of the ring have been investigated by a coupled thermo-mechanical 3D-FEA. The results show that the ovality of ring blank decreases with the increase of the rotational speed of driver roll or the decrease of the feed rate of idle roll. The results obtained can provide a guide for forming parameters optimization. Manuscript profile
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      102 - Finite Element Crushing Analysis, Neural Network Modelling and Multi-Objective Optimization of the Honeycomb Energy Absorbers
      M. Vakili M. Farahani A. Khalkhali
      The thin-walled honeycomb structures are one of the most common energy absorber types. These structures are of particular use in different industries due to their high energy absorption capability. In this article, the finite element simulation of honeycomb energy absor More
      The thin-walled honeycomb structures are one of the most common energy absorber types. These structures are of particular use in different industries due to their high energy absorption capability. In this article, the finite element simulation of honeycomb energy absorbers was accomplished in order to analyze their crushing behavior. 48 panels with different hexagonal edge length, thickness and branch angle were examined. In the following, the amounts of mean stresses versus the geometric variables using neurotic lattices were considered. Comparison between the finite element results and the obtained neural network model verified the high accuracy of the obtained model. Then the model was optimized by one of the efficient genetic algorithm methods called “Multi-objective Uniform-diversity Genetic algorithm”. The obtained optimum results provide practical information for the design and application of these energy absorbers regards to designer requirement. It was observed that honeycomb energy absorbers with 11.07 mm hexagonal edge length, 0.078 mm wall thickness and 123-degree branch angle have the maximum energy absorption over the panel mass. Manuscript profile
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      103 - The Choice of Automatic Welding Process and Technology by using WELD-EXP. Software
      Elyas Haddadi MohamadReza Shabgard
      During last ten years, change of consumption pattern, variety and modernity of consumers, variety of producers and competitors, changes and vacillation rates, cause developing and decreasing the amounts of produce expenses by using hardware and software progressing, whi More
      During last ten years, change of consumption pattern, variety and modernity of consumers, variety of producers and competitors, changes and vacillation rates, cause developing and decreasing the amounts of produce expenses by using hardware and software progressing, which are so important. In this respect, one of the possible solutions to increase the quality and enjoy the use of software possibilities is to perform producing systems. The aim of this article is to choose, automatic process and welding technology by using WELD-EXP. software. In this software, experience and knowledge of skilled men and expert form the rules in the expert system and knowledge base. After interchange of information and receive the necessary data from user, this software by studying and analyzing necessary instances, choose and suggest the best welding process or processes. Finally, the users confirm and complete it and present the welding process specification (WPS). Therefore, this way is time-consuming and save the expense of making and producing of weldments. Manuscript profile
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      104 - Control and Guidance of an Underwater Robot via Fuzzy Control Method
      Mehdi Ghanavati Afshin Ghanbarzadeh
      In this project guidance and control of underwater robot, including three engines and propeller attached to it, by Fuzzy control has been investigated. Fuzzy control is done based on human experience and requiered laws. The robot can also be controlled and guided by the More
      In this project guidance and control of underwater robot, including three engines and propeller attached to it, by Fuzzy control has been investigated. Fuzzy control is done based on human experience and requiered laws. The robot can also be controlled and guided by the user. This robot may be used in sea or swimming pool environment for finding goal point and locate in desired direction. In addition, this robot is able to follow a definite path and to do searching operation in that path. This robot is also able to overtake barriers on the surface or under the surface and forward toward target and path the barriers using fuzzy rules. In other words, while facing any barriers using fuzzy rules. In other words, while facing any barrier, robot decides necessary decision in such a way not to collide with it and path it. For simulation of the required system, webots' software which is strong software for mobile robot simulation and Maple's material software is used. This robot is capable to distance any obstacle in 3D and move towards the goal. Obstacle avoidance is done by fuzzy rules. Means when face any obstacle, the underwater robot decide for not collision and passes it. For the simulation system, Webots that is strong software for mobile robot simulation and mathematical software Maple is used. Manuscript profile
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      105 - Analysis of Effective Factors on Rail Failure and Exerted Stress on Rail and Wheel
      Vahid Monfared Saeed Adibnazari Habib Esfandiar
      Rails fracture by the growth of fatigue crack or critical crack is one of the prevalent defects in railway. The rail fracture, failure and stress analysis should be studied in order to prevention of rail fracture. In this paper, new formulation of contact stress for two More
      Rails fracture by the growth of fatigue crack or critical crack is one of the prevalent defects in railway. The rail fracture, failure and stress analysis should be studied in order to prevention of rail fracture. In this paper, new formulation of contact stress for two rolling bodies is presented, where the results are closed to the hertz stress formulation. Moreover, stress analysis is done by FEM and compared with hertz stress and new stress formulation results. Then, the stress analysis, fracture, prediction of fracture and path of crack motion in rail and wheel is studied, statically which plays important role in this field. Next, the methods of analysis of stress theory fracture with numerical and FEM is compared and it is consequently proved that these approaches have acceptable results compared to other results. Therefore it is possible to rely on these methods and their results. Next, relation between maximum displacement and maximum stress is presented, and path of crack growth and fracture is predicted. For the purpose of analysis, exerted pressure on the rail and wheel assembly is considered on the quadrant of elliptical contact surface, rather than the whole assembly. With this assumption, acceptable results will be obtained. Moreover, in order to prevent crack growth and penetration the plastic method and building of negative discharge energy hole with closed loop path is presented to restrict crack motion. Finally correction coefficient is introduced for the results. Manuscript profile
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      106 - Modal Coefficients Identification Using Wavelet Transform
      Hasan Jalali Fardin Parvizi
      Identification of damping parameter is usually more complicated and unreliable comparing to mass or stiffness identification in structural dynamics. There are many factors such as intermolecular friction, Coulomb friction and Viscous damping affecting the damping mechan More
      Identification of damping parameter is usually more complicated and unreliable comparing to mass or stiffness identification in structural dynamics. There are many factors such as intermolecular friction, Coulomb friction and Viscous damping affecting the damping mechanisms in a structure. Therefore it is difficult, and in some cases impossible, to describe the details of damping mechanisms by using mathematical tools. In order to overcome the difficulties arising when using different damping models, the equivalent viscous damping is used. The coefficient of equivalent viscous damping can be identified experimentally by measuring the structural response. During the past decades, many methods have been proposed for damping parameter identification employing time domain data (e.g. logarithmic decrement method) or frequency domain data (e.g. using frequency response functions). There are also time-frequency methods such as wavelet transform. This paper deals with identification of modal damping coefficients and natural frequencies of a structure using wavelet transform. The results obtained by using wavelet transform has a good agreement with those resulted from model updating in lower modes. Manuscript profile
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      107 - Transient Analysis of Heat and Mass Transfer via Natural Convection over a Vertical Complex Wavy Surface
      Morteza Ghadimi Amir Lotfi Cyrus Aghanajafi
      A numerical study of transient natural convection heat and mass transfer along a vertical complex wavy surface has been performed. A complex wavy surface was created from two sinusoidal functions, a fundamental wave and its first harmonic. The complex wavy surface is ma More
      A numerical study of transient natural convection heat and mass transfer along a vertical complex wavy surface has been performed. A complex wavy surface was created from two sinusoidal functions, a fundamental wave and its first harmonic. The complex wavy surface is maintained at uniform wall temperature and constant wall concentration. An implicit finite-difference scheme is used for analysis. The numerical results demonstrate that the additional harmonic substantially alters the flow field, temperature and concentration distribution near the surface. Also the numerical results show that the local heat and mass transfer rate for a complex surface are smaller than of a flat plate. This decreased local heat and mass transfer rate seems to depend on the ratio of amplitude surface. Manuscript profile
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      108 - Chaotic Motion and its Control for a non-Planar non-Linear Cantilever Beam with Parametric Excitation
      Javad Marzbanrad Morteza Seyedi Hosain Salehi Marzijarani
      In this paper, chaotic motion analysis and its control for a non-planar non-linear cantilever beam with axial and lateral parametric excitation in the free end is accomplished. This is a new method for control of chaotic motion of a non-linear planar beam. In this surve More
      In this paper, chaotic motion analysis and its control for a non-planar non-linear cantilever beam with axial and lateral parametric excitation in the free end is accomplished. This is a new method for control of chaotic motion of a non-linear planar beam. In this survey, internal resonance of the beam is 2:1 and the initial resonance is in the outside of plane and it is assumed a sub-resonance for inner plane. The beam is modeled with Lagrange method. Then, multi comparison method is used for system transformation of parametric and external excitation to the averaged equation where the constant load applied to them. Finally, with the usage of numerical simulation, an open loop control is designed for chaotic motion of non-planar cantilever beam which excited in the free end to reduce the beam vibration in one axis. The results are presented in the curves to show the limit of stability. Manuscript profile
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      109 - Effect of Non-Newtonian Models on Blood Flow in Artery with Different Consecutive Stenosis
      Mehdi Jahangiri Ahmad Haghani Reza Ghaderi Seyyed Mohammad Hosseini Harat
      In this paper, the ADINA finite element software was used for numerical investigation of laminar and non-Newtonian flow through a blood artery with consecutive stenosis. For modeling the non-Newtonian behavior of blood, six models were used, namely, Carreau, Carreau-Yas More
      In this paper, the ADINA finite element software was used for numerical investigation of laminar and non-Newtonian flow through a blood artery with consecutive stenosis. For modeling the non-Newtonian behavior of blood, six models were used, namely, Carreau, Carreau-Yasuda, modified Casson, Power law, generalized power law, and Walburn-Schneck. The results show that for all non-Newtonian models as well as the Newtonian model, the velocity of blood flow in the second stenosis is greater than the first stenosis. Also, up to 4D back of second stenosis, a reverse flow area is formed that causes the spread of disease and the formation of new plaque. As a general conclusion, it can be stated that due to the smaller values obtained from the power law and Walburn-Schneck models, as compared with the other models, for fluid velocity and wall shear stress, these two models must be applied with caution. Manuscript profile
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      110 - An Experimental Study on Full Toroidal Continuously Variable Transmission System
      H. S. Patil
      Abstract: A continuously variable transmission (CVT) is a transmission which may change step less by way of an infinite variety of effective gear ratios between maximum and minimum values. This contrasts with different mechanical transmissions that solely permit just a More
      Abstract: A continuously variable transmission (CVT) is a transmission which may change step less by way of an infinite variety of effective gear ratios between maximum and minimum values. This contrasts with different mechanical transmissions that solely permit just a few different distinct gear ratios to be selected. Continuously variable transmissions (CVTs) are mechanical devices that allow a continuous variation of the output velocity by adjusting its geometrical configuration. This offers several advantages over traditional transmissions such as better fuel efficiency, quieter operation, and a lower mass. Current efforts to reduce the vehicles, fuel consumption in order to protect the environment and save fuel have seen a recent resurgence in CVT research, especially in the automotive industry. The torque of the continuously variable transmission system with friction drive mechanism is transmitted by contacting roller with input and output disks. For the higher transmitted torque, it is necessary to apply large load in order to get higher friction force, which in turn generates severe high stress on the contact surfaces of roller and disks. The toroidal type CVT system has simple component arrays that have three contact points between roller and each input or output disk to get the torque transmitted This work documents a successfully developed experimental model of a toroidal continuously variable transmission (CVT) by adjusting its geometrical configuration of CVT design and compared the experimental results of speed, torque and power delivered at the output disc with those obtained by a theoretical. Manuscript profile
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      111 - Numerical Investigation on Thermal Performance of a Composite Porous Radiant Burner under the Influence of a 2-D Radiation Field
      MohamadMehdi Keshtkar
      This work presents a numerical study to investigate the heat transfer characteristics of a 2-D rectangular composite porous radiant burner (CPRB). In the construction of porous burner, the porous layer is considered to be of composite type consisting of upstream and dow More
      This work presents a numerical study to investigate the heat transfer characteristics of a 2-D rectangular composite porous radiant burner (CPRB). In the construction of porous burner, the porous layer is considered to be of composite type consisting of upstream and downstream layers with equal thickness but with different physical and radiative properties. In the present work, a two dimensional rectangular model is used to solve the governing equations for porous medium and gas flow.  In order to analyze the thermal characteristics of the CPRB, the coupled energy equations for the gas and porous medium are solved numerically and the discrete ordinates method is used to obtain the distribution of radiative heat flux in the porous media. Finally, the effects of various factors on the performance of CPRB are determined. Computational results show that high porosity and low scattering coefficient for downstream porous layer are desirable for maximizing the CPRB efficiency in comparison to a homogeneous one. Present results prove to be compatible with results obtained from previous studies. Manuscript profile
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      112 - Free Vibrations of Functionally Graded Circular Cylindrical Shells under Internal Pressure
      A. Davar S. Mohammad Reza Khalili H. Hadavinia
      Free vibration of simply supported circular cylindrical shell made of Functionally Graded Material (FGM) under internal pressure was investigated. The effective material properties are assumed to vary continuously along the thickness direction according to a volume frac More
      Free vibration of simply supported circular cylindrical shell made of Functionally Graded Material (FGM) under internal pressure was investigated. The effective material properties are assumed to vary continuously along the thickness direction according to a volume fraction power law distribution. First order shear deformation theory based on Love's first approximation theory was utilized in the equilibrium equations. The effects of FGM parameters such as material configuration and power law exponent, internal pressure as well as geometrical parameters such as thickness to radius and length to radius ratios on the vibration behavior were investigated. The validation of the results was achieved by comparing with those available in the literature. The results show that the vibration characteristics of Functionally Graded (FG) shells are greatly influenced by FGM parameters. Also, internal pressure and geometrical parameters considerably influence the frequency behavior regarded to different values of FGM parameters. Manuscript profile
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      113 - Investigation of Oxygen Enriched air intake on diesel engine exhaust emissions
      Mojtaba Amirshekari
      One of the methods to reduce the emissions in a diesel engine is by oxygen introduction into the combustion chamber which can be done by supplying the oxygen into the inlet manifold during suction stroke. Oxygen affects different parameters such as brake thermal efficie More
      One of the methods to reduce the emissions in a diesel engine is by oxygen introduction into the combustion chamber which can be done by supplying the oxygen into the inlet manifold during suction stroke. Oxygen affects different parameters such as brake thermal efficiency, fuel consumption, NOx and smoke at different load conditions. Load test was conducted for various concentrations of oxygen (21 to 27 percent) in terms of 2%. It is found that oxygen enrichment leads to better combustion which in turn results in less fuel consumption and an increase in brake thermal efficiency. It was found that about 25% oxygen enrichment in the inlet air results in the optimum performance and emission characteristics. The result shows that varying oxygen enrichment in the inlet air increases brake thermal efficiency and subsequently decreases brake specific fuel consumption. It was also found that an oxide of nitrogen (NOx) increases exponentially whereas smoke intensity falls bellow the normal level. One of the methods to reduce the emissions in a diesel engine is by oxygen introduction into the combustion chamber which can be done by supplying the oxygen into the inlet manifold during suction stroke. Manuscript profile
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      114 - Simulation of Air Gap Thickness on Air Spindle Vibrations in Ultra Precision Machine Tools
      Mohammad Akhondzadeh Mehrdad Vahdati
      Air spindles are one of the main elements of precise machine tools. Vibration of these spindles is one of the vital issues necessary for investigation. Among parameters which influence air spindle vibrations are rotational speed, compression air method, input nozzle dia More
      Air spindles are one of the main elements of precise machine tools. Vibration of these spindles is one of the vital issues necessary for investigation. Among parameters which influence air spindle vibrations are rotational speed, compression air method, input nozzle diameter, air gap pressure. In this study using ANSYS, the effects of air gap thickness on air spindle vibrations have been investigated. In this simulation the air gap is modelled by numbers of linear springs. Then the effect of air gap thickness on air spindle vibrations has been investigated. Rotor externally rotates around stator. Simulation results indicate that for static and transient analysis the values of radial displacements of rotor reduce by decreasing spring length (i.e. rotor and stator gap), and its minimum value are equal to 3.634 µm and 15.6 nm, respectively. Because of constant spring stiffness, in modal and harmonic analysis, results for different spring length haven’t any variation and are equal to 1.053 mm and 23.7 nm, respectively. Manuscript profile
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      115 - Non-linear simulation of drying of plain knitted fabric using mass-spring-damper model and genetic algorithm optimization
      Vajiha Mozafary Pedram Payvandy Mohammad Jalili
      In this study, the longitudinal shrinkage behavior of knitted fabrics during drying has been studied. In this context, a model is presented to predict the longitudinal shrinkage of plain knitted fabric during drying process. In order to model the shrinkage behavior, a 1 More
      In this study, the longitudinal shrinkage behavior of knitted fabrics during drying has been studied. In this context, a model is presented to predict the longitudinal shrinkage of plain knitted fabric during drying process. In order to model the shrinkage behavior, a 1DOF model consists of a mass, a linear spring and a linear damper have been used. In presented model the time-varying mass is considered due to fabric drying process. Nonlinear Equation of motion derived from the model have been solved using Three-order Straight Forward Expansion method. The results of the model were compared with the experimental results for five samples with different courses densities. The results shown that in high courses densities the presented model is capable enough to predict the longitudinal shrinkage of plain knitted fabric mass center during drying process. Error rate is 11.3 percent for the samples with high density. But with decrease in density, the error rate increases to 18 percent. Then the genetic algorithm is used to optimize the model. Using optimized model the simulated error rate fell into 5.7 percent for samples with high density and the rate fell to 6.1 percent with decrease in density. Manuscript profile
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      116 - Experimental and Numerical Investigation of Groove Pressed UFG Pure Aluminum
      akbar sajadi F. Javanroodi M. Borhani
      Fabrication of ultrafine grained materials by imposing severe plastic deformation for improvement of mechanical and physical properties of metals has been the focus of many researches over the past few years. In this process, a sheet is subjected to repetitive shear def More
      Fabrication of ultrafine grained materials by imposing severe plastic deformation for improvement of mechanical and physical properties of metals has been the focus of many researches over the past few years. In this process, a sheet is subjected to repetitive shear deformation conditions by utilizing asymmetrically grooved and flat dies through alternate pressing. In this study, a 2mm thick commercial pure aluminum sheet was subjected to repetitive pressing up to four passes. Mechanical properties including, hardness and tensity were obtained. Results show that, although increasing the number of passes causes higher strength magnitude, the strength’s slope decreases. After validation of finite element modeling, strain distribution and uniformity behavior of the grooved plate were investigated using plain strain and plain stress conditions. Results show that strain in the surface and near the teeth of the die is lower than other areas. Manuscript profile
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      117 - Investigation of Variance of Roller Burnishing Parameters on Surface Quality by Taguchi Approach
      Mohammad Mahdieh Ehsan Rafati Samaneh Kargar Sichani
      Surface roughness of engineering parts is very significant property that effectively influences on the wear and fatigue strength. There are many methods for improving surface quality of engineering parts such as grinding, lapping and honing. One of the methods for impro More
      Surface roughness of engineering parts is very significant property that effectively influences on the wear and fatigue strength. There are many methods for improving surface quality of engineering parts such as grinding, lapping and honing. One of the methods for improving surface quality is Roller Burnishing. Roller Burnishing improves surface quality of engineering parts by means of Cold working. Roller Burnishing depends on many factors such as RPM of work piece, feed rate of Burnishing tool and the penetration depth of Roller burnishing tool into the work piece. At the present paper, we have tried to investigate the effective factors of Roller Burnishing and optimize them by means of Taguchi approach. Manuscript profile
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      118 - Optimizing elliptical tank shape based on real-coded genetic algorithm
      sadegh yarmohammadi
      An elliptical tank cross-section is formulated to explore and optimization method, based on a real-coded genetic algorithm to enhance the roll stability limit of a tank vehicle. A shape genetic algorithm optimization problem is applied to minimize the overturning moment More
      An elliptical tank cross-section is formulated to explore and optimization method, based on a real-coded genetic algorithm to enhance the roll stability limit of a tank vehicle. A shape genetic algorithm optimization problem is applied to minimize the overturning moment imposed on the vehicle due to c.g. height of the liquid load, and lateral acceleration and cargo load shift. The minimization process is performed under some main constraints as cross-sectional area, overall height and width. The magnitudes of lateral and vertical translation of the cargo within the proposed optimal cross section under a constant lateral acceleration field are compared with those obtained with currently used elliptical cross-sections to demonstrate the performance potentials of the optimal shapes. A comparison of the vehicle overturning moment revealed that the proposed optimal tank geometry is approximately 12% higher than the vehicle equipped with currently used elliptical and circular cross section tanks. Manuscript profile
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      119 - Influence of weld process parameters on material characterization of friction stir welded joints of aluminium alloy AA6061-T6
      H. S. Patil Patil
      Abstract: Friction stir welding, a solid state innovative joining technique, is widely being used for joining aluminium alloys for aerospace, marine automotive and many other applications of commercial importance. FSW trials were carried out using a vertical machining c More
      Abstract: Friction stir welding, a solid state innovative joining technique, is widely being used for joining aluminium alloys for aerospace, marine automotive and many other applications of commercial importance. FSW trials were carried out using a vertical machining centre (VMC) on AA6061 alloy. The main objective of the present work was to evaluate the weld processing parameter of friction stir weld (FSW) process for AA6061-T6 alloy and to determine the properties of the obtained joints with respect of welding speed. Experiments have been conducted by varying the welding speed of 55-70 mm/min and the rotating speed was fixed at 1700rpm. Tensile properties, microstructure, microhardness, fractography, and corrosion resistance of FSW joints were investigated in this study. The result showed that  there was a variation of grain size  in each weld zone which depends upon the material and process parameters of FSW in the joint itself. The coarsest grain size was observed in heat affected zone (HAZ), followed by the thermomechanically affected zone(TMAZ) and the nugget zone(NZ). The maximum tensile strength of 184MPa and highest joint efficiency of 49.32% was obtained on the joint fabricated at 55mm/min of welding speed. Manuscript profile
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      120 - Optimal control with adaptive weighting coefficients for integrated vehicle dynamics control
      naser esmaeili S. Hamed Tabatabaei Oreh Reza Kazemi
      Abstract: In this work, an optimal control scheme with adaptive weighting coefficients is presented which coordinates different vehicle dynamics control objectives, thus ruling out possible conflicts among them. In a new approach, the weighting coefficients in optimal c More
      Abstract: In this work, an optimal control scheme with adaptive weighting coefficients is presented which coordinates different vehicle dynamics control objectives, thus ruling out possible conflicts among them. In a new approach, the weighting coefficients in optimal control are adjusted according to the vehicle state in the phase plane in such a way that a priority is given to each objective of handling and stability in each region. The optimal control acts as a high-level control for the vehicle body, which determines the body lateral force and yaw moment for stable vehicle motion. The body lateral force and yaw moment provide the inputs to the mid-level force (control) distribution module, which works out the desired lateral and longitudinal forces at each wheel. Therefore, the high-level control objectives are allocated to individual tire forces in an optimal manner with the assumption of a 4-wheel-independent car. A low-level control uses the desired individual tire forces to compute the steering angle and applied torque at each wheel. Simulation tests with a nonlinear vehicle model are conducted and comparison with the well-recognized work in the literature is made to show the efficiency of the proposed method.  Manuscript profile
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      121 - Design and Development of Limits of Stability and Postural Stability Protocols for a Computerized Dynamic Posturography
      Azadi Yazdani Nasser Fatouraee
      Upright balance control is an important human skill which can be impaired by aging and different disorders. Therefore, clinical and laboratory measures of balance assessment were established. The latest technology in the laboratory methods is a stabilometer with a compu More
      Upright balance control is an important human skill which can be impaired by aging and different disorders. Therefore, clinical and laboratory measures of balance assessment were established. The latest technology in the laboratory methods is a stabilometer with a computer or computerized dynamic posturography which assesses static and dynamic balance using body sways. A computerized dynamic posturography system consists of a computer and a stabilometer which is an unstable platform under patient's feet and calculates center of pressure on the platform to display it immediately on the screen. To evaluate weight shift ability, the patient should move his center of pressure in a determined path. Also, he should stay upright on the unstable platform or decreases its sways to show his ability to recover balance. For these purposes in the present study, two protocols "Limits of stability" (LOS) and "Postural stability" (PS) were designed and developed for a pre-made stabilometer with a maximum of 20 degrees deviation from horizontal in all direction to achieve the mentioned purposes. In the limits of stability protocol eight blinking targets are shown on the ideal limits of stability for the person randomly which he must reach by moving his body. In this case, the person's center of pressure is shown as a point on the screen that the person should transfer it to the targets. The other protocol is postural stability in which the person must minimize the platform swings. Hereby, another point is defined as the center of balance by which the deflections of the platform about two axes are converted into a point and represented on the display, so the person can see his function feedback. Finally, the protocols calculate and display the person's functional characteristics that can be saved to the computer of computerized dynamic posturography to demonstrate a diagram of the patient's functional progression. In addition to the balance assessment, the device improves balance and neuromuscular strength and is useful in medicine, laboratory researches, physiotherapy, sport and bodybuilding. Manuscript profile
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      122 - Mechanical Design and Simulation of a Saddle-Assistive Device for Sit-to-Stand Transfer in Healthy Subjects
      A. Hojjati Najafabadi S. Amini F. Farahmand
      Assistive device equipment can improve the performance of sit-to-stand (STS), standing, and walking of people with lower limb disability. The motorized assistive device is usually expensive and the use of another assistive device also makes an excessive force in the upp More
      Assistive device equipment can improve the performance of sit-to-stand (STS), standing, and walking of people with lower limb disability. The motorized assistive device is usually expensive and the use of another assistive device also makes an excessive force in the upper and lower extremity during (STS) transfer, which is not desirable for patients. In addition, only a few number of the non-motorized assistive devices that support all three phases; namely, sit-to-stand, standing, and walking are available. Consequently, improving and creating the new technology seems essential in this case. In this paper, the design procedure of saddle-assistive device is described in order to make use of the linear actuator in (STS) transfer and walk. Experimental results orientation of the shoulder during (STS) was recorded in the lab. Then, based on this analysis and simulation, saddle-assistive devices(S-AD) were designed and prototyped. Function prototype of the (S-AD) was done in the lab on a healthy person in (STS) and walking and then was compared with (STS) in normal mode. It is proposed due to the integration of the three phases in one device. Other advantages are force reduction on lower limbs, creating conditions of stability, and independence for patients with lower limb disability. Manuscript profile
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      123 - Vibration Analysis of a Multi-disk, Bearing and Mass Unbalance Rotor Using Assumed Modes Method
      R. Norouzi M. Rafeeyan H. Dalayeli
      In this paper, a simple and efficient method for modeling and solving the equations of a rotor with any number of disks, bearings and mass unbalances is presented using the assumed modes method. This model consists of a continuous shaft, arbitrary number of mass unbalan More
      In this paper, a simple and efficient method for modeling and solving the equations of a rotor with any number of disks, bearings and mass unbalances is presented using the assumed modes method. This model consists of a continuous shaft, arbitrary number of mass unbalances in any axial location and phase angle, and any number of rigid disks and bearings. This arrangement is extensively used in diverse applications. In this study, final governing differential equations are not derived because the assumed modes method is directly inserted to solving process. Some examples in both cases of free and forced vibration are performed. The results show the accuracy of this modeling and the ability of it to predicting the vibration behavior of the rotor in a complex combination of shaft, disk and bearing. This study also shows that the present approach can give the results as accurate as the most popular approach, i.e. the Finite Element Method. Manuscript profile
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      124 - Numerical Simulation of the Supersonic Flow over Forward-Facing Step in Micro Couette Flow Using Direct Simulation Monte Carlo Method
      Sajjad Sattari Mahsa Jahani Mofid Gorji-Bandpy
      This work deals with a numerical study on forward-facing steps situated in a supersonic flow. The primary aim of this paper is to examine the sensitivity of the velocity, density, pressure and temperature due to step-height variations of such forward-facing steps. Effec More
      This work deals with a numerical study on forward-facing steps situated in a supersonic flow. The primary aim of this paper is to examine the sensitivity of the velocity, density, pressure and temperature due to step-height variations of such forward-facing steps. Effects on the flowfield structure due to variations on the step height have been investigated by employing the Direct Simulation Monte Carlo (DSMC) method. The studied parameter contours for various values of step heights and profiles in three different sections of the channel are obtained. The results indicate that the fluid flow and temperature characteristics considerably depend on the step heights. The results was also compared with previous published works which showed excellent agreement. Manuscript profile
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      125 - Effects of friction stir welding tool plunge depth on microstructure and texture evolution of AA1100 to A441 AISI joint
      Hamed Aghajani Derazkola Majid Elyasi Morteza Hossienzadeh
      The aim of this article is study of tool plunge depth (TPD) effects on mechanical properties of friction stir welding of AA1100 aluminium alloy to A441 AISI steel. For this purpose the 0.1, 0.2, 0.4, and 0.6 mm TPD selected and other welding parameters kept constant. Th More
      The aim of this article is study of tool plunge depth (TPD) effects on mechanical properties of friction stir welding of AA1100 aluminium alloy to A441 AISI steel. For this purpose the 0.1, 0.2, 0.4, and 0.6 mm TPD selected and other welding parameters kept constant. The results shows that the frictional heat increases and stir zone grain size decreases with increasing TPD at both base metals. At higher TPD, the material press out from shoulder and base metals interface. The highest tensile strength allocated to the joint which welded whit 0.2 mm plunge depth. This joint had appropriate joint efficacy, material flow and microhardness compare other joints. Manuscript profile
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      126 - Finite Element Simulation of C.V. Joint Forging of Prid Using Arbitrary Lagrangian-Eulerian Method
      MohamadReza Seydi Mohsen Lohmousavi
      One of the most important parts of power transmission in automotives is C.V. joint, which consists of four components where exterior bowl is one of them. Due to its complexity, and importance in automobile and existence of high stresses, forging process is the only cost More
      One of the most important parts of power transmission in automotives is C.V. joint, which consists of four components where exterior bowl is one of them. Due to its complexity, and importance in automobile and existence of high stresses, forging process is the only cost effective method of production. Hence, the best method of production of this part is forging process. The exterior part of C.V. joint is produced through two subsequent stages. First, forward extrusion is applied followed by backward extrusion. In this research hot forward and backward extrusion of C.V. joint of PRAID with pre-heating while heat loss has taken into account, were simulated using finite element method. The Arbitrary Lagrangian-Eulerian method was employed to improve element distortions. Dies were considered as solid and elastic to investigate the thermal interactions of dies and the work piece. Deformation behavior, die contact pressure and punch force have been discussed by using the numerical results. Force diagrams during forging process according to die displacement and related results are discussed. Numerical results are compared with theoretical results for validation, meanwhile the comparison results are in good agreement. Manuscript profile
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      127 - Adaptive Control of Chaotic Nonlinear Gyros with Uncertain Coefficients of Dynamical Model
      Sayed Shahabodin Amelian HamidReza Koofigar
      In this paper, controlling the gyros with linear plus cubic damping is considered. Hence, an adaptive control algorithm is proposed to overcome the uncertainties in model parameters and the chaotic behavior of gyroscopes. It is noted that for general applications dynami More
      In this paper, controlling the gyros with linear plus cubic damping is considered. Hence, an adaptive control algorithm is proposed to overcome the uncertainties in model parameters and the chaotic behavior of gyroscopes. It is noted that for general applications dynamic model coefficient of gyros is not precisely determined, on the other hand, with respect to a particular coefficient gyroscopes demonstrate chaotic responses. The designed controller guarantees the tracking property and closed loop stability, despite the model uncertainties. The proposed algorithm is then modified to meet the control objectives without estimating the model parameters simplifying the implementation procedure. The stability analysis is presented based on the Lyapunov stability theorem. In order to show the effectiveness of the method, several simulations are also performed. With respect to the result, it is concluded that the performance of adaptive mechanism is verified the convergence of tracking error to zero is conformed; and the closed-loop stability is also verified. Manuscript profile
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      128 - Constrained Optimization of a Commercial Aircraft Wing Using Non-dominated Sorting Genetic Algorithms (NSGA)
      Ali Babaei Mohammad Setayandeh
      Abstract: In this paper, optimization of Boeing 747 wing has been accomplished for cruise condition (Mach Number=0.85, Flight Altitude=35000 ft), where an optimal wing shape is proposed. Objective functions are minimization of wing weight and drag force that as well as More
      Abstract: In this paper, optimization of Boeing 747 wing has been accomplished for cruise condition (Mach Number=0.85, Flight Altitude=35000 ft), where an optimal wing shape is proposed. Objective functions are minimization of wing weight and drag force that as well as confining design parameters, two functional constrains are applied. The first functional constrain is fuel tank volume in the aircraft wing which supplys the required fuel. The second functional constrain is the lift coefficient that should be equal to the initial lift coefficient. Design parameters are root chord, wing span and wing sweep angle. Non-dominating genetic algorithm has been used in optimization process for one optimal solution, until a set of solutions (pareto front) were obtained for two objective functions. Finally a criterion for selecting a best solution for the aircraft on the pareto frontier is addressed.Keywords: Optimization, Drag force, Wing weight, Multi-Objective Genetic Algorithm, Pareto set Manuscript profile
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      129 - Scheduling of Unrelated Parallel Machines using Two Multi Objective Genetic Algorithms with Sequence-Dependent Setup Times and Precedent Constraints
      Sahar Safaei Reihane Naderi Amir Sohrabi Amin Hatami
      Abstract: This paper considers the problem of scheduling N jobs on M unrelated parallel machines with sequence-dependent setup times. To better comply with industrial situations, jobs have varying due dates and ready times and there are some precedence relations between More
      Abstract: This paper considers the problem of scheduling N jobs on M unrelated parallel machines with sequence-dependent setup times. To better comply with industrial situations, jobs have varying due dates and ready times and there are some precedence relations between them. Furthermore sequence-dependent setup times and anticipatory setups are included in the proposed model. The objective is to determine a schedule that minimizes makespan and number of tardy jobs. The problem is NP-hard, so for obtaining an optimal solution in reasonable computational time, two multi objective genetic algorithms (MOGA) are proposed. To evaluate the proposed algorithms, random test problems are produced in medium and large sizes with tight due dates. After setting the parameters, the performances of these algorithms are evaluated using the concept of data envelopment analysis (DEA), distance method, and a number of non-dominated solutions.Keywords: Genetic algorithm, Makespan, Multi-objective, Parallel machine scheduling, Precedence constraints, Sequence-dependent setup times Manuscript profile
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      130 - Longitudinal and Lateral Vibration Analysis of Cables in a Cable Robot Using Finite Element Method
      Hami Tourajizadeh Mahdi Yousefzadeh Moharram Korayem
      In this paper, vibrational response of a variable-length cable in longitudinal, lateral and torsional directions is analysed in a cable robot using FE method. The flexibility of cables has remarkable effect on positioning of the end-effector in cable robots. Also consid More
      In this paper, vibrational response of a variable-length cable in longitudinal, lateral and torsional directions is analysed in a cable robot using FE method. The flexibility of cables has remarkable effect on positioning of the end-effector in cable robots. Also considering the fact that the length of the cables are time dependent in a dynamic cable structure like robocrane, the numerical approaches are preferable compared to analytic solutions. To do so, the cable is divided into finite elements in which the virtual work equation and Galerkin method can be implemented for the equations. Considering the stiffness matrix, the characteristic equations and Eigen values of each element can be defined. A simulation study is done in the ANSIS on a planar robocrane with 2-DOF and also for a spatial case with 6-DOF that is controlled by the aid of six variable-length flexible cables in the space for two different types of solid and flexible end-effectors. Whole the cable robot flexibility is analyzed simultaneously instead of separation calculation of each cable. Not only all of the 3-D vibrating behaviour of the whole structure is studied in this paper but also the lengths of the cables are considered as variable. The vibrating response of mode shapes, amplitude and frequencies are extracted and analysed, and the results are compared for two case of solid and flexible end-effector which shows the effect of the flexibility in the position of the end-effector and the tension of the cables in different situations. Manuscript profile
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      131 - Simulation and Experimental Study of Modern Fiber Metal Laminate Panels Used in Auto Body to Reduce Vehicle Weight
      Sadegh Rahmati HamidReza Khalili
      Automobile body plays crucial role in preventing the collision energy transfer in severe accidents to the passengers. If the collision energy is dissipated or saved in bumper or chassis, the amount of damage to the occupants would be minimized. Using novel laminated pan More
      Automobile body plays crucial role in preventing the collision energy transfer in severe accidents to the passengers. If the collision energy is dissipated or saved in bumper or chassis, the amount of damage to the occupants would be minimized. Using novel laminated panel (Fiber Metal Laminate) in auto body, and considering the characteristics such as high energy absorption, strength, high dent resistance, and very light weight, has caused significant reduction in injury to the car passengers. One of the major plans in auto industry is to lessen emission and fuel consumption using light weight material in auto body, which is recently achievable by replacing multi light layers with single metal layer panels, in auto body. These panels are usually made of two thin metal layers surrounding the core composite. The first point regarding panels is their strength against depression which is so called Dent Resistance. Weight reduction of panels should not sacrifice dent resistance of panels. The purpose of this paper is to investigate fiber metal laminate panels, dent resistance analysis and the amount of energy absorption of these panels, in order to implement in auto body. Strength, high dent resistance, and very light weight of such panels may lead into substantial reduction in crash injuries during car accidents. Manuscript profile
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      132 - Designing an Artificial Neural Network Based Model for Online Prediction of Tool Life in Turning
      A. Salimiasl A. Özdemir I. Safarian
      Artificial neural network is one of the most robust and reliable methods in online prediction of nonlinear incidents in machining. Tool flank wear as a tool life criterion is an important task which is needed to be predicted during machining processes to establish an on More
      Artificial neural network is one of the most robust and reliable methods in online prediction of nonlinear incidents in machining. Tool flank wear as a tool life criterion is an important task which is needed to be predicted during machining processes to establish an online tool life estimation system.In this study, an artificial neural network model was developed to predict the tool wear and tool life in turning process. Cutting parameters and cutting forces were used as input and tool flank wear rates were regarded as target data for creating the online prediction system. SIMULINK and neural network tool boxes in MATLAB software were used for establishing a reliable online monitoring model. For generalizing the model, full factorial method was used to design the experiments. Predicted results were compared with the test results and a full confirmation of the model was reached. Manuscript profile
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      133 - Stress Analysis of Tractor Tire Interaction whit Soft Soil using Non-linear 2D Finite Element Method
      Moslem Namjoo Naser Nankali
      Abstract: Compaction under tractors tires is of special concern because the weight of these machines has increased dramatically in the last years. These machines and others associated with crop cultural practices weight enough to significantly compact the soil, especial More
      Abstract: Compaction under tractors tires is of special concern because the weight of these machines has increased dramatically in the last years. These machines and others associated with crop cultural practices weight enough to significantly compact the soil, especially if the soil is soft with high moisture content during tilling, planting, or harvesting. The stress distribution and the size and form of the tire-soil interface are decisive for the stress propagation in the soil profile. The finite element method is a very useful numerical tool in evaluating different effects of tire on the soil. The goals of this study are to model the response of a soft soil, in relation to tire pressure and axle load. To validate the model by comparison with measured responses in the literature for such a soil and develop the 2D symmetric multi-laminated model of a tractor tire interaction with soft soil and to verify the result with measured field response data reported in the literature. In this study we use a (2D) axisymmetric tire model for the numerical simulation of soil-tire interaction under different load and inflation pressure. The Maximum soil-tire pressure for 70 kpa inflation pressure and 15kN axel load was 83.7 kpa which were approximately 30% less than the stress at the tire contact patch in the field test as cited in the literature. Although in previous investigations with a 3D analysis the difference was 36%. Maximum vertical stress at contact area with 150kPa inflation pressure and 15 kN axel load was 98.6 kPa that was not significantly different than was 101 kPa reported with 3D analysis. In general, more accuracy in 2D compared than whit 3D analysis was obtained due to more accurate meshing in 2D analysis. This investigation shows that maximum stresses in tire occurred at the side wall. Results showed that a simple 2D axisymmetric model can show soil-tire stresses whit good accuracy. Manuscript profile
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      134 - Investigation of rail track vibration due to fractured sleepers
      Hosein Mortezaei Mohamad Mahdi Jalili Mohammad Taghi Ahmadian
      In this paper effects of fractured sleepers on rail track vibration under moving wheelset have been investigated. Two parallel rails of the track have been modeled as Euler-Bernoulli beams on elastic points as rail pads. Also sleepers have been modeled as visco-elastic More
      In this paper effects of fractured sleepers on rail track vibration under moving wheelset have been investigated. Two parallel rails of the track have been modeled as Euler-Bernoulli beams on elastic points as rail pads. Also sleepers have been modeled as visco-elastic Euler-Bernoulli beams. It is assumed that, some sleepers under the rail track have been fractured and modeled by two beams. The wheelset has 5 DOF which are longitudinal, vertical and lateral movements plus roll and axial rotations. To determine normal contact force between wheel and rail, relative position of wheel and rail has been determined at each instant. Using the coordinate of each wheel points in rail coordinate system, the penetration of wheel in rail has been determined. To determine rail-wheel contact forces, Hertzian nonlinear contact theory and Kalker theory have been used. A computer program has been developed that numerically solves the equations of motion of the system for different operating conditions using Runge Kutta Cash-Karp computation method. Using this model the effects of wheelset velocity, wagon weight, number of fractured sleepers and fracture location on rail track vibration have been investigated. Manuscript profile
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      135 - Experimental Investigation of Laser Power Effect on Growth Rate of Intermetallic Compound in Al/Cu Bimetal Produced by Laser Cladding Method
      amin amani Sadegh Rahmati
      The aim of this project is to fabricated an aluminium-copper bimetal through the fusion method and examine its performance. An aluminium-copper-aluminium bimetal was built by the laser cladding method. The laser power as well as the annealing time effects on its interfa More
      The aim of this project is to fabricated an aluminium-copper bimetal through the fusion method and examine its performance. An aluminium-copper-aluminium bimetal was built by the laser cladding method. The laser power as well as the annealing time effects on its interfacial properties of the bonding’s formed through the laser cladding were investigated. To fabricate the multilayer bimetal, the laser beam characteristic including the beam radios, and Transverse Electromagnetic Mode (TEM), and focusing conditions were considered in a heat source model. The model was, next, integrated within SYSWELD package to predict the temperature distribution and clad bead profile during the laser cladding of the pre-placed copper powder layer on the aluminium substrate. After the samples preparation, the intermetallic compounds formed at the joints were explored through the Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) processes. Based on the experimental results, a laser power increase from 1100 W to 1150 W increases the intermetallic compound width, while an increase of 1150 W to 1200 W does not have much effect on the width. Also, increasing the annealing time results, increases the intermetallic compound thickness. In addition, based on obtained experimental results, four specimens are detected at the bimetal interface, one of which has 73.4 % copper and 26.1 % aluminium. The results also indicate that, with increasing both the laser power and annealing time, the electrical resistance of the samples decrease. Manuscript profile
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      136 - Kinematic Synthesis of a Novel Parallel Cable Robot as Artificial Leg
      Ebrahim Shahabi MirAmin Hosseini
      Accommodation of mechanism with human being’s physical characteristics creates the possibility of safe and efficient interaction between human being and robot. Regarding the fact that amputation of a limb in human beings causes several mental, economical and socia More
      Accommodation of mechanism with human being’s physical characteristics creates the possibility of safe and efficient interaction between human being and robot. Regarding the fact that amputation of a limb in human beings causes several mental, economical and social difficulties and problems, need to a substitute limb which has the most efficiency for the person after amputation is a vital need. The cable robots are the kinds of robots that the cable is used instead of rigid link. The cable robots have a simple appearance that some cables connect the motors to the final organ. In this research a robot with cable mover is designed and modeled as a tool in the case of creating movement with the most accordance for an artificial organ below the knee. In addition, in this mechanism some advantages are also considered including creating movement in two axes, its cheapness and lightness. In this research at first a primary design of the artificial organ is presented. The forward and inverse kinematic relations which are dominant on system are explained, in fact you can find different features with kinematic robots like dexterity, global condition, local condition, etc, and finally we study the available workspace for the system. Workspace in cable robots is different from other parallel robots, in this paper, first description about some methods for finding work space in cable-driven-robots and then use of force-closure workspace to find workspace for this system are presented. Manuscript profile
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      137 - Airplane Design Process in the Base of Roskam Method and Application on Design of an Unmanned Air Vehicle
      MeharanAli Azizi Hessam Salehipour Sima Farazi
      In This Article, an unmanned airplane vehicle (UAV) has been design using a new method(Roskam method). This design is based on the maximum payload of 4kg, maximum altitude of 2500m, cruise speed of 120 km/h at sea level and loiter of 60 min. Based on this, desing config More
      In This Article, an unmanned airplane vehicle (UAV) has been design using a new method(Roskam method). This design is based on the maximum payload of 4kg, maximum altitude of 2500m, cruise speed of 120 km/h at sea level and loiter of 60 min. Based on this, desing configuration of the UAV with the aim of patrolling, recognition, and data aquzation, has been done, and design parameters including three - view of airplane is presented. Manuscript profile
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      138 - Mechanical Properties of Basalt/Epoxy Composites
      Mahmoud Mehrdadshokriyeh Mehdi Memar
      The purpose of this paper is to determine mechanical properties of Basalt/Epoxy composites. Test samples were unidirectional composite samples which they are tested according to ASTM D790-96 standard test method by a universal testing machine. Ultimate strength, modulus More
      The purpose of this paper is to determine mechanical properties of Basalt/Epoxy composites. Test samples were unidirectional composite samples which they are tested according to ASTM D790-96 standard test method by a universal testing machine. Ultimate strength, modulus of elasticity and fracture energy of bending samples are gained. Then pay attention to conditions of unidirectional samples and doing tensile tests on samples, transition coefficients to transfer bending properties to tensile and compressive properties are gained. Using bending test results tensile and compressive properties of samples consist of strength and modulus of elasticity are derived. Manuscript profile
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      139 - Dynamic Analysis and Path Control of a Snake Like Robot
      Navid Negahbani Mostafa Ghayour
      In this paper a modular wheel less snake-like robot by considering viscous friction is modeled. The motion equations of the robot are derived. Then by imitating a real snake motion, the robot is controlled on the way that tracks the predefined trajectory. The controller More
      In this paper a modular wheel less snake-like robot by considering viscous friction is modeled. The motion equations of the robot are derived. Then by imitating a real snake motion, the robot is controlled on the way that tracks the predefined trajectory. The controller controls the center of mass and global orientation. The motion of the robot is simulated for tracking a line and a sine curve. It is shown that the robot tracks the trajectories smoothly. Manuscript profile
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      140 - Influence of Element Order in Various Aspect of Evolutionary Structural Optimization
      Ali GHodousian Seyfollah Sadodin Abbas Tabasi
      In recent year, the evolutionary structural optimization (ESO) method, has been applied as an effective tool for structures design. The concept of ESO method is to use the finite element results in each iteration of process and removal of inefficient material based on T More
      In recent year, the evolutionary structural optimization (ESO) method, has been applied as an effective tool for structures design. The concept of ESO method is to use the finite element results in each iteration of process and removal of inefficient material based on These results. In this method there are several experimental parameters such as rejection rate and evolutionary rate that are effective in results. This paper studies the influence of elements according to orders and in this regard has been applied eight node element and in addition to that it compares whit four node element results, is investigated influence in stress value, volume reduction, other parameters such as evolutionary rate and rejection rate. the results show that some parameters for low order elements are not suitable in high order elements problems and there for, has represented adequate value parameters. several examples are provided whit various boundary condition. Manuscript profile
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      141 - Exergy Analysis and Optimization of Combined Rankin Power and Ejector Refrigeration Cycle
      MohamadMehdi Rashidi Payman Lashgari
      In this paper, a new combined power and refrigeration cycle is proposed, which combines the Rankin power cycle and the Ejector refrigeration cycle. This combined cycle produces both power output and refrigeration output simultaneously. This cycle is driven by the flue g More
      In this paper, a new combined power and refrigeration cycle is proposed, which combines the Rankin power cycle and the Ejector refrigeration cycle. This combined cycle produces both power output and refrigeration output simultaneously. This cycle is driven by the flue gas of gas turbines, industrial waste heats, solar energy and geothermal energy. An exergy analysis is performed to guide the thermodynamic improvement for this cycle and a parametric analysis is conducted to evaluate the effects of the thermodynamic parameters that are significant on the performance of the combined cycle. The results indicate that the biggest exergy loss is due to the irreversibilities. The ejector causes the most effect on exergy loss. It is also shown that the turbine inlet pressure, the turbine back pressure, the condenser temperature and the evaporator temperature have significant effects on the turbine power output and exergy efficiency of the combined cycle. Manuscript profile
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      142 - Investigation of Drawing Ratio Effect on Chart Rupture in Hydroforming Process
      MohamadAmin Bahari Rouzbeh Alipour
      Hydroforming process in one of the most effective production method, for improving the drawing ratio in sheet metal forming process. This is due to the fact that in hydroforming process, forming takes place using a punch which drives the part forward via a controlled fl More
      Hydroforming process in one of the most effective production method, for improving the drawing ratio in sheet metal forming process. This is due to the fact that in hydroforming process, forming takes place using a punch which drives the part forward via a controlled fluid pressure. In this paper, deep drawing hydroforming for circular punch is investigated. Different pressure paths are tested using ABAQUS 6.7 software, in order to determine practical pressure constraint via simulation. Finally, drawing ratio effect on practical pressure constraint is investigated. In order to evaluate simulation accuracy, the obtained results are compared with some experimental results. Results indicate that by increasing drawing ratio, rupture curve is dropped significantly, and allowed zone area is reduced. Moreover, with increasing time, allowed zone area is expanded, and with increasing drawing ratio, allowed zone distance is reduced. Manuscript profile
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      143 - Atomistic and Continuum Simulations on Tensile Property of a Single Crystal Metal with Nano-holes
      Mehdi Rezaei Farimani Hamid Ekhteraei Toussi
      In this paper, we use Molecular Dynamics and Finite Element Simulations to determine the mechanical properties of single-crystal metal of silver (Ag) with nano-holes. The Lattice Transition method from 3-dimensions into 2-dimentions in molecular dynamics simulation as w More
      In this paper, we use Molecular Dynamics and Finite Element Simulations to determine the mechanical properties of single-crystal metal of silver (Ag) with nano-holes. The Lattice Transition method from 3-dimensions into 2-dimentions in molecular dynamics simulation as well as plane stress model in finite element method, is used to lessen the simulation time consuming. Elasticity module reduction due to the existence of holes, their shape and configuration types has been studied. It can be seen that the manner in which the elasticity module is reduced in both the molecular dynamics and finite element simulations are the same; however, it is essential to serve an atomistic simulation to have more exact results. Manuscript profile
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      144 - Culling Force Investigation in Turning Process via Ultrasonic Assisted Turning on Al7075 Workpiece
      Saeed Amini MohamadJavad Nategh Amir Abdollah
      In this paper, Ultrasonic assisted cutting (UAT) process has been investigated. The cutting technique is among the advanced machining techniques which improve cutting capability of materials. Vibratory tool is made under longitudinal mode with 10 micron amplitude and 20 More
      In this paper, Ultrasonic assisted cutting (UAT) process has been investigated. The cutting technique is among the advanced machining techniques which improve cutting capability of materials. Vibratory tool is made under longitudinal mode with 10 micron amplitude and 20 KHz frequency, in such a way that vibration is applied in cutting speed direction. Experiment carried out on Al7075; using ultrasonic assisted turning has lead to reduction in the cutting force, versus traditional cutting process. Moreover, further experiments were done aiming at investigating effective parameters in UAT machining process on Al7075 parts. These parameters include cutting speed, feed rate, depth of cut, and vibration amplitude. Statistical analysis on the experiment results were carried out, and different mathematical models for forecasting cutting force and optimizing machining parameters are presented in order to achieve minimum cutting force. At the end, cutting forces were compared for two machining processes namely ultrasonic assisted cutting (UAT) process, and traditional machining. Manuscript profile
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      145 - Calculation of Elastic Modulus of Reinforced Nanocomposites by Carbon Nanotubes using Finite Element Method, Averaging Approach and Micromechanics Relations
      Mahmood Shokrieh Saeed Niakan
      Carbon nanotube (CNT), due to extraordinary mechanical properties, is an effective Stiffener as reinforcement in resin for fabricating of nanocomposites. It is demonstrated by adding a small amount of CNT to the matrix, the elastic modulus of matrix increases remarkably More
      Carbon nanotube (CNT), due to extraordinary mechanical properties, is an effective Stiffener as reinforcement in resin for fabricating of nanocomposites. It is demonstrated by adding a small amount of CNT to the matrix, the elastic modulus of matrix increases remarkably. In this paper, the elastic modulus of CNT reinforced nanocomposites is obtained two-dimensionally using a finite element method (FEM), averaging approach and micromechanical. The obtained results are compared with experimental results that had already been reached by other researchers. It is shown that the experimental results are in acceptable agreement with the results presented in the present paper. Since the utilization of Micromechanics approach is an easier method, this method as used in the present paper can be used to calculate the elastic modulus of CNT reinforced nanocomposites Manuscript profile
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      146 - Investigation into the Importance of Pre-Design Procedure in Vibration Absorbers Installations
      Rouhollah Hoseini Hamzeh Salehipour
      In this work an improved method for designing a linear vibrational absorber, excited by random vibrations is presented and analyzed. First, analytical expressions, for non-stationary white noise accelerations, are derived. The criterion is different from the conventiona More
      In this work an improved method for designing a linear vibrational absorber, excited by random vibrations is presented and analyzed. First, analytical expressions, for non-stationary white noise accelerations, are derived. The criterion is different from the conventional criteria, used for structural design under random vibration, and it is based on minimum displacement or acceleration response of the main structure, without considering required performance against failure. In this study, in order to control the structural vibrations induced on a mechanical structure excited by non-stationary based acceleration random process, the Multi-objective optimum (MOO) design of a vibration absorber has been developed. This has been performed using the bees optimization algorithm. The analysis is developed by considering a case study of a multi degree of freedom system with uncertain parameters, subject to random vibrations and equipped with a vibration absorber. Results demonstrate the importance of performing a pre-design procedure and show that the multi-objective pre-design methodology is economical and leads to time reduction and raw data accumulation. This method is particularly well performed for structures with higher degrees of freedom (DOF. Manuscript profile
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      147 - Extracting Lateral Transfer Function of a Remotely Piloted Helicopter by System Identification Method Using 3-DOF Test Stand
      Hesamodin EbnodinHamidi Elyas Nezamoleslami Faridodin Javadifar
      At the beginning of this paper, design and manufacturing stages of the 3 degree of freedom test stand for a remotely piloted helicopter is described, in which the helicopter is able to rotate about its three primary accesses. In the next parts the dynamical model of the More
      At the beginning of this paper, design and manufacturing stages of the 3 degree of freedom test stand for a remotely piloted helicopter is described, in which the helicopter is able to rotate about its three primary accesses. In the next parts the dynamical model of the RPH in the yaw channel is presented and lateral transfer function of RPH (yaw channel) is extracted by performing several tests and gathering dynamical data. Least square method is used for system identification and finally results validation would be possible through comparison between simulated behavior of the RPH and experimental data of the test stand. Manuscript profile
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      148 - Finite Volume-Lattice Boltzmann Modeling of Viscous Flows
      Ahad Zarghami Mohamad Javad Maghrebi Jalal Ghasemi
      In this paper, a viscous flow simulation is presented using the Lattice Boltzmann Equation (LBE). A finite volume approach is adapted to discretize the LBE on a cell-centered, arbitrary shaped, rectangular tessellation. The formulation includes upwind scheme and high or More
      In this paper, a viscous flow simulation is presented using the Lattice Boltzmann Equation (LBE). A finite volume approach is adapted to discretize the LBE on a cell-centered, arbitrary shaped, rectangular tessellation. The formulation includes upwind scheme and high order descretization schemes for the flux term and collision operator respectively. A consistent open and solid boundary treatment according to cell-centered scheme also addressed, which resulted in a wider domain of stability and faster convergence. Validation of the results is conducted by symmetric sudden expansion. The results are compared with reliable analytical or experimental results, indicating the accuracy and robustness' of the proposed method for analyzing different flows of the interest. Manuscript profile
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      149 - Buckling of Functionally Graded Beams with Rectangular and Annular Sections Subjected to Axial Compression
      A. Heydari
      The current study presents a new analytical method for buckling analysis of rectangular and annular beams made up of functionally graded materials with constant thickness and Poisson’s ratio. The boundary conditions of the beam are assumed to be simply supported and cla More
      The current study presents a new analytical method for buckling analysis of rectangular and annular beams made up of functionally graded materials with constant thickness and Poisson’s ratio. The boundary conditions of the beam are assumed to be simply supported and clamped. The stability equations were obtained by using conservation of energy. The critical buckling load and first mode shape were obtained using Variational Calculus method. Increasing in buckling capacity and improvement in the behavior of functionally graded beams in comparison to homogenous beams have been investigated. After simplifying results, Duffing differential equation for homogeneous beam without oscillations was obtained and validity of this new work was proved. Manuscript profile
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      150 - Finite Element Simulation of Plasma Arc Welding Process for Ferrite Stainless Steel
      Ali Moarefzadeh Mehdi Ahmadi Najafabadi
      In this paper, thermal effect of plasma arc welding is investigated, and temperature field of ferrite stainless steel is acquired. Thermal effect of plasma arc and subsequently the generated temperature field in the work piece is the key for analysis and optimization of More
      In this paper, thermal effect of plasma arc welding is investigated, and temperature field of ferrite stainless steel is acquired. Thermal effect of plasma arc and subsequently the generated temperature field in the work piece is the key for analysis and optimization of this welding process, which is the main goal of this paper. Finite element simulation of welding process by SIMPLEC method and ANSYS software is achieved, using FSI solver for getting stainless steel temperature field, effect of parameters variation on temperature field, and process optimization for different situations of plasma and shielding gases (Argon, Helium, and mixture of both). Lastly, the results of other papers are used to verify the correctness of this paper’s results. The temperate field results have determined the effects of welding parameters, and are used to optimize plasma welding process for improving weld quality. Optimization results for different gases indicates that due to special heat of Helium gas, there is extra potential with respect to Argon gas to narrow the plasma arc and concentrate inlet heat over stainless steel. Manuscript profile
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      151 - Numerical Simulation of Abrasive Water jet Cutting Process using the SPH and ALE Methods
      H. Shahverdi M. Zohoor S. M. Mousavi
      On account of some complexities such as fluid-structure interaction and extra-large deformation problems, complete simulation of abrasive water jet cutting process is very hard. The main goal of this paper is to overcome these difficulties through comprehensive simulati More
      On account of some complexities such as fluid-structure interaction and extra-large deformation problems, complete simulation of abrasive water jet cutting process is very hard. The main goal of this paper is to overcome these difficulties through comprehensive simulation in LS-DYNA commercial software. For this purpose the Smoothed Particle Hydrodynamics (SPH) and Arbitrary Lagrangian Eulerian (ALE) methods are employed. Utilizing these methods, the depth of water jet penetration and mechanism of erosion are simulated for a certain test case. In addition, the effect of water pressure and traverse speed on depth of penetration are examined. Comparison between the obtained results using both methods showed that the numerical results are in good agreement with available experimental data. Manuscript profile
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      152 - A New method for Production of Porous Aluminum Castings
      A.K. Shaik Dawood1
      Abstract Porous materials are commonly found in nature and as industrial materials such as wood, carbon, foams, ceramics and bricks. In order to use them effectively, their mechanical properties must be understood in relation to their micro-structures. Foam made from no More
      Abstract Porous materials are commonly found in nature and as industrial materials such as wood, carbon, foams, ceramics and bricks. In order to use them effectively, their mechanical properties must be understood in relation to their micro-structures. Foam made from non-flammable metal will remain non-flammable and the foam is generally recyclable back to its base material. This research work is mainly concentrated in  producing porous aluminum castings using melt route Metallic foams typically retain some physical properties of their base material thus density and % Porosity is found. Porous castings were developed by melt route using soaked Precursors, steel net , aluminum net and by casting around granules technique. Manuscript profile
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      153 - Process Parameters Optimization in Gas Blow Forming of Pin-type Metal Bipolar Plates using Taguchi and Finite Element Methods
      M. Moradian A. Doniavi V. Modanloo V. Alimirzaloo
      Metal bipolar plates are the most important parts of the fuel cells and recently these plates are used instead of graphite ones.In the present study, gas blow forming of a pin-type aluminum 5083 bipolar plate has been studied. After the simulation of the process, the FE More
      Metal bipolar plates are the most important parts of the fuel cells and recently these plates are used instead of graphite ones.In the present study, gas blow forming of a pin-type aluminum 5083 bipolar plate has been studied. After the simulation of the process, the FE model has been validated using experimental results. Then, the effects of parameters including maximum pressure of the gas, pressurization profile and corner radius of the pin on thinning ratio and forming depth of final part have been investigated. Nine experiments were designed using the Taguchi L9 orthogonal array and the experiments were performed using the FE model. The signal to noise (S/N) ratio and the analysis of variance (ANOVA) techniques were carried out to determine the effective parameters and the contribution of each parameter. The maximum pressure of 1.2 MPa, SP2 pressurization profile and corner radius of 0.2 mm lead to the minimum thinning ratio. Also, it was found that to maximize the forming depth, the maximum pressure of 2 MPa, SP1 pressurization profile and corner radius of 0.3 mm should be selected. Also, ANOVA analysis showed that the most significant parameters on thinning ratio and forming depth are corner radius and maximum pressure, respectively. Manuscript profile
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      154 - A Simple Method for Designing a Duct for a Multi-Component Ducted Propulsion System
      N. M. Nouri Mehrdad Kalantar Neyestanaki Saber Mohammadi
      The present paper numerically discusses the design procedure of marine ducts used for multi-component ducted propulsion systems at the stern of an axisymmetric submerged body. The results are presented in the form of tables showing the effects of dihedral angel as well More
      The present paper numerically discusses the design procedure of marine ducts used for multi-component ducted propulsion systems at the stern of an axisymmetric submerged body. The results are presented in the form of tables showing the effects of dihedral angel as well as camber ratio of the duct as the two most important geometrical parameters on hydrodynamic performance of the propulsion system. Furthermore, a correlation has been extracted between the results of two and three dimensional analysis of ducted propellers. The results show that the design procedure of the duct used for a ducted propulsion system could be performed using some two dimensional analyses. The simulations are performed using a Reynolds averaged Navier Stokes Equations (RANS) based Computational Fluid Dynamics (CFD) tool. Manuscript profile
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      155 - The Strain Rate Effect on Bending Properties of Basalt and Carbon Fibers Reinforced Phenolic Composites
      Moslem Najafi Seyyed Mohammad Reza Khalili Reza Eslami-Farsani
      In this study, the strain rate effect on the bending properties of fiber reinforced composites for three types of polymer composites namely phenolic resin reinforced by woven basalt fibers, woven carbon fibers, and woven basalt/ woven carbon fibers at a total volume fra More
      In this study, the strain rate effect on the bending properties of fiber reinforced composites for three types of polymer composites namely phenolic resin reinforced by woven basalt fibers, woven carbon fibers, and woven basalt/ woven carbon fibers at a total volume fraction of approximately 35% has been determined. Flexural tests have been conducted at low range of strain rates included 0.03 min-1, 0.06 min-1 and 0.09 min-1. Specimens with identical geometry have been used in all the tests. Experimental results showed that the strain rate has a significant effect on the material response in bending. Results showed that, both the flexural modulus and the ultimate flexural strength of the three types of composites are increased with the increasing in the strain rate. Also, the bending properties of composites reinforced with woven carbon fibers are very sensitive to the strain rate during the test.    Manuscript profile
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      156 - A New Approach for Non Contact Measuring of Tension in Fixed and Moving Wires
      Hooman Banitalebi Mansour Rafeeyan Ehsan khodaei
      In this paper, based on equations of lateral vibrations of wires, a non contact method for measuring instantaneous tension in a wire is introduced. The lateral vibration of the string is measured using an eddy current transducer and is sent to a computer. This signal is More
      In this paper, based on equations of lateral vibrations of wires, a non contact method for measuring instantaneous tension in a wire is introduced. The lateral vibration of the string is measured using an eddy current transducer and is sent to a computer. This signal is then imported to suitable software for fast Fourier transform (FFT) processing. The first natural frequency of the string is calculated online using FFT plot of the imported signal. This proposed method can be used for measuring tension for both fixed and moving wire with constant velocity, which is a usual case in wire processes. The results show the good agreement with theoretical values and the errors of the method is up to 8% at the worst case. This experimental study shows that this simple and low cost new method can be included in existing non-contact wire measuring tension apparatuses. Manuscript profile
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      157 - Path Following of a High Speed Planing Boat Based on Gauss Pseudospectral Method
      M. T. Ghorbani
      In this paper, the problem of optimal path following for a high speed planing boat is addressed. First, a nonlinear mathematical model of the boat’s dynamics is derived and then the Serret-Frenet frame is presented to facilitate the path following control design. To sat More
      In this paper, the problem of optimal path following for a high speed planing boat is addressed. First, a nonlinear mathematical model of the boat’s dynamics is derived and then the Serret-Frenet frame is presented to facilitate the path following control design. To satisfy the constraints on the states and the input controls of the boat's nonlinear dynamics and minimize both the cross tracking and heading error, a nonlinear optimal controller is formed. To solve the resulted nonlinear constrained optimal control problem, the Gauss pseudospectral method (GPM) is used to transcribe the optimal control problem into a nonlinear programming problem (NLP) by discretization of states and controls. The resulted NLP is then solved by a well-developed algorithm known as SNOPT. The results illustrate the effectiveness of the proposed approach to tackle the boat path following problem. Manuscript profile
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      158 - Investigation of Machining Parameters in Wire Electrical Discharge Machining (WEDM) on the Surface Roughness & Cutting Speed of Tungsten Carbide
      Mehdi Jafarian GholamHosein Dehghan Abbas Vafaeisefat
      Surface roughness is one of the most important parameters that plays very critical role in determining the quality of engineering components. A good surface quality resulting in improve of fatigue strength, corrosion and wear resistance of the workpiece. On the other ha More
      Surface roughness is one of the most important parameters that plays very critical role in determining the quality of engineering components. A good surface quality resulting in improve of fatigue strength, corrosion and wear resistance of the workpiece. On the other hand, increasing cutting speed and decreasing time of machining are desirable for manufacturers in order to reduce costs and increase rate of production. According to importance of above subjects, having high surface with low cost is required to have proper understanding of cutting parameters of WEDM. In this study, the effect of parameters such as Power, Time-off pulse, Open circuit voltage and Servo voltage on Tungsten carbide is investigated. Manuscript profile
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      159 - Prohibition of boiler feed water pump failure in Power Plant
      batool soleimani
      This paper deals with a failure investigation of boiler feed pump’s shaft of a steam power plant. Boiler feed water pump is a specific type of pump used to pump, feed water into a steam boiler and is one of most important part of steam power plants. Feed pumps failure m More
      This paper deals with a failure investigation of boiler feed pump’s shaft of a steam power plant. Boiler feed water pump is a specific type of pump used to pump, feed water into a steam boiler and is one of most important part of steam power plants. Feed pumps failure may cause failure of another part of steam power station, therefore keep them safe is an important problem. There are 12 feed pumps in Bandar Abbas power plant. They are old and because of failure of one of them and for trying to avoid repetition of this problem, work condition of 3 dimensional pump’s shaft is modeled with Abaqus software that uses finite element method for analysis. Causes of failure of pump and stresses forced on it are investigated and finally some suggestions likes use of soft starting and inverter are presented. Manuscript profile
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      160 - EVALUATION OF FATIGUE LIFE OF FRICTION STIR WELDED 7075-T651 ALUMINUM ALLOY JOINTS
      Ahmed Khalid Hussain Kanukati Vinay Kumar Mohd Zubair Nizami Syed Yousufuddin
      Abstract – Aluminium 7075- T651 alloys are widely used in the production of light weight structures requiring a high strength to weight ratio and high corrosion resistance. The effect of processing parameters on fatigue life of 7075- T651 aluminium joints produced More
      Abstract – Aluminium 7075- T651 alloys are widely used in the production of light weight structures requiring a high strength to weight ratio and high corrosion resistance. The effect of processing parameters on fatigue life of 7075- T651 aluminium joints produced by friction stir welding was investigated in the present study. Welding samples were made by employing rotating tool speed of 770, 900 and 1200 r.p.m, welding speeds of 70, 75 and 80 mm/min. After welding process, mechanical properties of samples were evaluated by means of fatigue testing machine at room temperature. Results were clearly illustrated that as tool speed increases, fatigue life decreases. The highest fatigue life was obtained with 80mm /min welding feed and weld speed of 1200 r.p.m Manuscript profile
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      161 - Impact Behavior of Ceramic-Metal Armour by Al2O3-Nano SiC Nano Composite
      reza azarafza Ali Arab Ali Mehdipoor Ali Davar
      Abstract: Alumina (Al2O3) is one of the most practical ceramics used in making ceramic-metal armours. To improve the properties of alumina, some other materials are added to it. In this paper, SiC material as Nano powder is added to alumina, and four armour samples of t More
      Abstract: Alumina (Al2O3) is one of the most practical ceramics used in making ceramic-metal armours. To improve the properties of alumina, some other materials are added to it. In this paper, SiC material as Nano powder is added to alumina, and four armour samples of this new ceramic with different volume fractions (V.F. ) including 0%, 5%, 10% and 15% of SiC particles are made. Then, the samples are warmed up by hot press and their fracture toughness, bending strength and density are measured. Then, it is found that the armour sample made of alumina with V.F. of 10% of SiC particles shows more desirable properties as compared to the other armour samples. So, the computer simulation and ballistic test are done using alumina with V.F. of 10% of SiC particles and the obtained results are compared with those of ballistic test of pure alumina. In the simulations, it is observed that the pure alumina with the thickness of 10 mm and aluminum substrate of thickness 4.8 mm is broken due to the normal impact of a projectile with 800 m/s speed, but the new armour made of the present new ceramic is able to withstand the same conditions and no fracture is observed after impact. The ballistic tests were also done using the present new ceramic-Aluminum armour samples with ceramic thicknesses of 6, 8 and 10 mm, respectively to determine the smallest thickness at which the fracture is occurred. It was found that the armour with the ceramic layer thickness of 6 mm got fractured, whereas the others were able to withstand the conditions of the ballistic test. Manuscript profile
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      162 - Optimization of Tangential Cutting Force in Turning Operation in Machining of Unidirectional Glass Fiber Reinforced Plastics
      Surinder Kumar
      In this paper, Taguchi method is applied to find optimum process parameters for turning UD-GFRP rods using polycrystalline diamond cutting tool. The process parameters considered include cutting speed, depth of cut, cutting environment (dry and wet) and feed rate. The e More
      In this paper, Taguchi method is applied to find optimum process parameters for turning UD-GFRP rods using polycrystalline diamond cutting tool. The process parameters considered include cutting speed, depth of cut, cutting environment (dry and wet) and feed rate. The experiments were conducted by L16 orthogonal array as suggested by Taguchi. Signal to Noise ratio and ANOVA are employed to analyses the effect of turning process parameter on the tangential cutting force. The results from confirmation runs indicated that the determined optimal combination of machining parameters improved the performance of the machining process. The percent contributions of cutting speed (2.46%), depth of cut (73.82%), dry and wet (3.89%) and feed rate (8.02%) in affecting the variation of tangential force are significantly larger (95 % confidence level). It has been found that the wet cutting environment reduces the tangential force. Depth of cut is the factor, which has great influence on tangential force, followed by feed rate. Manuscript profile
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      163 - The Effect of Packing on Temperature and Pressure Drop in Mechanical Counter Flow Cooling Tower
      HamidReza Goshayeshi AmirReza Mamouri
      Cooling towers are widely used in most industrial units to reject waste heat to the atmosphere. This paper deals with an experimental analysis of heat and mass transfer phenomena between water and air by direct contact in a cooling tower. The tower is filled with 6 type More
      Cooling towers are widely used in most industrial units to reject waste heat to the atmosphere. This paper deals with an experimental analysis of heat and mass transfer phenomena between water and air by direct contact in a cooling tower. The tower is filled with 6 type packing. In this study temperature and pressure drop and tower characteristics was used in determining experimentally the thermal performance of the cooling tower. Temperature drop decreases as water mass flow rate increases, pressure drop increases as mass flow rate ratios increases and tower characteristics increases as water mass flow rate increases. The data registered in the experimental set up were employed to obtain correlation of the tower characteristics. Manuscript profile
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      164 - A New Method for Biomodelling and Rapid Prototyping of Human's Hard Tissues as Substituting Prostheses
      Kasra Karbaschi
      3D imagination of human's organs has become feasible by digital image processing techniques and algorithms via CT or MRI images in recent years. In this study, a new method for reverse engineering and biomodelling of hard tissues by CATIA cloud points' concept has been More
      3D imagination of human's organs has become feasible by digital image processing techniques and algorithms via CT or MRI images in recent years. In this study, a new method for reverse engineering and biomodelling of hard tissues by CATIA cloud points' concept has been considered. Comparing with the current softwares (e.g. BioBuild or Mimics) has shown the new method's easiness of implementing and modelling, final model's high accuracy, easiness of data exchanging with the rapid prototyping systems and reduction of need for having anatomical background for interpreting the CT or MRI images. Manuscript profile
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      165 - Analysis of Internal Combustion Engines Operating Parameters with Waste Heat Recovery by Two-stage Organic Rankine Cycle
      saeid javan mojtaba tahani mohammad javad khodaei
      In this paper, the amount of wasted heat from different parts of a 12 liter compression ignition engine and their potential for waste heat recovery were investigated. Then, two-stage configuration of organic rankine cycle was introduced for simultaneous heat recovery fr More
      In this paper, the amount of wasted heat from different parts of a 12 liter compression ignition engine and their potential for waste heat recovery were investigated. Then, two-stage configuration of organic rankine cycle was introduced for simultaneous heat recovery from exhaust gases and coolant. Finally, parameters like hybrid generated power, engine thermal efficiency and brake specific fuel consumption were studied in different engine speeds and full engine load. As a result, by using this method, it is possible to produce 35 kW hybrid power, which causes 9.5% reduction in brake specific fuel consumption. Manuscript profile
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      166 - Design and performance evaluation of Tuned Vibration Absorber for the vibration control of a centrifugal pump
      Anant Sheth
      With the prolonged use of domestic centrifugal pump, due to erosion, corrosion and an unbalance the sever vibration of the pump are resulted. An erratic sound coming out of pump makes the user uncomfortable. Here, Tuned Vibration Absorber (TVA) is used as a vibration co More
      With the prolonged use of domestic centrifugal pump, due to erosion, corrosion and an unbalance the sever vibration of the pump are resulted. An erratic sound coming out of pump makes the user uncomfortable. Here, Tuned Vibration Absorber (TVA) is used as a vibration controlling device. It is designed to reduce the RMS velocity below 20% of the circumferential speed, at which the impeller is balanced. Natural frequency were found both by analytical and the numerical methods. A fan cover is considered as a TVA, tuned to the operating frequency and the dominating higher frequencies have been tackled by designing new TVA. Here with TVA, the vibration has been reduced to the permissible limit and the amplification factor is within the allowable limit. Manuscript profile
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      167 - Simulation of Air Pad Shape on Pressure Distribution in Air Gap of Air Table in Ultra Precision Machine Tools
      Mohammad Akhondzadeh Mehrdad Vahdati
      Air pads are applicable in ultra precision machines very much. Two main components of these machines, spindle and table, use the advantages of such systems. The performance and efficiency of air pads have big influence on the whole machine quality. Parameters affecting More
      Air pads are applicable in ultra precision machines very much. Two main components of these machines, spindle and table, use the advantages of such systems. The performance and efficiency of air pads have big influence on the whole machine quality. Parameters affecting pressure distribution of air tables may be considered as, 1) air compressing method, 2) air nozzle diameter, shape, and size, 3) number of air pads, 4) air gap thickness, etc. In this study, effects of air pad shape on pressure distribution in air gap have been investigated using ANSYS. In this simulation, FOTRAN environment have been employed. Investigated shapes for air pads are triangle, rectangle, pentagon, hexagon, ellipse and circle. Pressure distribution-distance from orifice has been plotted for each air pad shape. The results indicate that the rectangle air pad has best pressure distribution. Manuscript profile
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      168 - Effects of Geometrical Tolerances on Residual Stresses in a Compound Shrink Fitted Pressure Vessel
      Mohammad Sedighi M. T. Noorian A. H. Jabbari
      Shrink fit process is a useful technique in order to introduce beneficial residual stress in compound pressure vessels. In this paper, the effects of geometrical tolerances on residual stresses have been studied for a compound shrink fitted pressure vessel, practically. More
      Shrink fit process is a useful technique in order to introduce beneficial residual stress in compound pressure vessels. In this paper, the effects of geometrical tolerances on residual stresses have been studied for a compound shrink fitted pressure vessel, practically. Three layers, which are designed based on an optimum nominal thickness and overlap dimensions and tolerances, have been fitted by shrink fitting to obtain a multi-layered high pressure vessel with desirable residual stress distribution. But in the manufacturing process, variations of inner and outer diameter of each layer have been observed within the design tolerances. The geometrical tolerances considerably affect the residual stresses. In this work, experimental results for residual stress are obtained from measurements of inner diameter of innermost cylinder due to two stages of shrink fitting. Then, the residual stress distribution is compared with analytical solution and finite element method at the lower limit and upper limit of tolerance domains. It is shown that very small geometrical tolerance could have a significant effect on residual hoop stress distribution. Also, the experimental results have a good agreement with analytical and finite element results. Manuscript profile
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      169 - Effects of Process Parameters on Superplastic Forming of a License Plate Pocket Panel
      Mohammad Hasan Shojaeefard Abolfazl Khalkhali Elyar Miandoabchi
      Superplastic forming (SPF) is a manufacturing process utilized in the automotive industry to produce complex geometry aluminum or magnesium alloy components which cannot be fabricated at room temperature. This paper investigates the effects of the die entry radius and t More
      Superplastic forming (SPF) is a manufacturing process utilized in the automotive industry to produce complex geometry aluminum or magnesium alloy components which cannot be fabricated at room temperature. This paper investigates the effects of the die entry radius and the interfacial friction coefficient on the required forming time and thickness distribution of a superplastic formed part. A commercial finite element software, ABAQUS/Implicit, is applied to simulate forming of AA5083 aluminum alloy into a license plate pocket panel. The results indicate that for a fixed friction coefficient, increasing the entry radius reduces the forming time and enhances the formed part quality, in terms of thickness distribution. It is also shown that the lower the friction coefficient, the higher the sensitivity of the forming time to the die entry radius variations.// Manuscript profile
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      170 - Heat transfer of Nano-fluids as working fluids of swimming pool heat exchangers
      Nariman Ashrafi Yashar Bashirzadeh
      The present experimental study reports on enhancement of heat transfer by addition of nanoparticles to the working fluid of commercial swimming pool heat exchangers under laminar flow condition. Three different concentrations of Titanium dioxide nanoparticles were added More
      The present experimental study reports on enhancement of heat transfer by addition of nanoparticles to the working fluid of commercial swimming pool heat exchangers under laminar flow condition. Three different concentrations of Titanium dioxide nanoparticles were added to the water as working fluid of a typical forced convective heat exchanger used to transfer heat to public swimming pools. The experimental setup is capable of measuring velocity, heat transfer rate, and temperature at different points. TiO2 nanoparticles with mean diameter of 20 nm were used. The effects of concentration of suspended nanoparticles and that of Reynolds number on forced convective heat transfer were investigated. It is observed that at 0.1%, 0.5% and 1% weight concentration of suspended TiO2 nanoparticles, the average convective heat transfer coefficient improved by 1.1%, 15.9% and 31.6% respectively. The coefficient is further increased at higher Reynolds numbers. The efficiency of heat exchanger is evaluated for different scenarios. Manuscript profile
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      171 - Fabrication of AA1060/Al2O3 Composites by Warm Accumulative Roll Bonding Process and Investigation of its Mechanical Properties and Microstructural Evolution
      M. Heydari Vini P. Farhadipour
      Recently accumulative roll bonding (ARB) has been used as a novel method to produce particle reinforced metal matrix composites. The accumulative roll bonding as a severe plastic deformation (SPD) rolling procedure aimed at enhancing the mechanical properties of metals More
      Recently accumulative roll bonding (ARB) has been used as a novel method to produce particle reinforced metal matrix composites. The accumulative roll bonding as a severe plastic deformation (SPD) rolling procedure aimed at enhancing the mechanical properties of metals and alloys. The process consists in rolling series of overlapped sheets with a thickness reduction ratio (e.g. 50%). In this study, warm accumulative roll bonding (Warm- ARB) process has been used to produce Aluminum Metal Matrix Composite (AMMC: AA1060/-5% Al2O3). AA1060 strips were roll bonded as alternate layers up to 5 rolling passes with 300°C preheating for 5 minutes before each pass. The microstructure and mechanical properties of composites have been studied after different Warm- ARB passes by tensile test, Vickers micro hardness test and scanning electron microscopy (SEM). The results demonstrated that adding alumina particles into AMMCs improves both the strength and tensile toughness of composites. Moreover, the fracture surfaces of samples after the tensile test have been studied during various ARB cycles by scanning electron microscopy (SEM). Also, the results showed that mechanical properties such as tensile strength and average Vickers micro hardness improved with increasing the number of warm ARB cycles. Also, the elongation and tensile toughness of samples dropped in the primary cycles and improved in continuing with increasing the warm ARB cycles. Finally, warm ARB process would allow producing particle reinforced with good mechanical properties. Manuscript profile
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      172 - Faults diagnosis of a girth gear using discrete wavelet transform and artificial neural networks
      Mahmuod Akbari Hadi Homaei Mohammad Heidari
      In this paper, a fault diagnosis system based on discrete wavelet transform (DWT) and artificial neural networks (ANNs) is designed to diagnose different types of fault in gears. DWT is an advanced signal-processing technique for fault detection and identification. Five More
      In this paper, a fault diagnosis system based on discrete wavelet transform (DWT) and artificial neural networks (ANNs) is designed to diagnose different types of fault in gears. DWT is an advanced signal-processing technique for fault detection and identification. Five features of wavelet transform RMS, crest factor, kurtosis, standard deviation and skewness of discrete wavelet coefficients of normalized vibration signals has been selected. These features are considered as the feature vector for training purpose of the ANN. A wavelet selection criteria, Maximum Energy to Shannon Entropy ratio, is used to select an appropriate mother wavelet and discrete level, for feature extraction. To ameliorate the algorithm, various ANNs were exploited to optimize the algorithm so as to determine the best values for ‘‘number of neurons in hidden layer” resulted in a high-speed, meticulous three-layer ANN with a small-sized structure. The diagnosis success rate of this ANN was 100% for experimental data set. Some experimental set of data has been used to verify the effectiveness and accuracy of the proposed method. To develop this method in general fault diagnosis application, an example was investigated in cement industry. At first, a MLP network with well-formed and optimized structure (20:12:3) and remarkable accuracy was presented providing the capability to identify different faults of gears. Then this neural network with optimized structure is presented to diagnose different faults of gears. The performance of the neural networks in learning, classifying and general fault diagnosis were found encouraging and can be concluded that neural networks have high potential in condition monitoring of the gears with various faults. Manuscript profile
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      173 - Numerical Investigation of Laser Bending of Perforated Sheets
      Mehdi Safari Mehdi Ebrahimi
      In this work, laser bending of perforated sheets has been investigated numerically. Laser bending of perforated sheets is more complicated than non-perforated sheets due to their complex geometries. In this paper, laser bending of perforated sheets is studied numericall More
      In this work, laser bending of perforated sheets has been investigated numerically. Laser bending of perforated sheets is more complicated than non-perforated sheets due to their complex geometries. In this paper, laser bending of perforated sheets is studied numerically in the form of thermo-mechanical analysis with ABAQUS/IMPLICIT code. For this purpose, the effects of process and sheet parameters such as laser output power, laser scanning speed, laser beam diameter and the number of punches in the sheet are investigated on the bending angle of laser formed perforated sheet. The results show that the larger punch diameters lead to decrease in bending angle in the laser formed perforated sheets. Also, it is concluded that the bending angle of the perforated sheet is decreased with increasing laser scanning speed. In addition, bending angle is decreased with decreasing laser beam diameter. Manuscript profile
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      174 - An Investigation of Lid Driven Cavity Flow Using Large Eddy Simulation
      Iman Nourollahi
      In this paper we use of large eddy simulation method for 2 dimensional incompressible fluid in square lid-driven cavity. We also apply smagorinsky SGS model for attach sub grid scales. In order to we have written a computer program with finite volume method and implicit More
      In this paper we use of large eddy simulation method for 2 dimensional incompressible fluid in square lid-driven cavity. We also apply smagorinsky SGS model for attach sub grid scales. In order to we have written a computer program with finite volume method and implicit for discretization unsteady governing equations and we use of simple algorithm for pressure term. Our computation get from Re=100 up to Re=10000 and we obtain mean horizontal velocity, mean vertical velocity in central line, stream line and pressure contour and also we have calculated fluctuation of velocities and in finally we accepted Reynolds stress in Re=10000. The results are in good agreement with the experimental and numerical data. Manuscript profile
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      175 - Statistical Analysis and Optimization of Factors Affecting the Spring-back Phenomenon in UVaSPIF Process Using Response Surface Methodology
      M. Vahdati R. A. Mahdavinejad S. Amini
      Ultrasonic Vibration assisted Single Point Incremental Forming (UVaSPIF) process is an attractive and adaptive method in which a sheet metal is gradually and locally formed by a vibrating hemispherical-head tool. The ultrasonic excitation of forming tool reduces the ave More
      Ultrasonic Vibration assisted Single Point Incremental Forming (UVaSPIF) process is an attractive and adaptive method in which a sheet metal is gradually and locally formed by a vibrating hemispherical-head tool. The ultrasonic excitation of forming tool reduces the average of vertical component of forming force and spring-back rate of the formed sample. The spring-back phenomenon is one of the most important geometrical errors in SPIF process, which appear in the formed sample after the process execution. In the present article, a statistical analysis and optimization of effective factors on this phenomenon is performed in the UVaSPIF process based on DOE (Design of Experiments) principles. For this purpose, RSM (Response Surface Methodology) is selected as the experiment design technique. The controllable factors such as vertical step size, sheet thickness, tool diameter, wall inclination angle, and feed rate is specified as input variables of the process. The obtained results from ANOVA (Analysis of Variance) and regression analysis of experimental data, confirm the accuracy of mathematical model. Furthermore, it is shown that the linear, quadratic, and interactional terms of the variables are effective on the spring-back phenomenon. To optimize the spring-back phenomenon, the finest conditions of the experiment are determined using desirability method, and statistical optimization is subsequently verified by conducting the confirmation test. Manuscript profile
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      176 - Multi layered finite element analysis of graded coatings in frictional rolling contact
      R. Jahedi S. Adibnazari
      A plain strain analysis of frictional rolling contact on an elastic graded coating is presented in this paper. Finite element method is applied to gain an understanding of the stresses and contact zone properties caused during rolling contact. The effects of friction, m More
      A plain strain analysis of frictional rolling contact on an elastic graded coating is presented in this paper. Finite element method is applied to gain an understanding of the stresses and contact zone properties caused during rolling contact. The effects of friction, material stiffness ratio and coating thickness on stresses in contact zone and coating/substrate interface are studied. Shear modulus of softening and stiffening graded coatings change with exponential, power law and linear functions. The substrate is homogenous and the rigid cylindrical roller moves in a steady state condition with constant velocity. The coating is modeled in multi layers and a 2-D hard contact of rolling surfaces is considered. The analytical results verify the present method and show a good agreement. It is shown that thinner thicknesses have more effects on stresses and energy density, but these effects are not seen for thicknesses larger than a specific limit. Manuscript profile
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      177 - A Practical Approach to Analysis of Hydromechanical Deep Drawing of Superalloy Sheet Metals by Using Finite Element Method
      Milad Janbakhsh Mohammad Riahi Faramarz Djavanroodi
      Hydromechanical deep drawing (HDD) is one of the most convenient processes in which a sheet metal is drawn against a counter pressure rather than a rigid die in conventional stampings. This process has been increasingly used to produce aerospace and automotive component More
      Hydromechanical deep drawing (HDD) is one of the most convenient processes in which a sheet metal is drawn against a counter pressure rather than a rigid die in conventional stampings. This process has been increasingly used to produce aerospace and automotive components. More recently, aerospace industry is demanding new materials with capability to produce high strength to weight ratio products. Also several investigations have been carried out on hydromechanical deep drawing, numerical considerations in order to design the process parameters to produce a cost-effective with high quality component by using this process for superalloy cups has not been investigated. Nickle-based superalloy sheet metals are more prominent in aviation and spaceflight industries. In this paper, numerical simulation of hydromechanical deep drawing for Haynes230 nickle based superalloy has been investigated. Moreover, the pressure paths which yield rupture and wrinkling have been realized. Furthermore, differences between applying uniform and gradual pressure into the pressure chamber have been detected to nominate a pressure path for successfully producing a superalloy cup made by HDD. Subsequent to that, chamber pressure against punch travel curves were depicted. For this investigation, 3-D finite element method was employed and the results obtained from numerical simulation were validated using experimental data already available in the literature. Manuscript profile
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      178 - Finite Element Prediction on the Machining Stability of Boring Machine with Experimental Verification
      R. Barzegar M. Mahboubkhah V. Zakeri R. Matin H. Hosseingholi Pourasl F. Abdollahzadeh Bina
      The occurrence of chatter vibrations in boring operation has a great influence in improving workpiece dimensional accuracy, surface quality and production efficiency. In this paper instability analysis of machining process is presented by dynamic model of boring machine More
      The occurrence of chatter vibrations in boring operation has a great influence in improving workpiece dimensional accuracy, surface quality and production efficiency. In this paper instability analysis of machining process is presented by dynamic model of boring machine. This model, which consists of machine tool’s structure, is provided by finite element method and ANSYS software. The model is evaluated and corrected with experimental results by modal testing on boring machine in which the natural frequencies and the shape of vibration modes are analyzed. The natural frequencies of this modal testing are extracted through Pulse Labshop and ME’scope modal analysis software.Finally, the stability lobes obtained from this model are plotted and compared with experimental results Manuscript profile
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      179 - A study on the numerical simulation of thermo-mechanical behavior of the novel functionally graded thermal barrier coating under thermal shock
      N. Nayebpashaee H. Vafaeenezhad S. M. M. Hadavi S. H. Seyedein M. R. Aboutalebi H. Sarpoolaky
      An attempt was made to investigate the thermal and residual stress distribution in a novel three layer (La2Zr2O7/8YSZ/NiCrAlY) during a real-like heating regime which includes heating, service time and final cooling. For achieving maximum accuracy and consistency in cal More
      An attempt was made to investigate the thermal and residual stress distribution in a novel three layer (La2Zr2O7/8YSZ/NiCrAlY) during a real-like heating regime which includes heating, service time and final cooling. For achieving maximum accuracy and consistency in calculation of thermal and mechanical properties of hybrid coating system, all related and required properties were introduced to the software in temperature-dependent mode. Element modification approaches like mass scaling leads to a considerable reduction in running time while satisfying and not violating accuracy and converging criteria and constrains. Applying adaptive hybrid meshing techniques which applies both mesh–part dependency and independency during numerical iterative solution avoids element distortion and diverging in coupled problem. Heat flux and nodal temperature contours indicated that, most of damaging and harmful thermal load and residual stresses concentrate on ceramic top coats and this may lead less harm and life time reduction in the substrate. Manuscript profile
    • Open Access Article

      180 - A New Rolling Pressure Model for An Actual Reversing Cold Rolling Strip Mill
      M. Heydari Vini
      The forging model for cold rolling is one of the rolling models which is used in rolling calculations. In this model, the final rolling pressure is an average value and it is not as accurate for actual and industrial cases. Also, by using forging model, friction hill cu More
      The forging model for cold rolling is one of the rolling models which is used in rolling calculations. In this model, the final rolling pressure is an average value and it is not as accurate for actual and industrial cases. Also, by using forging model, friction hill curves are plotted due to the central point of rolling bite length while frictional stresses intersect at the neutral point of rolling bite. In this study, a new model based on the forging model is presented to determine the rolling pressure during cold rolling process for using in a reversing tandem mill, where this is called “Improved forging model”. In the proposed model, the intersection of the frictional forces is the neutral point. Finally, the computing results from this new model coincide well with the precedent investigations. Manuscript profile
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      181 - An investigation of Reynolds number effect on the aerodynamics of bluff body with sharp edges
      Amir Bak Khoshnevis Amir Mamouri Farzad Mir
      In general, the aerodynamic stability of long span bridges is evaluated based on the results of wind tunnel tests in the low Reynolds number region, because in almost all wind tunnel tests, it is impracticable to satisfy Reynolds number similitude. Therefore, in order t More
      In general, the aerodynamic stability of long span bridges is evaluated based on the results of wind tunnel tests in the low Reynolds number region, because in almost all wind tunnel tests, it is impracticable to satisfy Reynolds number similitude. Therefore, in order to correctly evaluate conventional wind tunnel test results, Reynolds number effects on the aerodynamic force coefficients acting on bridge decks must be carefully investigated. This paper investigate the Reynolds number effect on the aerodynamics of bridge deck section measured in the wide Reynolds number region from  to  based on the dimension of deck height in smooth flow. For the simulation of fluid flow, open-circuit and blowing wind tunnel was used for which the maximum nominal turbulence was 0.1%. The results show that increasing Reynolds number has less effect on the drag coefficient and Strouhal number and parameters in downstream of the model. In other words, variation of drag coefficient and Strouhal number is very small in Reynolds numbers over 20000. Increasing Reynolds number would not be followed with an outstanding change at value of velocity defect but causes to reduce half width, of course, it has no effect in rate growth of half width.  Manuscript profile
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      182 - Comparison of Tube Formability in Electromagnetic Forming and High speed hydroforming
      mohammad hossein mousavi mohsen loh mousavi
      Abstract: Electromagnetic forming and high speed hydroforming are two new methods of tube formin. In this research, the results of expansion forming of tubes using electromagnetic forming and high speed hydroforming are compared by numerical modeling. In this study, fir More
      Abstract: Electromagnetic forming and high speed hydroforming are two new methods of tube formin. In this research, the results of expansion forming of tubes using electromagnetic forming and high speed hydroforming are compared by numerical modeling. In this study, firstly, the results of numerical solution of electromagnetic forming process in ABAQUS software are compared with experimental test results of other references. Then, results of numerical solution of high speed hydroforming in Abaqus software are compared with experimental test results. Finally, these forming methods are compared with each other in terms of displacement and thickness distribution. There is good agreement on bulge tip displacement results obtained by experimental tests and the results of numerical simulation. The results show that forming and deformation of electromagnetic forming process has been far faster than high speed hydroforming. However, a high speed hydroforming can be used in applications such as fitting of rings on tubes instead of electromagnetic forming. Keywords: Electromagnetic Forming, high speed Hydroforming, Finite Element Analysis Manuscript profile
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      183 - Effect of Expulsion on Energy Absorption Capability of Low Carbon Steel Resistance Spot Welds
      Majid Pouranvari Pirouz Marashi
      This paper aims at investigating the effects of weld nugget size and expulsion on the mechanical properties of low carbon steel resistance spot welds using tensile-shear test. Mechanical performance of spot welds are described in terms of failure mode, peak load and fai More
      This paper aims at investigating the effects of weld nugget size and expulsion on the mechanical properties of low carbon steel resistance spot welds using tensile-shear test. Mechanical performance of spot welds are described in terms of failure mode, peak load and failure energy obtained from the tensile-shear test. The effects of voids and porosity as well as electrode indentation associated with expulsion on the peak load and failure energy of spot weld are discussed. Results showed that although expulsion does not reduce load carrying capacity of spot welds, it decreases their energy absorption capability. This can be attributed to the change in the failure location of the base metal in expulsion free welds to fusion zone/heat affected zone boundary in expulsion-experienced welds. Manuscript profile
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      184 - Flow Balance of an Extrusion Die for Production of a U-Shaped Profile
      Abbas Zolfaghari Amihosein Behravesh
      The main objective of an extrusion die is flow balancing as an unbalanced flow causes a distorted product together with residual stress. In this paper a strategy is presented for flow balancing a U-shaped profile with different wall thicknesses. For this purpose, a chok More
      The main objective of an extrusion die is flow balancing as an unbalanced flow causes a distorted product together with residual stress. In this paper a strategy is presented for flow balancing a U-shaped profile with different wall thicknesses. For this purpose, a choker bar is provided at thicker wall to locally restrict excessive flow passing through the thicker section. For optimal design some of die dimensions are considered parametric which will be variable in three levels. The analysis of flow was performed using FLUENT software in order to get the best combination of the parameters which produces the best balance. After the optimum design was obtained, an experimental die is manufactured. It is considered in the manufacture of the die that height of choker to be variable during extrusion for finely adjusting the balance. Results demonstrate that experiments are in good agreement with simulations. Manuscript profile
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      185 - The effect of carbon nanotube waviness and aspect ratio on the buckling of cross-ply laminated FG-CNTRC plates using EFG Method
      Shahrooz Shams Behzad Soltani
      This article deals with the buckling analysis of perfectly bonded cross-ply laminated composite plates reinforced by wavy carbon nanotubes (CNTs) under in-plane loads using element free Galerkin (EFG) method based on first-order shear deformation theory (FSDT). The wavy More
      This article deals with the buckling analysis of perfectly bonded cross-ply laminated composite plates reinforced by wavy carbon nanotubes (CNTs) under in-plane loads using element free Galerkin (EFG) method based on first-order shear deformation theory (FSDT). The wavy single-walled CNTs and Poly-co-vinylene are used for the fibers and the matrix, respectively. The CNT fibers are distributed in the polymer matrix in four types of arrangements in each layer. The material properties of the laminated nanocomposite plates are estimated through a micromechanical model based on the extended rule of mixture. The minimum potential energy approach is utilized to obtain the governing equations and the stiffness matrices. Full transformation approach is employed to enforce essential boundary conditions. The accuracy and convergency of the EFG method is established by comparing the obtained results with available literature. Then, the effects of CNT volume fraction and waviness, aspect ratio and distribution type of CNTs as well as plate aspect ratio, plate width-to-thickness ratio and boundary conditions on the buckling behaviour of cross-ply laminated functionally graded carbon nanotube reinforced composite (FG-CNTRC) plates are investigated. The numerical results show that the CNT waviness and aspect ratio have significant effects on the buckling behaviour of FG-CNTRC plates. Manuscript profile
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      186 - Measuring Vibration in the Air Slide Tables of Ultra Precision Machines With the Different Number of Air Pockets
      Mehrdad Vahdati Sayed AliReza Rasouli
      Vibration in the air slide tables of ultra precision machines prevents gaining accuracies within nanometer level. In this work, dissimilar types of internal vibration including small vibrations and pneumatic hammers have been tested and some measures have been offered t More
      Vibration in the air slide tables of ultra precision machines prevents gaining accuracies within nanometer level. In this work, dissimilar types of internal vibration including small vibrations and pneumatic hammers have been tested and some measures have been offered to reduce their effects. This paper has also proceeded to the vibration tests on the air slide tables built with different number of air cell (air pocket). Comparison in critical pressures, self-excited vibration analysis, and predicting the behavior of contrastive points of the table (that a tool or a work piece might get installed on it) are the results of experiments by different variations of air pressures. Manuscript profile
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      187 - Developing a control strategy for AFM nano- micro manipulation
      H. RaeisiFard A. K. Hoshiar
      Nowadays, with the growing use of AFM (Atomic Force Microscope) nanorobots in the fabrication of nanostructures, research in this area has been proliferated. The major limiting of manipulation process is the lack of real-time observation. Computer simulations have been More
      Nowadays, with the growing use of AFM (Atomic Force Microscope) nanorobots in the fabrication of nanostructures, research in this area has been proliferated. The major limiting of manipulation process is the lack of real-time observation. Computer simulations have been widely applied to improve the feasibility of the process. The existing 2D strategies are incapable of presenting the feasibility of the process. Therefore, 3D simulations of effective forces during the manipulation process and the control mechanism of the process have been presented in this research, where the effective parameters are investigated. To evaluate the validity of the presented results, a FEM simulation is proposed. It is observed that the two sets of results (the analytical method and the finite element approach) have adequate correlation, while the discrepancy which is in an acceptable range, is due to the different solving technique of the finite element method. By applying the presented models, it is now possible to accurately predict the effective forces for fabricating the nanostructures. Manuscript profile
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      188 - Experimental Investigation of the Flow Control of Wake Cylinder by a Plate with Different Geometrical Ends
      A.B. Khoshnevis AmirReza Mamouri AmirReza Mamouri V. Barzenoni
      An experimental study was carried out on the wake of a cylinder on the back of which a plate is installed parallel to the fluid flow, with different terminal angles, where the Reynolds number is 50000. At the end of the plate, blades with the height of 0.25 equal to the More
      An experimental study was carried out on the wake of a cylinder on the back of which a plate is installed parallel to the fluid flow, with different terminal angles, where the Reynolds number is 50000. At the end of the plate, blades with the height of 0.25 equal to the cylinder diameter and with 45, 90 and 135 degrees angle from the horizon, are installed where the cylinder diameter is equal to the plate length. The plate effects on the variation of drag coefficient, medium velocity profiles, reduced velocity, half of the entrance, turbulence intensity and Strouhal number are investigated. The results showed that the drag coefficient for cylinder including the plate, regardless of the end angle, is smaller than the isolated cylinder. The existence of a plate with a terminal angle of 45 degree led to more reduction in drag coefficient of the cylinder. Manuscript profile
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      189 - A hybrid approach based on the genetic algorithm and Monte Carlo method to optimize the 3-D radiant furnaces
      Babak Kamkari Shoeib Mahjoub Leila Darvishvand
      This study presents an optimization methodology to obtain the uniform thermal conditions over the 3-D design body (DB) in 3-D radiant furnaces. For uniform thermal conditions on the DB surfaces, optimal temperature of the heater and the best location of the DB inside th More
      This study presents an optimization methodology to obtain the uniform thermal conditions over the 3-D design body (DB) in 3-D radiant furnaces. For uniform thermal conditions on the DB surfaces, optimal temperature of the heater and the best location of the DB inside the furnace are obtained by minimizing an objective function. The radiative heat transfer problem is solved on the basis of the Monte Carlo method (MCM) to calculate the heat fluxes on the DB surfaces. The genetic algorithm (GA) is used to minimize the objective function defined based on the calculated and desired heat fluxes. The results indicate that thermal conditions on the DB surfaces are greatly influenced by the location of the DB and temperature of the heater. It is concluded that the introduced method is well capable to achieve the uniform thermal conditions on the DB surfaces by finding the optimal values for temperature of the heater and the best location for the DB inside the radiant furnace. Manuscript profile
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      190 - Effect of the Micro Wire-EDM Process Parameters on the Recast Layer in the Molybdenum Micromachining
      Mohammad Tahmasebipour Y. Tahmasebipour A. Shabani M. Boujari Aliabadi
      The Micro wire electrical discharge machining (Micro wire-EDM) process is a modern machining process with various applications in manufacturing micro-parts. The recast layer remaining on the machined surfaces is an inevitable complication of this process. This layer can More
      The Micro wire electrical discharge machining (Micro wire-EDM) process is a modern machining process with various applications in manufacturing micro-parts. The recast layer remaining on the machined surfaces is an inevitable complication of this process. This layer can subsequently affect the machined parts performance. To optimize the recast layer in the micro wire-EDM of the molybdenum microparts, effect of the process parameters on the distribution amplitude of the recast layer was investigated using the Taguchi method. The obtained results showed that the optimal levels of the micro wire-EDM process parameters for achieving the optimal distribution amplitude of the recast layer are as follows: spark pulse-on time of 0.2 μs, cutting speed of 7 mm/min, process voltage of 17 V, and wire tension of 0.45 kg. Also the importance order of the effect of the process parameters on the distribution amplitude of recast layer is as follows: spark pulse-on time, process voltage, cutting speed, and wire tension. Manuscript profile
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      191 - Investigation of water balance in water recovery of closed steam injection gas turbine cycles
      Mohsen Ghazikhani Ali Mohammadian Iman Mirzaii
      An industrial gas turbine has the characteristic of decreasing output power on hot summer days while electricity demand peaks. Steam injection in gas turbines has been used for many years to prevent the loss of performance of gas turbines caused by high ambient temperat More
      An industrial gas turbine has the characteristic of decreasing output power on hot summer days while electricity demand peaks. Steam injection in gas turbines has been used for many years to prevent the loss of performance of gas turbines caused by high ambient temperature. Vodoley system is a Closed Steam Injection Gas Turbine Cycle (CSIGTC), which is known as a self-sufficient in steam production. In this study the influence of steam injection in Mashhad Power Plant GE-F5 gas turbine parameters was experimentally investigated. Moreover a computer modelling has been used to study water balance in a CSIGTC system. The results show that although system has additional water treatment process, applying it increases thermal efficiency up to 35.33 percents for 25 MW of power output at an ambient temperature of 40 ˚C. Also water balance considerations show for a direct contact condenser of 96% efficiency and the exhaust temperature of 420 ˚C at turbine outlet, about 7.8 kg/s of make up water is needed under ISO rating of gas turbine (101.3 kPa, 15 ˚C) which must be provided for the CSIGTC system. This amount of water is about 51% of injected steam. Manuscript profile
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      192 - Trajectory Optimization of Spherical Parallel Robots Using Artificial Neural Network
      Reza Alibakhshi
      This article addresses an efficient and novel method for singularity-free path planning and obstacle avoidance of parallel manipulator based on neural networks. A modified 4-5-6-7 interpolating polynomial is used to plan a trajectory for a spherical parallel manipulator More
      This article addresses an efficient and novel method for singularity-free path planning and obstacle avoidance of parallel manipulator based on neural networks. A modified 4-5-6-7 interpolating polynomial is used to plan a trajectory for a spherical parallel manipulator. The polynomial function which is smooth and continuous in displacement, velocity, acceleration and jerk is used to find a path avoiding obstacles and singularities. The polynomial is further modified to plan a trajectory with minimum passing length through the obstacle and singularity, and the best kinematics conditioning index, as well. An artificial neural network is implemented to solve forward kinematics of the manipulator to estimate the distance between gripper and singularity or obstacle in Euler coordinate. Moreover, the simulation results prove the efficiency of the proposed algorithm. Manuscript profile
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      193 - Abrasive flow machining: A review on new developed hybrid AFM process
      ali kiani Mojtaba Esmailian Hosein Amirabadi
      The abrasive flow machining technique uses a self-deforming tool, an abrasive laden media that is passed back and forth in the passage geometry of the hollow workpiece with the assistance of two hydraulically operated cylinders placed opposite to each other. The materia More
      The abrasive flow machining technique uses a self-deforming tool, an abrasive laden media that is passed back and forth in the passage geometry of the hollow workpiece with the assistance of two hydraulically operated cylinders placed opposite to each other. The material is removed by abrasion generating finer surfaces in the area where flow is restricted. But this method has a low material removal rate. As the time advances, various variants of AFM have been developed by different researchers to increase the productivity and improve the surface finish. Thus a combination of AFM and its process variants were developed to increase material removal rate and surface finish. This article provides a comprehensive review of recent developments in the process variants of AFM and the respective media. Manuscript profile
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      194 - Optimizing Mechanical Properties of POM/Graphene Nanocomposites Prepared by Spray Method
      H. Asadollahi-Yazdi M. Shariati A. Imam M. Ghatee
      : In this study, a spray approach is applied to produce POM/graphene nanocomposite using a hot press mold and an automatic spray. The layer-by-layer spray method is used to fabricate these composites with different Wt. % of graphene particles, spray pressure, nozzle-to- More
      : In this study, a spray approach is applied to produce POM/graphene nanocomposite using a hot press mold and an automatic spray. The layer-by-layer spray method is used to fabricate these composites with different Wt. % of graphene particles, spray pressure, nozzle-to-mold distance at different temperatures. Taguchi approach as a popular method for Designing of Experiments (DOE) was used for statistical control of the parameters influenced by the synthesis process. The main idea in the present study was to determine the optimal characteristics by investigation of interaction effects in the manufacturing of POM/graphene nanocomposite. Thus, the optimal values obtained were 180oC for the mold temperature, 0.55m for the nozzle-to-mold distance and 3*105 Pa for the spray pressure. Finally, the experimental procedure done, showed that in samples fabricated by 1.8 Wt. % of graphene, the fracture strain decreased about 30% and the UTS and elastic modulus improved 40% and 60%, respectively. Manuscript profile
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      195 - Optimal Robust Design of Sliding-mode Control Based on Multi-Objective Particle Swarm Optimization for Chaotic Uncertain Problems
      Mohammadjavad Mahmoodabadi Milad Taherkhorsandi
      The aim of this paper is to present an optimal robust Pareto design of sliding-mode control for chaotic uncertain problems. When designing and applying sliding mode control to challenging dynamic systems, it is crucial to gain optimal control effort and minimum tracking More
      The aim of this paper is to present an optimal robust Pareto design of sliding-mode control for chaotic uncertain problems. When designing and applying sliding mode control to challenging dynamic systems, it is crucial to gain optimal control effort and minimum tracking errors, simultaneously. In this regard, multi-objective particle swarm optimization (periodic CDPSO) benefiting from crucial factors such as divergence and convergence operators, the leader selection method, and the adaptive elimination technique is utilized to design the optimal control approach via obtaining the Pareto front of objective functions addressing the trade-off between the states errors and control effort. Afterward, the Pareto front acquired by the periodic CDPSO algorithm is contrasted with those obtained via other prominent algorithms in the literature including Sigma method, Modified NSGAII, and MOGA. Eventually, the numerical results elucidate the effectiveness of the proposed optimal control scheme in terms of optimal control effort and minimum tracking errors. Manuscript profile
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      196 - Study on Effective Parameters on Machining Power and Presenting the Predictive Models in Machining of EN-AC 48000 Aluminum Alloy
      Hamid Zarepour Hessam ShahAli Esmaeil Soltani
      In this research using statistical analysis the effect of machining parameters such as cutting velocity, feed rate, and tool type on machining power (Pm) in machining process of EN-AC 48000 aluminum alloy has been studied. A Taguchi L27 standard array has been utilized More
      In this research using statistical analysis the effect of machining parameters such as cutting velocity, feed rate, and tool type on machining power (Pm) in machining process of EN-AC 48000 aluminum alloy has been studied. A Taguchi L27 standard array has been utilized as the most economical array to evaluate the factors and their interaction. EN-AC 48000 alloy is frequently used in automotive and aerospace industry. Machining of this alloy is of vital importance because of generating the built-up edge and tool wear. Machining power is an essential factor affecting tool life, dimensional accuracy, and machining efficiency. Three types of cutting tools specialized for machining the aluminum alloys have been used for machining experiments. The effect of factors and their interactions have been studied; moreover, the optimum levels of factors have been offered. Finally, regression models to predict the machining power and related confirmation tests have been represented to evaluate the adequacy of equations. Manuscript profile
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      197 - Numerical Analysis of Plate’s Vibration Behavior with Non-linear Edge under Various Boundary Conditions
      Kasra Karbaschi Hasan Hasanzadeh
      Wide range of planar structures in new technologies has attracted special consideration. In this research vibration behavior of plates with non-linear edges is investigated by means of finite difference (FD) method. For this issue, classical and analytical solutions for More
      Wide range of planar structures in new technologies has attracted special consideration. In this research vibration behavior of plates with non-linear edges is investigated by means of finite difference (FD) method. For this issue, classical and analytical solutions for plates with linear edges were analyzed and mutual equations, needed for numerical calculation were extracted. By expanding the current equations to the non-linear edged plates (e.g. elliptical plates), natural frequencies of this special structure were analyzed numerically and computer simulation with ANSYS software. According to the un-existence of classical or analytical solution for this special configuration, closeness of numerical analysis and computer simulation confirms the accuracy of selected method in this study. Manuscript profile
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      198 - NUMERICAL SIMULATION OF RAYLEIGH-TAYLOR INSTABILITY
      Ahmad Sedaghat S Mokhtarian
      Rayleigh-Taylor (RT) instability has a growing importance in many fields including aircraft industry and astrophysics. The development and the growth of RT instability were investigated using sinusoidal disturbances with different wavelength at the interface of two flui More
      Rayleigh-Taylor (RT) instability has a growing importance in many fields including aircraft industry and astrophysics. The development and the growth of RT instability were investigated using sinusoidal disturbances with different wavelength at the interface of two fluids. Numerical simulations were performed by solving Navier-Stokes unsteady equations with the VOF formulation. Results of the 2D simulation are compared with experimental results. It is shown that beyond a critical time, not captured experimentally, the mushroom shape of RT instability turns into a helical path or breaks down into a patchy shape depending on the shape of disturbance. Nonlinear instabilities responsible for such behaviour are apparent when the wavelength exceeds 10 times a length scale introduced here. Manuscript profile
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      199 - Design Enhancement of EGR System for Improved Vibration Performance on Truck Diesel Engine
      Karthikeyan Subramanian
      In the diesel engine Exhaust Gas Recirculation (EGR) components, valve and connecting pipes are the critical components and fails often during new engine development. These components are important for meeting NOx emissions norms. Therefore design of these components sh More
      In the diesel engine Exhaust Gas Recirculation (EGR) components, valve and connecting pipes are the critical components and fails often during new engine development. These components are important for meeting NOx emissions norms. Therefore design of these components should remain robust. But the challenge in design is compact packaging of complete EGR components on the engine consequently vibration related failure plays a major role. Normally in pneumatic EGR valve, shaft spring stiffness plays a major role for shaft opening and closing. But in this layout during emission testing, shaft is self-opened without feedback signal from sensor this is due to resonance and this problem is solved by increasing the spring stiffness. The next key components is the EGR pipes, the flexible bellows on these pipes are useful for thermal expansion during hot conditions. In this case the bellow crack failure is observed due to vibration. Therefore design improvements were made by proper design of bellow geometry and bracket support for these pipes facilitated prevention of EGR pipe failure. Overall this paper describes the methodology to conduct proper failure investigation to identify the root cause for vibration related failures of EGR system during new product development. Manuscript profile
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      200 - Numerical Investigation of Heat Transfer in Circular Perforated Plates Exposed to Parallel Flow and Suction
      Mohamad Moghimian Behnam Rahmanian MohamadReza Safaei Marjan Goudarzi
      Unglazed transpired solar collectors are widely used for heating outside air directly, these days. Pre-heating ventilation air for large spaces and heating air for crop drying, are some of the applications of these kinds of collectors. The outside air is drawn straight More
      Unglazed transpired solar collectors are widely used for heating outside air directly, these days. Pre-heating ventilation air for large spaces and heating air for crop drying, are some of the applications of these kinds of collectors. The outside air is drawn straight from ambient, uniformly through the whole surface of a perforated absorber (transpired, dark-colored plate) exposed to the sun. That helps the air to be heated. Performance of these collectors is dependent on various parameters, such as geometry and type of perforations, suction velocity and the wind. In this study the role that wind (with constant direction and parallel to the plate) plays in performance of an unglazed transpired collector, is investigated by employing a commercial computational fluid dynamics code. In this study, plates are perforated with circular holes on either a square or triangular layout, covering the practical range of independent parameters such as, suction velocity, porosity, plate thickness, plate conductivity and wind velocity. Effectiveness, efficiency and pressure drop of these collectors are determined and the variations of these parameters with respect to variations of independent parameters are analyzed. It is shown that the performance of collectors on triangular layout, in similar conditions, is better than the same collector, on square layout. Manuscript profile
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      201 - Design and Manufacture of Clutch Pedal Linkage with Clutch Cable
      Sadegh Rahmati Peyvand Najafi
      An interface part is used between clutch pedal and clutch cable in Peugeot, Samand, RD and Peugeot pars. This part is consisted of two pieces. The Main body is made of polyamide 6.6 and the second part is made of CK45.Due to the fact that the two pieces are made of diff More
      An interface part is used between clutch pedal and clutch cable in Peugeot, Samand, RD and Peugeot pars. This part is consisted of two pieces. The Main body is made of polyamide 6.6 and the second part is made of CK45.Due to the fact that the two pieces are made of different assembling geometry with respect to each other, therefore, has caused performance problems which may result in clutch cable failure. Thus, a new interface part is designed in such a way that has a better assembling geometry and has overcome the previous problems and improved part functionality. Manuscript profile
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      202 - Analytical and Simulation of Free-Free Beam Subjected to Concentrated Impact Loadings
      Reza Mohamadipour Ebrahim Harirbafan Mohsen Mohseni
      Impact loading of free-free beam is of high interest to researchers as well as industry application. In this article a free-free beam subjected to concentrated impact loading is considered. Beam material is considered to be a rigid perfect plastic. Different combination More
      Impact loading of free-free beam is of high interest to researchers as well as industry application. In this article a free-free beam subjected to concentrated impact loading is considered. Beam material is considered to be a rigid perfect plastic. Different combinations of loads, energy absorption and load location are considered. The result of the analysis show that when the load is less than critical load, the beam acts as a rigid body and when the load is greater than critical load three different mechanisms prevail. The result of the experiment is compared with analytical as well as simulation process using ABAQUS. The results of the compression are in good agreement with experimental investigation. Manuscript profile
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      203 - Characterization and Determination of Critical Interlaminar Fracture Toughness of Carbon- Epoxy with Arcan Specimen
      Masoud Nikbakht Naghdali Choupani
      In recent years, the application of composite materials in aircraft and space vehicle structural components has become increasingly popular. Preventing failure of composite structural systems has been an important issue in engineering design. Due to the lack of through- More
      In recent years, the application of composite materials in aircraft and space vehicle structural components has become increasingly popular. Preventing failure of composite structural systems has been an important issue in engineering design. Due to the lack of through-the-thickness reinforcement, structures made from laminated composite materials and adhesively bonded joints are highly susceptible to failure caused by interfacial crack initiation and growth. The delamination phenomenon in a laminated composite structure may reduce the structural stiffness and strength and redistribute the load in a way that the structural failure is delayed or may lead to structural collapse. As the most application of these materials is in space structures, the failure of a composite structure component can lead to a catastrophic failure of the structure as whole, thus, an accurate quantitative measurement and understanding of damage and determination of remaining useful service life plays a vital role in prediction of failure of such structures. To do so, first, the fracture properties of material should be determined. To calculate these properties, there are several experimental methods. Among them, the modified Arcan test is one of the most apposite methods for in-plane mixed-mode loading condition. In this investigation, a new specimen has been introduced to reduce cost and problems concerning utilization of adhesively. The critical fracture parameters of carbon-epoxy woven laminated composite material, which is of paramount materials in industry, in room temperatures is calculated both with experimental and numerical methods. These parameters include the critical stress intensity factors and critical strain energy release rate on crack tip. The geometric correction factors for modified Arcan test are calculated with a 2D finite element analysis. Finally, the values of critical fracture properties are calculated using these geometric modification factors and critical loads generated via experimental procedure. Manuscript profile
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      204 - Injection into Orbit Optimization using Orthogonal Polynomials
      Sedigheh Shahmirzaee Jeshvaghany Farshad Pazooki Alireza Basohbat Novinzaddeh
      In this study, the problem of determining an optimal trajectory of a nonlinear injection into orbit problem with minimum time was investigated. The method was based on orthogonalpolynomial approximation. This method consisted of reducing the optimal control problem to a More
      In this study, the problem of determining an optimal trajectory of a nonlinear injection into orbit problem with minimum time was investigated. The method was based on orthogonalpolynomial approximation. This method consisted of reducing the optimal control problem to a system of algebraic equations by expanding the state and control vector as Chebyshev or Legendre polynomials with undetermined coefficients. The main characteristic of this technique was that it converted the differential expressions arising from the system dynamics and the performance index into some nonlinear algebraic equations, thereby greatly simplifying the problem solution. Our research effort focused on applying a Chebyshev series expansion to optimize the trajectory profile of a point-mass Satellite Launch Vehicle (SLV). This paper is divided as follows: first, the Chebyshev and Legender series expansion to optimization are introduced. Then, the flight mechanics model of the point-mass SLV is given. Next, our optimization problem is described and optimization results are presented and discussed. Manuscript profile
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      205 - Vehicle Interior Structure Borne Noise Calculation Using Finite Element Method
      MohamadHosein Navidfar Saeed Ziyaee Rad Mohamad Esfahanian Amir Khorram
      In this paper the interior noise level of a vehicle due to structural vibration, named structure borne noise, as a part of NVH analysis has been investigated. First structural analysis is performed and vibrational behavior of structure carried out due to power plant exc More
      In this paper the interior noise level of a vehicle due to structural vibration, named structure borne noise, as a part of NVH analysis has been investigated. First structural analysis is performed and vibrational behavior of structure carried out due to power plant excitations. Then interior acoustic cavity response for such excitation and resultant noise is determined. Vibrational analysis is performed on three dimensional structure and internal cavity, by considering all the effective components and vibrational tracks in the cabin. Finally, the acoustical behavior of the cavity in different frequencies predicted by cavity normal modes, and results are used to reduce noise level through passive noise control methods. Manuscript profile
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      206 - Analysis of Nano-Particles Motion in 3D and Axisymmetric Models through a Multiple Aerodynamic Lens and Comparison with Applied Models
      Farhad Reiszadeh Abbas Nikbakht
      In this research between 3-dimensional and axisymmetric modeling for movement of nano-particles in passing through a aerodynamic lens, and also between these models and famous model of Wang & Liu was compared. For this purpose, output of nano-particles penetration, More
      In this research between 3-dimensional and axisymmetric modeling for movement of nano-particles in passing through a aerodynamic lens, and also between these models and famous model of Wang & Liu was compared. For this purpose, output of nano-particles penetration, divergence angel, and nano-particle velocity with Wang & Liu model was compared. Geometrical model used for aerodynamic lens compared to past research is more complete and has been selected based on practical model. With regard to low density of nano-particles, hypothesis of one way interaction between liquid and molecule has been selected. That is, movement of nano-particles does not have any effect upon flowing field. Trajectory of nano-particles with diameters of 1, 2, 6, 10, 30 and 50 were investigated. Cumulative fraction of radial that shows the amount of nano-particles divergence compared to axial system for diameters of 2, 6, 10, 20, and 30 were calculated in both three dimensional model and symmetrical model and compared with Wang & Liu model. Results are shownd that nano-particles with lower diameter because of more influence from outside power become farther and this matter create difference between results of two model, since in three dimensional model, nano-particles are affected in three ways by this power. These resultd show that axisymmetric modeling in nano-particles movement is not accurate and exact. Also, there is a good conformity between applied model and Wang & Liu model. Manuscript profile
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      207 - Effects of Cooling Air Direction and Velocity on a Branwheat Biscuit’s Temperature in the Cooling Line of Razavi Food Industries Company
      Ali Sanayeei Amin Behzad Mehr Sayed Masoud Hoseini Sarvari
      An investigation has been carried out on the temperature of a biscuit on the cooling line of Razavi Food Industries Company. For thispurpose, the time variations of Biscuit’s top surface temperature in traveling from oven to packing station on the conveyor packing More
      An investigation has been carried out on the temperature of a biscuit on the cooling line of Razavi Food Industries Company. For thispurpose, the time variations of Biscuit’s top surface temperature in traveling from oven to packing station on the conveyor packing station by conveyors has been studied. The Fourier field equation for transient heat transfer is used as the basis for the deterministic modeling of a single biscuit.The biscuit-conveyors interface is considered as an adiabatic surface. Forced convection, natural convection and radiative heat transfer mechanisms on the top of the biscuits are investigated. The effects of cooling air temperature and also its direction on the temperature reduction of biscuit top surface has been shown. In addition validation of the numerical method has been shown by comparison with the measured data that has been obtained experimentally in the company. Manuscript profile
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      208 - Fluctuating Flow Characteristics and Heat Transfer from Two in-Tandem Square Cylinders
      Amin Etminan
      In this paper, the flow around bluff bodies with different cross sections and determination of forces acts on them are investigated.This paper presents the results of a numerical study on the flow characteristics and heat transfer over two equal square cylinders in a ta More
      In this paper, the flow around bluff bodies with different cross sections and determination of forces acts on them are investigated.This paper presents the results of a numerical study on the flow characteristics and heat transfer over two equal square cylinders in a tandem arrangement. Spacing between the cylinders is 5 widths of the cylinder and the Reynolds number ranges from 1 to 200, Pr=0.71. Both steady and unsteady incompressible laminar flow in the two-dimensional regime are studied. A study of the effects of spatial resolution and blockage on the results is provided. In this paper, the instantaneous and mean streamlines, vorticity and isotherm patterns for different Reynolds numbers are presented and discussed. Also the global quantities such as pressure and viscous drag coefficients, Strouhal number and Nusselt number are determined and discussed for various Reynolds numbers. Manuscript profile
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      209 - Determining Maximum Dynamic Load Carrying Capacity of Cable Robots Between Two End Points of Workspace
      Moharam Habibnejad Khaled Najafi Mehdi Bamdad
      In this paper, according to high load capacity and rather large workspace characteristics of cable driven robots (CDRs), maximum dynamic load carrying capacity (DLCC) between two given end points in the workspace along with optimal trajectory is obtained. In order to fi More
      In this paper, according to high load capacity and rather large workspace characteristics of cable driven robots (CDRs), maximum dynamic load carrying capacity (DLCC) between two given end points in the workspace along with optimal trajectory is obtained. In order to find DLCC of CDRs, joint actuator torque and workspace of the robot constraints concerning to non-negative tension in cables are considered. The problem is formulated as a trajectory optimization problem, which is fundamentally a constrained nonlinear optimization problem. Then the iterative linear programming (ILP) method is used to solve the optimization problem. Finally, a numerical example involving a 6 DOF CDR is presented and results are discussed. Manuscript profile
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      210 - Parametric Analysis of Square Thin Walled Section in Energy Absorption due to Oblique Load
      Reza Mohamadipour Khodadad Vahedi Sayed MohamadReza Emam
      In this study, first energy absorption of axial and bending loading is considered. Next, thin walled structures under oblique loading are investigated using ABAQUS computer simulation, where 180 different cases are simulated. Simulation results of the thin walled struct More
      In this study, first energy absorption of axial and bending loading is considered. Next, thin walled structures under oblique loading are investigated using ABAQUS computer simulation, where 180 different cases are simulated. Simulation results of the thin walled structures under oblique loading were compared with the experimental results of Nagel, and good agreement was perceived. Simulation results revealed that, the amount of energy absorption for thin walled structures is reducing with collision angle. Moreover, the energy absorption performance of thin walled structures can be controlled by geometric parameters; in particular, thickness as one of the most effective parameters in controlling the amount of energy absorption must be considered. Manuscript profile
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      211 - Statistical Control of Root Dimensions of Gas Turbine Blade in Creep Feed Grinding Process
      AhmadReza Fazeli Ebrahim Sharifi
      In this project creep feed grinding process of gas turbine blade root is investigated with the aim of consistant and controlable production. Inthispaper, effectiveness of creep feed grinding process prometers suchas wheel speed, workpiece speed, grind depth and dresser More
      In this project creep feed grinding process of gas turbine blade root is investigated with the aim of consistant and controlable production. Inthispaper, effectiveness of creep feed grinding process prometers suchas wheel speed, workpiece speed, grind depth and dresser speed are investigated. This investigation include their interaction on thelob of gas torbine blade root, as amajor cause of a erosion of grinding dresser, using designof experiment (DOE). Before conducting the experiments, the creep feed grinding machine was checked in order to verify the repeatability and performance assurance of the machine, using Statistical Process Control (SPC). After conducting the experiments, a mathematic model for predicting torbine blade lobe was developed using experiment results and various analyses are analyzed by variance analysis and predicted mathematic model of lobe of turbine blade is obtained and by using thise model and amount of desirable lobe of blade, input parameters for optimum production are achieved. It is found that increasing of wheel speed, workpiece speed, grinding depth and slower dresser speed, have advantages for obtaining smaller lobe of blade within tolerance. Manuscript profile
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      212 - Gas Pipeline Corrosion Mapping Using Pulsed Eddy Current Technique
      M. S. Safizadeh M. Hasanian
      Oil and gas transmission pipelines are critical items of infrastructure in providing energy sources to regions and countries. Steel pipes are commonly used which can be subject to both internal and external corrosion. This paper presents an advanced nondestructive inspe More
      Oil and gas transmission pipelines are critical items of infrastructure in providing energy sources to regions and countries. Steel pipes are commonly used which can be subject to both internal and external corrosion. This paper presents an advanced nondestructive inspection technique for detection of oil-gas pipeline corrosion defect. The Pulsed Eddy Current (PEC) method has been successfully applied in corrosion detection of unburied gas pipeline without removing the insulation. First, the principles of pulse eddy current method is pointed out then, the pulsed eddy current test on a pipe is simulated by Maxwell software to obtain optimum test parameters. To test the new technique, some artificial defects are fabricated on the inner surface of a gas pipe to simulate different corrosions phenomena in practice. Three isolation layers are applied to the pipe in order to show the efficiency of PEC in the detection of wall thinning areas without removing the insulation. Manuscript profile
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      213 - Numerical Study of Effective Parameters on Cold Rolling of Tri-layers Al/St/Al and Cu/Al/Cu
      Mohamad Sedighi Edvin Golestanian Mahmoud Honarpishe
      In this paper, the rolling force and reduction ratio have been investigated in multilayer strip rolling. For this purpose, two different set of multilayers have been selected which are Al/St/Al and Cu/Al/Cu layouts. At first, the validation of the numerical analysis was More
      In this paper, the rolling force and reduction ratio have been investigated in multilayer strip rolling. For this purpose, two different set of multilayers have been selected which are Al/St/Al and Cu/Al/Cu layouts. At first, the validation of the numerical analysis was performed by using an experimental test. After validation of the numerical results, two set of multilayer layouts were simulated and the total rolling force and the reduction ratio of each layer have been obtained. Finally, the effect of friction factor between the strip and the roll on the rolling force and reduction ratio has been studied. The results show that stiffness of each layer and the thickness ratio (clad to core) have significant effects on the layers thickness reduction. Also by increasing the friction factor between roll and strip, the clad thickness reduction is decreased and the core thickness reduction and rolling force will be increased. Manuscript profile
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      214 - Analysis of Elastic-Plastic Behavior of Fiber Metal Laminates Subjected to In-Plane Tensile Loading
      H. Esfandiar S. Daneshmand M. Mondali
      Fiber metal laminates are hybrid laminates consisting of thin alternating bonded layers of aluminum and fiber/epoxy. ARALL (Aramid aluminum laminate) and GALARE (glass fiber reinforced aluminum laminate) are specific kinds of fiber metal laminates that consist of thin a More
      Fiber metal laminates are hybrid laminates consisting of thin alternating bonded layers of aluminum and fiber/epoxy. ARALL (Aramid aluminum laminate) and GALARE (glass fiber reinforced aluminum laminate) are specific kinds of fiber metal laminates that consist of thin aluminum sheets along with Kevlar/Epoxy and Glass/Epoxy composite layers, respectively. In this study, nonlinear tensile behavior of GLARE fiber metal laminates under in-plane loading conditions has been investigated. Due to the elastic-plastic behavior of aluminum layers, elastic analyses are not enough to accurately predict the tensile response. Thus, it is necessary to consider and explain the inelastic deformation behavior of GLARE laminates after yielding of aluminum alloy layers. Two appropriate analytical approaches, the orthotropic plasticity and modified classical laminated plate theories, have been used to predict the stress-strain response and deformation behavior of GLARE laminates. An acceptable agreement was observed between the two models. Results show that the GLARE behavior is almost bilinear under tensile loading condition and the tensile strength of unidirectional GLARE laminates are substantially stronger than aluminum alloys in the longitudinal direction. Manuscript profile
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      215 - Free Chattering Fuzzy Sliding Mode Controllers to Robotic Tracking Problem
      reza azarafza SAEED MOHAMMAD Hoseni MOHAMMAD FARROKHI
      Sliding mode control (SMC) is a powerful approach to solve the tracking problem for dynamical systems with uncertainties. However, the traditional SMCs introduce actuator chattering phenomenon which performs a desirable behavior in many physical systems such as servo co More
      Sliding mode control (SMC) is a powerful approach to solve the tracking problem for dynamical systems with uncertainties. However, the traditional SMCs introduce actuator chattering phenomenon which performs a desirable behavior in many physical systems such as servo control and robotic systems, particularly, when the zero steady state error is required. Many methods have been proposed to eliminate the chattering from SMCs which use a finite DC gain controller. Although these methods provide a free chattering control but they deals with only the steady state error and are not able to reject input disturbances. This paper presents a fuzzy combined control (FCC) using appropriate PID and SMCs which presents infinite DC gain. The proposed FCC is a free chattering control which guarantees a zero steady state error and rejects the disturbances. The stability of the closed loop system with the proposed FCC is also proved using Lyapunov stability theorem. The proposed FCC is applied to a two degree of freedom robot manipulator to illustrate effectiveness of the proposed scheme. Manuscript profile
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      216 - Effect of Post-Cure Time on Residual Stress Distribution in Carbon/Epoxy Laminated Composites
      Mahmood Shokrieh Saeed Akbari Roknabadi
      This research investigates the effect of the post-cure time on the residual stresses in laminated composites. Laminated composites were made of T300 carbon fibers and epoxy resin. The post-cure process was carried out at the constant temperature of 120 °C for 6 and 12 h More
      This research investigates the effect of the post-cure time on the residual stresses in laminated composites. Laminated composites were made of T300 carbon fibers and epoxy resin. The post-cure process was carried out at the constant temperature of 120 °C for 6 and 12 hours for two specimens. The slitting method was employed to determine through-thickness residual stress distribution of the composite laminates. The experiment results show that the increasing the post-cure time lead to the reduction of maximum residual stress as well as the uniformity of the residual stress distribution in laminated composites. Therefore, increasing the post-cure time is an effective way of reducing the destructive effects of residual stresses in laminated composites. Manuscript profile
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      217 - Severe Plastic Deformation of Nanostructured Cu-30%Zn Tubes at Increased Temperatures
      V. Tavakoli Ghader Faraji M. Afrasiab M. M. Mashhadi
      Severe plastic deformation (SPD) methods were developed for producing of metals and alloys with ultrafine grained (UFG) microstructures having high strength. Parallel tabular channel angular pressing (PTCAP) as a noble severe plastic deformation (SPD) method was used to More
      Severe plastic deformation (SPD) methods were developed for producing of metals and alloys with ultrafine grained (UFG) microstructures having high strength. Parallel tabular channel angular pressing (PTCAP) as a noble severe plastic deformation (SPD) method was used to produce ultrafine grained (UFG) and nanostructured Cu-30%Zn tubes. In this paper, the effect of PTCAP process temperature on the deformation microstructures and mechanical properties were investigated using experimental tests. Optical microscopy (OM) and scanning electron microscopy (SEM) were used to evaluate microstructural evolutions and fractured surface analysis. Microhardness and tensile tests were employed to mechanically characterize the PTCAP processed samples. The results showed the strength and the hardness decrease with increasing process temperature up to 100℃, but at 200℃, strength and hardness increase in comparison to that in 100℃. The rise in the strength and hardness of the sample processed at 200℃ compared to that at 100℃ is because of the partial recrystallization, forming new fine grains with high angle boundaries and twin boundaries. Twinning is dominant deformation mechanism of brass material in order to low stacking fault energy (SFE). Observations revealed that the failure mode in PTCAPed brass was a ductile rupture with the existence of deep dimples. It also indicates that the temperature has no obvious effect on the fracture mood. Manuscript profile
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      218 - Non Destructive Evaluation of Glass-Epoxy Composite using Impact-echo Method
      MohammadMahdi Amiri M. Tabatabaee Ghomi Gh. Liaghat
      In this paper a new method for Nondestructive testing or Nondestructive evaluation is proposed for Glass-Epoxy composite. For this purpose, impact-echo is used to evaluate the properties of composite materials, detecting internal defects and thickness measurement. In th More
      In this paper a new method for Nondestructive testing or Nondestructive evaluation is proposed for Glass-Epoxy composite. For this purpose, impact-echo is used to evaluate the properties of composite materials, detecting internal defects and thickness measurement. In the impact-echo method a steel ball impacts on a composite plate and generates stress waves or P-waves which will be transferred into the plate. The results show that impact response of the composite plate for dominant thickness frequency for measuring thickness and locating the defect is in agreement with the normal measurement. Results represent that this method could be used for thickness measurement and flaw detection of Epoxy-Glass composites with a reasonable accuracy. Manuscript profile
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      219 - Numerical simulation of turbulent flow around an airfoil with blunt trailing edge aerodynamic characteristics modification of this airfoil with base and aerodynamic cavity
      H Sayadi a.r. shateri
      This paper is a computational study of the behavior of aerodynamics  characteristics of an airfoil with blunt trailing edge and  studies the effects aerodynamic performance caused by modifications made to the trailing edge. Blunt trailing edge airfoils are of interest i More
      This paper is a computational study of the behavior of aerodynamics  characteristics of an airfoil with blunt trailing edge and  studies the effects aerodynamic performance caused by modifications made to the trailing edge. Blunt trailing edge airfoils are of interest in the engineering of large wind turbine blades because they allow for a strong structure with a high aerodynamic lift to structural weight ratio. Blunt trailing edge airfoils would not only provide a number of structural benefits, such as decreased structural volume and ease of fabrication and  handling, but they have also been found to improve the lift characteristics of thick airfoils. the incorporation of blunt trailing edge airfoils would allow blade designers to more freely address the structural demands without having to sacrifice aerodynamic performance. These airfoils do have the disadvantage of generating high levels of drag as a result of the low-pressure steady or periodic flow in the near-wake of the blunt trailing edge. Also vortex shedding in this airfoils, induces fluctuating loads and radiated noise. In the present investigation, we tested the effects of two cavities on the base drag and wake of an airfoil with blunt trailing edge. In two-dimensional subsonic flows, any method that increases the base pressure of the airfoil with blunt trailing edge consequently reduces the base drag. When the cavity is introduced to the trailing edge, the base pressure increases. Also the cavity caused trapping and stabilizing the vortex Manuscript profile
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      220 - Effects of tool material on the machinability of titanium (Grade-5) alloy by using RSM
      kali Dass
      This paper presents the findings of experimental investigations into the effects of cutting speed, feed rate, depth of cut and approach angle on the machinability of titanium (Grade-5) alloy. Also the comparison for the two different cutting materials inserts polycrysta More
      This paper presents the findings of experimental investigations into the effects of cutting speed, feed rate, depth of cut and approach angle on the machinability of titanium (Grade-5) alloy. Also the comparison for the two different cutting materials inserts polycrystalline diamond (PCD) and cubic boron nitride (CBN) with similar tool geometry for similar machining parameters is also carried out. Design of experiment technique i.e. response surface methodology (RSM) has been used to accomplish the objectives of the experimental study. The experimental plan for four factors at three level using face centre, centred composite design (CCD) was employed. The results indicated that the approach angle as a dominant factor on the surface roughness and the tangential force evaluation as machinability criteria .The PCD insert showed that in comparison to CBN cutting inserts have better surface finish and smaller cutting force for the level of parameters considered for investigations in machinability study of Titanium (Grade-5) alloy. Manuscript profile
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      221 - An Experimental Investigation of the Effects of Fiber Laser Percussion Drilling: Influence of Process Parameters
      Mahmoud Moradi Alireza Mohazab Pak Ali Khorram
      This study is focused on investigating the parameters of laser percussion drilling process of nickel-base super alloy Inconel 718 with thickness of 1 mm. Fiber laser with the power of 500 watts was used as the laser source. Laser pulse frequency, duty cycle, laser power More
      This study is focused on investigating the parameters of laser percussion drilling process of nickel-base super alloy Inconel 718 with thickness of 1 mm. Fiber laser with the power of 500 watts was used as the laser source. Laser pulse frequency, duty cycle, laser power, focal point position, were assumed as the laser drilling process variables. The hole geometry features, i.e. entrance hole diameter, circularity of entrance hole, and hole taper were measured. The results indicated that pulse frequency of laser has a direct influence on the entrance hole diameter. Increasing the duty cycle leads to increases in hole taper. By increasing the laser power, entrance diameter and hole taper increases. Manuscript profile
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      222 - Thermo-mechanical nonlinear vibration in nano-composites polyethylene shell reinforced by CNT's embedded elastic
      morteza raminnia
      In this study, thermo-mechanical nonlinear vibration of a polyethylene (PE) cylindrical shell embedded in an elastic foundation was investigated. The shell is reinforced by armchair Carbon nanotubes (CNTs) where characteristics of the equivalent composite being determin More
      In this study, thermo-mechanical nonlinear vibration of a polyethylene (PE) cylindrical shell embedded in an elastic foundation was investigated. The shell is reinforced by armchair Carbon nanotubes (CNTs) where characteristics of the equivalent composite being determined using Mori-Tanaka model. The elastic medium is simulated using the spring constant of the Winkler-type,  . Employing nonlinear terms of strains-displacements based on Donell's theory, stress-strain relation, first order shear deformation theory and Hamilton's principal, the governing equations were obtained. Differential quadrature method (DQM) is used to calculate the nonlinear frequency of the shell. The influences of geometrical parameters, orientation angle of CNTs and elastic foundation constants on the nonlinear vibration of the shell were investigated. Results showed that the nonlinear effect represented by nonlinear frequency ratio is considerable at lower . Manuscript profile
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      223 - Analytical and Numerical Buckling Analysis of Carbon Nanotube Reinforced Annular Composite Plates
      Esmail Asadi J. E. Jam
      The buckling analysis of annular composite plates reinforced by carbon nanotubes subjected to compressive and torsional loads are studied in this paper. The Mori-Tanaka method is employed to calculate the effective elastic modulus of composites having aligned oriented s More
      The buckling analysis of annular composite plates reinforced by carbon nanotubes subjected to compressive and torsional loads are studied in this paper. The Mori-Tanaka method is employed to calculate the effective elastic modulus of composites having aligned oriented straight CNTs. The effects of CNTs volume fractions, orientation angles, boundary conditions and geometric ratio of plate are discussed. The results are calculated by analytical method based on classical plate theory and FE methods using ANSYS software and third order shear deformation theory for moderately thick laminated plates. It is found that the stability of plate increases as the thickness or inner to outer ratio rises and when the CNTs arranged in the circumferential direction the highest buckling load is achieved. Manuscript profile
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      224 - Time-Dependent Reliability Analysis of Mechanical Structures using an Analytical Approach
      Mohammad Reza Moarefzadeh
      Time-dependent reliability analysis of mechanical structures is concerned by the use of an outcrossing approach. In this approach the so-called outcrossing rate plays a critical role and thus it is important to estimate it as straight ward as possible. Despite the avail More
      Time-dependent reliability analysis of mechanical structures is concerned by the use of an outcrossing approach. In this approach the so-called outcrossing rate plays a critical role and thus it is important to estimate it as straight ward as possible. Despite the availability of a variety of methods to estimate this rate in the literature, still more general and at the same time less sophisticated approaches are desired. In this paper, an analytical method is proposed to evaluate the required outcrossing rate in which the basics of "Parallel System Reliability Formulation" in the framework of directional simulation are used. To indicate the accuracy and efficiency of the method, it is applied to carry out the reliability analysis of a hydrokinetic turbine blade. Since the random variables/processes involved in this analysis possess a set of extremely different variances (and thus make a so-called "non-proportional space); it is shown that the proposed method is also capable to satisfactorily employ a technique of directional importance sampling in order to prohibit massive computations, normally required in such spaces. The results of the analysis show that the proposed method could be successfully applied for the circumstances whose involving processes may be non-stationary and whose space of random variables/processes is extremely non-proportional. Manuscript profile
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      225 - Analytical Investigation of Rupture Phenomena in Sheet Hydro-forming Process by Hemispherical Punch
      Alireza Naddaf Oskouei Mohammad Reza Elhami Iman Karami Fath
      Rupture and wrinkling are two prevalent phenomena that happen in hydro-forming process. Many efforts have been made to achieve the upper and lower bounds for the pressure related to rupture and wrinkling of sheet, respectively. The aim of this investigation is to improv More
      Rupture and wrinkling are two prevalent phenomena that happen in hydro-forming process. Many efforts have been made to achieve the upper and lower bounds for the pressure related to rupture and wrinkling of sheet, respectively. The aim of this investigation is to improve the upper bound of fluid pressure in hydro-forming process by hemispherical punch. In this article, analytical study of the upper bound of fluid pressure based on new assumption of Hill theory is presented. Next, governing equations of the process is derived; and numerical methods are used to solve these equations. In this process, the effect of material and geometric properties on the upper bound pressure is investigated. The results then are compared with experimental and theoretical based on Tresca criterion. The investigation on the effect of geometry and material shows that increasing of the sheet thickness raises the upper bound pressure. Moreover, the reduction of sheet to punch diameter ratio leads to increase of the upper bound pressure. Decrease of the friction force as well as increase of the anisotropic coefficient both causes the rise of upper bound pressure. Finally, the increase of work hardening parameter leads to the rise of rupture place. Manuscript profile
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      226 - Study on heat generation and distribution during friction stir welding of AA1100 aluminum alloy
      Hamed Aghajani Derazkola Hamed Jamshidi Aval
      In this article effects of friction stir welding (FSW) tool rotational and traverse speeds were studied on heat generation and temperature distribution in welding zone of AA1100 aluminium alloy. Computational fluid dynamics method was used to simulate the process with c More
      In this article effects of friction stir welding (FSW) tool rotational and traverse speeds were studied on heat generation and temperature distribution in welding zone of AA1100 aluminium alloy. Computational fluid dynamics method was used to simulate the process with commercial CFD Fluent 6.4 package. To enhance the accuracy of simulation in this Study, the welding line that is located workpieces interface, defined with pseudo melt behaviour around the FSW pin tool. Simulation results showed that with increase of FSW tool rotational speed, the generated heat became more and dimensions of the stir zone will be bigger. The calculation result also shows that the maximum temperature was occurred on the advancing side. The computed results showed that with increasing tool linear speeds the heat generation experienced growth down trend. With increasing traveling speeds the time to reach maximum temperature in stir zone growth but the tool rotational speed dose not effect on time to reach maximum temperature. The model outcomes shows that more than 85% total heat was produced by tool shoulder and the maximum heat with selected parameters in this study was 801 kelvin degrees. Manuscript profile
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      227 - Design and implementation of feedback linearization control method to determine the DLCC of 6R manipulator
      Leila Alizadeh Saravi Moharam Habibnejad Saeed Rafee Nekoo
      In this study, feedback linearization (FL) for 6R manipulator is designed, simulated and implemented. The presented input-output FL controller has achieved the desired performance for the complicated nonlinear terms in the arm’s dynamic equations. Simulations were used More
      In this study, feedback linearization (FL) for 6R manipulator is designed, simulated and implemented. The presented input-output FL controller has achieved the desired performance for the complicated nonlinear terms in the arm’s dynamic equations. Simulations were used to test the performance of the controller for point-to-point motion as well as continuous trajectory. The results of the point-to-point motion simulations and experiments were compared, where it indicates that the proposed approach preserved smooth motion in a very short process time with good accuracy. The dynamic load carrying capacity (DLCC), which is a criterion to determine FL controller performance on 6R robot, is also investigated, based on saturated torque of the motors and allowable error bounds. Moreover, it was shown that the control law is able to accurately represent closed-loop equations and simultaneously imposed desirable behavior on 6R robot. Manuscript profile
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      228 - A thermoelasticity solution for thick cylinders subjected to thermo-mechanical loads under various boundary conditions
      Mehdi Ghannad Mohammad Parhizkar Yaghoobi
      In this paper, a thermoelasticity solution for steady state response of thick cylinders which are subjected to pressure and external heat flux in inner surface is presented. Displacement field obeys the kinematics of the first order shear deformation theory (FSDT). It i More
      In this paper, a thermoelasticity solution for steady state response of thick cylinders which are subjected to pressure and external heat flux in inner surface is presented. Displacement field obeys the kinematics of the first order shear deformation theory (FSDT). It is assumed that the temperature varies both along the length and the thickness. The variation of the temperature occurs linearly through the thickness. Using energy method, the equilibrium equations and general boundary conditions are derived for the cylinder. Based on the developed analytical solution, adequate numerical results are depicted to provide an insight into the influence of the thermal and mechanical loads and boundary conditions on thermo-mechanical behavior of cylinder. Results show that shear stresses are noticeable at boundaries; moreover, temperature, displacement fields and stresses are strongly depended on length. Furthermore, the capability of the proposed method to solve any axisymmetrically cylindrical shells with general boundary conditions and thermo-mechanical loading is proven. Manuscript profile
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      229 - Investigation of CNT Defects on Mechanical Behavior of Cross linked Epoxy based Nanocomposites by Molecular Dynamics
      farshid Aghadavoudi Hossein Golestanian* Yaghoub Tadi Beni
      Although carbon nanotubes (CNT) have been employed as reinforcements in nanocomposites, presence of nano scale defects such as Stone-Wales and vacancy defects in carbon nanotubes (CNT) weakens the mechanical properties of these materials. In this paper the effects of de More
      Although carbon nanotubes (CNT) have been employed as reinforcements in nanocomposites, presence of nano scale defects such as Stone-Wales and vacancy defects in carbon nanotubes (CNT) weakens the mechanical properties of these materials. In this paper the effects of defects in CNTs on nanocomposite elastic behavior are investigated using molecular dynamics. Stiffness matrices of CNT and nanocomposite indicated the transversely isotropic behaviour of nanocomposite molecular model. Longitudinal and transverse Young's moduli for both perfect and defected CNT/epoxy nanocomposites are determined. A comparison between the results illustrates that the number and type of CNT defects have significant effects on mechanical behaviour of nanocomposite. Based on molecular dynamics results, CNT defects significantly affect the Young's modulus particularly in the transverse direction. Comparison between molecular simulation predictions and rule of mixtures results indicates that some correlation factors must be incorporated when using the micromechanical theories at nano scales. Manuscript profile
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      230 - Dynamic Design Principles of a Thrust Stand and Methods of Improving Frequency Response
      Mojtaba Heydari Amir Alaedin Motallebi Sadegh Rahmati Ebrahim Harirbafan
      Successful development, evaluation, and qualification of propulsion systems such as turbojet and turbofan engines and rocket motors require the measurement of the performance and reliability of these systems. Thrust stands or testers are instruments for solid and liquid More
      Successful development, evaluation, and qualification of propulsion systems such as turbojet and turbofan engines and rocket motors require the measurement of the performance and reliability of these systems. Thrust stands or testers are instruments for solid and liquid motors test. These apparatuses extract the characteristics of motors such as temperature, pressure, force and torque. In this paper, the dynamic design principles of a typical thrust stand have been detailed and methods to improve dynamic response have been developed. A thrust stand should be affected by random vibrations of solid motors as slightly as possible during firing. At first some Power Spectral Density (PSD) of three kinds of solid motors has been calculated by MATLAB codes. Then a number of tester structures by Solidworks have been designed and their dynamic responses have been determined by ANSYS codes. An attempt has been made to improve dynamic responses through changing the structure. Results showed that just some models could be improved. Increase of natural frequencies protects the structure from motors random vibrations. Truss structure is a good choice for testers. Decrease of mass, using different types of tube sections and short members are effective methods for improving dynamic responses. Manuscript profile
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      231 - Laboratory Investigation of Austenitic Stress Relieved Spring
      Yaser Moghani Crus Aghanajafi Mehdi Ahmadi
      Springs are the mechanical parts which have many application in industries. Static and dynamic forces cause relaxation in these parts so that they lose some of their free length and reaction force. Springs constant are very important in airplane and vailway industry sin More
      Springs are the mechanical parts which have many application in industries. Static and dynamic forces cause relaxation in these parts so that they lose some of their free length and reaction force. Springs constant are very important in airplane and vailway industry since constant and variable forces are applied to them in period time, therefore it is necessary to avoid decreasing in spring constant in this condition. In this research, at first manufactured springs were stress relieved under different temperatures. In the next step constant displacements were applied to stress relieved springs by means of designed fixture. Springs constant changes and rate of these changes during different stages of the test were obtained. Results shownd that the stress relieving at 300 ° C has the best effect on prevention of decreasing in springs constant and free length under static long-term load. Manuscript profile
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      232 - Simulation of Laminar and Turbulent Flow around Tube Bundles and Effect of Rynolds Number
      Mansour Talebi
      When flow passes over the tube bundles, energy of flow transfers to the tubes. The Fluid Induced Vibrations (FIV) imposed on the tubes is one of the important problems in analyzing the tube bundles and causes several problems. In this work, first, laminar flow around ci More
      When flow passes over the tube bundles, energy of flow transfers to the tubes. The Fluid Induced Vibrations (FIV) imposed on the tubes is one of the important problems in analyzing the tube bundles and causes several problems. In this work, first, laminar flow around circular cylinder asymmetrically in a channel is simulated. The Reynolds number is 20 and 100. The lift forces to tube are not zero. Also flow over tube bundle with twenty-four rods is simulated and flow characteristics are obtained. In this problem, the Reynolds Number is 50 to 40000 and the pressure contours, streamlines and velocity vectors are obtained. At last, turbulent flow over a tube bundle with special boundary condition is calculated. For turbulent modeling, the Large Eddy Simulation Method with Smagorinsky and Mix model and the Parallel programming method is used. Flow pattern and characteristics are obtained. Numerical results show a very good agreement with experimental results and reveal interesting flow behavior which is applicable to steam generators of nuclear power plants. Manuscript profile
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      233 - Analysis of the Dynamical Behavior of the Delay Mechanism in a Projectile Motion Controller, Using 3D Finite Element Simulation
      Salman Naderi Mehdi SalmaniTehrani Kourosh Hasanpour
      In this paper, dynamical behavior of the delay mechanism of a special projectile controller is studied, using 3D finite element simulation. The controller considered here is among of high-acceleration mechanical controllers. Due to high linear and angular accelerations More
      In this paper, dynamical behavior of the delay mechanism of a special projectile controller is studied, using 3D finite element simulation. The controller considered here is among of high-acceleration mechanical controllers. Due to high linear and angular accelerations of the projectile and also explosion risk, experimental investigation is very limited and almost impossible. So, numerical simulation is a valuable tool for designing of this kind of controllers. In the simulations here, the metal coil and its ring belt are the deformable parts of the model, while other parts are assumed to be rigid. Plastic deformation of these deformable parts, during the projectile motion, has a very important effect on the proper operating of the controller. To study the effect of coil material properties, a bilinear stress-strain curve with different yield stress was assumed. The simulation results show that there is an optimum yield stress for the metal coil, by which the appropriate operation of controller may be reached. For the special controller considered here, this optimum yield stress is about 285(MPa). All simulations made use of ABAQUS commercial software. Manuscript profile
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      234 - Prediction of the Subsurface Crack Growth Lifetime in Railroad Wheel of the Iranian Railway System
      Rahmatollah Ghajar Javad Alizadeh
      In the last decade, decrease of the wear rate, increase in the axel load, and the velocity of the trains have changed the main damage mechanism of railway wheels from wear to rolling contact fatigue (RCF). RCF may lead to surface and subsurface cracks. The interaction b More
      In the last decade, decrease of the wear rate, increase in the axel load, and the velocity of the trains have changed the main damage mechanism of railway wheels from wear to rolling contact fatigue (RCF). RCF may lead to surface and subsurface cracks. The interaction between wear and RCF, removes the surface cracks, but the subsurface crack propagate gradually, and may lead to deeper and more dangerous fractures. In this study, by considering an elliptical subsurface crack, the lifetime of an Iranian railway system wheel has been predicted using FEM, and under RCF condition. To this end, a 3D model of a cracked R7T wheel with 920mm diameter in contact with UIC60 rail has been prepared and analyzed in Abaqus FEM software. The histories of the stress intensity factors of the subsurface crack have been extracted in one cycle wheel rolling. Then, equivalent stress intensity factors have been calculated using Tanaka and Liu-Mahadevan models. Finally, wheel lifetime has been predicted by Walker relation. This paper provides a local criterion of critical crack length and crack growth lifetime that is essential for frequent inspections of railroad wheel. Manuscript profile
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      235 - Taylor-Couette Flow Instabilities in Journal Bearings
      Ahmad Sedaghat Saeed Jafari Iman Rouholamin
      In industry, flow instabilities are important in journal bearings at high rotational speeds. For inviscid flows between two rotating coaxial cylinders, an instability criterion was introduced by Taylor-Couette. However, viscosity may play as stabilizer or destabilize in More
      In industry, flow instabilities are important in journal bearings at high rotational speeds. For inviscid flows between two rotating coaxial cylinders, an instability criterion was introduced by Taylor-Couette. However, viscosity may play as stabilizer or destabilize in such flows. In this work, stability theories were reviewed for two coaxial rotating cylinders. Then, flow instability patterns, velocity, pressure, and vorticity fields were simulated using Fluent. In this method, the fluid flow was assumed laminar and by gradually increasing the relative rotational speeds between two coaxial cylinders, the critical Taylor number was calculated and compared with Taylor analytical solution. By increasing Taylor number, it is observed that vortices become stronger and instabilities appear in the form of cellular square patterns. The characteristics of these cellular square patterns were examined. Manuscript profile
    • Open Access Article

      236 - Study of Metallurgical Properties Effects and Effective Parameters on Fracture Bio-Medical Stainless Steel 316L of Human's Body
      MohamadHosein Mirghasemi MohamadReza Salmani
      In recent years, more attention is paid to stainless Steel 316L as fracture plate and fixation in human's body. Present studies are focused on surface and metallurgical properties of this material. Biocompatibelity of this material and its superior mechanical properties More
      In recent years, more attention is paid to stainless Steel 316L as fracture plate and fixation in human's body. Present studies are focused on surface and metallurgical properties of this material. Biocompatibelity of this material and its superior mechanical properties has made it the most demanded biomaterial. In this research, four different implants are investigated in three stages. Four commercial brands of implants from Germany, Switzerland, India and Iran are selected. Mechanical tests such as impact, hardness and fatigue are done on this implant, according to their corresponding standard. Scanning electronic microscope (SCM) is used to investigate surface fracture, and optical microscope for microstructure, to determine kind of fracture. Corrosion test is simulated in the body using hank solution to determine implant corrosion. Aim of this research is quality evaluation with respect to mechanical properties and failure resistance. Moreover, regardless of brand it is aimed to investigate medical/metallurgical methods to present implant failure inside the body. Iranian brand is more or less similar to Sweden and German brand, however, Indian brand is not compatible to medical standards in term of microstructure, chemical composition and mechanical properties Manuscript profile
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      237 - Multi-objective Suspension Optimization of a 5-DOF Vehicle Vibration Model Excited by Random Road Profile
      Mohammad Hasan Shojaeefard Abolfazl Khalkhali Pedram Safarpour Erfani
      The vehicle driving comfort has become one of the important factors of vehicle quality and receives increasing attention. In this paper, optimal points of vehicle suspension parameters are generated using modified non-dominated sorting genetic algorithm (NSGA-II) for Pa More
      The vehicle driving comfort has become one of the important factors of vehicle quality and receives increasing attention. In this paper, optimal points of vehicle suspension parameters are generated using modified non-dominated sorting genetic algorithm (NSGA-II) for Pareto optimization of 5-degree of freedom vehicle vibration model considering three conflicting functions simultaneously. In this way random profile is considered for the road excitation. Objective functions are vertical acceleration of seat, relative displacement between sprung mass and forward tire and relative displacement between sprung mass and rear tire. Results are compared with the previous works. Such comparison shows good behaviour of the optimum design points proposed in this work. Manuscript profile
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      238 - Stress analysis of rotational shaft with a constant angular speed using strain gradient theory
      mostafa homayouni
      In classical mechanics, considering Hook’s law stress is a linear function of strain. While in strain gradient theory stress is a function of strain and strain differentials. In this paper, Novel formulation relating stress and strain and also new boundary conditions ar More
      In classical mechanics, considering Hook’s law stress is a linear function of strain. While in strain gradient theory stress is a function of strain and strain differentials. In this paper, Novel formulation relating stress and strain and also new boundary conditions are derived based on minimum potential energy principle. In strain gradient theory a length coefficient parameter is defined. This statistical parameter shows that material behaviour in microscopic scale depends on material dimensions. In classical elasticity dependency of the material behaviour on material size could not be described due to the lack of length coefficient parameter. Here also a total stress tensor, different from the Cauchy’s stress tensor, is defined which can be used as a total stress tensor in momentum equation. Using strain gradient theory, strain field for a rotational shaft with a constant angular speed is analytically studied. Knowing displacement field, total stress tensor also can be computed. In the derived displacement field in addition to two Lame constants there is also a material constant. Formulations based on strain gradient theory turn to those of classical mechanics if length coefficient is neglected. Results of stress analysis using strain gradient theory and those of classic mechanics are compared. Manuscript profile
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      239 - Using Adaptive Meshing for Solving the Transonic Flow around Airfoils
      Sayed AmirAbbas Oloumi Mehran Ameri
      Numerical analyses have shown that successful flow simulations and the accuracy of solution noticeably depend on the number of nodes used in computational meshing. A suitable meshing should have the capability of adapting with main flow parameters. Because the number of More
      Numerical analyses have shown that successful flow simulations and the accuracy of solution noticeably depend on the number of nodes used in computational meshing. A suitable meshing should have the capability of adapting with main flow parameters. Because the number of total nodes that can be used in numerical simulation is limited, making such grid for complex flows is almost difficult, if it is not impossible. Also, the regions of large solution gradients are not defined at the beginning. So using adaptive meshing in numerical solving methods is desired. Among adaptive meshing methods, adaptive-grid redistribution and embedding methods have been considered more by researchers. Combination of these two methods is more complex than each one alone. For the purpose of analyzing the accuracy and the efficiency of solution, the combination is used for solving two dimensional Euler equations in two model problems. The results show that using combination of adaptive-grid redistribution and embedding methods requires less nodes and therefore less memory and computation time. Therefore combination of this adaptive meshing is suitable. Manuscript profile
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      240 - Combustion Modeling of Lycopodium Particles by Assuming the Temperature Difference Between Gas and Particle
      Mehdi Bidabadi AliReza Rahbari
      In this paper, the effect of temperature difference between gas and particle in the structure of premixed flames propagation in combustible system, containing uniformly distributed volatile fuel particle, in an oxidizing gas mixture, is analyzed. In the present work, eq More
      In this paper, the effect of temperature difference between gas and particle in the structure of premixed flames propagation in combustible system, containing uniformly distributed volatile fuel particle, in an oxidizing gas mixture, is analyzed. In the present work, equations based on the premixed flames of organic dust are used and then required relations for gas and particle are derived. Consequently, governing equations and needed boundary conditions are applied and an analytical method is used for solving these equations. It must be said that the structure of the flame consists of a preheat zone, a reaction zone and a convection zone. Finally, the variation of dimensionless temperature of gas and particle, particle mass friction, equivalence ratio of gas and particle, flame temperature and burning velocity of gas and particle are shown in figures. Manuscript profile
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      241 - Assessment of Foolad Mobarakeh ST14 Low Carbon Steel Sheet for Automobile Frames
      Ehsan Mohamadi Mehdi Taheri Amir Zomorodian
      In this research formability behavior and texture of St14 low carbon steels produced by Foolad Mobarakeh plant for deep drawing application had been studied. Plate textures were characterized by X-ray Diffraction technique. To evaluate formability behavior one dimension More
      In this research formability behavior and texture of St14 low carbon steels produced by Foolad Mobarakeh plant for deep drawing application had been studied. Plate textures were characterized by X-ray Diffraction technique. To evaluate formability behavior one dimensional tensile test was carried out and related parameters were recognized. Moreover Eriksson experiment and spherical pattern printing on samples were also implemented to scheme ultimate formability curve (FLD). Ultimate formability curve area was calculated using plane strain variations (FLD0). Effect of mechanical parameters on ultimate formability curve consist of yield strength, tensile strength, strain hardening coefficient, perpendicular anisotropy and texture were also studied.The results show that by increasing yield strength and tensile strength, lower area of ultimate formability curve decreases. In contrast by increasing total elongation, strain hardening coefficient and perpendicular anisotropy parameter, plate formability has been enhanced Manuscript profile
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      242 - Temperature Distribution Analysis in a Laser Heating With Different Values of Cross Section and Beam Intensities
      Mohammad Akbari
      The rapid melting of a semi- infinite body due to the absorption of a CW laser beam radiation has been studied. The enthalpy technique for the solution of phase change problems has been used in an explicit finite difference form to calculate the transient temperature di More
      The rapid melting of a semi- infinite body due to the absorption of a CW laser beam radiation has been studied. The enthalpy technique for the solution of phase change problems has been used in an explicit finite difference form to calculate the transient temperature distribution in the semi-infinite body and the growth rate of the melt pool. The technique has been modified so that it is not necessary to assign a constant temperature, Tm, to the mesh element that contains the melt front. Instead, a new value of temperature is calculated for the grid point at each time step by incorporating the energy boundary condition at the solid- liquid interface. Calculations have been carried out for laser beam with circular and elliptical profile and for a range of material translational speeds. The numerical results were compared with the experimental data. Increasing the translational speed causes the heat affected zone and the size and shape of melt pool to become smaller. Manuscript profile
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      243 - Feature Recognition of Sheet Metal Components and Strip Layout Design in Bending Progressive Dies using Fuzzy Set Theory
      Vahid Abedini Behrouz Arezou Mohsen Shakeri
      Sheet metal components design and manufacture need a great deal of experience and know-how. Strip layout design is usually done with trial and error until best design for strip layout is finally achieved. Knowledge for the system is formulated from plasticity theories, More
      Sheet metal components design and manufacture need a great deal of experience and know-how. Strip layout design is usually done with trial and error until best design for strip layout is finally achieved. Knowledge for the system is formulated from plasticity theories, experimental results, and the empirical knowledge of field experts. In this paper, an algorithm which can automatically design the bending sequence for progressive dies is described. A computer program is developed based on the algorithms and it composed of several modules, namely: feature recognition and design advisory module, flat pattern layout module and strip layout module. In the feature recognition module, all of the features of a 3-D component can be recognized automatically and checked against some manufacturability rules. In the second module, the flat pattern layout of the component is created automatically. In the strip layout module, the bending sequence is determined using fuzzy set theory. The system is developed in Visual Basic on a Solid Works platform. The software can also be used as an advisory system for die designers. Manuscript profile
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      244 - Mold Less Casting, a New Method for Droplet Based Part Manufacturing
      Mehrdad Vahdati Hamed Kalami
      In the new method of rapid manufacturing, the molten metal is dropped on a substrate, making layers after another. This method has the potentiality to be used for complicated castings which are difficult to make their molds and patterns as usual ways. In droplet-based m More
      In the new method of rapid manufacturing, the molten metal is dropped on a substrate, making layers after another. This method has the potentiality to be used for complicated castings which are difficult to make their molds and patterns as usual ways. In droplet-based manufacturing process the castings are constructed by molten metal droplets having proper flow rate, temperature and diameter. In this paper a new system is designed and constructed which makes 3D parts and patterns by depositing molten metal droplets. Raw material wire melts and droplets are generated in droplet generating head. Molten metal Droplets deposit on a high temperature bed making the first layer. Next layers place on the previous ones to shape the final arbitrary part. These droplets are surrounded by natural air. Here tin60%, lead40% alloy wire is used. it is possible to apply other materials or wires having different diameters just with a little change in system. The wire is fed in special speeds which lead to different rates of droplets leaving the nozzle. Droplets have three properties which affect the layers and depositing way. These properties are droplet temperature and volume and their deposition rate. To control them several parameters of the system must be adjusted appropriately. At first it is assumed that these machine parameters are outlet nozzle diameter and feeding wire speed and also droplet temperature which affect droplet volume and deposition rate. Droplet temperature is measured exactly where they leave outlet nozzle. Droplet volume is estimated by several experiments, which lead to learn how different machine parameters create various droplet volumes. By knowing droplet volume and feeding wire speed, droplet rate can be calculated.In this paper the design essence of the constructed droplet based manufacturing machine is told. And dependency of droplet properties to machine adjustments is studied. These studies are done to control droplet properties. By knowing droplet properties, the moving speed of CNC heating table is determined. Manuscript profile
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      245 - Investigation and Analysis of CNG Tank Mass Effects On Main Components of Vehicle Performance
      Khodadad Vahedi Reza Fathollahi MohamadReza Emam
      In addition to increment of the vehicle sprung mass, the main physical effects of addition of CNG tank to the vehicle are the longitudinal and height displacement of center of gravity, which have the most influences on the handling, braking, roll stability and spin stab More
      In addition to increment of the vehicle sprung mass, the main physical effects of addition of CNG tank to the vehicle are the longitudinal and height displacement of center of gravity, which have the most influences on the handling, braking, roll stability and spin stability of the vehicle. Increment of CNG tank mass to the sprung mass of the vehicle increases the vehicle under-steer gradient, decreases roll stability and increases stability of vehicle on the straight line and S bends; meanwhile climbing ability of the front wheels drive vehicle is decreased. Due to increment of CNG tank to the sprung mass of the vehicle, the probability of vehicle spinout is increased, when driver brakes severely. First, we investigate the main components of vehicle dynamic performances which are affected by increment of CNG tank have been clarified. By using the available data and dominated equations on vehicle dynamic behavior, the vehicle performance has been analyzed. Manuscript profile
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      246 - Investigation on Microstructure and Production of Coaxial Cable Foam Insulation using Butane Gas
      Mehdi Nazri AmirHosein Behravesh Payman Shahi
      This paper presents an investigation on the effect of temperature and raw material on microstructure of fine cellular foam used as the insulation of coaxial cables. A set up was prepared and used to produce fine cellular foamed insulation. As the physical blowing agent, More
      This paper presents an investigation on the effect of temperature and raw material on microstructure of fine cellular foam used as the insulation of coaxial cables. A set up was prepared and used to produce fine cellular foamed insulation. As the physical blowing agent, butane was used. The effect of temperature on the microstructure of polyethylene (PE) was worth to note. At high temperature, due to low melt strength, large cells with low cell density was observed. As the temperature was decreased, the number of nucleated cells was increased and also a decrese in cell size was observed. Too law a temperature, caused a decrese in number of nucleated cells. To investigate the effect of raw material on microstructure, a blend of polyethylene (LDPE-HDPE) was used. This blend, via increasing the melt strength, led to a microstructure with150 micron cell size. Finally, the attenuation property of the produced cable with optimum microstructure was compared with a same cable produced with chemical foam insulation. The results showed 17% reduction in attenuation property of the coaxial cable with physical foam insulation. Manuscript profile
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      247 - Evaluation of the using Al2O3/EG and TiO2/EG nanofluids as coolants in the double-tube heat exchanger
      Navid Bozorgan
      Abstract: In this study, Al2O3/EG and TiO2/EG nanofluids as coolants have been used in the double-tube heat exchanger. The hot solvent inlet heat exchanger must be cooled down with a specified amount. We can use nanofluids as coolants in the heat exchanger for optimizat More
      Abstract: In this study, Al2O3/EG and TiO2/EG nanofluids as coolants have been used in the double-tube heat exchanger. The hot solvent inlet heat exchanger must be cooled down with a specified amount. We can use nanofluids as coolants in the heat exchanger for optimization of the heat transfer area. Therefore, the efficacy of nanofluids as coolants is verified. Furthermore, flow rate of coolant is optimized by using the Al2O3/EG and TiO2/EG nanofluids in the heat exchanger. Thus with decreasing the heat transfer area and flow rate of the coolant, we can reduce the costs such as pumping power, fouling costs, etc in a double-tube heat exchanger. The heat transfer relations between hot solvent and nanofluids as coolants in the heat exchanger have been investigated. The results showed that the overall heat transfer coefficient was high, when the probability of collision between nanoparticles and the wall of the heat exchanger was increased under higher concentration. Consequently, we calculated the heat transfer coefficient, overall heat transfer coefficient, friction factor, pressure drop and pumping power for Al2O3/EG and TiO2/EG nanofluids used as coolants in a double-tube heat exchanger. Manuscript profile
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      248 - Potential of a Low Heat Rejection Diesel Engine with Renewable Fuels
      venkata murthy M.V.S. Krishna
      Investigations are carried out to evaluate the performance of a low heat rejection (LHR) diesel engine consisting of air gap insulated piston with 3-mm air gap, with superni (an alloy of nickel) crown and air gap insulated liner with superni insert with different operat More
      Investigations are carried out to evaluate the performance of a low heat rejection (LHR) diesel engine consisting of air gap insulated piston with 3-mm air gap, with superni (an alloy of nickel) crown and air gap insulated liner with superni insert with different operating conditions of crude jatropha oil with varied injection timing and injection pressure.  Performance parameters of brake thermal efficiency (BTE), exhaust gas temperature (EGT) and volumetric efficiency (VE) are determined at various magnitudes of brake mean effective pressure. Pollution levels of smoke and oxides of nitrogen (NOx) are recorded at the peak load operation of the engine. Combustion characteristics of the engine of peak pressure (PP), time of occurrence of peak pressure(TOPP), maximum rate of pressure rise (MRPR) and time of occurrence of maximum rate of pressure (TOMRPR) are measured with TDC (top dead centre) encoder, pressure transducer, console and special pressure-crank angle software package. Zero dimensional, multi-zone combustion model is assumed to predict combustion characteristics and validated with experimental results. Conventional engine (CE) showed deteriorated performance, while LHR engine showed improved performance with crude jatropha oil operation at recommended injection timing and pressure and the performance of both version of the engine is improved with advanced injection timing and higher injection pressure when compared with CE with pure diesel operation. Peak brake thermal efficiency increased by 4%, smoke levels decreased by 4% and NOx levels increased by 37% with vegetable oil  operation on LHR engine at its optimum injection timing, when compared with pure diesel operation on CE at manufacturer’s recommended injection timing. Manuscript profile
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      249 - Two-Phase Heat Transfer and Pressure Drop of Carbon Dioxide in Pipes
      Zahara Baniamerian Cirus Aghanajafi
      Applying two-phase flows improves heat transfer rate which is an important objective in most of applications. Due to environmental concerns and corresponding regulations, carbon dioxide ( ), naturally exists in the atmosphere, has been reintroduced as a possible replace More
      Applying two-phase flows improves heat transfer rate which is an important objective in most of applications. Due to environmental concerns and corresponding regulations, carbon dioxide ( ), naturally exists in the atmosphere, has been reintroduced as a possible replacement for the most of commonly used refrigerants in air conditioning applications. High pressure working conditions of carbon dioxides had been the only difficulty in applying it in industrial applications for many years. Nowadays, by progressing in manufacturing technologies, the mentioned difficulty can be simply solved and attempts are resumed for replacing HFCs by carbon dioxide. There are limited numbers of experiments applying carbon dioxide as working fluid and due to common laboratories restrictions, that decrease the possibilities of repetition of experiments, there are dominant differences in results of present experiments in the literature. Having specific thermo-physical characteristics, carbon dioxide behaves different from other refrigerants in two-phase conditions. Therefore applying models based on other refrigerants for simulating carbon dioxide behavior results in dominant deviations from reality. In the present article the most recent experiments on carbon dioxide is gathered and investigated from aspect of heat transfer and pressure drop. Most of internal two-phase flows reach the annular flow pattern which has further heat transfer rate in compare with other flow patterns. This issue leads us to select this flow pattern in this article. The most important objective of the present study, apart from having a review on the performed studies, is to compare carbon dioxide efficiency with that of other refrigerants. At last it will appear that applying carbon dioxide as working fluid results in much more heat transfer rate and much less pressure drop level in compare with similar conditions of other refrigerants. Manuscript profile
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      250 - Numerical and experimental study of parameters affecting metal forming using rubber pads, on parts with radius of curvature
      armin mahshidifar Abbas Vafaeesefat
      Production and preparation of many parts of the aircraft body including wings with long length, smooth form, and large radius of curvature are amongst the most important challenges in this industry. In this paper, the effective factors in the rubber pad forming method o More
      Production and preparation of many parts of the aircraft body including wings with long length, smooth form, and large radius of curvature are amongst the most important challenges in this industry. In this paper, the effective factors in the rubber pad forming method on a pieces contain curvature radius have been investigated by finite element method. The effect of variables such as curvature radius, sheet thickness, rubber pad thickness, rubber hardness, lubrication condition, spring back phenomena have been analyzed. To validate the finite elements simulation, the experimental results were compared. Then, other above-mentioned variants were studied. The obtained results indicate that there is a close differentiation between the numerical and experimental works. Moreover, the cited parameters have different effect on part quality Manuscript profile
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      251 - The Effects of Joint Clearance on the Dynamics of the 3-RPR Planar Parallel Manipulator
      Seyyed Mojtaba Varedi-Koulaei Mahdi Bamdad
      In reality, clearances in the joints are inevitable due to the defects arising from manufacturing process, design tolerances, and wearing after a certain working period. It leads to a chaotic behaviour including the impact loads which results in an unpredictable respons More
      In reality, clearances in the joints are inevitable due to the defects arising from manufacturing process, design tolerances, and wearing after a certain working period. It leads to a chaotic behaviour including the impact loads which results in an unpredictable response in the system. Since clearance introduces an additional uncontrollable degree of freedom to the manipulator, it causes error and could not be neglected in the manipulator design or analysis. In this study, the dynamic behavior of a planar mechanism with revolute joints, in the presence of clearances is investigated. The planar 3-RPR parallel manipulator with six revolute clearance joints is modelled in MSC.ADAMS software and the simulation results are presented. Moreover, the effects of clearance size on the dynamic characteristics of a planar mechanical system are analysed and compared. What is found out is the prediction of the dynamic error due to the joints clearance for this parallel robot. Manuscript profile
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      252 - Optimization of the Manufacturing Process of Natural Fibre Thermoplastic Composites in order to Minimize Warpage
      Mahmoud Shokrieh Saman Safari
      In this study, the effective factors on warpage in short fibre reinforced thermoplastic composites has been studied. First of all, the effective factors in manufacturing process were detected and then in order to decrease the number of experiments, the approach of Desig More
      In this study, the effective factors on warpage in short fibre reinforced thermoplastic composites has been studied. First of all, the effective factors in manufacturing process were detected and then in order to decrease the number of experiments, the approach of Design of Experiments has been applied. By using micromechanics theory in composites and coefficients of thermal expansion models, a dedicaded code has been used to set up the experimnts. Then the effect of each significant parameter drived and the most effective parameter on warpage phenomenon is detected. At last by using Taguchi's optimization method, warpage of short fibre reinforced thermoplastic composites has been minimized. Manuscript profile
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      253 - Investigations on Surface Integrity and Electrochemical Behavior of Machined Co-Cr-Mo Bio-implant Alloy
      K. A. Jagtap R. S. Pawade K. V. Giradkar
      A decisive constraint for the long-term stability of the artificial joint is to minimize the release of debris particles. The wear/debris induced osteolysis and aseptic loosening are the result of failure of metal-on-metal joint implants. SPD processes have been used to More
      A decisive constraint for the long-term stability of the artificial joint is to minimize the release of debris particles. The wear/debris induced osteolysis and aseptic loosening are the result of failure of metal-on-metal joint implants. SPD processes have been used to adapt the surface integrity properties by generating ultrafine or even nano-sized grains and grain size gradients in the surface region of work materials. These fine grained materials often show enhanced surface integrity properties and improved functional performance (wear resistance, corrosion resistance, fatigue life, etc.) compared with their predictable coarse grained counterparts. To identify the implant material’s post machined behaviour in biological environment, the experiments were planned by precision CNC turning process and accordingly post machined surfaces were analyzed by contact type and electrochemical measurement processes. The work includes effect of machining parameters on machined surface roughness and corrosion rate by an electrochemistry of Co-Cr-Mo bio-implant alloy. The minimum machined surface roughness value 0.450 µm shows minimum corrosion rate as 0.00002 mm/year. It is also shown that feed rate is having predominating effect on machined surface roughness and rake angle is on corrosion rate of Co-Cr-Mo bio-implant alloy. Manuscript profile
    • Open Access Article

      254 - An anisotropic axisymmetric model for wrought magnesium alloys
      mohamad ali khayamian hamid jahed
      The global environmental concerns have put the light weighting of structures on the fore front of the research in transportation industry. Among other light weight alloys, the transportation industry is considering magnesium intensive light body-in-white structure in au More
      The global environmental concerns have put the light weighting of structures on the fore front of the research in transportation industry. Among other light weight alloys, the transportation industry is considering magnesium intensive light body-in-white structure in automotive applications. Although the research in modeling technique areas is very active, a suitable practical model mimicking the severe asymmetry and anisotropy of magnesium is lacking. Loading-unloading behavior of wrought magnesium alloy over a wide range of strain has been obtained experimentally and is presented here.  It is shown that while the material behaves elastically isotropic, it shows a different yield in tension and compression with a high Bauschinger effect. This is attributed to the magnesium multiple deformation mechanisms of slip, extension/contraction twinning, and de-twinning resulting in an asymmetric yield and a direction dependent performance.  Up-to-date there are no plasticity model commercially available that can capture these behavior. Therefore, it is necessary to develop a simple and efficient model that can serve as benchmarking tool for plasticity models evaluation. Such model is presented in this paper. The axisymmetric elastic-plastic model of Jahed and Dubey (1997) has been extended to wrought magnesium alloys. An asymmetric yield function is adapted and the obtained behavior in loading and unloading is directly incorporated in the solution process. It is shown that the results are significantly different from isotropic assumptions. Manuscript profile
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      255 - The Effect of Operational Cutting Parameters in the Wire Electro Discharge Machining (WEDM) on Micro Hardness of Alloy Surface Layer
      AliAkbar Lotfi Saeed Daneshmand Saeed Adib Nazari
      In this study, as for the re-casting, surface alloying and re-solidification layer of this alloys at the work piece level machining with Wire Electro discharge machining (WEDM), changes of surface micro hardness with changes of operational parameters has been studied. T More
      In this study, as for the re-casting, surface alloying and re-solidification layer of this alloys at the work piece level machining with Wire Electro discharge machining (WEDM), changes of surface micro hardness with changes of operational parameters has been studied. Therefore, study shows using surface alloying phenomena with the diffusion of wire material into the machined surface and selection of operational parameters and suitable materials for wire cutting, surface mechanical properties can be modified simultaneously with the workpiece machining process. Also Shown in this study, by changing operating parameters such as peak power and open circuit voltage, the diffusion of wire material into the workpiece surface layer is increased, whereas with increasing pulse off time and dielectric flushing pressure, the diffusion of wire material into the workpiece surface layer is decreased. At last with increasing these parameters also change of micro hardness surface layer accompanied by a change alloy surface layer formed on the surface. Manuscript profile
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      256 - Effect of AFM Cantilever Geometry on the DPL Nanomachining Process
      A. R. Norouzi M. Tahmasebipour
      With the development of micro and nanotechnology, machining methods at micro and nanoscale have now become interesting research topics. One of the recently-proposed methods for sub-micron machining, especially nanomachining, is dynamic plowing lithography (DPL) method. More
      With the development of micro and nanotechnology, machining methods at micro and nanoscale have now become interesting research topics. One of the recently-proposed methods for sub-micron machining, especially nanomachining, is dynamic plowing lithography (DPL) method. In this method an oscillating tip is used for machining soft materials such as polymers. The geometry of the oscillating beam and its vibrational properties are the most important parameters in this nanomachining process. In this study, effects of the AFM beam geometry on its stiffness coefficient, resonant frequency, beam stability, and the maximum stress created in the beam structure were investigated for 12 different general shapes using the finite element method. The obtained results indicate that circular and square membranes are the most favourable AFM cantilever geometries because these structures provide higher machining force and speed; while for noisy conditions and environments, straight and V-shaped beams are recommended (because of their higher stability factor) for the DPL nanomachining process. Manuscript profile
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      257 - Modeling and Simulation of Nano Structures with Using Molecular Dynamics
      Ali Kafash Houshyar Negin Beryani Saeed Daneshmand
      According to recent achievements in Nano technology we can see its effects in different engineering fields. In Nano manufacture process the first essential step is modeling coordinately in order to make it available different software are developing for this propose. In More
      According to recent achievements in Nano technology we can see its effects in different engineering fields. In Nano manufacture process the first essential step is modeling coordinately in order to make it available different software are developing for this propose. In this paper Nano modeling for two papers is developed first understanding structure in Nano and micro size and second simulations of molecular movements in Nano size. In this paper fundamental concepts of both methods are discussed and MATLAB based software is developed for this purpose. In first step cubic and cylindrical shapes are modeled by the software then some simulations in which temperature’s effect modeled are presented. In second part a 2D model based on molecular dynamics is presented wit using this model we can find effects of force on AFM cantilever’s tip which has a great important in different Nano manufacture areas. Manuscript profile
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      258 - An Intelligent Knowledge Based System for CO2 Laser Beam Machining for Optimization of Design and Manufacturing
      Morteza Sadegh Amalnik
      This paper addresses the concept of CO2 Laser beam machining (LBM) and development of intelligent knowledge base system (IKBS) for CO2 LBM. Feature based design is used for acquiring design specification. For optimization of laser beam machining computer based concurren More
      This paper addresses the concept of CO2 Laser beam machining (LBM) and development of intelligent knowledge base system (IKBS) for CO2 LBM. Feature based design is used for acquiring design specification. For optimization of laser beam machining computer based concurrent engineering environment is used. The IKBS is linked to feature base cad system. The IKBS is also linked to material database which holds attributes of more than 50 types of materials. It is also linked to Laser database which holds attributes of 3 types of laser machine. IKBS is also linked to Laser machine variables and parameters. For each design feature, IKBS provides information such as machining cycle time and cost and machining rate. By changing machine parameters, we can optimize machining cycle time and cost and cutting rate. The IKBS can be used as an advisory system for designers and manufacturing engineers. It can also be used as a teaching program for new CO2 laser operators in computer based concurrent engineering environment. Manuscript profile
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      259 - Characterization of Stress Concentration in Thin Cylindrical Shells with Rectangular Cutout Under Axial Pressure
      O. Sam Daliri M. Farahani
      In this paper, stress concentration in the thin cylindrical shell with rectangular cutout subjected to uniform axial pressure was investigated using a parametric finite element model. Design of experiments techniques and statistical analysis was used to provide a model More
      In this paper, stress concentration in the thin cylindrical shell with rectangular cutout subjected to uniform axial pressure was investigated using a parametric finite element model. Design of experiments techniques and statistical analysis was used to provide a model for characterizing the critical stress in these components. The influences of the geometrical parameters and their combinations were studied in detail. It was observed that the length to width ratio of the cutout, the length and the radius to thickness ratio of the cylinder were significant parameters for describing the stress concentration around the cutout, respectively. By increasing the length to width ratio as a main effective geometrical factor in the stress concentration, the stress around the cutout was increased significantly. Based on the statistical analysis conducted in this study, a formula was derived which can predict the stress concentration around the cutout of the cylinder with the accuracy more than 84% (R2 = 88.7%, R2pred = 84.6%, R2adj= 86.7%). Manuscript profile
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      260 - Investigation of Effects of Stress Relieving Parameters on Reduction of Austenitic Spring Free Length During Periodic Loading
      Yaser Moghani Mehdi Ahmadi Najafabadi Cirus Aghanajafi
      After springs production, different residual stresses are created in the inner and outer surfaces of spring wires. Some of these stresses for example compressive residual stresses are useful and some are harmful. The effects of vareation of these stresses are caused spr More
      After springs production, different residual stresses are created in the inner and outer surfaces of spring wires. Some of these stresses for example compressive residual stresses are useful and some are harmful. The effects of vareation of these stresses are caused spring relaxation and decrising in their free length when they are loaded intermittently. For review this phenomena in this research, first a test device with 0.5 Hz operational frequency was made. Then with the idea of operation mechanism of milling machines dividing attachment and cams mechanism and performance, a fixtures was designed and manufactured in order to apply displacement and preload to springs. In the next step manufactured springs were stress relieved under different temperatures and times.After that they were loaded intermittently and their free lengths after 10,000 cycles were measured. Investigation on tests results showed the effects of changes in temperature and time of stress relieving on springs free length decreasing. Two approximate equations with first and second degree were extracted from experimental data. Finally, optimal operation of stress relieving was obtained . Manuscript profile
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      261 - Analytical and Numerical Investigation of the Deformation Length in Roll Forming Process of Circular Tubes
      Mehdi SalmaniTehrani Moslem Bahrami
      Deformation Length is one of the most important parameters in cold roll-forming process, which plays a fundamental role in determining the inter-distance between the stations and rate of deformation. Deformation length was first introduced by Bhattacharyya. He also obta More
      Deformation Length is one of the most important parameters in cold roll-forming process, which plays a fundamental role in determining the inter-distance between the stations and rate of deformation. Deformation length was first introduced by Bhattacharyya. He also obtained a closed-form relation for this length in roll-forming of symmetric channel section. In this paper, deformation length in the roll forming of the circular cross section is examined and determined. To do this, analytical method and finite element simulation are used. The analytical method presented in this paper is based on the approach of Bhattacharya's suggestion. Due to the fact that the deformed sheet geometry is more complex, hence the related equations of strain and deformation energy would become more complex too, and therefore analytical solution is going to be more difficult compared to symmetric channel section. Using the present analytical method, deformation length is computed for a specific numerical case study and the analytical results are compared with the results of finite element simulation of the ABAQUS commercial software. Correlation between the analytical and finite element simulation results demonstrates the validity of the presented analytical method. In the end, the effects of forming parameters on the deformation length are studied. Manuscript profile
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      262 - Failure and Stress Analysis of Glass Fiber Reinforced Laminated Composite Pinned Joints
      Suresh Babu Valeru Tarasasanka Cherukuri
      In this study, behavior of pin-loaded glass fiber reinforced with polyethylene laminated composites with different stacking sequence and different dimensions has been observed experimentally and stress analysis was performed using ANSYS software. The aim is to investiga More
      In this study, behavior of pin-loaded glass fiber reinforced with polyethylene laminated composites with different stacking sequence and different dimensions has been observed experimentally and stress analysis was performed using ANSYS software. The aim is to investigate stresses, failure strength and failure mode of composite laminates containing a pin loaded hole when the material exhibits linear elastic behavior. The logical methodology for modeling the joint problem uses the two major steps:, failure analysis and stress analysis. Failure analysis is done experimentally and stress analysis is done by using ANSYS software. To investigate and verify to the analytical predictions of mechanical behavior, and to observe the failure characteristics of the pin-loaded composites, a series of experiments was performed with eight different material configurations, in all, over 36 specimens. The edge distance-to-hole diameter ratios and width-to-hole diameter ratios of plate were changed. For this part of study, layered composite materials were manufactured in our Institute. The stress distribution around the hole in pin-loaded glass-fiber with polyethylene laminate was performed, and In addition, ANSYS was performed to compare effects of different boundary conditions used to simulate the pin load on stress distributions around the hole. Manuscript profile
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      263 - Effects of Scan Direction and Orientation on Mechanical Properties of Laser Sintered Polyamide-12
      Jack Nelson Greg Galloway Allan Rennie Tom Abram Graham Bennett
      In order to understand the impact of layer-wise scanning direction in the Selective Laser Sintering process, test coupons were manufactured for mechanical testing from DuraForm™ Polyamide powder. The effects of laser energy density, varying between 0.003 and 0.024 J/mm2 More
      In order to understand the impact of layer-wise scanning direction in the Selective Laser Sintering process, test coupons were manufactured for mechanical testing from DuraForm™ Polyamide powder. The effects of laser energy density, varying between 0.003 and 0.024 J/mm2 were examined in test specimens rotated 90º through the Z axis. SLS machines do not always facilitate ‘cross-hatching’ of layers and therefore orientation has a major influence on part quality. When employed, the cross-hatching technique scans successive layers perpendicularly to the previous. Studying how parts perform with scan lines in a common direction, will assist in the understanding of how SLS parts behave in practice. Results showed that physical density, tensile strength and elongation rose with energy density up to 0.012 J/mm². This initial rise was due to a continued improvement in particle fusion with increasing energy density. Above 0.012 J/mm², these properties started to decline at different rates depending on their orientation (scan direction) on the part bed. Specimen’s oriented perpendicularly to the X axis exhibited a greater elongation at the expense of tensile strength, when compared to parallel specimens. Manuscript profile
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      264 - An Investigation on Hydrogen Embrittlement of the Cr-Si Spring Steel Using Slow Strain Rate Test and Weibull Model
      Hamid Nazemi Maryam Ehteshamzadeh
      In this paper, the hydrogen embrittlement of the high strength Cr-Si spring steel with after Zn-12%Ni electroplating, have been evaluated. Slow strain rate test with 3.34 × 10-6 sec-1 strain rate was performed, and the hydrogen embrittlement index of the different sampl More
      In this paper, the hydrogen embrittlement of the high strength Cr-Si spring steel with after Zn-12%Ni electroplating, have been evaluated. Slow strain rate test with 3.34 × 10-6 sec-1 strain rate was performed, and the hydrogen embrittlement index of the different samples was calculated. The effect of shot peening before plating and the baking after plating and also the effect of applying a nickel interlayer by electroless method, is examined by using the weibull statistical model. The results showed that alloying Zn with nickel considerably reduce the diffusion of hydrogen on the substrate steel structure. So that it increases the average failure time of samples from 4.9 hours for pure Zn to 8.7 hours for Zn- Ni. By applying nickel interlayer, the failure time increased to 11.15 hour. Also by shot peening process before electroplating, the average failure time increased to 12.7 hours which showed the least amount of hydrogen embrittlement among the studied samples. Baking after the electroplating of Zn-Ni samples without interlayer, leaded to an increase in the failure time to 10.15 hours. While baking in samples containing nickel interlayer, showed the opposite effect, reducing the failure time to 8.15 hours. Manuscript profile
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      265 - Investigation on Stress Distribution of Functionally Graded Nanocomposite Cylinders Reinforced by Carbon Nanotubes in Thermal Environment
      Mohammad morad Sheikhi Hamidreza Shamsolhoseinian Rasool Moradi dastjerdi
      In this paper, stress and displacement fields of functionally graded (FG) nanocomposite cylinders reinforced by carbon nanotubes (CNTs) subjected to internal pressure and in thermal environment are investigated by finite element method. The nanocomposite cylinders are c More
      In this paper, stress and displacement fields of functionally graded (FG) nanocomposite cylinders reinforced by carbon nanotubes (CNTs) subjected to internal pressure and in thermal environment are investigated by finite element method. The nanocomposite cylinders are combinations of single-walled carbon nanotubes (SWCNTs) and isotropic matrix. Material properties are estimated by a micro mechanical model (Rule of mixture), using some effective parameters. In this simulation, an axisymmetric model is used; uniform and four kinds of linear functionally graded (FG) distributions of CNTs along the radial direction is assumed, in order to study the stress distributions. Effects of the kind of distribution and volume fraction of CNT and also, thermal environment, and geometry dimension of cylinder are investigated on the stress and displacement distributions of the FG nanocomposite cylinders. It is shown that, CNTs distribution and environment temperature are important factors on the stresses distribution of the nanocomposite cylinders. Manuscript profile
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      266 - Application of Grey Relational Analysis for Optimizing Weld pool geometry parameters of Pulsed Current Micro Plasma Arc Welded AISI 304L stainless steel sheets
      SIVAPRASAD KONDAPALLI SRINIVASA RAO CHALAMALASETTI NAGESWARA RAO DAMERA
      Pulsed Current Plasma Arc Welding (PCPAW) is one of the most widely used welding processes in sheet metal manufacturing industry. In any fusion arc welding process, the weld bead geometry plays an important role in determining the mechanical properties of the weld and h More
      Pulsed Current Plasma Arc Welding (PCPAW) is one of the most widely used welding processes in sheet metal manufacturing industry. In any fusion arc welding process, the weld bead geometry plays an important role in determining the mechanical properties of the weld and hence quality of the weld.  Moreover, the geometry of weld bead involves several simultaneously multiple quality characteristics such as front width, back width, front height and back height, which must be closely monitored, controlled and optimized. This paper presents the optimization of the PCPAW process by using the grey relational analysis considering the aforementioned quality characteristics. The specific targets are maximum front width and back width, minimum front height and back height. Experiments were performed under different welding conditions such as peak current, back current, pulse rate and pulse width using AISI 304L stainless steel sheets of 0.25mm thick. An Response Surface Method (RSM) based Central Composite Design (CCD) experimental design is used to conduct experiments. Optimal welding parameters were determined by the grey relational grade obtained from the grey relational analysis. Optimal results have been verified through confirmation experiments. Manuscript profile
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      267 - Free Vibration Analysis of S-FGM-Coated and S-FGM-Undercoated Plates with Classical Boundary Conditions
      Reza Amininejad AliReza Mohajerani AliReza Samsami Shahab Amininejad
      This work presents free vibration analysis of laminated rectangular plates with classical boundary conditions based on the classical plate theory (CPT). The first involves an S-FGM plate with different boundary conditions. Then involves a two-layer plate in which an S-F More
      This work presents free vibration analysis of laminated rectangular plates with classical boundary conditions based on the classical plate theory (CPT). The first involves an S-FGM plate with different boundary conditions. Then involves a two-layer plate in which an S-FGM layer is coated on a homogeneous substrate with classical boundary conditions, simply called an S-FGM-coated plate; the other involves a three-layer plate in which an S-FGM employed for inter-medium layer and different homogeneous materials are in top and bottom layers with classical boundary conditions; this is called an S-FGM-undercoated plate. The Young’s modulus of FGM plates is assumed to vary in the thickness direction and the poisson's ratio remain constant throughout the FGM plate. The material gradations in FGM portion of laminate structures follow sigmoid functions, therefore these plates are called S-FGM. For multi-layer structures, the calculations of the quantities defined herein become complex, therefore, a method is used to easily and efficiently calculating them in this investigation. The results are first compared with the ABAQUS software, showing an excellent agreement. Then frequency parameters of three plates for different boundary conditions and aspect ratios are graphically presented for a wide range of gradient index. Manuscript profile
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      268 - Frequency Analysis of a Cable with Variable Tension and Variable Rotational Speed
      Moharam Habibnejad AliAkbar Alipour
      In this paper coupled nonlinear equations of motion of a suspended cable with time dependent tension and velocity are derived by using Hamilton’s principal. A modal analysis for a stationary sagged cable is initially carried out in order to identify the dynamic sy More
      In this paper coupled nonlinear equations of motion of a suspended cable with time dependent tension and velocity are derived by using Hamilton’s principal. A modal analysis for a stationary sagged cable is initially carried out in order to identify the dynamic system. The natural solution is directed to compute the natural frequencies and mode shapes of the free vibration of a suspended cable. Natural frequencies and mode shapes are plotted versus a dimensionless parameter l, known as static sag character. In case of moving cable, the tension force and the rotary speed of the pullies are assumed to be sinusoidal functions. Galerkin mode summation approach is utilized to discretize the nonlinear equations of motions. Numerical simulations are carried out in the time domain. A frequency analysis is then carried out and effects of the frequency of tension force and rotary speed on the belt dynamic responses are studied. Manuscript profile
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      269 - The Main Parameters Assessment of Clod and Stone Separation from Potato Crop (Inclined Belt Type) in Potato Harvester
      Hosein Mosalanejad Hosein Mobli Afsaneh Poursoltan
      Harvesting practices of potato is one of the most difficult, troublesome and sensitive stages. Potatoes enter the machine with huge amounts of clod and stones: In the meantime separation of potato some stone and clod, which are the same size as of that the potatoes, sha More
      Harvesting practices of potato is one of the most difficult, troublesome and sensitive stages. Potatoes enter the machine with huge amounts of clod and stones: In the meantime separation of potato some stone and clod, which are the same size as of that the potatoes, shall be confide red a major problem. Many methods of study by investigators are based on physical properties of potato, stone and clod. In the present research with regards to the farm conditions and economic situation of the Iranian farmers, the beveled conveyor method is recommended. In this method, primarily a schematic design of the separating section of the stones and clod and the crop was produced and important parameters such as the surface angle, conveyor-belt motion speed and type of the conveyor, which play a key role in the separation stage, were studied. The test was carried out on the factorial basis and complete random block, using 3 angles factors in 5 levels (5,10,15.17.5 and 20 degrees) and the speed on 5 levels (100,200,300,400 and 600 RPM) and the belt type with 2 surfaces (soft and rough) repeated 5 times. The SPSS software was used to analyze data. The result revealed that the ideal combination of the angle, speed and belt type for acquiring the highest separation rate and the least amount of mix clod, stones of the separated potatoes are the order, and the crop would be the angle 15 degrees, the speed of 300 RPM, with the use of soft belt, and the angle of 17.5 degrees and the speed of 200 RPM is recommended for a rough belt. Manuscript profile
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      270 - Microstructure and Mechanical Properties of AZ91 Magnesium Cup Processed by a Combined Backward Extrusion and Constrained Ironing Method
      M. Khodsetan Ghader Faraji V. Tavakkoli K. Abrinia
      A combined metal forming process consisted of backward extrusion (BE) and constrained ironing (CI) is used to produce thin walled ultrafine grained (UFG) magnesium cups. In this new method, the initial thick-walled cup is formed from the bulk material using the BE proce More
      A combined metal forming process consisted of backward extrusion (BE) and constrained ironing (CI) is used to produce thin walled ultrafine grained (UFG) magnesium cups. In this new method, the initial thick-walled cup is formed from the bulk material using the BE process and then the CI process is used to produce a UFG thin-walled cups. The advantage of the CI process is applying compressive stresses that are suitable to form hard to deform materials like magnesium alloys without fracture while achieving higher thickness reduction ratio (TRR). The results showed that after this new combined method, the tensile strength raised to 233 MPa, from the initial values of 123 MPa. Simultaneous improvement in strength and ductility attributes to very high hydrostatic compressive stresses and also breakage of Mg17Al12 precipitates in to smaller parts that facilitate the movement of dislocation. Also, the hardness increased to about 233 MPa from the initial values of 58 HV. Significant grain refinement was also taken place and the grain size in the BE+CI sample reduced to ~1 μm from the initial value of ~150 μm due to imposing high value of strain. This combined method is very promising for processing of UFG thin-walled cup-shaped samples from hard to deform materials. SEM images illustrated the brittle fracture at unprocessed and BE samples with existence of wide crack and shallow-elongated dimples but BE+CI sample revealed brittle fracture with fewer cracks due to hydrostatic pressure. Manuscript profile
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      271 - Crack Identification of a Continuous Beam Like Structure in the Presence of Uncertain Modal Data by Stochastic Model Updating
      yahya khatami hamid ahmadian
      The problem of crack identification in continuous beam like structures is considered. The cracks’ locations and their depths are identified by employing experimental modal test results performed on the structure. The cracks are modeled using generic elements to include More
      The problem of crack identification in continuous beam like structures is considered. The cracks’ locations and their depths are identified by employing experimental modal test results performed on the structure. The cracks are modeled using generic elements to include the coupling effects between shear forces and bending moments at the crack section. In the identification procedure eigen- sensitivity analysis of continuous structure is performed by implicit differentiation of structure characteristic equation. The experimentally obtained modal results are exposed to uncertainty including measurement errors, uncertainties in model order determination and etc. Uncertainty may also originate from manufacturing tolerances that are irreducible. To quantify uncertainties, a stochastic model updating is preformed on the structure using multiple sets of modal data. The crack locations and the depths are set to be unknown parameters of the model to be identified using model updating. Stochastic distributions of multiple measurements are determined and via the desired uncertainty propagation method the distribution of model modal predictions is also formed. The model random parameters are determined by matching the distributions of these two sets modal data. The identification process is mainly divided into two adjustment steps of matching the parameters mean value and their related covariance matrix. Here, the uncertainty propagation is performed by the so-called Monte-Carlo simulation for simulating the random processes. Manuscript profile
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      272 - Investigation of Surface Roughness on Aerodynamic Characteristics of Missiles
      Saeed Daneshmand
      Nowadays, we live in a world which quality, speed, accuracy and cost are the most important parameters in parts' design and manufacturing. Due to the complexity of part manufacturing, traditional and nontraditional manufacturing techniques are used. Aerodynamic tests us More
      Nowadays, we live in a world which quality, speed, accuracy and cost are the most important parameters in parts' design and manufacturing. Due to the complexity of part manufacturing, traditional and nontraditional manufacturing techniques are used. Aerodynamic tests usually requires one or several models for testing in wind tunnels and these models typically have particular complexities in which necessitates different techniques such as machining, casting or rapid prototyping in order to manufacture them; However, these techniques imply certain advantages and disadvantages. Selection of an optimal method affects the results and quality of manufacturing. In this study, the surface roughness experimental effect of a projectile on its aerodynamic coefficients is investigated. For this purpose, three projectiles with three levels of high, medium and rough surface quality were built and analyzed in different angles of attack and velocities, the aerodynamic coefficients and the ratio of lift to drag. The results indicated that at high velocities and high angles of attack, it is better to use a model with the highest surface quality because it reduces the drag and increases the ratio of lift to drag, thus has influence on the aerodynamic coefficients and with increasing roughness, critical Reynolds number is also reduced. Manuscript profile
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      273 - Comparative Investigation in a Turbine Blade Passage Flows with Several Different Turbulence Models
      Mahmoud Ebrahimi MohammadHosein Rouzbahani
      In the present work a two dimensional numerical investigation of steam flows in a turbine blade passage is performed. A finite volume approach has been used and the pressure–velocity coupling is resolved using the SIMPLE algorithm. The purpose of this paper is to More
      In the present work a two dimensional numerical investigation of steam flows in a turbine blade passage is performed. A finite volume approach has been used and the pressure–velocity coupling is resolved using the SIMPLE algorithm. The purpose of this paper is to find that one of the used turbulent models is better for this kind of studies. A structured mesh arrangement with boundary layer mesh was adopted to map the flow domain in the blade passage. Pressure profiles around the blades for all models results are compared with the experimental data and good agreement is observed. The three models results of k–ε turbulence models (standard, Realizable and RNG) have compared with Spalart-Allmaras and k-ω SST models. Based on the results obtained, that all of these models can simulate the flow with reasonable result but the Spalart-Allmaras model and REALIZABLE k-ε model is better than other models with significant in shock capturing. Based on result, Spalart-Allmaras and k-ω SST models showed a larger boundary layer on suction trailing edge than k- ε models family. Although using REALIZABLE k-ε model leading to savings in computational cost and time. Manuscript profile
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      274 - Experimental investigation and mathematical modeling of the composite ceramic cutting tools with alumina base in the machining process of PH-hardened Austenitic-ferritic (Duplex) stainless steel
      Ehsan Ahmadi Rasool Homami Sadegh Rahmati
      Abstract: The lifetime of a cutting tool is an important and determinant parameter for evaluating its performance. The amount of tool abrasion affects seriously dimensions and surface quality of the working piece so that one of the main factors to determine the lifetime More
      Abstract: The lifetime of a cutting tool is an important and determinant parameter for evaluating its performance. The amount of tool abrasion affects seriously dimensions and surface quality of the working piece so that one of the main factors to determine the lifetime of a tool is the level of its wearing. For this purpose, an abrasion standard is defined for each particular tool above which the tool is not applicable any more. In the current paper, studies are concentrated on the machining of PH-hardened Austenitic-ferritic (Duplex) stainless steel (330HRC) to analyze the effect of tool wear on the lifetime of the ceramic cutting tool with Alumina base (aluminum oxide). Abrasion tool parameters like Flank wear, Crater wear, and Notch wear have been considered. To develop the mathematical models for the parameters considered in tool wear, the experimental results are applied in multi regression analysis (MRA) and the results obtained by these models are considered and analyzed by the analysis of variance (ANOVA). Manuscript profile
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      275 - Approximate model and clonal selection algorithm based optimization of heating channels for variotherm injection mold
      Xiping Li Ningning Gong Tingwei Ji
      The integration of an approximate model and a clonal selection algorithm (CSA) is considered to one of the most effective ways to solve complex optimization design problems in engineering. In this study, first, a process for developing an approximate model and the princ More
      The integration of an approximate model and a clonal selection algorithm (CSA) is considered to one of the most effective ways to solve complex optimization design problems in engineering. In this study, first, a process for developing an approximate model and the principles of clonal selection algorithms were presented. Then, a variotherm temperature injection mold used to produce a large liquid crystal display (LCD) TV panel was demonstrated and an approximate model for optimizing the layout of the heating channels in the mold was established. Third, the clonal selection algorithm program was coded according to the aforementioned principles to solve the established approximate model. Finally, the layout of the heating channels was optimized and the optimal solutions were obtained. Finite element simulation and industrial injection production indicated that the integration of the approximate model and clone selection algorithm used in this study to optimize the layout of the heating channels for the injection mold was very effective. Manuscript profile
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      276 - Prediction of Rupture Using Ductile and MSFLD Damage in T- Shape Tube Hydro-Forming Process
      hossein ghazavi Nosratollah Solhjoei
      Hydro-forming is a fabrication process that uses a fluid medium to form a piece by using high internal pressure. In tube hydro-forming, a tubular blank is placed between two dies, sealed and pressurized water injected, deforming the tube walls in the cavity form of the More
      Hydro-forming is a fabrication process that uses a fluid medium to form a piece by using high internal pressure. In tube hydro-forming, a tubular blank is placed between two dies, sealed and pressurized water injected, deforming the tube walls in the cavity form of the dies. Exist Several typical hydro-forming processes such as T- shapes, cross-shapes and Y- shapes. Successful hydro-forming depends on selection of proper tubular blank, sound preform shape and internal pressure. In this paper, 3D model of hydro-forming process of T-shape tube has been simulated by finite element method. Two damage model, coupled with von Mises plastic criterion, have been applied to predict where and when onset of ductile and MSFLD rupture occur in the process. All studies presented in this paper have been carried out on aluminium alloy EN AW-7108 T6. Manuscript profile
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      277 - Numerical Analysis of Rectangular Isotropic and Orthotropic Thin Plates Based on the Radial Point Interpolation Method (RPIM)
      MohamadMehdi Najafzadeh Majid Alavi AliReza Nezam Abadi Mohsen Kogani
      In the recent paper, one of the numerical methods without element, for static analysis of thin plates displacement based on classical plates theory (CPT), has been presented. In this method, the domain of problem solving is shown only by the means of a set of nodes, and More
      In the recent paper, one of the numerical methods without element, for static analysis of thin plates displacement based on classical plates theory (CPT), has been presented. In this method, the domain of problem solving is shown only by the means of a set of nodes, and there is no need to any mesh scheme or element. One of the kinds of element free methods used here is the Radial Point Interpolation Method (RPIM). In order to access to the governing equations, the Hamilton principle is used in the form of Galerkin weak form. Using interpolating functions, the field variables, namely the displacement, are approximated, and by applying the governing equations, the convergence and the accuracy of the present method are studied. Results of the present method are compared with the results of the exact solution of analytical methods of plates and also with the finite element method (FEM). In addition, the effects of thickness ratio to length, appearance coefficient, and node distribution are discussed. Manuscript profile
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      278 - Presenting a New Method for High Speed Incremental Forming
      M. Vahdati A.R. Vahdati
      Recently, incremental sheet metal forming (ISMF) process as one of the new methods in rapid prototyping collection has been considered by researchers. This process is based on a defined path in CNC controller and applies a spherical-head tool that supplies the required More
      Recently, incremental sheet metal forming (ISMF) process as one of the new methods in rapid prototyping collection has been considered by researchers. This process is based on a defined path in CNC controller and applies a spherical-head tool that supplies the required pressure for sheet metal forming. Despite affirmation of process ability in forming symmetric geometries, some of its aspects such as: high cost in die design and its manufacturing, high cost in using NC machine tools and time consuming forming processare its constraints. Hereupon, a new method for incremental sheet metal forming on turning machine has been presented. This process uses a spherical-head tool in tool-holder turret, forming sheet metal in symmetric geometries in shortest possible time without requiring a die. With a view to increasing sheet formability, two types of forming strategies were designed and implemented. Finally, the best forming strategy based on final forming depth and effective strain calculations is introduced. Manuscript profile
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      279 - Experimental Versus Numerical Investigation into the Effects of Hoop Welding in Metallic Pressure Vessels with Spherical Caps
      Jaber Mirzaei GH Rahimi Saleh Yazdani
      In this paper, an experimental and numerical investigation into the effect of the hoop welding in metallic pressure vessel is presented. In the experimental manufacturing, hoop welding was used to attach the cylindrical body of the vessel, and the effect of welding into More
      In this paper, an experimental and numerical investigation into the effect of the hoop welding in metallic pressure vessel is presented. In the experimental manufacturing, hoop welding was used to attach the cylindrical body of the vessel, and the effect of welding into stress and strain distribution is carried out. Experimental strains are obtained by using the strain gauges attached to predetermined places and stresses calculated by using Hook’s law in composite materials. The results of the two methods are compared with each other. Manuscript profile
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      280 - Shock Suspension System Review and Analysis of Airplane During Landing
      Mohamad Vaezinejad Saeed Mahjoub Moghadas Sadegh Rahmati
      In designing the landing gear of an airplane, one of the most important factors to consider, is the effect of landing airplane on body, and the role of shock absorber as an energy absorber resulting from landing. In this thesis, the landing gear of airplane has been ana More
      In designing the landing gear of an airplane, one of the most important factors to consider, is the effect of landing airplane on body, and the role of shock absorber as an energy absorber resulting from landing. In this thesis, the landing gear of airplane has been analyzed using two approaches namely theoretical and simulation software. First, dynamic equations of landing airplane were investigated in six degrees of freedom and then, these equations were converted into space state and consequently solved using MATLAB software. In second approach, the airplane was modeled in ADAMS and different states of landing such as landing with two wheels, landing with three wheels, passing over a bump and taxi were compared and analyzed. Finally, using the above approaches velocity and displacement of airplane mass center were investigated, discussed and compared. Manuscript profile
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      281 - Nonlinear vibration and instability of embedded viscose-fluid-conveying pipes using DQM
      Mohammad Mehdi Ghaitani Ali Ghorbanpour Arani Hasan Khademizadeh
      In this paper, nonlinear vibration and instability response of an embedded pipe conveying viscose fluid is investigated. The pipe is considered as a Timoshenko beam embedded on an elastic foundation which is simulated by spring constant of the Winkler-model and the shea More
      In this paper, nonlinear vibration and instability response of an embedded pipe conveying viscose fluid is investigated. The pipe is considered as a Timoshenko beam embedded on an elastic foundation which is simulated by spring constant of the Winkler-model and the shear constant of the Pasternak-model. The external flow force, acting on the beam in the direction of the flexural displacement is described by the well-known Navier-Stokes equation. The corresponding governing equations are obtained using Hamilton's principle considering nonlinear strains and first shear deformation theory. In order to obtain the nonlinear frequency and critical fluid velocity for clamped supported mechanical boundary condition at two ends of the pipe, Differential quadrature method (DQM) is used in conjunction with a program being written in MATLAB. The effect of dimensionless parameters such as aspect ratios of length to radius of the pipe, Winkler and Pasternak modules, fluid velocity and viscosity as well as the material type of the pipe on the frequencies and instability of pipe are investigated. Results indicate that the internal moving fluid plays an important role in the instability of the pipe. Furthermore, the nonlinear frequency and instability increases as the values of the elastic medium constants  and viscosity of fluid increases. Manuscript profile
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      282 - Analytical and Experimental Analysis of Axisymmetric Deep Drawing Process
      Najmeddin Arab
      There are mainly two methods of deep drawing analysis; experimental and analytical/numerical. Experimental analysis can be useful in analyzing the process to determine the process parameters that produce a defect free product, and the analytical/numerical modeling can b More
      There are mainly two methods of deep drawing analysis; experimental and analytical/numerical. Experimental analysis can be useful in analyzing the process to determine the process parameters that produce a defect free product, and the analytical/numerical modeling can be used to model and analyze the process through all stages of deformation. This approach is less time consuming and more economical.  Sheet metal forming often includes biaxial in-plane deformation with non-proportional strain paths. In deep drawing of cylindrical cup, the deformation in the flange in dominated by pure shear deformation, while it changes to plane strain when the material is drawn into the die. This paper deals with the analysis of deep drawing of circular blanks into axi-symmetric cylindrical cup using numerical modeling. The blank drawability has been related both theoretically and experimentally with the initial diameter of the blank and deep drawing parameters. The strains in the radial and circumferential directions have been measured. A correlation on the flange thickness variation by taking into account the work hardening with the analytical and experimental values also has been searched Manuscript profile
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      283 - An Investigation on Effective Parameters in Cylindrical Surface Finishing of Hot Resistance Stainless Steel AISI 321 by Magnetic Abrasive Finishing (MAF) Method
      Omid Khalilorahmani
      AbstractIn this study, the three parameters of the abrasive particle size, distance of tool to the work piece, and the rotational speed of cylindrical surface finishing of steel AISI 321 by abrasive particles in the MAF magnetic field was studied. The advantages of this More
      AbstractIn this study, the three parameters of the abrasive particle size, distance of tool to the work piece, and the rotational speed of cylindrical surface finishing of steel AISI 321 by abrasive particles in the MAF magnetic field was studied. The advantages of this process that can be noted are the lack of residual stress after the process and modification of the coaxial shaft. Surface roughness was considered as a function of rotational speed (RPM), the distance between tool and work piece (GAP) and the size of the abrasive particles.Special tools for finishing the cylindrical surface (shaft) are designed from mentioned material and the rotational motion of the shaft is provided by the lathe. Experiments were performed according to full factorial method, using abrasive powders consisting of a mixture of silicon carbide SiC with carbonyl iron Fe in different particle size and SAE40 oil. After the surface roughness measurement of samples, the influence of various parameters on the final surface quality was evaluated, the results have shown that in the mentioned stainless steel shaft finishing, variables of 1. Distance between tool and work piece 2.Abrasive particle size 3. Rotation speed, respectively, have the highest influence on obtained surface roughness. Finally, by using the neural network analysis, a better condition in terms of three parameters was obtained to achieve better surface finish. Manuscript profile
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      284 - Study of the Effect of Lubricant Emulsion Percentage and Tool Material on Surface Roughness in Machining of EN AC 48000 Alloy
      Esmaeil Soltani Hessam Shahali
      EN-AC 48000 aluminum alloy is an important alloy in industries. Machining of this alloy is of vital importance due to built-up edge and tool wear. Three type of cutting tools including coated carbide (CD1810), uncoated carbide (H10), and polycrystalline diamond (CD10) h More
      EN-AC 48000 aluminum alloy is an important alloy in industries. Machining of this alloy is of vital importance due to built-up edge and tool wear. Three type of cutting tools including coated carbide (CD1810), uncoated carbide (H10), and polycrystalline diamond (CD10) have been used in this research In This Paper, the effect of machining parameters including lubricant emulsion percentage and tool material on surface roughness has been studied in machining process of EN-AC 48000 aluminum alloy. A L9 Taguchi standard orthogonal arrey has been applied as experimental design to investigate the effect of the factors and their interaction. Nine machining tests have been accomplished with three random repetitions, resulting in twenty seven experiments. Emulsion percentage of lubricant is selected in three levels including 3% , 5% and 10%. Statistical analysis has been employed to study the effect of factors and their interactions using ANOVA method. Moreover, optimal factors level has been presented through signal to noise ratio (S/N) analysis . Also, a regression model has been provided to predict the surface roughness. Finally, the result of the confirmation tests have been presented to verify the adequacy of the predictive model. In this research, surface quality was improved about more than 9% by using lubricant and statistical optimization method. Manuscript profile
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      285 - Heat Transfer Characteristics and Optimization of a Porous Radiant Air Heater, Using DOM, under the Influence of 2-D Rectangular Radiative Field
      MohamadMehdi Keshtkar AbdoReza Ganjalian Nasab
      This work presents the heat transfer characteristics of a new type of porous radiant air heater that operates on the basis of effective energy conversion method between flowing gas enthalpy and thermal radiation. At each layer, the gas and solid phases are considered in More
      This work presents the heat transfer characteristics of a new type of porous radiant air heater that operates on the basis of effective energy conversion method between flowing gas enthalpy and thermal radiation. At each layer, the gas and solid phases are considered in non-local thermal equilibrium, and combustion in the porous radiant burner is modeled by considering a non-uniform heat generation zone. The homogeneous porous media, in addition to its convective heat exchange with the gas, may absorb, emit, and scatter thermal radiation. In order to determine the thermal characteristics of the proposed porous radiant air heater, a two-dimensional model is used to solve the governing equations for porous medium and gas flow, moreover discrete ordinates method is employed to obtain the distribution of radiative heat flux in the porous media. In order to validate the applied numerical method at the present analysis, the results are compared with some reported theoretical and experimental results of other investigators, where good agreement is observed. Manuscript profile
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      286 - Predictive modeling of surface roughness and material removal rate in turning of UD-GFRP composites using carbide (K10) tool
      Surinder Kumar
      This work presents an experimental investigation of the influence of the six important machining parameters (tool nose radius, tool rake angle, feed rate, cutting speed, cutting environment (dry, wet and cooled) and depth of cut) on surface roughness & material remo More
      This work presents an experimental investigation of the influence of the six important machining parameters (tool nose radius, tool rake angle, feed rate, cutting speed, cutting environment (dry, wet and cooled) and depth of cut) on surface roughness & material removal rate in the machining unidirectional glass fiber reinforced plastics (UD-GFRP) composite using carbide (K10) cutting tool during turning operation. Orthogonal L18 array in Taguchi method was employed to carry out the experimental work. ANOVA is performed for significant parameter and later Regression model is developed for the significant parameters. Validation (confirmatory) results indicate that the model is suitable for surface roughness & material removal rate during the study Manuscript profile
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      287 - Irreversibility Analysis and Numerical Simulation in a Finned-Tube Heat Exchanger Equipped with Block Shape Vortex Generator
      M. Ghazikhani E. Noorifar A. Mohammadian
      In this paper the effect of block shape Vortex Generators (VGs) on an air-water fin-tube heat exchanger has been studied experimentally using exergy analysis method. Also the effect of these VGs on increasing heat transfer rate has been simulated numerically and the Res More
      In this paper the effect of block shape Vortex Generators (VGs) on an air-water fin-tube heat exchanger has been studied experimentally using exergy analysis method. Also the effect of these VGs on increasing heat transfer rate has been simulated numerically and the Results show a good agreement with the experiments. In this research we used a wind tunnel to produce wind flow over heat exchanger in the range of 0.054 kg/s to 0.069 kg/s. Hot water was circulating with the steady volume flow rate of 240 L/h and the temperature of 44 to 68 centigrade in the system. These experiments have been repeated with and without VGs on the heat exchanger. Results show using the VGs has reduced Air Side Irreversibility to Heat transfer Ratio (ASIHR). To reveal the effect of VGs on heat exchanger performance with respect to reducing ASIHR, a quantity is used namely Performance of Vortex Generator (PVG). The results represent that PVG values are in the range of less than 15% to over 35% which represents the good effects of VGs on the heat exchanger performance. Manuscript profile
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      288 - Creep and Creep-Rupture Characteristics of Lead and Sn70%-30% Lead Alloy
      Esmaeil Barzekar MohamadReza Forouzan
      Materials exhibit significant creep behavior at temperatures above 40% of their absolute melt temperature. Lead, tin and their alloys are such materials which experience significant creep behavior in room temperature. One of the most important applications of the tin-le More
      Materials exhibit significant creep behavior at temperatures above 40% of their absolute melt temperature. Lead, tin and their alloys are such materials which experience significant creep behavior in room temperature. One of the most important applications of the tin-lead alloys is soldering electronic circuits in electronic industry, and for lead are isolation walls and wet batteries. Room temperature for lead is about 50% and for tin70%-lead30% is about 63% of their absolute melting temperature, and considering creep damage during their structural design is of prime importance. In this paper, creep and creep rupture data of these two materials are investigated experimentally. Diagrams obtained from experiment in the applied form, are presented for the application in computer simulation and forecasting connections life cycle. Creep rupture diagrams in the form of time hardening in the creep primary stage are presented to give strain-time relation and Larson-miller and Monkam-Grant parameters. The steady state creep rate relation for both materials in terms of stress function is also provided. Manuscript profile
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      289 - Effect of Welding Parameters on Microstructure and Mechanical Properties of Friction Stir Spot Welded of Titanium Alloy TiAl6V4
      Saeid Nader Masoud Kasiri- Asgarani kamran amini Morteza Shamanian
      In this study, friction stir spot welding (FSSW) is applied to join the TiAl6V4 titanium alloy with 1.5 mm thickness and then the effect of rotational speed and tool dwell time on microstructure and mechanical properties is investigated. In this regard, the speed of the More
      In this study, friction stir spot welding (FSSW) is applied to join the TiAl6V4 titanium alloy with 1.5 mm thickness and then the effect of rotational speed and tool dwell time on microstructure and mechanical properties is investigated. In this regard, the speed of the tool rotation was considered as 800, 1000, and 1200 rpm, as well as the tool dwell time was set at 7 and 12s. Microstructural evaluation was carried out using optical microscopy (OM) and scanning electron microscopy (SEM). In addition, tensile-shear and hardness studies were performed to analyze mechanical properties. The obtained results from microstructural evaluation show that the welded joints consist of two regions, namely the SZ and the HAZ-regions. Additionally, microstructure of the SZ-region was identified in the form of α/β layer within the initial β-phase. The results of tensile/shear tests and micro-hardness test indicated that the joint strength and hardness are enhanced with increasing the rotational speed and dwell time. The tensile/shear strength is increased from 2.7 to 15 KN with increasing the rotational speed at constant dwell time of 7s, and also is increased from 7.3 to 17.25 KN with increasing the rotational speed at constant dwell time of 12s. The maximum tensile/shear strength was achieved for the welded joint with the dwell time of 12s and rotational speed of 1250 rpm. The hardness of SZ, HAZ regions and base metal are measured around 380 to 420, 340 to 380, and 300 to 340, respectively. Manuscript profile
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      290 - Design and Control of a 3 DOF Hand Skeleton for Rehabilitation after Stroke
      M. Dehghani Rorani S. Rahmati
      Stroke is one of the most common diseases among the elderly with high personal and societal costs. In recent years, robotic rehabilitation for stroke has become an active area of research for assistance, monitoring and qualifying the rehabilitation treatments. The key i More
      Stroke is one of the most common diseases among the elderly with high personal and societal costs. In recent years, robotic rehabilitation for stroke has become an active area of research for assistance, monitoring and qualifying the rehabilitation treatments. The key issue needed for improving rehabilitation system is that patient feedback should be taken into account by the robotic rehabilitation systems for providing rehabilitation treatment. Changes in the delivery of rehabilitation treatment are an important issue since the patient or specialist should be able to express their sense about doing things and apply the needed improvements in treatment. Therefore, in this study, a three degree-of-freedom (3-DOF) exoskeleton design of a thumb has been investigated. Then, a control structure is provided for greater security in which the patient feedback is evaluated in order to make necessary automatic changes in method of treatment (changing speed and force). In this design, a versatile framework with high performance is offered to simultaneously control thumb force and position regarding the patients’ feedback. This may help to keep the patient in the treatment process, reduce interventions and therapist caseload, effective automatic transmission of treatment and pain relief during the course of treatment. The results of the study suggest that the force and speed on the thumb can be changed during the rehabilitation period according to the patient's needs. This advantage may be considered as an essential step for improvement of the rehabilitation efficiency. Manuscript profile
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      291 - Analysis and Optimization of Reducing Steady State Time for Heating Systems
      Farhad Talebi Sayed Mehdi Sayed Nasrollah Fatemeh Yousefi
      Present paper is a result of consideration in reducing steady-state time of heating systems. For this purpose one should study boundary condition of the system until steady state condition. In the research, a laboratory heating system was considered using numerical simu More
      Present paper is a result of consideration in reducing steady-state time of heating systems. For this purpose one should study boundary condition of the system until steady state condition. In the research, a laboratory heating system was considered using numerical simulation and the numerical results were compared with several experimental tests. Studies shows that the steady-state time reduces significantly via two major methods called "Initial Heat Method" and "Initial Velocity Method". These two methods can apply in experimental tests planning and also in numerical simulation programs. Complete results for the experiments of both methods were presented in previous papers, and a little survey of them with some physical analysis from similar heating systems was explained in this research. Furthermore two correlation equations were presented for dimensionless time vs. dimensionless initial heat and dimensionless initial velocity using statistical methods. Manuscript profile
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      292 - Determining the Optimal Size and Operation Sensitivity Analysis of a CCHP System Implemented in a Residential unit in Tehran
      Adel Gholami Arman Fathi
      Abstract: Implementing a combined cooling, heating and power system(CCHP) to cool, heat and produce electricity is growing rapidly due to its efficiency and low emissions. In this paper, using economic analysis, the size and operation detail of the required gas engine a More
      Abstract: Implementing a combined cooling, heating and power system(CCHP) to cool, heat and produce electricity is growing rapidly due to its efficiency and low emissions. In this paper, using economic analysis, the size and operation detail of the required gas engine and the specific electricity, cooling and heating load curves for a one year operating period has been determined. The proposed CCHP system meets thermal demands of the facility and has been evaluated under such strategy. Net Annual Profit (NAP) has been introduced as an objective function to be maximized through a developed nonlinear mixed integer programming software. The operation strategy and the payback period of the chosen system have also been determined. A study with the purpose of including or excluding subsidy prices has been carried out. Furthermore, a sensitivity analysis was elaborated in order to show the dependency of optimal solutions to some key contributing factors such as fuel price, electricity buying price and electricity selling price. Results show that, these parameters have significant effect on the system’s performance. Manuscript profile
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      293 - Investigation of Process Parameters, Gate Position and its Shape Effect on Dimensional Accuracy of Injected Plastic Part
      Payman Shahi AmirHosein Behravesh Behrouz Arezou Mehdi Mahmoudi
      Injection molding is the most widely used process for producing plastic parts.In this process, an important issue is to predict and optimize the warpage before manufacturing. In this paper, a simulation with MOLDFLOW software is proposed to optimize the injection moldin More
      Injection molding is the most widely used process for producing plastic parts.In this process, an important issue is to predict and optimize the warpage before manufacturing. In this paper, a simulation with MOLDFLOW software is proposed to optimize the injection molding process. The optimization process aims at minimizing the warpage of the critical injection molding part in which process parameters, gate location and its shape are the design variables. Moldflow Plastic Insight software is used to analyze the warpage of the injection molding part. The mold temperature, melt temperature, injection time, packing pressure and packing time are regarded as process parameters. The results shown that to reduce warpage in plastc part not only the process parameters should be optimized but also effect of gate shape and especially its position should be considered in precise parts. Moreover the results shown that moldflow injection molding simulation software is able to accurately predict the part warpage, but it doesn’t consider the viscoelastic behaviour of plastic material in process. Manuscript profile
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      294 - Multi Purpose Optimization for Design of Circular Hydrostatic Axial Bearings Using Genetic Algorithm
      Mohsen Dashti Asghar Dashti
      In this paper, a multi purpose function is presented for optimum design in circular hydrostatic axial bearings. One or more parameters that are directly or indirectly dependent on given data are optimized. Usually in the local optimization methods, it is not possible to More
      In this paper, a multi purpose function is presented for optimum design in circular hydrostatic axial bearings. One or more parameters that are directly or indirectly dependent on given data are optimized. Usually in the local optimization methods, it is not possible to optimize several parameters simultaneously. In this research, simultaneous optimization of the power loss and the oil temperature rise as effective parameters for increase in efficiency of bearing is considered. The genetic algorithm is used in simultaneous optimization of the power and the temperature values. The accuracy of the multi purpose optimization is evaluated by a practical sample and the obtained results of simultaneous combination of parameters effect are compared with distinct functions. Manuscript profile
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      295 - Estimation of the Time-Dependent Heat Flux Using Temperature Distribution at a Point in a Three Layer System with None Homogeneous Boundary Conditions
      Mohammad Mohammadiun
      In this paper, the conjugate gradient method coupled with adjoint problem is used in order to solve the inverse heat conduction problem and estimation of the time- dependent heat flux using the temperature distribution at a point in a three layer system with none homoge More
      In this paper, the conjugate gradient method coupled with adjoint problem is used in order to solve the inverse heat conduction problem and estimation of the time- dependent heat flux using the temperature distribution at a point in a three layer system with none homogeneous boundary conditions. Also, the effect of noisy data on final solution is studied. For solving this problem the general coordinate method is used. The inverse heat conduction problem of estimating the transient heat flux, applied on part of the boundary of an irregular region is solved in this paper. The present formulation is general and can be applied to the solution of boundary inverse heat conduction problems over any region that can be mapped into a rectangle. The obtained results for few selected examples show the good accuracy of the presented method. Also the solutions have good stability even if the input data includes noise. Applications of this model are in the thermal protect systems (t.p.s.) and heat shield systems. Manuscript profile
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      296 - Pareto Optimal Design of Passive and Active Vehicle Suspension Models
      Mohammadjavad Mahmoodabadi Seyed Mehdi Mortazavi Yazdi
      It would be difficult to deny the importance of optimization intheareasof science and technology. This is in fact, one of the most critical steps in any design process. Even small changes inoptimization can improve dramatically upon any process orelementwithin a process More
      It would be difficult to deny the importance of optimization intheareasof science and technology. This is in fact, one of the most critical steps in any design process. Even small changes inoptimization can improve dramatically upon any process orelementwithin a process. However, determining whetheran optimization approach willimprove on an original design is usually a question that its response in this study has led to an optimal design out of an existing car model. First of all, the optimization of a passive car-quarter model has been accomplished by means of a genetic algorithm. This initial optimization gives a figure of points named ''Pareto optimum points''. Secondly, through selecting a point amongst them, the design of active model has been completed and optimized based on genetic algorithm. Continuing with this thought, a similar process has been also accomplishedwith a car-half vehicle model with five degrees of freedom. Though the last optimized active model may prove a more reliable efficient design due to the more comprehensive feature related to the degrees of freedom, the results of each optimization should be considered and maysupply equally attractive anddiverse choicesas well. Anyway, let's focus on the final purposewhich is to reduce the vibrations as much as possible. This is what is observed through all the optimization jobs in this study. Comparison of these results with those reported in the literature affirms the excellence of the proposed optimal designs. Manuscript profile
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      297 - Study of Nucleation and Meta Stable Phenomena’s and Applications
      Farshid Mardkhri Cyrus Aghanajafi
      The subject we discussion about are Nucleation and Meta stable phenomena’s , superheat liquids , supercold liquids and meanwhile applications of this liquids. all in all Meta stable situation can occur in three condition: First while changing liquid phase to gas p More
      The subject we discussion about are Nucleation and Meta stable phenomena’s , superheat liquids , supercold liquids and meanwhile applications of this liquids. all in all Meta stable situation can occur in three condition: First while changing liquid phase to gas phase by heating , Second changing liquid phase to solid phase by cooling , Third while moving water stream in subsonic nozzles or supersonic nozzles before condensation process occur. Of curse first and second conditions more than third condition view in nature and various industrials and productions of engender in first and second conditions are more than third condition. Of curse skews and turbulences that explain about them can disassemble this conditions. Meanwhile getting relations show that superheat degree have maximum and minimum amount . Manuscript profile
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      298 - Investigating the Effect of Manganese Content on the Properties of High Manganese Austenitic Steels
      Seyyed Amin Torabi Kamran Amini Masab Naseri
      In this study, in order to investigate the effect of increasing the manganese content on microstructure and mechanical properties of high manganese austenitic steels, three alloys with successive increases in weight percentages of manganese (7.55, 13.1, and 16.5) and ca More
      In this study, in order to investigate the effect of increasing the manganese content on microstructure and mechanical properties of high manganese austenitic steels, three alloys with successive increases in weight percentages of manganese (7.55, 13.1, and 16.5) and carbon (0.8 and 1.2) were cast in the presence of a constant amount of chromium (1.5 wt.%) and silica (0.6 wt.%). The samples experienced solution annealing heat treatment comprised of austenitizing at 1100°C for 2 h followed by rapid quenching in stirred water. Hardness, tensile, and wear tests were conducted by dry sand/rubber-wheel abrasion method. Microstructural observations were performed by using optical (OM) and scanning electron microscopies (SEM) and energy dispersive spectroscopy (EDS). The obtained results revealed that after heat treatment a uniform austenite structure has developed in all three samples. With increase of weight percent of the elements from sample 1 to sample 3, the hardness value reaches from 191 to 218 Vickers. Also, with increase of manganese weight percent from 7.55 to 16.5, the ultimate tensile strength and wear resistance showed 11% and 29% increase, respectively, to the effect that the most enhanced mechanical properties and maximum wear resistance were observed in sample 3 with 16.5wt.% of manganese. This improvement in mechanical properties and wear resistance is related to the formation of the solid solution in the matrix, the increase of hardenability, and the increase of work hardening capacity resulted from the increase of manganese percentage. Examination of the abraded surfaces demonstrated that the involved wear mechanism was scratch wear mechanism. Manuscript profile
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      299 - Volume fraction optimization of four-parameter FGM beams resting on elastic foundation
      saeed kamarian
      This paper deals with volume fraction optimization of Functionally Graded (FG) beams resting on elastic foundation for maximizing the first natural frequency. The two-constituent functionally graded beam consists of ceramic and metal. These constituents are graded throu More
      This paper deals with volume fraction optimization of Functionally Graded (FG) beams resting on elastic foundation for maximizing the first natural frequency. The two-constituent functionally graded beam consists of ceramic and metal. These constituents are graded through the thickness of beam according to a generalized power-law distribution. One of the advantages of using generalized power- law distribution is the ability of controlling the materials volume fraction of FG structures for considered applications. The primary optimization variables are the four parameters in the power-law distribution. Since the search space is large, the optimization processes becomes so complicated and too much time consuming. Thus a novel meta–heuristic called Imperialist Competitive Algorithm (ICA) which is a socio-politically motivated global search strategy is applied to find the optimal solution. A proper and accurate Artificial Neural Network (ANN) is trained by training data sets obtained from generalized differential quadrature (GDQ) method to reproduce the behavior of the structure in free vibration. The ANN improves the speed of optimization process by a considerable amount. The performance of ICA is evaluated in comparison with other nature inspired technique Genetic Algorithm (GA). Comparison shows the success of combination of ANN and ICA for design of material profile of FG beam. Finally the optimized material profile for the optimization problem is presented. Manuscript profile
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      300 - Investigation of Mechanical Property and Microstructure of Nanocomposite AZ31/SiC Fabricated by Friction Stir Process
      ahmad haghani Sayed Hassan Nourbakhsh Mehdi Jahangiri
      The friction stir process (FSP) is a solid state process, which has been used to insert reinforcing particles into the structure of a material to create a composite with improved properties. Magnesium is a light structural metal that is increasingly used in the aerospac More
      The friction stir process (FSP) is a solid state process, which has been used to insert reinforcing particles into the structure of a material to create a composite with improved properties. Magnesium is a light structural metal that is increasingly used in the aerospace and automobile industries. In this research, SiC nanoparticles were added to AZ31 alloy using FSP in two overlaps of 100% and 50% passes. In 100% pass overlapping, nanoparticles were added in 4, 8 and 16 volume percentages and in 50% pass overlapping only nanoparticles in 4 volume percent were added. The FSP process performed as 4 consecutive passes in both overlaps along with rapid cooling. Microstructure, hardness and tensile strength of created composites were examined. The results suggested that adding reinforcing materials causes reduction in the size of the grains, uniformity of structure and increase in the hardness of material. SiC nanoparticles distributed uniformly through the AZ31 alloy. By increasing volume fraction of reinforcing materials, yield stress of the material increased but ultimate stress and formability properties reduced. In 50% overlapping state, the yield stress in directions, either parallel or perpendicular to the pin direction, increased rather than 100% overlapping state, but the ultimate stress and elongation properties reduced. This reduction was greater in the perpendicular direction relative to the pin direction. Manuscript profile
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      301 - The effect of orientation on optimum insulation position in the wall of a building with natural ventilation in hot and dry climate
      mehdi najafian Alireza Bahrami
      In this study, the effect of wall orientation on the optimum insulation position in the wall from different perspectives is studied numerically. Using Crank- Nicolson One dimensional transient heat conduction equation is solved for the wall with convection boundary cond More
      In this study, the effect of wall orientation on the optimum insulation position in the wall from different perspectives is studied numerically. Using Crank- Nicolson One dimensional transient heat conduction equation is solved for the wall with convection boundary conditions. Outdoor temperature is considered as a periodic function of time. Since natural night ventilation is used in the building, indoor temperature is constant during day time while air conditioning (AC) system is ON and is time dependent when AC is OFF. A time dependent indoor temperature is calculated and used as a boundary condition at the wall inner side. For the position of insulation in the wall six practical configurations are considered and time lag (TL), decrement factor (DF) and total conduction heat gain (TCHG) is calculated for all configurations. It is seen that, from minimum TCHG perspective, the best configuration for all directions is when insulation is used in the inner side of the wall. The minimum TCHG is occurred at an angle of 200⁰ from the south. It can be concluded that different perspectives may lead to different results for the optimum insulation position in the wall. Manuscript profile
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      302 - Study and Analysis of Al2O3-SiC Nanocomposite Ceramics’ Fracture Toughness using Vickers Indenter
      AliReza Moradkhani HamidReza Baharvandi Mehdi Tajdari Abbas Vafaee Sefat
      The basic trait in the ceramics is their high brittle or low fracture toughness, and the main criteria in the design and application is specifying the fracture toughness in ceramics. In this paper, a new method is proposed to determine the fracture toughness of ceramics More
      The basic trait in the ceramics is their high brittle or low fracture toughness, and the main criteria in the design and application is specifying the fracture toughness in ceramics. In this paper, a new method is proposed to determine the fracture toughness of ceramics, which is enhanced in lowering the cost of fracture toughness determination relative to the previous methods. Hence due to the low cost and case of access of alumina (Al2O3) which is extensively used in ceramics industry, it is applied as the most important source for achieving the objectives. Pure alumina has excellent properties such as refractory and high hardness on one hand, and has disadvantages such as low fracture toughness on the other hand. In order to improve its mechanical properties, various additives such as nano scale silicon carbide (SiC) powder are used. In this paper, alumina micro powder having 5% nano magnesium oxide by weight were mixed separately with silicon carbide nano particles of 2.5%, 5%, 7.5%, 10% and 15% to construct various types of ceramics, with different physical and mechanical properties. Semi experimental equation for their fracture toughness determination was presented and used for other brittle materials. This equation has minimal cost of experiments for determining fracture toughness of different brittle materials. Manuscript profile
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      303 - Nonlinear bending analysis of thick functionally graded plates based on third-order shear deformation plate theory
      Payman Naderpour Aazam Ghassemi Nosratollah Solhjoei
      In this paper the nonlinear bending analysis of thick functionally graded plates subjected to mechanical loading is studied. The formulation is derived based on the third-order shear deformation plate theory and Von Kármán type non-linearity. Young’s modulus is assumed More
      In this paper the nonlinear bending analysis of thick functionally graded plates subjected to mechanical loading is studied. The formulation is derived based on the third-order shear deformation plate theory and Von Kármán type non-linearity. Young’s modulus is assumed to vary according to a power law distribution in terms of the volume fractions of the constituents. The principle of virtual work is used to obtain the weak form of the governing differential equations. The most important advantage of employed numerical solution in this work is that the whole plate is considered as one element and the components of displacement field are interpolated over the entire domain, then a hierarchical finite-element scheme is developed. The validity and the accuracy of the method are verified by comparisons made with other solutions. In addition; the effect of numbers of interpolation functions on the accuracy of results is studied. It is concluded that accurate results are obtained even by few numbers of interpolation functions. Manuscript profile
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      304 - Analytical and Numerical Determination of Residual Stresses in Thick Composite Laminated Plates
      AhmadReza Ghasemi Hesamaddin Mashhadi
      In this paper, deep hole drilling method for measurement of non-uniform residual stress in thick composite laminated plates is simulated. The deep hole method is a well known method for measurement of residual stress in large metallic components. In this method, first a More
      In this paper, deep hole drilling method for measurement of non-uniform residual stress in thick composite laminated plates is simulated. The deep hole method is a well known method for measurement of residual stress in large metallic components. In this method, first a hole is drilled perpendicular to the surface of the laminate and the hole diameter is measured accurately after wards. Then, by trepanning process the residual stresses will be released. The hole diameter is re-measured accurately and recorded. Finally, the residual stresses can be calculated through the difference in diameter of the hole. The finite element software, ANSYS 11. is used for analysis and simulation of the method. Also, for three dimensional simulation of the deep hole drilling method the three-dimensional "solid brick layered 46" is used. The hole diameter was 10mm that is smaller than other dimensions. First, convergence test has been applied to optimize the size of the mesh so that the results are reliable. Three types of loading Fx, Fy and Fxy were applied to finite element analysis. These results have been compared with Lekhnitskiiۥs solution and Savin ۥs for orthotropic materials. Lekhnitskii solved problems for stresses around different shapes of holes under different loads using series method. As it can be observed the results of this simulation are in good agreement with Lekhnitskiiۥs and Savin ۥs solution. Manuscript profile
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      305 - Analysis of Two Dimensional Steady-State Heat Conduction Problems by MLPG Method
      GholamHosein Baradaran MohammadJavad Mahmoodabadi
      Numerical solutions obtained by the Meshless local Petrov–Galerkin (MLPG) method are presented for two-dimensional steady-state heat conduction problems. The MLPG method is a truly meshless approach, and neither the nodal connectivity nor the background mesh is required More
      Numerical solutions obtained by the Meshless local Petrov–Galerkin (MLPG) method are presented for two-dimensional steady-state heat conduction problems. The MLPG method is a truly meshless approach, and neither the nodal connectivity nor the background mesh is required for solving the initial-boundary-value problem. The penalty method is adopted to efficiently enforce the essential boundary conditions, the moving least squares approximation is used for interpolation schemes and the Heaviside step function is chosen for test function. The results show that the present method is very promising in solving engineering two-dimensional steady-state heat conduction problems. Manuscript profile
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      306 - Anisotropy Induced Biaxial Stress-Strain Relationships in Aluminum Alloys
      Milad Janbakhsh Mohammad Riahi Faramarz Djavanroodi
      Recently, offshore and ocean engineering have been dealing with novel materials that play a significant role in reducing the weight of structures used in the ship construction industry. 5XXX series of aluminum alloys are of the novel alloys are suitable for construction More
      Recently, offshore and ocean engineering have been dealing with novel materials that play a significant role in reducing the weight of structures used in the ship construction industry. 5XXX series of aluminum alloys are of the novel alloys are suitable for construction of ship hulls and the topside structures of offshore platforms. Within different 5XXX aluminum alloys, AA5083 is of great importance which is extensively used in the ship construction industry. In the present study, formability of AA5083-H111 aluminum alloy is investigated in room temperature by using uni-axial tensile tests and hydraulic bulge tests. Tensile tests were performed to evaluate materials anisotropy in different directions with respect to rolling direction. Anisotropy coefficients were then used to correct flow stress curves obtained by balanced biaxial bulge tests. Moreover, flow stress curves obtained from both tests were separately introduced to an explicit commercial finite element code. Comparisons showed that numerical simulation done in this study stand in according with the experiments. Manuscript profile
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      307 - Reliability and limitations of Impact-Echo Method for Thickness Measurement of Orthotropic Composite Plates
      M. Amiri M. Tabatabaee Ghomi Gh. Liaghat
      In this paper, an Impact-Echo method has been used to numerically simulate low velocity impact of a steel ball on laminated composite plates in order to measure the plate's thickness. For the purpose of simulation, Ls-Dyna finite element code has been employed to expres More
      In this paper, an Impact-Echo method has been used to numerically simulate low velocity impact of a steel ball on laminated composite plates in order to measure the plate's thickness. For the purpose of simulation, Ls-Dyna finite element code has been employed to express the behaviour of impact between steel ball and composite plates. Furthermore, a single node near the impact area has been chosen and its displacement was demonstrated during the impact time on a graph by the software. After that, displacement-time graph was transformed to amplitude-frequency domain graph by means of Fast Fourier Transform which was done by MATLAB software. The peak frequency was used to calculate the plate's thickness. The calculated thickness was verified by real plate thicknesses and this comparison shows an acceptable agreement between simulation and experimental results. Manuscript profile
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      308 - Impeller trimming of an Industrial Centrifugal Viscous Oil Pump
      Wen Guang Li
      Abstract: Impeller trimming is a proper way to alter the performance of centrifugal pump with a constant speed so as to meet the demand on the specified flow rate and head in pumping systems. The affinity law accounting for the impeller trimming is the key relation to d More
      Abstract: Impeller trimming is a proper way to alter the performance of centrifugal pump with a constant speed so as to meet the demand on the specified flow rate and head in pumping systems. The affinity law accounting for the impeller trimming is the key relation to determine the pump performance with a trimmed impeller. There seems no experimental study dealing with such an affinity law for centrifugal oil pump handling water and viscous oils. In this paper, an experimental investigation into the performance of an industrial centrifugal oil pump of type 65Y60 was explored when the original impeller was trimmed four times. In the experiments water and viscous oils served as the working liquid, respectively. The trimming exponents at both best efficiency and shut-off points were worked out, and compared to those in the existing affinity law for impeller diameter reduction and water. These exponents are very helpful for engineers to determine a trimmed impeller diameter for centrifugal oil pumps handling water and viscose oils with a relative high viscosity. Meanwhile the “rising-efficiency effect” was revealed when a trimmed impeller is delivering highly viscous oils. Manuscript profile
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      309 - Two - dimensional modeling of a two - layer porous burner for household applications under the influence of a radiation field
      Mohammad Keshtksr R. Janati Far
      Abstract: This work presents a numerical study to investigate the heat transfer characteristics of a 2-D rectangular composite porous radiant burner (CPRB). In the construction of porous burner, the porous layer is considered to be composite consisting of upstream and d More
      Abstract: This work presents a numerical study to investigate the heat transfer characteristics of a 2-D rectangular composite porous radiant burner (CPRB). In the construction of porous burner, the porous layer is considered to be composite consisting of upstream and downstream layers with equal thickness but with different physical and radiative properties. In the present work, a two dimensional rectangular model is used to solve the governing equations for porous medium and gas flow.  In order to analyze the thermal characteristics of the CPRB, the coupled energy equations for the gas and porous medium are solved numerically and the discrete ordinates method is used to obtain the distribution of radiative heat flux in the porous media. Finally, the effects of the various factors on the performance of CPRB are determined. Computational results show that the high porosity and low scattering coefficient for downstream porous layer are desirable for maximizing the CPRB efficiency in comparison to homogeneous one. Comparison between the present results with those obtained by other investigators shows a good agreement. Manuscript profile
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      310 - Experimental Investigation of Surface Roughness for Fused Deposition Modelled Part with Different Angular Orientation
      sreedhar pugalendhi
      Fused deposition modeling (FDM) is a filament based rapid prototyping system provides us to manufacture real parts with multiple production-grade materials, such as ABS-M30, PC, PPSF and PC-ABS blend. Fused deposition modeling technology, essentially perform using layer More
      Fused deposition modeling (FDM) is a filament based rapid prototyping system provides us to manufacture real parts with multiple production-grade materials, such as ABS-M30, PC, PPSF and PC-ABS blend. Fused deposition modeling technology, essentially perform using layer manufacturing process. More complex 3D physical models can be efficiently fabricated without geometric limitation by this technology; a remarkable reduction in production life cycle has been achieved. However, due to the Layer Manufacturing process, stair case effect is unavoidable which results in poor surface finish. In this paper, the surface roughness of a model having surfaces at different angles produced by fused deposition modelling machine is analyzed to understand the effect of different angled surfaces on the surface roughness of the model of FDM produced part model. Manuscript profile
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      311 - Kinematic Analysis of a Novel 3-CRS/PU Parallel Manipulator
      Mir Amin Hosseini
       In this research work, a novel parallel manipulator with high positioning and orienting rate is introduced. This mechanism has two rotational and one translational degree of freedom. Kinematics and Jacobian analysis are investigated. Moreover, workspace analysis and op More
       In this research work, a novel parallel manipulator with high positioning and orienting rate is introduced. This mechanism has two rotational and one translational degree of freedom. Kinematics and Jacobian analysis are investigated. Moreover, workspace analysis and optimization has been performed by using genetic algorithm toolbox in Matlab software. Because of decreasing moving elements, it is expected much more better dynamic performance with respect to other counterpart mechanisms with the same degrees of freedom. In addition, using couple of cylindrical and revolute joints increased mechanism ability to have more extended workspace. Manuscript profile
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      312 - Design of Cellular Manufacturing using Mathematical Programming: a comparative study with simulation modelling
      Hassan Farsijani Mohsen Shafiei Nikabadi
      Machine-part family formation is one of major applications of group technology (GT). The machine cell formation problem in cellular manufacturing system (CMS) involves the decomposition of the manufacturing system into machine cells. Part families are identified such th More
      Machine-part family formation is one of major applications of group technology (GT). The machine cell formation problem in cellular manufacturing system (CMS) involves the decomposition of the manufacturing system into machine cells. Part families are identified such that they are fully processed within a machine cell. The problem of cell design is a very complex task with wide ranging implications for any organization. Cell design is generally understood as the problem of identifying a set of part types that are suitable for manufacturing on a group of machines. Among the many methods utilized in cell design, the distance or dissimilarity between two entries is fairly less used. In this study, a mathematical programming model based on the Minkowski distance measure to minimize the total distance between entries is introduced. Furthermore, a hypothetical manufacturing facility with 10 machines and 15 parts is used as a case. Finally, simulation models are developed for two manufacturing systems, a new cellular manufacturing and a conventional job shop manufacturing system. The main purpose of this paper is to combine different techniques such as the design and evaluation of a cellular manufacturing system. Manuscript profile
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      313 - A New Approach for Determining the Optimum Pressure–Time Diagram in Superplastic Forming Process
      Hamed Sheikhalishahi Mahmoud Farzin Reza Jafari Nedoushan Mohammad Ali Rasouli Masoud Aliheidar
      Superplastic materials show huge amount of deformation in low strain rates and temperature above half of melting point. In superplastic forming, estimating the pressure–time diagram and thickness distribution has significant importance. Utilizing numerical methods, the More
      Superplastic materials show huge amount of deformation in low strain rates and temperature above half of melting point. In superplastic forming, estimating the pressure–time diagram and thickness distribution has significant importance. Utilizing numerical methods, the involved parameters in superplastic forming can be optimized for such estimations. In the present paper, the simulation of superplastic forming of a cup-shape part is demonstrated, assigning the proper constitutive equation. In the following, a noble approach for estimating the pressure–time diagram, using finite element method, is presented and by using this approach, the optimum pressure–time diagram for the forming process is estimated while the effects of process parameters such as friction index and strain rate on pressure–time diagram and thickness distribution is evaluated. Simulation results are compared with other researches results, which show satisfactory agreement.  Manuscript profile
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      314 - Expert System Approach for Manufacturability Evaluation of Nd: YAG Laser Beam Machining Process
      M. Sadegh Amalnik*
      In this paper, an expert system (ES) is developed for manufacturability evaluation of ND:YAG laser in computer based concurrent engineering. The expert system evaluates machining cycle time and cost in less than 30 seconds. Experimental verification and validity of the More
      In this paper, an expert system (ES) is developed for manufacturability evaluation of ND:YAG laser in computer based concurrent engineering. The expert system evaluates machining cycle time and cost in less than 30 seconds. Experimental verification and validity of the expert system is carried out. The results of expert system are compared with the results of experimental laser beam machine. Results are presented. The results of the expert system show machining cycle time and cost for expert system is about 10 percent less than the experimental one. In addition material is selected by the expert system. It gives valuable information to help designers and manufacturing engineers to improve design and manufacturing. The expert system links with design feature library, material database and laser beam machine database. The design specification is acquired through a feature based approach. Material database holds attributes of more than 10 types of materials. Laser beam machine database holds attributes of 2 types of laser beam machine and machine parameters. For each design feature, the expert system provides information needed for manufacturability evaluation and estimation of machining cycle time and cost. It can be used for design and manufacturing optimization. The expert system can be used as an advisory system for designers and manufacturing engineers. It can be used as a teaching program for new laser operators in computer based concurrent engineering environment. Manuscript profile
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      315 - Evaluation of the Heat and Mass Transfer and Exergy in the Counter Flow Wet Cooling Tower of Khuzestan Steel Company (KSC)
      Navid Bozorgan Nariman Bozorgan
      A thermodynamic analysis of the counter flow wet cooling tower (CWCT) in the Steelmaking unit of the Khuzestan Steel Company (KSC) is performed in this paper. We evaluated both energy and exergy formulations for analyzing the heat and mass transfer, exergy and second-la More
      A thermodynamic analysis of the counter flow wet cooling tower (CWCT) in the Steelmaking unit of the Khuzestan Steel Company (KSC) is performed in this paper. We evaluated both energy and exergy formulations for analyzing the heat and mass transfer, exergy and second-law efficiency in this cooling tower. The Lewis factor Lef is an indication of the relative rates of heat and mass transfer in an evaporative process. In many performance analyses of the cooling tower, Lef is assumed to be 1 in order to simplify the heat and mass transfer equations between air and water. If so, evaporative loss is negligible. But in this paper, although heat and mass transfer equations and their numerical solutions are more complicated, Lef is calculated for all parts of the tower in order to achieve more accurate results in predicting air and water conditions into the cooling tower in the analysis on the performance of this cooling tower. Manuscript profile
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      316 - Monitoring of Pipe-Wall Thickness and Thinning Rate by Ultrasonic Technique
      Farzaneh Salehi Farhang Honarvar Anthony Sinclair
      An important issue in power generation and petrochemical industries is the monitoring of pipe wall thickness and corrosion/erosion rate. The pipes are usually subject to erosive and/or corrosive environments and any failure could be catastrophic. While periodic manual u More
      An important issue in power generation and petrochemical industries is the monitoring of pipe wall thickness and corrosion/erosion rate. The pipes are usually subject to erosive and/or corrosive environments and any failure could be catastrophic. While periodic manual ultrasonic thickness measurement is the common practice in many industries, in certain cases, where higher accuracies are required, continuous monitoring systems are required. This paper introduces a measurement algorithm that can accurately measure the pipe wall thickness and estimate the pipe- wall thinning rate. The algorithm incorporates a model-based estimation technique for estimating the pipe wall thickness and thinning rate. It is an on-line non-intrusive ultrasonic thickness measurement tool for quick and accurate estimation of the erosion/corrosion rate and remaining pipe-wall thickness. The technique is applied to data measured from a pipe carrying high temperature liquid. The results show that the system can measure thinning rates as low as 10 µm/year within 5 days of data collection. Manuscript profile
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      317 - Proportional-derivative Fuzzy Control of Conjugated Polymer Actuators
      A. Amirimighadam M. Maarefdoust
      Conjugated polymer actuators can be employed to achieve micro and nano scale precision, and have a wide range of applications including biomimetic robots, and biomedical devices. In comparison to robotic joints, they do not have friction or backlash, but on the other ha More
      Conjugated polymer actuators can be employed to achieve micro and nano scale precision, and have a wide range of applications including biomimetic robots, and biomedical devices. In comparison to robotic joints, they do not have friction or backlash, but on the other hand, they have complicated electro-chemo-mechanical dynamics which makes modelling and control of the actuator really difficult. Besides the positive characteristics of these actuators, they have some disadvantages such as creep, hysteresis, highly uncertain and time-varying dynamics. This paper consists of two major parts. In the first part the Takagi–Sugeno (T–S) Fuzzy model is used to represent the uncertain dynamic of the actuator, and the resulted Fuzzy model will be validated using experimental data. In the second part a proportional-derivative fuzzy controller is designed to control the highly uncertain dynamic of conjugated polymer actuator. In order to optimize the performance of fuzzy controller, Genetic Algorithm (GA) is used for tuning the output membership functions. The obtained results show that the designed controller can achieve good performance despite the existence of uncertain actuator dynamics and also it has a better performance than conventional PID controller. Manuscript profile
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      318 - Flow Study of Wood Plastic Composite Through a Circular Die in an Extrusion Process
      N. Jafarian Jam E. Soury
      This paper presents a theoretical study on wood plastic composite's (WPC's) flow, based on empirical data provided by a twin screw extruder and experimental data from a rotational rheometer. Four circular extrusion dies were designed and manufactured to produce rod shap More
      This paper presents a theoretical study on wood plastic composite's (WPC's) flow, based on empirical data provided by a twin screw extruder and experimental data from a rotational rheometer. Four circular extrusion dies were designed and manufactured to produce rod shaped products with various diameters (D) and length-to-diameter ratios (L/D). Also other parameters such as screw speed (N), polymer matrix type, polymer viscosity (m) and percentage of wood content (W) were selected as the process or material factors to investigate the relationship between the flow characteristics and the above mentioned factors. Moreover, frequency sweep experiments were performed on the selected composites using rotational plate rheometer. The results from these experiments have been studied by using power law and Bingham plastic models which are believed as proper models for WPC in the literature. The results show that Bingham plastic model can explain the flow characteristics of this composite much better. Moreover, although the results of a frequency sweep test can give the required values for parameters in the Bingham plastic model, these quantities will be different with those from empirical experiments. Manuscript profile
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      319 - Influence of Vibratory Finishing Process by Incorporating Abrasive Ceramics and Glassy Materials on Surface Roughness of CK45 Steel
      Payam Saraeian Mostafa Gholami Amir Behagh Omid Behagh Hamid Reza Javadinejad Mohammad Mahdieh
      The vibratory finishing is one of the important mass finishing processes. This can be applied for finishing many metallic and non- metallic components using abrasive materials such as steel, ceramic, natural materials and etc. The vibratory finishing process is used for More
      The vibratory finishing is one of the important mass finishing processes. This can be applied for finishing many metallic and non- metallic components using abrasive materials such as steel, ceramic, natural materials and etc. The vibratory finishing process is used for some purposes such as surfaces polishing, deburring, oxide layer removing and rounding the edges. Evaluation of surface roughness changes with time that is one of the important parameters during the vibratory finishing process. In this study, the effects of the working time and abrasive materials are investigated on the surface roughness changes of CK45 steel samples. The ceramic, glass and mixed abrasive particles are used as the abrasive media. The experiments are performed at different time from 10 to 120 minutes in the dry environment. Finally, the surface roughness values of samples were measured and then fitted by a regression equation for description of the surface roughness changes with time. According to the results, the maximum surface finish was obtained after 120 minutes by using mixed abrasive materials. The surface roughness improved approximately 60%. Manuscript profile
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      320 - Experimental and Analytical Study of Aluminum-oxide Nanofluid Implication for Cooling System of an Amphibious Engine
      Mohamad Najafi M. Najafi
      The aim of this manuscript is to study the implication of aluminium-oxide nanofluid for an amphibious vehicle engine (viable on land and under water) cooling system both analytically and experimentally. To achieve this, a one-dimensional model of the engine cooling syst More
      The aim of this manuscript is to study the implication of aluminium-oxide nanofluid for an amphibious vehicle engine (viable on land and under water) cooling system both analytically and experimentally. To achieve this, a one-dimensional model of the engine cooling system (radiator) is considered through a computational fluid code in which the mass flow rate for a range of the coolant temperature is assumed to be constant. By knowing the volumetric flow rate of the air passing over the radiator, the heat transfer rates for different aluminium-oxide nanofluid volume concentrations at different amphibious engine gears are determined. The analytical results indicate that a 7% aluminium-oxide nanofluid increases the engine radiator heat transfer performance by 24.9%, while the experimental results show that the coolant outlet temperature is about 3˚C lower than the case without the nanofluid in the coolant. Manuscript profile
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      321 - Theoretical and Experimental Study on Vibration of Cracked Shafts Using Order Analysis
      Mahdi Farahmandian Morteza Homayon Sadeghi
      In this paper, the effects of transverse cracks on rotating shaft were studied. According to earlier works, crack shaft failure decrease the critical speed of the shaft and also exhibit a nonlinear vibration behaviour leading to increases the amplitude of 1X and 2X harm More
      In this paper, the effects of transverse cracks on rotating shaft were studied. According to earlier works, crack shaft failure decrease the critical speed of the shaft and also exhibit a nonlinear vibration behaviour leading to increases the amplitude of 1X and 2X harmonics (first and second order of rotational speed in torsional vibration). This suggests that the application of order analysis to be very effective. Moreover, vibrations arising from resonance frequencies of the system can be differentiated from other ones, by using this method. For this purpose in this article, first, un cracked and cracked shaft were mathematically modelled and numerical analysis was carried out to obtain the vibration response for both healthy and faulty shaft. Then order analysis method was applied on the vibration signals obtained from the model. Finally, an experiment was also carried out on a laboratory scale test rig to verify effectiveness of the order analysis in practice. The results show that the vibration orders arising from torsional vibration can be clearly sensed by the transducers installed on the supports which primarily measure the bending vibrations. Manuscript profile
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      322 - Finite element investigation and optimization of tool wear in drilling process of difficult-to-cut nickel base superalloy using response surface methodology
      Mojtaba Kolahdoozan Farhad Azimifar Saeed Rismani Yazdi
      In this research, our attempt is to monitor tool wear through the chip formations, forces, and temperature of edge of drill while drilling in superalloy plate to optimizes effective parameters, which lead to facilitate machining process to, improved tool life, and enhan More
      In this research, our attempt is to monitor tool wear through the chip formations, forces, and temperature of edge of drill while drilling in superalloy plate to optimizes effective parameters, which lead to facilitate machining process to, improved tool life, and enhance the productivity. In this study, Inconel718 superalloy material, and cemented coated carbide tool was selected for investigation of tool wear mechanism. Mathematical models were deduced by software Minitab to express the influence of the main cutting variables such as cutting speed, feed rate and tool diameter on tool wear. A wear process model of twist drill is established based on finite element method. The 3D FEA model established here provides a new approach for studying the mechanism of drill wear. The predictive models in this study are believed to produce values of tool wear close to those readings recorded experimentally with a 95% confident interval, verified using ANOVA. The result from the simulation results are agreed with experimental value and predictive value from RSM, proving the ability of the tool wear model in correctly forecasting the tool wear. Manuscript profile
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      323 - Bone Surface Model Development Based on Point Clouds Extracted From CT Scan Images
      I. Asheghi Bonabi S. J. Hemmati
      In the present study a procedure is proposed for the development of bone surface models by using point clouds that can be extracted from CT scan images. Since the images are as multiple two dimensional sections, three methods of surface fitting are considered: ruled, sk More
      In the present study a procedure is proposed for the development of bone surface models by using point clouds that can be extracted from CT scan images. Since the images are as multiple two dimensional sections, three methods of surface fitting are considered: ruled, skinning and global approximation methods. The required algorithms were discussed in fields of image processing and curve and surface fitting. For the purpose of further exploring the modelling requirements and results, and gaining further insights into the impacts of effective parameters, a computer program was developed. By adopting a detailed case study and analysis approach, three samples of the cattle’s bones were selected and scanned with CT scan. Similar protocols corresponding to the human body bones were used during the scanning process. Subsequently, the surface models of the sample output from the program were transferred to CAD software. Moreover, the samples were scanned with COMET5™scanner after removing the flashes surrounding the bones. It was observed that although the bone surface modelling is feasible within 0.25 and 0.75 mm accuracy range with these algorithms, skinning method works better compared to other two algorithms in terms of processing speed and increasing the ratio of data compaction. The use of control points balance algorithm and smoothing the contours, used in this paper, will greatly improve the performance of the program as well. Manuscript profile
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      324 - Numerical Analysis of Circular Pre-notched U-Channel Section Distortions in Cold Roll-Forming Process
      S. Sattar S. Mazdak E. Sharifi
      Cold roll forming is a process in which a metal sheet gets a desired section form by passing through a series of rotating rollers. Predicting the amount of the distortion in pre-notched cold formed sections still remains challenging in cold roll forming industry, depend More
      Cold roll forming is a process in which a metal sheet gets a desired section form by passing through a series of rotating rollers. Predicting the amount of the distortion in pre-notched cold formed sections still remains challenging in cold roll forming industry, depending on the shape and position of the holes. This study investigates the influence of variation of the design parameters on the defects of the U-channel sections produced by cold roll forming process with circular pre-notches. To analyze the important parameters in deforming the circular holes during the cold roll forming of U-channel sections, a three-dimensional finite element model has been taken into account. A range of variation for design factors in forming the U-channel sections with pre-notches is set, including radius of circular holes, distance between the holes and the flange edge, hole spacing, sheet thickness, and type of material. Furthermore, using the response surface methodology, a set of tests are designed and modeled employing Finite Element analysis. Afterward, a set of output parameters such as edge buckling, the wave of the holes, the change in hole size, hole spacing, and the distance between the holes and the edge of the flange, are considered. Utilizing Analyses Of Variance (ANOVA), the accuracy of the linear regression models was conducted in this study. The accuracy of the simulated models is examined by comparing the analysis results with the experimental results. Finally, the effect of the important parameters on the defects of the product has been extracted in both the statistical form as well as mathematical functions applying response surface methodology. The results show that as the radius of the hole increases, edge buckling increases. The increase of the hole radius increases the edge wave on the holes. The hole width of the product is bigger and the hole length is smaller than the nominal measuring. Manuscript profile
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      325 - Process Parameters Optimization to Improve Dimensional Accuracy of Stereolithography Parts
      sadegh Rahmati Farid Ghadami
      Stereolithography process limits wider applications due to low dimensional accuracy comparing with CNC. To improve accuracy and reduce part distortion, understanding the physics involved in the relationship between the setup input parameters and the part dimensional acc More
      Stereolithography process limits wider applications due to low dimensional accuracy comparing with CNC. To improve accuracy and reduce part distortion, understanding the physics involved in the relationship between the setup input parameters and the part dimensional accuracy is prerequisite. In this paper, a model is proposed to find and optimize important parameters to achieve a high accuracy and also, to prediction dimensional accuracy with various values of parameters. For this purpose, the result of a previous study is used. It is found in Stereolithography these factors, respectively, have a most impact on dimensional accuracy in parts built SLA: layer thickness, hatch style, hatch spacing, hatch fill cure depth and hatch overcure. The proposed neural network model in this paper is able to predict dimensional accuracy with about 6 percents error. Manuscript profile
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      326 - Design an Artificial Foot using Series Elastic Actuator
      Ali Moazemi goudarzi Hossein Kheirollahi Mohammad Fazeli Misagh Imani
      : Investigating the mechanical behaviour of a healthy human ankle shows that it can be simulated by a mechanism composed of simple elements such as spring, and actuator. Hence, appropriate design of this mechanism can be resulted to an artificial ankle that can help amp More
      : Investigating the mechanical behaviour of a healthy human ankle shows that it can be simulated by a mechanism composed of simple elements such as spring, and actuator. Hence, appropriate design of this mechanism can be resulted to an artificial ankle that can help amputees properly. Researches show that whatever the biomechanical behaviour of artificial ankle is similar to that of natural ankle, it can be used by consuming less energy. Considering biomechanical behaviour of normal ankle in a walking gait, required parameters for designing of an artificial ankle composed of springs and electromechanical actuator will be determined. Finally, to verify the suggested model, a prototype will be materialized and tested. Manuscript profile
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      327 - Numerical investigation of Electrohydrodynamic effect on Lift and Drag Forces on an airfoil in low Reynolds air flow
      Mostafa Ashna
      In this paper, the effect of electric field on two-dimensional low Reynolds air flow around an airfoil and variation of the forces acting on the airfoil is numerically investigated. The electric current and Poisson’s equations are solved and the outcome is considered as More
      In this paper, the effect of electric field on two-dimensional low Reynolds air flow around an airfoil and variation of the forces acting on the airfoil is numerically investigated. The electric current and Poisson’s equations are solved and the outcome is considered as a source term in the momentum equations. The energy equation is not considered due to its weak effect on the phenomena. The finite volume method is utilized to solve both the electrical and flow equations. The results demonstrate that the forces acting on the body can be altered and controlled by imposing high voltage electric field. Manuscript profile
    • Open Access Article

      328 - Engineering Design of the Guidance System of the 6R Tele-robot based on DTMF
      Moharam Habibnejad Korayem Saeed Rafee Nekoo A. Habibnejad Korayem
      In this article, the advantages of navigation based on dual tone multiple frequencies (DTMF) technique through telecommunication lines is studied. First, the calculations of direct and inverse kinematics of the manipulator in computer are transferred to the PIC micropro More
      In this article, the advantages of navigation based on dual tone multiple frequencies (DTMF) technique through telecommunication lines is studied. First, the calculations of direct and inverse kinematics of the manipulator in computer are transferred to the PIC microprocessors center. Next, each PIC is required to control and automate the relevant link separately. The main purpose of this work is making it possible to control the robot via a telephone line and without a modem. In order to apply this idea, computer is analyzed the data which received from the operator and insert the necessary instructions through the serial port using AVR microcontroller in the embedded hardware at the phone line and sends them to the hardware of the robot. Then the robot is performed the processes as a closed loop design and provides the necessary feedback for the computer. Real-time control, low volume of software and hardware computations and the possibility of using the phone lines with low and medium bandwidth in addition to ADSL lines simultaneously are the special features of this method. In the proposed method, control data and the corresponding feedbacks are transmitted as the remote closed loop control, which can be combined in the developing stages with other control methods such as neural networks which results the maximum productivity. At the end of this work, examination of the time delay of tele-controller system and experimenting according to the ISO9283 standard, specific to the accuracy of the robot, is carried out. Manuscript profile
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      329 - Stress distribution in functionally graded nanocomposite cylinders reinforced by wavy carbon nanotube
      Rasool Moradi-Dastjerdi M. M. Sheikhi H. R. Shamsolhoseinian
      This work reports the effect of nanotube aspect ratio and waviness index on stress and displacement distributions of functionally graded nanocomposite cylinders reinforced by wavy single walled carbon nanotubes based on a mesh-free method. The mechanical properties of t More
      This work reports the effect of nanotube aspect ratio and waviness index on stress and displacement distributions of functionally graded nanocomposite cylinders reinforced by wavy single walled carbon nanotubes based on a mesh-free method. The mechanical properties of these composites are assumed to be graded along radial direction and estimate by a micro mechanical model. In the mesh-free analysis, moving least squares shape functions are used for approximation of displacement field in the weak form of motion equation and the transformation method is used for the imposition of essential boundary conditions. Effects of CNT waviness and aspect ratio, kind of distribution and volume fraction of carbon nanotubes and also boundary conditions and thickness of cylinder are investigated on the static responses of these cylinders. It is observed that CNT waviness has a significant effect on the effective reinforcement of the nanocomposites. Manuscript profile
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      330 - VISCOUS DRAG REDUCTION ON AXISYMMETRIC BODIES USING HELICAL RIBLETS
      Ali Davari
      A series of subsonic wind tunnel tests was conducted on an ogive-cylinder-flare configuration at zero angle of attack to study the effects of small helical protuberances on viscous drag reduction behavior. The experiments have been carried out on a smooth model and two More
      A series of subsonic wind tunnel tests was conducted on an ogive-cylinder-flare configuration at zero angle of attack to study the effects of small helical protuberances on viscous drag reduction behavior. The experiments have been carried out on a smooth model and two wire-wrapped models with different spacing between the helical riblet rings, known as pitch length. In the present experiments, the pitch length to model diameter ratio for the wire-wrapped models were 0.5 and 1.0 and the velocity profiles at 19 streetwise locations as well as the pressure distribution on the model at the same positions have been measured and compared for the smooth model and the two wire-wrapped ones. The results show about %10 reduction in the local skin friction drag for the wire-wrapped model in comparison with the smooth one. The investigations also showed that depending on the boundary layer thickness, optimum values could be found for the riblet diameter and its pitch length for which, the maximum reduction would be achieved in the local friction drag Manuscript profile
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      331 - Experimental and Numerical Investigation of the Arms Displacement in a New Electrothermal MEMS Actuator
      M. Kolahdoozan A. Rouhani Esfahani M. Hassani
      Microgrippers can be effectively applied for handling, positioning and assembling of the micro components. In the present study, a new design of a U-shape electrothermal microgripper was fabricated and developed with the voltages correspond between 1 to 10 volts. The mi More
      Microgrippers can be effectively applied for handling, positioning and assembling of the micro components. In the present study, a new design of a U-shape electrothermal microgripper was fabricated and developed with the voltages correspond between 1 to 10 volts. The microgripper was made of silicone with thickness of 25 microns, and pieces between 460 to 480 microns. The proposed microgripper has a simpler design and more facile fabrication comparing to most reported electrothermal microgripper. The behavior of the microgripper was simulated in COMSOL software to measure the displacement of the arms which hold and heat generations during the voltage changes. The present microgripper has more thermal and voltage tolerance comparing to other electrothermal microgripper. Furthermore, the obtained amount of tip displacement for voltage changes is acceptable. Another simulation method based on a three layer artificial neural network model (ANN) was carried out. Feed forward back propagation algorithm was employed as training algorithm to predict the displacement. The obtained results from both models proved that ANN model had better estimation due to the mean absolute percentage error of 1.024% and determination coefficient of 0.9995. Moreover, they confirm higher capability and accuracy of ANN in prediction of arms displacement compared to FEM. Manuscript profile
    • Open Access Article

      332 - Experimental Investigation of Effective Parameters on a New Incremental Tube Bulging Method Using Rotary Tool
      S. M. H. Seyedkashi S. J. Hashemi Ghiri F. Rahmani
      Nowadays, dieless and flexible sheet forming methods are gaining much interest in prototyping and low production. In this research, a new method is developed to change the cross-sectional area of metal tubes in a longitudinal direction without using special dies. This t More
      Nowadays, dieless and flexible sheet forming methods are gaining much interest in prototyping and low production. In this research, a new method is developed to change the cross-sectional area of metal tubes in a longitudinal direction without using special dies. This technique is based on the force applied by a rotary tool to the inside/outside surface wall of a tube. The forming tool is mounted on a CNC milling machine and moves spirally with a specific pitch. In order to study the effects of process parameters on the product quality, a full factorial design of experiments was designed and performed. The input parameters were the feeding depth, forming pitch and tool velocity. Three responses including roughness, minimum thickness and production time were precisely measured for this purpose. The results showed that surface quality and minimum thickness is reduced with increasing the forming pitch and feeding depth. Tool rotational velocity does not have a significant effect on the forming parameters except for production time. Using a multi-objective response optimization, forming pitch of 0.25 mm, feeding depth of 1.25 mm and velocity of 800 mm/min were found to be the best configuration. Manuscript profile
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      333 - Numerical and Analytical Investigation of the Sandwich sheet Rolling Process ConsideringCoulomb Friction
      Vali Alimirzaloo
      Sandwich sheet rolling process is investigated using an analytical method (slab method) and a numerical method (finite element method). The horizontal stress distribution in the layers, the rolling pressure along the contact interface and the neutral point between the r More
      Sandwich sheet rolling process is investigated using an analytical method (slab method) and a numerical method (finite element method). The horizontal stress distribution in the layers, the rolling pressure along the contact interface and the neutral point between the roll and the sheet are investigated. Then the affects of the parameters such as the friction between the sheet and the roll, shear yield stress ratio of the matrix and clad layers, front and back tensions on the rolling characteristics such as the pressure and neutral point position are studied. The results demonstrate that the finite element method results are very near to the slab method resultsand extra simplifying assumptions in the slab method cause low deviance in the results. In both methods As the friction coefficient increases, the rolling pressure increases and the neutral point nears the entrance of the roll gap. As the shear yield stress ratio increases, the rolling pressure increases but the neutral point doesn’t transmitted. As the front or back tensions is applied on the sandwich sheet, the rolling pressure decreases and the neutral point transmitted inverse of the tension direction. Manuscript profile
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      334 - Fracture Toughness of HVOF Thermally Sprayed WC-12Co Coating in Optimized Particle Temperature
      M. Jalali Azizpour M. Salehi
      In this paper the fracture toughness of WC-12Co coatings in optimum particle temperature in high velocity oxy fuel (HVOF) process have been studied by means of Vickers indentation. Multiple linear regression model applying Minitab, were used to determine the relationshi More
      In this paper the fracture toughness of WC-12Co coatings in optimum particle temperature in high velocity oxy fuel (HVOF) process have been studied by means of Vickers indentation. Multiple linear regression model applying Minitab, were used to determine the relationship and interaction between HVOF parameters and particle temperature. For genetic algorithm optimization, the signal to noise ratio was applied as a functional output of design of experiments. The results of validation test show a good agreement between obtained optimum condition and the results of genetic algorithm. The fracture toughness obtained by Vickers indentation shows the direct effect of particle temperature on coating toughness. The maximum amount of signal-to-noise using the genetic algorithm for velocity and temperature is 53.07 and -64.62, which equals 450.2 m/s and 1702ºC respectively. The results show that the Fracture toughness of WC-12Co deposited by LPG fuel in smallest level of temperature is 2.83MPa(m)1/2 compared to 1.32MPa(m)1/2 in highest temperature. The spray watch diagnostic system, micro-hardness test, Vickers indentation, X-Ray diffraction, EDS and scanning electron microscopy have been used for this purpose. Manuscript profile
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      335 - Vibration Analysis of an Initially Pre-stressed Rotating Carbon Nanotube Employing Differential Transform Method
      Farzad Ebrahimi Gholam Reza Shaghaghi
      Abstract: In this paper, nonlocal Euler–Bernoulli beam theory is employed for transverse vibration analysis of an initially pre-stressed size-dependent rotating nanotube. The nonlocal Eringen theory takes into account the effect of small size, which enables the present More
      Abstract: In this paper, nonlocal Euler–Bernoulli beam theory is employed for transverse vibration analysis of an initially pre-stressed size-dependent rotating nanotube. The nonlocal Eringen theory takes into account the effect of small size, which enables the present model to become effective in the analysis and design of nanosensors and nanoactuators. Governing equations are derived through Hamilton’s principle and they are solved applying semi analytical differential transform method (DTM). It is demonstrated that the DTM has high precision and computational efficiency in the vibration analysis of nanotubes. The good agreement between the results of this article and those available in literature validated the presented approach. The detailed mathematical derivations are presented and numerical investigations are performed while the emphasis is placed on investigating the effect of the several parameters such as preload stress, hub radius, angular velocity and small scale parameter on vibration behaviour rotating nanotubes in detail. It is explicitly shown that the vibration of a spinning nanotube is significantly influenced by these effects.Keywords: Spinning carbon nanotube; Vibration; Differential Transform method; Nonlocal Elasticity Theory Manuscript profile
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      336 - Prismatic Series of Elastic Actuator: Modelling and Control by ICA and PSO-tuned Fractional Order PID
      Somayeh Norouzi Ghazbi Alireza Akbarzadeh
      Abstract: This paper presents dynamic modelling and control of a linear prismatic series of elastic actuator. The capability of generating large torques is why this actuator is increasingly used in human-assistive robotic systems. Due to having human in the loop, the ac More
      Abstract: This paper presents dynamic modelling and control of a linear prismatic series of elastic actuator. The capability of generating large torques is why this actuator is increasingly used in human-assistive robotic systems. Due to having human in the loop, the actuator requires precise control. A fractional PID controller known for its improved performance is used for the control, due to having additional degrees of freedom than the classical PID. The actuator has one servo driver and five controller gains to be tuned. The gains are optimized using both Particle Swarm Optimization (PSO) and Imperialist Competitive Algorithms (ICA). Comparison of the results from the two optimization methods illustrates that the PSO tuned FOPID controller has a slightly better performance, faster convergence and better settling time. Next, the PSO tuned controller is compared with a Genetic Algorithm (GA) tuned PID controller. It is shown that the PSO tuned FOPID controller continues to offer better performance, especially in terms of its rise time and settling time.Keywords: Series elastic actuator, Fractional order PID, Imperialist competitive algorithm, Particle swarm optimization, Control Manuscript profile
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      337 - Analytical Solution for Buckling of Composite Sandwich Truncated Conical Shells subject to Combined External Pressure and Axial Compression Load
      Foozieh Morovat
      Abstract: The present study deals with the buckling analysis of the laminated composite truncated conical sandwich shells with flexible core subjected to combined axial compressive load and external pressure. Higher order governing equations of the motion are presented More
      Abstract: The present study deals with the buckling analysis of the laminated composite truncated conical sandwich shells with flexible core subjected to combined axial compressive load and external pressure. Higher order governing equations of the motion are presented for conical composite sandwich shells, where they are derived from the Hamilton principle. Then, by the use of Improved Higher-order Sandwich Shell Theory, the base solutions of the governing equations are obtained in the form of power series via general recursive relations. The first order shear deformation theory is used for the face sheets and a 3D-elasticity solution of weak core is employed for the flexible core. By application of various boundary conditions such as clamped and simply-supported edges, the natural frequencies of the conical composite sandwich shell are obtained. The obtained results are compared with the numerical results from FEM analysis and good agreements are achieved. An extensive parametric study is also conducted to investigate the effect of total thickness to radius ratio on the buckling load.Keywords: Buckling, Composite, Sandwich Truncated Conical Shell, Combined Load Manuscript profile
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      338 - The Effects of Local Variation in Thermal Conductivity on Heat Transfer of a Micropolar Fluid Flow Over a Porous Sheet
      Reza Keimanesh Cyrus Aghanajafi
      This study is considering a micropolar fluid flow over a porous stretching sheet in the presence of thermal radiation and uniform magnetic field. The effects of local variation in thermal conductivity of micropolar fluid on heat transfer rate from the sheet are investig More
      This study is considering a micropolar fluid flow over a porous stretching sheet in the presence of thermal radiation and uniform magnetic field. The effects of local variation in thermal conductivity of micropolar fluid on heat transfer rate from the sheet are investigated; besides, the impacts of radiation, magnetic field and porous sheet on variations of thermal boundary layer thickness are considered. The results show that the increase of thermal conductivity thickens thermal boundary layer, so heat transfer rate decreases. In addition, intensification of magnetic field and the presence of radiation lower the absolute values of temperature gradient on the wall, and reduce the cooling rate of the sheet. On the contrary, the increase of suction and material parameter has positive influence on cooling rate of the sheet. Manuscript profile
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      339 - Finite Element Simulation and Experimental Study on Energy Absorption of 3D Woven Glass Fiber Composite Sandwich Panels
      Amir Shirani Mohsen Lohmousavi
      Abstract: In this paper, the results of experimental and numerical simulation of low velocity impact process have been carried out to investigate energy absorption of composite sandwich panels with 3D woven fabrics of glass fibers and epoxy resin. For this purpose, diag More
      Abstract: In this paper, the results of experimental and numerical simulation of low velocity impact process have been carried out to investigate energy absorption of composite sandwich panels with 3D woven fabrics of glass fibers and epoxy resin. For this purpose, diagrams of force-displacement of the quasi-static and quasi-dynamic impact tests were studied. For the finite element simulation, Sandwich panel is considered as a composite material with anisotropic elastic properties. In this simulation, Hashin’s damage criteria have been used to model the fracture mechanics. The energy absorption in quasi-dynamic test is greater than the quasi-static test. Comparison of the numerical and experimental simulation shows good agreement between the results.Keywords: 3-Dimensional reinforcement, Impact behavior, Finite element analysis (FEA), Lay-up (manual/automated) Manuscript profile
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      340 - Dynamic Modeling and Sensitivity Analysis of the Spherical Nanoparticle Topography using Piezoelectric Microcantilevers
      Reza Ghaderi
      Piezoelectric microcantilevers (MCs) are a new generation of microbeams used in atomic force microscopes (AFMs). Due to their miniaturization of AFMs as well as their increased imaging precision and speed, these MCs are more popular than their classical counterparts. Gi More
      Piezoelectric microcantilevers (MCs) are a new generation of microbeams used in atomic force microscopes (AFMs). Due to their miniaturization of AFMs as well as their increased imaging precision and speed, these MCs are more popular than their classical counterparts. Given the widespread application of these beams in nanoparticle topography, analysis of their vibrating motion has attracted much attention in research circles. Exact vibratiing analysis as well as study of the vibrating motion of these beams plays a key role in increasing their measuring accuracy in topography, and contribute to their optimum design. To this end, the nonlinear differential equation of vibratiing motion of a MC was initially derived through Lagrange’s method. Subsequently, the modal analysis and multiple time scale (MTS) methods were implemented to obtain an analytical solution to this equation. The effect on the nonlinear vibrational motion of the interaction between the nanoparticle and the probe was studied. The extended Fourier amplitude sensitivity test (eFAST) was conducted to analyze the nonlinearity sensitivity of the motion. The results obtained from this analysis made it possible to determine optimal geometric dimensions for the MC to increase its sensitivity to motion nonlinearity. Simulation results showed that, at higher inclined angles, the MC sensitivity to vibrational motion nonlinearity increased. The sensitivity analysis results revealed that the MC thickness and the length of its tip had the greatest effect on the MC sensitivity to the nonlinear force of interaction. Manuscript profile
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      341 - Numerical Simulation of Turbulent Nano-fluidFlow in a Circular Elbow
      Afshin Ahmadi Nadooshan Marzieh Jafari farsani
      force convection heat transfer of turbulent nano fluid flow in 90 and 60 degree elbow is simulated by using FLUENT. Single phase model has been implemented to study such a flow field and standard
      force convection heat transfer of turbulent nano fluid flow in 90 and 60 degree elbow is simulated by using FLUENT. Single phase model has been implemented to study such a flow field and standard Manuscript profile
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      342 - Ultrasonic Assisted Equal Channel Angular ‎Extrusion Process ‎‎(UAECAE)‎
      Hamed Razavi Yaghoub Tadi Beni Mohammad Baharvand
      Equal channel angular extrusion (ECAE) is one of the most powerful processes for manufacturing microstructure and nanostructure ‎materials. This process is a kind of severe plastic deformation technique, which requires large extrusion force. In this study, the numer More
      Equal channel angular extrusion (ECAE) is one of the most powerful processes for manufacturing microstructure and nanostructure ‎materials. This process is a kind of severe plastic deformation technique, which requires large extrusion force. In this study, the numerical and experimental investigation of extrusion ‎force in ultrasonic assisted equal channel angular extrusion process (UAECAE) is carried out. ABAQUS Software is used for 2D ‎finite element analysis of the process considering superimposed ultrasonic vibrations to the round billet work material. Experimentally, the conventional and ultrasonic assisted ECAE are performed with copper material to validate simulation results. The reduction in extrusion force is observed due to ultrasonic vibrations. In order to achieve more ‎average force reduction, it is recommended that the ‎extrusion speed decreases and (or) vibrations amplitude ‎increases. Stress and strain distributions are numerically investigated in various vibrational conditions and die angles. The best die angle to obtain optimum force ‎reduction is 120º. In other die angles, vibrations ‎amplitudes of 15‎ μm‎ and higher ‎is necessary. Ultrasonic vibrations lead to oscillatory stresses with reduced ‎average value, but do not influence the amount of plastic strain ‎distribution. Achieving the beneficial products in ‎ECAE requires heavy special equipment, whereas using UAECAE will lead to more accessible equipment. ‎Finally, some optimal process parameters such as die angle, vibrations amplitude, for the proper application of these vibrations are ‎proposed. Manuscript profile
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      343 - Development of Boundary Layer of Highly Elastic Flow of the Upper Convected Maxwell Fluid over a Stretching Sheet
      Meysam Mohamadali Nariman Ashrafi
      High Weissenberg boundary layer flow of viscoelastic fluids on a stretching surface has been studied. The flow is considered to be steady and two dimensional. Flows of viscoelastic liquids at high Weissenberg number exhibit stress boundary layers near walls. These bound More
      High Weissenberg boundary layer flow of viscoelastic fluids on a stretching surface has been studied. The flow is considered to be steady and two dimensional. Flows of viscoelastic liquids at high Weissenberg number exhibit stress boundary layers near walls. These boundary layers are caused by the memory of the fluid. Upon proper scaling and by means of an exact similarity transformation, the non-linear momentum and constitutive equations of each layer transform into the respective system of highly nonlinear and coupled ordinary differential equations. Effects of variation in pressure gradient and Weissenberg number on velocity profile and stress components are investigated. It is observed that the value of stress components decrease by Weissenberg number. Moreover, the results show that increasing the pressure gradient results in thicker velocity boundary layer. It is observed that unlike the Newtonian flows, in order to maintain a potential flow, normal stresses must inevitably develop in far fields. Manuscript profile
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      344 - Experimental Study and Finite Element Simulation of Residual Stress in Welded Sections of Steel P91 Pipes with Multi-pass Welding
      Davood Azadi Nosratollah Solhjoei SayedAli Mousavi
      All the producing and assembling processes exert residual stress on the pieces that may lead to structural failure. Therefore, calculating the residual stress in such structures has been common in recent years. In this article, distribution of temperature and residual s More
      All the producing and assembling processes exert residual stress on the pieces that may lead to structural failure. Therefore, calculating the residual stress in such structures has been common in recent years. In this article, distribution of temperature and residual stress resulting from arc welding in three-pass butt joint in P91 austenitic stainless steel pipes is calculated and estimated using the finite element method and experimental data. Simulating the welding process has been carried out three- dimensionally using Abaqus software. Distribution of the arc thermal flux has been identified based on the Goldak two-elliptical model using DFLUX subprogram in Abaqus software. The numerical method has been employed by doing thermoelastoplastic analysis and the technique of birth and death of the elements to model the welding passes and the melted elements. Then, using central hole drilling method, residual stress gradient of the thickness at distance 3mm from the welding line on the pipe is measured. Finally, the maximum percentage of error, through the results obtained from experimental measurements and finite element method, was reported 27% which is scientifically reasonable. The results show that the residual environmental stress in the internal surface of the pipe from the welding central line to 8.7mm varies with the gradient of 610MPa from 296MPa to -314MPa. Such a drastic stress distribution leads to genesising some cracks on the welded pipes. Manuscript profile
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      345 - Numerical Simulation of Fluid Flow in Random Granular Porous Media using Lattice Boltzmann Method
      MohamadMehdi Keshtkar
      In this paper, fluid flow between two parallel flat plates that are partially filled with two-dimension porous media is investigated numerically using single relaxation time (SRT) lattice Boltzmann method (LBM) at pore scale. The considered obstacles are random, circula More
      In this paper, fluid flow between two parallel flat plates that are partially filled with two-dimension porous media is investigated numerically using single relaxation time (SRT) lattice Boltzmann method (LBM) at pore scale. The considered obstacles are random, circular, rigid and granular with uniform diameters. Single component and single-phase viscous Newtonian fluid are considered as working fluid. There are no overlaps between obstacles. It supposed incompressible, steady and laminar flow and no chemical reaction performed in porous media. Velocity vectors and streamlines in this domain depicted. The effect of varying Reynolds number on the pressure drop or pressure gradient and Darcy drag are studied. Dimensionless permeability calculated as a function of porosity and Knudsen number. To vary porosity, obstacles diameter changed but their places considered constant. With increasing Knudsen number, the dimensionless permeability is increased. In addition, effect of domain resolution on pressure gradient investigated. The results demonstrate that lattice Boltzmann method will be very useful in fluid flow simulation through porous media. Manuscript profile
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      346 - Studying the Shear and Discharge Rate of Proteins in Microfluidic Junctions, Under Electrokinetic EffectsStudying the Shear and Discharge Rate of Proteins in Microfluidic Junctions, Under Electrokinetic Effects
      Babak kamali Doust Azad Sasan Asiaei Borhan Beigzadeh
      Changes of hydrodynamic parameters in microchannel branches affect the suspended biological samples in blood. To prevent denaturation and hemolysis, we have numerically investigated the effect of divergence angle on shear rate and velocity at branch entrance (discharge More
      Changes of hydrodynamic parameters in microchannel branches affect the suspended biological samples in blood. To prevent denaturation and hemolysis, we have numerically investigated the effect of divergence angle on shear rate and velocity at branch entrance (discharge rate), under electroosmotic flow. In such flow, hydrodynamic properties are also affected by zeta potential at the microchannel walls. We have also studied the effect of change of zeta potential (ξ) proportion at main channel wall (ξ1) to that of branch channel (ξ2), on the discharge rate to find its maximum for different divergence angles. In the divergence angle of 60° and while zeta potential at the branch wall is equal to its value at main channel wall, the tendency of particles to pass through the branch is the highest among all examined degrees. At the zeta potential proportion of ( ξ1/ξ2 =0.5), the change of divergence angle has almost no effect on the maximum velocity in the branch. In addition, with increase of divergence angle from 60° to 150°, the shear rate at the branch will become 2.1 times higher. Manuscript profile
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      347 - Numerical Study of Coupled Non-Gray Radiation and Separation Convection Flow in a Duct using FSK Method
      Meysam Atashafrooz Seyyed Abdolreza Gandjalikhan Nassab Khosro Lari
      In this research, the coupling between non-gray radiation and separation convection flow in a duct is investigated numerically. Distributions of absorption coefficients across the spectrum are obtained from the HITRAN2008 database. The full-spectrum k-distribution metho More
      In this research, the coupling between non-gray radiation and separation convection flow in a duct is investigated numerically. Distributions of absorption coefficients across the spectrum are obtained from the HITRAN2008 database. The full-spectrum k-distribution method is used to deal with the non-gray part of the problem, while the gray radiation calculations are performed using the Planck mean absorption coefficient. To find the divergence of radiative heat flux distribution, the radiative transfer equation (RTE) is solved by the discrete ordinates method (DOM). The effects of radiation-conduction parameter, scattering coefficient and wall emissivity on thermal behaviors are investigated for both gray and non-gray mediums. In addition, the results of gray medium are compared with non-gray results as a real case. The results show that in many cases, use of gray simulations is not acceptable and leads to significant errors, especially in non-scattering medium with high values of radiation-conduction parameter and wall emissivity. Manuscript profile
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      348 - Mechanical Properties and Microstructural Evolution of AA5083/Al2O3 Composites Fabricated by Warm Accumulative Roll Bonding
      Mohammad Heydari Vini M. Sedighi Mehdi Mondali
      In this study, warm accumulative roll bonding (Warm- ARB) process has been used to produce Metal Matrix Composite (MMC: AA5083/-5% Al2O3). Starting materials were roll bonded as alternate layers up to 5 rolling cycles with 300°C preheating for five minutes before ea More
      In this study, warm accumulative roll bonding (Warm- ARB) process has been used to produce Metal Matrix Composite (MMC: AA5083/-5% Al2O3). Starting materials were roll bonded as alternate layers up to 5 rolling cycles with 300°C preheating for five minutes before each cycle. The microstructure and mechanical properties of composites have been studied after different Warm- ARB cycles by tensile test, Vickers micro hardness test and scanning electron microscopy (SEM). The results revealed that during higher Warm- ARB cycles, breaking the layers of alumina particles led to the generation of elongated dense clusters with smaller sizes. This microstructural evolution led to improvement in the hardness, strength and elongation during the Warm- ARB process. The results demonstrated that the dispersed alumina clusters improved both the strength and tensile toughness of thecomposites. Finally, Warm- ARB process allowed producing metal particle reinforced with high uniformity, good mechanical properties and high bonding strength. Manuscript profile
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      349 - Trajectory Path Planning of Cable Driven Parallel Manipulators, Considering Masses and Flexibility of the Cables
      Sobhan Sohrabi H. R. Mohammadi Daniali A. R. Fathi
      Cable driven parallel manipulator (CDPM) is a special class of parallel manipulator in which the rigid extensible links are replaced by actuated cables. It is necessary to take into consideration the cable dynamics, i.e.; its mass, flexibility and curved shape for manip More
      Cable driven parallel manipulator (CDPM) is a special class of parallel manipulator in which the rigid extensible links are replaced by actuated cables. It is necessary to take into consideration the cable dynamics, i.e.; its mass, flexibility and curved shape for manipulating a long-span CDPM. These terms complicate governing equation of motion in a way that special tactic are applied for simulation and solving this problem. Flexibility and mass of cables impose vibration and error in path trajectory planning. Effect of varying stiffness in precise performance of CDPM is surveyed. The cables are modelled, in ADAMS software to illustrate the dynamical behaviours of the manipulator for comparison with the simulated results. Moreover, an algorithm is developed to study the effects of velocity and acceleration of the end-effector on the dynamics of CDPMs. Moreover it is shown that the evolutionary computing algorithms are so effective in solving complicated nonlinear dynamic path trajectory planning. Simulations for different trajectories of two CDPMs are included to demonstrate the efficiency of the proposed algorithm. Manuscript profile
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      350 - Experimental Investigation of Incremental Forming Process of Bilayer Hybrid Brass/St13 Sheets
      R. Ashouri H. Shahrajabian
      In this study, the incremental forming of two layers’ brass/St13 sheets through the single-point process was experimentally examined. To investigate the formability of sheet in this process, the desired shape was designed through solid works software, and then sur More
      In this study, the incremental forming of two layers’ brass/St13 sheets through the single-point process was experimentally examined. To investigate the formability of sheet in this process, the desired shape was designed through solid works software, and then surf cam application was used to observe tool motion and extraction of CNC program. G-codes were transferred to the CNC machine and the incremental bilayer sheets forming process was carried out in two different modes, that is, in one case, the brass sheet was placed on top and the steel sheet below, and in the other case they exchanged places. Afterwards, the effects of parameters such as forming tool diameter, vertical step size, and feed rate at three levels on fracture height, fracture angle, and strain were studied. In order to minimize the experiments, the experiment design based on response surface method (RSM) was employed. The results indicated that by increasing the tool diameter, vertical step, feed rate, the fracture angle, and fracture height decreased. The maximum fracture height and angle were estimated 46.5 mm and 71.44 degree, respectively, with tool diameter of 10 mm, speed of 1800 mm/min, and vertical step size of 0.25 mm. According to strain measurement results, steel sheets could bear higher strain rate than brass sheets, and in the case that the steel sheet was on top, the fracture height of bilayer sheet increased. The maximum strain of 0.72 was obtained in SB mode with tool diameter of 10 mm, feed rate of 1000 mm/min and vertical step of 0. 5. Manuscript profile
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      351 - Evaluation of Parameters Affecting Magnetic Abrasive Finishing (MAF) of Superalloy Inconel 718
      Mehrdad Vahdati SeyedAlireza Rasouli
      Superalloys generally are among the materials with poor machinability. The removal of metal contaminations, stains, and oxides can positively affect their performance. Magnetic Abrasive Finishing (MAF) is a method which uses a magnetic field to control the material remo More
      Superalloys generally are among the materials with poor machinability. The removal of metal contaminations, stains, and oxides can positively affect their performance. Magnetic Abrasive Finishing (MAF) is a method which uses a magnetic field to control the material removal. As another advantage, this method can be used to polish materials such assuperalloys which have high strength and special conditions. In this paper, we investigated the magnetic abrasive finishing of nickel-base superalloy Inconel 718. Since the process is highly influenced by several effective parameters, in this study we evaluated the effects of some of these parameters such as percentage of abrasive particles, gap, rotational speed, feed rate, and the relationship between size of abrasive particles and the reduction of average surface roughness. Using Minitab software package the experiments were designed based on a statistical method. Response surface method was used as the design of the experiment. The regression equation governing the process was extracted through the assessment of effective parameters and analysis of variance. In addition, the optimum conditions of MAF were also extracted. Analysis of the outputs of MAF process experiments on IN718 revealed that gap, weight percent of abrasive particles, feed rate, rotational speed, and size of abrasive particles were the factors that affected the level of changes in surface roughness. The distance between the magnet and the work piece surface, i.e. the gap, is the most important parameter which affects the changes in surface roughness.  The surface roughness can decrease up to 62% through setting up the process at its optimum state i.e. in a rotational speed of 1453 rpm, feed rate of 10 mm/min, percentage of abrasive particles equal to 17.87%, size of particles equal to #1200, and gap size of 1 mm. There is a discrepancy of 13% between this prediction and the predicted value by the regression model. With mounting a magnet with a different pole beneath the work piece, magnetic flux density increases up to 35%. Manuscript profile
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      352 - Experimental Study of the Effect of Impeller Geometrical Parameters on Fluid Hydrodynamics in Copper Solvent Extraction Mixer
      S. Parvizi S. Aosati E. Keshavarz Alamdari
      Dynamic mixers are widely used in hydrometallurgical processes. Improvement in mixers’ efficiency is one of the greatest challenges in this research.The geometrical factors of the impeller are of the most important elements affecting hydrodynamics and efficiency. More
      Dynamic mixers are widely used in hydrometallurgical processes. Improvement in mixers’ efficiency is one of the greatest challenges in this research.The geometrical factors of the impeller are of the most important elements affecting hydrodynamics and efficiency. Type, diameter, speed and off-bottom clearance of impeller are investigated in this work. These factors are validated by experimental setup. Mixing time is assumed fixed. Materials composition is set according to solvent extraction unit of Sarcheshmeh copper complex, Iran. The setup is manufactured according to the mixer dimensions in industrial unit. The hydrodynamic behavior of mixture is visualized by using an advanced imaging and lighting system. The effect of impeller speed in the range of 75 to 275 rpm on the position of eddies and fluid hydrodynamics are investigated. According to the results, at impeller speeds more than 200 rpm dead zones around the baffles are intend to be vanished. Furthermore, the effect of off-bottom clearance on hydrodynamics is studied. Optimum clearance to tank diameter ratio are determined 0.4 and 0.33 for 100 and 200 rpm, respectively. Results shows Rushton impeller with 6 vertical blades and impeller to tank diameter of 0.33 is optimum. Manuscript profile
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      353 - Fuzzy-GSA Based Control Approach for Developing Adaptive Cruise Control
      M. Bostanian
      Adaptive Cruise Control (ACC) controls vehicle speed and its distance to the proceeding vehicle in the same lane. In this paper a two-level control architecture is proposed to control both velocity and distance to the leading vehicle by taking advantage of fuzzy logic c More
      Adaptive Cruise Control (ACC) controls vehicle speed and its distance to the proceeding vehicle in the same lane. In this paper a two-level control architecture is proposed to control both velocity and distance to the leading vehicle by taking advantage of fuzzy logic control (FLC) approach. Then the control parameters were tuned by Gravitational Search Algorithm (GSA) to ensure achieving the fastest and most accurate control response. To evaluate performance of the proposed scheme, a speed profile was developed in simulation based test platform to measure performance of the proposed ACC in different maneuvers including some velocity tests and a distance control maneuver. The results revealed that the proposed approach had a stable and fast response which satisfied the requirements of an ACC. Manuscript profile
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      354 - Precision Force Measurement and Control in Micro Ultrasonic Machining
      Hamid Zarepour Firouzabadi
      Micro ultrasonic machining (Micro-USM) is a process with a great capability to generate micro features in hard and brittle materials. Despite some developments in micro-USM process, issues such as precision measurement and control of the machining force, which is crucia More
      Micro ultrasonic machining (Micro-USM) is a process with a great capability to generate micro features in hard and brittle materials. Despite some developments in micro-USM process, issues such as precision measurement and control of the machining force, which is crucial for stable machining conditions, need further investigations. In this paper, the precision measurement and control of the machining force is studied using a newly-developed force measurement configuration. The results of the force measurement for different levels of static force, abrasive particle size and amplitude of vibration demonstrated that the variation of measured machining force increases at higher static forces. Furthermore, a better control over the static load was acquired when feeding the abrasive slurry with particle size of 0.37 mm as compared to 1 mm and 3 mm particles leading to more stable machining conditions in micro-USM process. Finally, applying lower levels of vibration amplitude to the workpiece resulted in more stable machining conditions and lower static load errors. Manuscript profile
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      355 - Impact of Energy Dampers in Improvement of Impulsive Response of Double Layer Grids Space Structures
      H. Zarrintala A. Maleki M. Darvishhashemi
      The main purpose of the study is to evaluate the effectiveness of these dead-points mono laterally in controlling the space location of the structures against the explosion loading in this regard. For the reason, nonlinear dynamical analyses on three kinds of structures More
      The main purpose of the study is to evaluate the effectiveness of these dead-points mono laterally in controlling the space location of the structures against the explosion loading in this regard. For the reason, nonlinear dynamical analyses on three kinds of structures under two layers’ space location with two dead-points of FLD (Force Limiting Device) and TID (Tube Inversion Device) and without dead-point for explosion loading have been carried out and the related results were compared together in this case. For the related analysis, ABAQUS/Explicit software has been applied efficiently. This study shows that the destructor of inversed energy of the TID has an influential impact on the reduction of the displacement in this case. Manuscript profile
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      356 - Geometrical Parameters of Rectangular AFM Cantilevers Producing Highest Sensitivity in Excitation of Second Mode in Air Environment
      Mehrnoosh Damircheli
      Today, improving the quality of the images acquired by the atomic force microscope (AFM) and obtaining the close properties of various samples are among the most important and challenging issues tackled by researchers. One of the key mechanisms of achieving these object More
      Today, improving the quality of the images acquired by the atomic force microscope (AFM) and obtaining the close properties of various samples are among the most important and challenging issues tackled by researchers. One of the key mechanisms of achieving these objectives is the excitation of higher modes, which raises the sensitivity of the AFM and consequently improves the resolution. To attain this goal, it is imperative to design or select a type of cantilever which is able to excite the second mode and produce maximum sensitivity in higher modes, especially the second mode. In this paper, an AFM cantilever with rectangular cross section has been investigated in air medium. The cantilever has been modeled by the Timoshenko beam model and the normal and tangential forces between cantilever tip and sample have been considered in the simulations. By changing the geometrical parameters of the AFM’s cantilever and tip including length, width, thickness of cantilever, the angle between cantilever and sample surface, mass of tip, length of tip and Radius of tip, the frequency ratio of the second mode to first mode varies. The geometrical parameters that produce the minimum frequency ratio can increase the self-excitation probability of the second mode due to the excitation of the first mode simultaneously. The optimum geometrical parameters are derived that can increase the chance of higher mode excitation. The results indicate that the sensitivity of the second mode to sample stiffness also increases optimal geometrical parameters that yield the minimum frequency ratio; and, as a result, a higher contrast is achieved and it leads users to utilize the cantilevers with optimum geometry for achieving best contrast in imaging and properties estimation of unknown samples. Manuscript profile
    • Open Access Article

      357 - Workspace Analysis of 2-PR(Pa)U- 2-PR(Pa)R New Parallel Mechanism
      Mehran Mahboubkhah Sajjad Pakzad
      Parallel kinematic machines, are closed loop structures which have more accuracy, stiffness and ability to withstand high loads. Kinematic of these mechanisms is complicated due to their closed–loop structure, parallel pods, joint constraints and movement constrai More
      Parallel kinematic machines, are closed loop structures which have more accuracy, stiffness and ability to withstand high loads. Kinematic of these mechanisms is complicated due to their closed–loop structure, parallel pods, joint constraints and movement constraints. This paper proposes a new parallel mechanism that has four degrees of freedom. In workspace analysis algorithm, conversion of inverse kinematics after providing the moving platform position (position and orientation) from search algorithm, provides basis position for testing the physical limitations of machine. Workspace of the mechanism is obtained by extracting analytical relations and consequently computational programs are written in MATLAB software. Sweep operations is started by dividing the workspace into x – y planes or horizontal sections with fixed spaces of z, then after sweeping all points of the plane, sweep operations of the next plane begins.Constraints and physical limitations considered in this mechanism includes moving restriction of saddle, collision of basis to rails, joint angles and collision of basis to moving platform. If any of these limits are violated, considered point would not be considered in the workspace. Then, to evaluate the correctness of the obtained results of workspace analysis, a suggested mechanism is simulated in SolidWorks software and obtained workspace is validated in this study. Also position kinematic and workspace analysis results are verified experimentally. Manuscript profile
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      358 - Estimation of Thrust Stand Structure Fatigue Life Under Solid Motors Random Vibrations Effects
      Mojtaba Heydari Saeed MahjoubMoghadas Ebrahim Harirbafan AmirAlaedin Motallebi
      Successful development, evaluation, and qualification of propulsion systems such as turbojet and turbofan engines and rocket motors require the measurement of the performance and reliability of these systems. Thrust stands or testers are instruments for solid and liquid More
      Successful development, evaluation, and qualification of propulsion systems such as turbojet and turbofan engines and rocket motors require the measurement of the performance and reliability of these systems. Thrust stands or testers are instruments for solid and liquid motors test. In this paper, a method for calculating of solid motors random vibrations effects on a thrust stand structure is developed. At first some Power Spectral Density (PSD) of three kinds of solid motors has been calculated by MATLAB codes. Then a typical thrust stand which has been designed based on special dynamics principles, has been modeled in Solidworks and transferred to ANSYS. In ANSYS, the structure has been analyzed modal and spectral. Then each motor's PSD has been applied on structure separately and maximum stress has been determined by ANSYS codes. Fallowed by structure fatigue life has been estimated by a formula derived from compound of Miner's cumulative fatigue damage ratio equation and Gaussian distribution curve. Results showed amount of PSD at first frequencies has more effect on structure fatigue life and just based on maximum motor thrust can not come to a definite conclusion about the vibrations effects. Manuscript profile
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      359 - Design and Weight Optimization of Pin Loaded Composite Plates
      Mohamad Alipour Mahmoud Mehrdad Shokrieh
      In design and optimization process of laminated composite structures, the number of layers, layer angles, stacking sequence, material types and etc should be specified. Each of aforesaid parameters can be applied as a design variable. In this paper the target is to mini More
      In design and optimization process of laminated composite structures, the number of layers, layer angles, stacking sequence, material types and etc should be specified. Each of aforesaid parameters can be applied as a design variable. In this paper the target is to minimize the weight of laminated composite pin loaded structures. The laminated composite structures are designed based on the load of pin.Pin mounting in laminated composite plates causes stress concentration around the hole of pin. In this research the programming facility of FE software (ANSYS) is used for design and optimization of laminated plate. Constrains of minimization problem is based on Tsai-Wu criterion. The pin loaded plate is divided to two regions: the around of hole and far away from hole. The optimization process is solved concurrently and interactively for two regions. The selected stacking sequences are the quasi isotropic, cross ply and angel ply. The target is to obtain a configuration with accessible number of plies. For this reasom the branch and bound method was used.The obtained results show that the quasi isotropic plate is stronger than cross ply plate and cross ply plate is stronger than angle ply plate. But this order is reversed in a special load. In the other words the cross ply plate is being stronger than quasi isotropic plate in this case. In this paper also effect of geometric parameters over the strength of pin loaded plates are investigated. Manuscript profile
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      360 - Numerical Study of Increasing Error Order in Finite Difference Method Used for Analyzing the Rectangular Isotropic Plate's Vibration Behavior
      MohamadHosein Kargarnovin Kasara Karbaschi Hasan Hasanzadeh
      Now a days, structures with planar geometry such as Sheet metals, have attracted special consideration among advanced techno logia, and hence investing vibration behavior of sheet metal is of prim important . In particular regarding dynamical investigations, if the natu More
      Now a days, structures with planar geometry such as Sheet metals, have attracted special consideration among advanced techno logia, and hence investing vibration behavior of sheet metal is of prim important . In particular regarding dynamical investigations, if the natural frequencies get ignored, the resonance phenomena can exert noun computing damages to the structure and systems. In this research for investigating the plates' vibration behavior, finite difference method with error orders of and is implemented. At first, the classical and analytical solutions are reviewed and then relevant equations, needed for numerical analysis, are extracted for those mentioned error orders. Finally the obtained natural frequencies for both modes are compared non-dimensionally. In this research , finite difference method using error order , is being applied for the first time, however the results of various references and simulation with ANSYS software are used to verify the outcome and accuracy of the proposed method. Manuscript profile
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      361 - Analysis of Liquid - Fuel Vortex
      Esmaeil Esfandiary Mehran Moradi Bouzar Ghasemi
      For a long time, many efforts have been taken on improving gas turbine performance to increase the propulsive force and keep the chamber walls cool. In this regard, implementation of cyclonic and vortex engines have been proposed. According to increasing in the engine e More
      For a long time, many efforts have been taken on improving gas turbine performance to increase the propulsive force and keep the chamber walls cool. In this regard, implementation of cyclonic and vortex engines have been proposed. According to increasing in the engine efficiency and keeping the chamber walls cool, the bidirectional vortex flow which is exited in the vortex engine, makes researchers more interested in it. In the vortex engine, due to its specific geometry, two vortex layers are established. The combustion occurs in the inner vortex layer, while the outer layer protects the walls from excessive heat transfer. The vortex engine with gas fuel and oxidizer has been manufactured in laboratory scale at Virginia Institute of Technology and it is under investigation. Practical usage of the vortex engine, with both liquid and solid fuels, has its own significance. Investigation and analysis of the flow field in such a chamber have been conducted in different research centers during last five years. The significant results of these studies are the analytical and numerical solution of the flow field by applying many simplifying assumptions. Selecting proper materials, determining the engine dimensions, designing injector plate, and some other parameters in engine manufacturing process require the flow field to be modeled in the combustion chamber which needs the governing equations to be solved. For investigating of the flow field in the vortex engine, the mass conservation, momentum conservation, and energy equations have to be solved. If the flow is turbulent, the equations become more complicated and many assumptions are needed to simplify the problem. Note that, by assuming the flow to be incompressible, the energy equation becomes segregated from the other equations. At the first stage, the goal of this project is to investigate the previous analytical solution and modify it to become compatible with other numerical and experimental results, provide numerical solution of the governing equations with the least possible assumptions, and compare the obtained numerical and analytical results with each other. Since the governing equations are non-linear and the flow is turbulent, it is impossible to solve the problem analytically in details. The flow will be simulated with respect to the result of numerical solution and applying the conventional methods and the results will be presented. It is to be noted that, if the fuel is liquid, modeling the spray combustion in a two-phase (gas-liquid) flow field is required, which will be described in this project as well. According to the flow field analysis, the propulsive and aero-dynamical results of the engine will be available, which are required to determine the designation parameters and manufacturing of the vortex engine test rig. Afterwards, by establishing the fundamental requirements for installing the appropriate test rig for the vortex engine, manufacturing of this test rig with its accessories will be described in details. The obtained results of this project, including the flow field investigation, test rig designation and implementation, are the first steps to achieve mass production of the vortex engine with both liquid and gas fuels which, according to its innovation and efficiency, has its own significance. Manuscript profile
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      362 - On Using the Fourth Order Finite Difference Method in Studying Orthotropic Rectangular Plate's Vibration Behavior
      MohamadHosein Kargarnovin Kasara Karbaschi Hasan Hasanzadeh
      Structures with planar geometries and analyzing their vibration behavior have attracted special and deep consideration these days. In this research for investigating the orthotropic plates' vibration behavior, finite difference method with error orders of and are implem More
      Structures with planar geometries and analyzing their vibration behavior have attracted special and deep consideration these days. In this research for investigating the orthotropic plates' vibration behavior, finite difference method with error orders of and are implemented. At first, the classical and analytical solutions are surveyed and then relevant equations, needed for numerical analysis, are extracted for those mentioned error orders. Finally the obtained natural frequencies for both modes are compared non-dimensionally. Also simulation with ANSYS software is performed for validation of the results and confirmation of the proposed method's accuracy. Manuscript profile
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      363 - Numerical Analyses of Steady Non-Newtonian Flow over Flat Plate on Intermediate Reynolds Numbers by Finite Volume Method
      Yashar Maghmoumi Sayed Mahmoud AbolHasan Alavi MohamadReza Safaei Iman Nourollahi
      Thepresent work attempts to characterize the flow of power-law fluids past a flat plate. However, since high viscosity (or equivalently low Reynolds number). Is often the case for non-Newtonian fluid flows, the errors resulting from applying boundary layer theory can be More
      Thepresent work attempts to characterize the flow of power-law fluids past a flat plate. However, since high viscosity (or equivalently low Reynolds number). Is often the case for non-Newtonian fluid flows, the errors resulting from applying boundary layer theory can be substantial and experimental or computational validation, which is often lacking, is particularly needed. This is part of the objective of the present paper. In this paper we consider a perpendicular grid, parallel to X and Y coordinate axis and to solve discretized form of the governing equations, control volume method and SIMPLE algorithm is compiled. Calculation have carried out writing a Visual Basic 6.0 language to test the reliability of the results comparisons are made with both Newtonian and fluent software in non-Newtonian case. It is found that at lower Reynolds numbers the boundary layer approximation is considered to be inadequate. All so the accuracy of boundary layers estimations are studied. The results show that by in creasing the power coefficient and fluid power the boundary layer size will increase and by decreasing them it will decrease. Manuscript profile
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      364 - Aerodynamic Parameter Corrections for Surface to Air Missiles Using Tail Flap Vibration Feedback
      AhmadReza Khougar Mohsen Azadeh
      The Transfer functions of missiles change during flight. For proper control and desired performance of missiles through different situations during flight, their aerodynamic derivatives and mass inertia parameters need to be corrected at different working points. In thi More
      The Transfer functions of missiles change during flight. For proper control and desired performance of missiles through different situations during flight, their aerodynamic derivatives and mass inertia parameters need to be corrected at different working points. In this paper the feedback of the tail flap vibrations are used to specify the gains and the aerodynamic parameters of a surface to air missile, for use in the transfer functions. The vibration characteristics of the tail flaps are usually good index of the missile’s speed and consequently its dynamic pressure which, can be used for aerodynamics and gain correction in different working points in the transfer functions. The vibration feedback from the tail flaps were used in a six degree of freedom missile simulation integrated with the tail flaps vibration model and the IMU model. Simulation results and its comparison with recorded results from test flights, shows that the vibration feedback from the tail flaps can quite adequately be used for estimation of missile speed, dynamic pressure, and correction of aerodynamic parameters of the transfer functions. Manuscript profile
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      365 - Application of the Inverse Heat Conduction Method in Identifying a Cavity Inside Materials
      MohamadMehdi Mizanadl Mohsen Dashti Mahmoud Khodadad
      In present paper, the inverse problem of cavity identification, i.e. determining the location and geometric shape of a cavity inside a two dimensional elastic body using temperature measurements obtained by performing a simple heat conduction test is investigated. The B More
      In present paper, the inverse problem of cavity identification, i.e. determining the location and geometric shape of a cavity inside a two dimensional elastic body using temperature measurements obtained by performing a simple heat conduction test is investigated. The Boundary Element Method (BEM) coupled with Genetic Algorithm (GA) and Conjugate Gradient Method (CGM) is used to solve this inverse problem. A fitness function which is the squared differences between measured temperatures and calculated ones at the same locations on the exterior boundary of a sample containing a cavity is minimized using CGM. Considering that inverse problems are generally ill-posed and local optimization methods require a good initial guess, a mete heuristic model based on GA for determining a good initial guess of the cavity is presented in this study. Then this initial guess is used by CGM to achieve accurate location and geometric shape of cavity. The major cases application of this research is in the casting industry. Manuscript profile
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      366 - Vibration Analysis and Design of Dynamic Absorber in a Vertical Drilling Machine
      MohamadReza Elhami Mojtaba Heydari
      One of the main factors in poor performance of machine tools is undesirable vibrations. Unbalancing in rotary elements of machine tools cause induced vibration in machine head that influences on precision of processing material. The work presented in this paper is inten More
      One of the main factors in poor performance of machine tools is undesirable vibrations. Unbalancing in rotary elements of machine tools cause induced vibration in machine head that influences on precision of processing material. The work presented in this paper is intended to resolve this problem. In this paper, a 3- DOF system has been modeled with design parameters in a machine tool. Based on technical specification of material used in this milling machine real amount of parameters were calculated. The equations solved and the amplitude movement of machine head in a crucial condition of vibration obtained. The main aim of optimization in this work is to reduce this amplitude by considerable amount. For this purpose, two approaches have been suggested. The first approach is solving the dynamic equations of 3-DOF model and changing stiffness and damping property of machine body material so that reduce the head movement to the desired level. It was found that such an especial material is not easy available and in case of finding, is not economical. Therefore, the second approach was suggested, i.e. adding a dynamic absorber to the drilling machine in three different positions to improve the situation. In this approach, only one DOF is added to the model and solve four differential equations with unknowns of mass (MD) and stiffness constant of spring (KD) for dynamic absorber. The mechanical impedance was used for these equations and the results obtained in complex coordination. In MATLAB, a procedure for optimization of MD and KD of dynamic absorber has been developed. Finally, the range of available MD and KD in industrial market was defined. The results have shown that adding dynamic absorber both more effective and more economical than changing material. The final achievement is though, the place of installing dynamic absorber. If the dynamic absorber install on the machine head is much more effective than putting in the base of machine tools, as a regular practice. Finally, a design criteria has been suggested for mass and stiffness of the dynamic absorber. Manuscript profile
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      367 - Elasto-plastic Analysis of Thick Walled Tanks Subjected to Internal Pressure
      Abbas Heydari MohamadTaghi Kazemi
      In this article, the Elasto-plastic analysis of thick walled FG tanks subjected to internal pressure is elaborated. Today, thick walled tanks containing liquids with high pressure are used in the chemical industries. The high internal pressure causes part of the thickne More
      In this article, the Elasto-plastic analysis of thick walled FG tanks subjected to internal pressure is elaborated. Today, thick walled tanks containing liquids with high pressure are used in the chemical industries. The high internal pressure causes part of the thickness of reservoir to yield; therefore, we need the Elasto-plastic analysis. In this study, Elasto-plastic behavior of FG cylindrical and spherical vessels under internal pressure is studied. For comparison with FG tanks, Elasto-plastic behavior of homogeneous tanks obtained. For this purpose, the assumption of ideal plastic behavior under axial symmetry conditions with using the Tresca criterion for the spherical and cylindrical tanks made of Al A359/SiCp is used. Power model is used for describe the gradual changes of mechanical properties in radial direction of FG material. It is shown that the analytically expressed results of the analysis of FG tanks after simplification coincide with homogeneous reservoirs. Furthermore, the bearing capacity of internal pressure will be higher relative to the homogenous tanks. Manuscript profile
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      368 - Investigating the Effect of Geometric Parameters on the Twist Angle in Roll-Forming of Non-Symmetric Channel Section, Using Finite Element Simulation
      Mehdi SalmaniTehrani Mehdi Nikforouz
      Cold roll-forming is a process in which the roll of sheet is formed by passing continuously through the set of rotary rollers without changing thickness in a cool way until it is formed to the desired profile. In this paper a parametric study on the section twist angle More
      Cold roll-forming is a process in which the roll of sheet is formed by passing continuously through the set of rotary rollers without changing thickness in a cool way until it is formed to the desired profile. In this paper a parametric study on the section twist angle in roll-forming the non-symmetric channel is presented, using finite element simulation. At first finite element simulation results are validated by comparing the computed longitudinal strain, near the flange edge, with previously published experimental strains, for a special symmetric channel section. Here symmetric channel section was considered for verifying the finite element results, because of the lack of previous researches on non-symmetric channel section. Then by repeating the finite element simulation for similar section but with different flange width and changing the geometrical parameters such as flange width difference, sheet thickness and profile angle the effect of these parameters on twist angle is investigated. Investigating the results show that section twist angle is increased by decreasing the profile angle and sheet thickness and by increasing the flange width difference. All simulations were carried out using the commercial software ABAQUS 6.7. Manuscript profile
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      369 - Heat Exchangers in A C3MR LNG Plant, Cooling Curves and Their Effects on Efficiency
      Hamid Safari Masoud Fasihbeygi
      In this paper, we are going to improve the energy efficiency of an industrial C3MR base load LNG plant by changing its refrigerant components and its mole fractions in liquefaction and subcooling cycles based on the cooling curves generated in the main liquefaction and More
      In this paper, we are going to improve the energy efficiency of an industrial C3MR base load LNG plant by changing its refrigerant components and its mole fractions in liquefaction and subcooling cycles based on the cooling curves generated in the main liquefaction and subcooling heat exchangers. Later on, selection features of the elements will be discussed. First, non-optimized C3MR plant models and the obtained cooling curves reveals. The process is modeled by using the Hysys® software. The PRSV equation of state is used for thermodynamics properties calculations both for the natural gas and the refrigerants. Two methods for modeling and optimization are explained and the results are compared. The first optimization method is done by a try and error method, which uses temperature vs. enthalpy diagrams or thermodynamics second law (Exergy loss). This method is based on decreasing the temperature difference between hot and cold streams. In the second method, optimizer of Hysys® is used. In this method, a random mole fraction suggests by optimizer at each step and the plant’s consumption work calculates. By comparing the obtained consumption’works and choosing the least one, the relative mole fractions determines as the optimized refrigerants. The convergence of results of method 1 and 2 (The mole fractions of liquefaction and subcooling refrigerants) proves the accuracy of these methods and the models and primary predictions. The results show that by optimization of mixed refrigerants, it is possible to decrease the energy demand about 10.4 MW (5.36 %). Manuscript profile
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      370 - 2D Model of Floor Surface Roughness in Micro Milling Operation
      Shahriyar Kournavand Behnam Motakef Imani
      The micro milling operation is one of the manufacturing processes, which can produce 3D parts in the range of less than a millimetre. Miniaturization of components results in increasing the ratio of surface area to volume of components, which in turn increases the role More
      The micro milling operation is one of the manufacturing processes, which can produce 3D parts in the range of less than a millimetre. Miniaturization of components results in increasing the ratio of surface area to volume of components, which in turn increases the role of surface on the component performance. Therefore, anticipating the relationship between micro milling parameters and surface roughness is of extreme importance. In this paper, a model is proposed which combines the geometric profile of tool end and coordinates of the major cutting edge, which is able to anticipate the profile and surface roughness of the groove floor. The micro-end-mill geometry is considered in macro and micro scales. Relationship between the major cutting edge coordinates and tool profile are derived. Introducing different cutting mechanisms in micro milling operation, effect of different factors such as elastic recovery, and minimum chip thickness, are considered for calculating surface roughness. Feed effect, end edge radius, and effect of minimum chip thickness on surface roughness are investigated for Stainless Steel 316 using the performed simulation of MATLAB software. Moreover, micromilling operation results of the proposed model were compared with experimental results, and correctness of the simulation was validated. In addition, effects of feed per tooth on surface roughness and chip formation were also investigated. Manuscript profile
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      371 - Numerical Study on Propagation of Flame in Laminar Pre-Mixed Combustion
      Ali Lohrasbi
      Premixed combustion is widely used for reducing pollutant emission from combustion chambers. However, these systems may be sensitive to complex phenomena such as flashback. In the present study flame, flashback and structure of premixed laminar flames are investigated t More
      Premixed combustion is widely used for reducing pollutant emission from combustion chambers. However, these systems may be sensitive to complex phenomena such as flashback. In the present study flame, flashback and structure of premixed laminar flames are investigated theoretically. The mathematical model includes the axi-symmetric continuity, Navier Stocks, energy, and species equations. Combustion is modeled as one-step overall reaction using experimental relation with Arrhenius finite rate model. Flashback is examined as a function of wall velocity gradient, tube radius, and fuel concentration in mixture. The analysis is done in two stages. In the first stage, analysis is done traditionally where the value of flashback criteria is calculated and the unstable region of combustion is obtained. In the second stage, flame is kept to propagate into the region of investigation to study the flame structure. Because of complexity of flame flashback, difficulties of performing the experiments confronting flashback phenomena, and fire hazard, the numerical simulation of this phenomenon is strongly recommended. Manuscript profile
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      372 - An Analytical Model for Free Vibration Analysis of Smart Annular FGM Plates Integrated with Piezoelectric Layers
      Farzad Ebrahimi Abbas Rastgoo
      In this paper, a nonlinear free vibration analysis of thin annular functionally graded (FG) plate integrated with two uniformly distributed actuator layers made of piezoelectric (PZT4) material on the top and bottom surfaces of the annular FG plate is presented based on More
      In this paper, a nonlinear free vibration analysis of thin annular functionally graded (FG) plate integrated with two uniformly distributed actuator layers made of piezoelectric (PZT4) material on the top and bottom surfaces of the annular FG plate is presented based on Kirchhoff plate theory. The material properties of the FGM core plate are assumed to be graded in the thickness direction according to the power-law distribution in terms of the volume fractions of the constituents and the distribution of electric potential field along the thickness direction of piezoelectric layers is simulated by a sinusoidal function such that the Maxwell static electricity equation is satisfied. The differential equations of motion are solved analytically for various boundary conditions of the plate. The analytical solutions are derived and validated by comparing the obtained resonant frequencies of the piezoelectric coupled FG annular plate with those of an isotropic core plate. In numerical study, the emphasis is placed on investigating the effect of varying the gradient index of FG plate on free vibration characteristics of the structure. In addition, good agreement between the results of this paper and those of finite element (FE) analyses validated the present approach. The analytical solutions and findings contribute towards a simplified model for the parametric study and understanding of vibration of piezoelectric-coupled FGM annular plate. Manuscript profile
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      373 - modeling and normal stress analysis in viscoelastic damper
      Mohamad Eskafi
      In this study we consider PCF (Plane Couette Flow) which is introduced by two parallel planes which have same velocity in opposite direction and the distance between them is filled by viscoelastic fluid. By this way we have modeled viscoelastic damper. The constitutive More
      In this study we consider PCF (Plane Couette Flow) which is introduced by two parallel planes which have same velocity in opposite direction and the distance between them is filled by viscoelastic fluid. By this way we have modeled viscoelastic damper. The constitutive equation of JS (Johnson-Segalman) has been used for dynamic analysis of viscoelastic damper’s behavior. By using this equation we can examine normal stress which is existed in the fluid and achieve more accurate results about stability of flow between two planes. At first problem formulation is covered. The general conservation and constitutive equations, as well as the boundary and initial conditions are covered for a JS fluid. The Galerkin projection is applied, using Chandrasekhar functions, for 1-D disturbance from the base (Couette) flow. An arbitrary number of modes are included, to lowest order, the formulation leads to a six-dimensional system. Linear stability analysis around the base flow and nontrivial steady-state solution branches is carried out. The influence of inertia on transient flow is studied. Discussion and concluding remarks are finally given. This study has been done specially for PCF of fluids with high molecular weight such as combination of a Newtonian solvent and a polymer solute. Manuscript profile
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      374 - THE ENERGY AND EXERGY ANALYSIS OF SINGLE EFFECT ABSORPTION CHILLER
      Farshad PanahiZadeh Navid Bozorgan
      The first and second laws of thermodynamics have been employed to evaluate energy and exergetic efficiency of the single effect absorption chiller which is used for air conditioning purpose. The performance analysis has been carried out by developing a computer program More
      The first and second laws of thermodynamics have been employed to evaluate energy and exergetic efficiency of the single effect absorption chiller which is used for air conditioning purpose. The performance analysis has been carried out by developing a computer program in EES and modeling the chiller and its components. To evaluate entropy of the water/lithium bromide solution at any point, an empirical correlation has been utilized. Exergy destruction and thermodynamic properties at any point in the cycle are evaluated by using related equations or build in property data. The results showed that maximum exergy destruction was occurred in the generator and the absorber at various operating conditions and these components had greater effect on the energy and exergetic efficiency rather than condenser and evaporator. Thus, it can be clearly stated that the generator and absorber are the most important components of the absorption chiller. The results also showed the exergetic efficiency was less than the energy efficiency due to exergy destruction taking place within the absorption chiller. Therefore, it can be concluded that the exergy analysis has been proven to be a more powerful tool in pinpointing real losses and can be used as an effective tool in designing an absorption chiller and obtaining optimum operating conditions. Manuscript profile
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      375 - Numerical Simulation of 2-D Incompressible Flow in Micro Semi-circular Cavity by LBM
      Mina Alafzadeh Shahram Talebi
      Abstract: Since the field of micro electromechanical systems (MEMS) continues to grow, the flow in micro devices have become an area that receives a significant attention. The microscopic flows are usually characterized by the Knudsen number (Kn). When the characteristi More
      Abstract: Since the field of micro electromechanical systems (MEMS) continues to grow, the flow in micro devices have become an area that receives a significant attention. The microscopic flows are usually characterized by the Knudsen number (Kn). When the characteristic size of the particle decreases down to a value comparable to the mean free path of the molecules, the continuum assumption fails and the Navier-Stokes equations with no-slip boundary conditions cannot be applied, so the numerical method which is not based on continuity of the flow is needed. Recently the lattice Boltzmann method (LBM) has received considerable attention by fluid dynamic researches. The LBM is based on the lattice Boltzmann equation with Bhatnagar-Groos-Krook (BGK) collision approximation. In this paper the incompressible laminar flow in a 2D micro semi-circular cavity with lid driven is simulated by LBM. It should be mentioned that the flow in semi-circular cavity in macro scale has been simulated too and the obtained results were found to be in good agreement with those given from the finite volume method. In the present work, the computational results showed that the slip could have influence on the center of vortex and moved it in horizontal and vertical direction in semi-circular cavity. Computing the friction coefficient on the lid driven presented that the friction coefficient was increased as Kn was increased. The slip could affect on the maximum velocity in cavity too and decreased it. Manuscript profile
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      376 - Investigating Effect of Using Piezoelectric layers on the Forced Vibration of Circular Plates
      AliAkbar Jandaghian AliAsghar Jafari
      This deals with the harmonic forced vibration of a circular plate surface bonded by two piezoelectric layers, based on the Kirchhoff plate model. The form of electric potential field in the piezoelectric layer is assumed such that the Maxwell static electricity equation More
      This deals with the harmonic forced vibration of a circular plate surface bonded by two piezoelectric layers, based on the Kirchhoff plate model. The form of electric potential field in the piezoelectric layer is assumed such that the Maxwell static electricity equation is satisfied. The differential equations of motion are solved analytically for clamped edge boundary condition of the plate. The solutions are expressed by elementary Bessel functions. The results are verified by those obtained from finite-element analysis and results from others article. Manuscript profile
    • Open Access Article

      377 - A semi-analytical solution for time-variant thermoelastic creep analysis of functionally graded rotating disks with variable thickness and properties.
      Mohammad Ghorbani
      Abstract: A time domain semi-analytical solution to study thermoelastic creep behavior of functionally graded rotating axisymmetric disks with variable thickness is presented. The rate type governing differential equations for the considered structure are derived and an More
      Abstract: A time domain semi-analytical solution to study thermoelastic creep behavior of functionally graded rotating axisymmetric disks with variable thickness is presented. The rate type governing differential equations for the considered structure are derived and analytically solved. To solve these equations, the disk is divided into some virtual sub-domains. General solution of equilibrium equations in each sub-domain can be obtained by imposing the continuity conditions at the interface of the adjacent sub-domains together with global conditions. Finally, solution in terms of rate of stress and strain is obtained. The advantage of present work, is to avoid simplifications and restrictions, which are normally associated with other creep solution techniques in the literature. Results for the stress and strain rates presented due to centrifugal force and thermal loadings for different boundary conditions. Results obtained are verified with those available in the literature for easier cases. Manuscript profile
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      378 - Using the Bees Algorithm with the Boundary Elements Method to Solve the Inverse Problem of Transient Heat Conduction
      Mohsen Ardakani Seyd Mohammad MizanAdl
      Abstract: In this paper, a new population-based search called the Bees Algorithm (BA) is presented to estimate the time-dependent heat transfer coefficient and the corresponding heat flux at the boundaries of a two-dimensional body subjected to transient heat conduction More
      Abstract: In this paper, a new population-based search called the Bees Algorithm (BA) is presented to estimate the time-dependent heat transfer coefficient and the corresponding heat flux at the boundaries of a two-dimensional body subjected to transient heat conduction, using the temperature measurements at discrete nodal locations on the boundaries, where heat flux is specified as the boundary condition. In the forward problem, a two dimensional transient heat conduction problem subjected to heat flux boundary conditions is solved for temperature distribution at the boundaries using the boundary elements method. In the inverse problem the heat transfer coefficient (h) at the boundaries where thermal conditions are over specified is estimated by minimizing an objective function which is defined as the sum of the squared differences between the measured and computed temperatures at the nodal locations on the boundary. The Bees algorithm which is a new global evolutionary optimization method is used to investigate the inverse problem. The average value of the heat transfer coefficient at the boundaries is assumed over each time interval from initial time until the final steady-state time. The optimum parameters of Bees algorithm are found and used to estimate the heat transfer coefficient as a function of time. The effect of temperature measurement errors on the identification process is also investigated. Manuscript profile
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      379 - Microstructure and Mechanical Properties of Al2O3-SiC Nanocomposites with 0.05% MgO and Different SiC Volume Fraction
      Ali Reza Moradkhani Mehdi Tajdari
      Abstract: In this study, Al2O3–SiC nanocomposites have been fabricated by mixing of alumina powder containing 0.05% weight magnesium oxide and silicon carbide nano powders, followed by hot pressing at 16500C. The mechanical properties of Al2O3-SiC nanocomposites contain More
      Abstract: In this study, Al2O3–SiC nanocomposites have been fabricated by mixing of alumina powder containing 0.05% weight magnesium oxide and silicon carbide nano powders, followed by hot pressing at 16500C. The mechanical properties of Al2O3-SiC nanocomposites containing different volume fraction (2.5, 5, 7.5, 10 and 15%) of nano scale SiC particles were investigated and compared with those of alumina. The MgO additive was able to promote the densification of the nanocomposites. Al2O3-SiC powders were prepared by planetary milling in isopropanol. The fracture mode and microstructure of specimens was investigated by means of scanning electron microscopy. The nanocomposites were tougher compared to alumina when they were hot pressed at the same temperature. The young’s modulus is decreased by increasing the volume percent of SiC. The values hardness and fracture toughness of the nanocomposites is increased by increasing the volume percent of SiC up to 7.5% and then decreased slightly. The ballistic energy dissipation ability is decreased by increasing the volume percent of SiC up to 5% and then increased slightly. The Scanning electron microscopy observations showed that fracture mode is changed from intergranular for alumina to transgranular for nanocomposites. It also shows the growth of grain is decreased by increasing the volume fraction of SiC particles. Finally X-ray diffraction analysis indicated that there was no chemical reaction between Al2O3 and SiC particles. Manuscript profile
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      380 - Sliding Mode Control of AFM in Cantact Mode during Manipulation of Nano-particle
      M. H Korayem M. Noroozi Kh. Daeinabi
      Abstract: Application of atomic force microscope as a manipulator for pushing-based positioning of nano-particles has been of considerable interest during recent years. However a detailed modeling of the interaction forces and control on the AFM tip is important for pro More
      Abstract: Application of atomic force microscope as a manipulator for pushing-based positioning of nano-particles has been of considerable interest during recent years. However a detailed modeling of the interaction forces and control on the AFM tip is important for prosperous manipulation control, a reliable control of the AFM tip position during the AFM-based manipulation process is a main issue. The deflection of the AFM tip caused by manipulation force is the one of nonlinearities and uncertainties which causes difficulties in accurately controlling the tip position, the tip can jump over the target nano-particle then the process will fail. This study aims to design a sliding mode controller (SMC) as robust chattering-free control in contact-mode to control the AFM tip during nano-manipulation process for accomplishment of a precise and effective nano-manipulation task in order to achieve the full automatic nano-manipulation system without direct intervention of an operator. The nano-probe is used to push the spherical micro/nano-particle. Nano-scale interaction forces, elastic deformation in contact areas, and friction forces in tip/nano-particle/substrate system are considered. The first control purpose is controlling and positioning the microcantilever tip at a desired trajectory by the control input force which can be exerted on the microcantilever in the Y direction by a piezo actuator located in the base of the microcantilever. The second control target is PZT-driven positioning stage in AFM-based nano-manipulation in the X,Y in the falt surface. The simulation results show that the designed controllers have been able to make the desired variable state to track specified trajectory during a nano-scale manipulation. Manuscript profile
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      381 - Numerical Simulation of Turbulent Flow and Heat Transfer in a B-Type Section Pipe with Porous Bottom Wall
      Reza Aliabbasi M. Khayat M. Taeibi-Rahni
      In this work, three-dimensional turbulent forced convection flow through a B-Type Section Pipe, which porous material inserted at the bottom wall, is investigated numerically. The B-Type section pipe are used in cooling systems, such as cars’ radiators. The main purpose More
      In this work, three-dimensional turbulent forced convection flow through a B-Type Section Pipe, which porous material inserted at the bottom wall, is investigated numerically. The B-Type section pipe are used in cooling systems, such as cars’ radiators. The main purpose of this research is to enhance heat transfer and to reduce the scales of such systems. The governing equations are formulated according to the volume averaging method. The results are verified by comparing them with some valid numerical data. The dependence of the Nusselt number and pressure drop on the porosity, permeability and Reynolds number are investigated. The results indicate that, at the maximum flow rate, the heat transfer can be enhanced about 8 times by using porous material while the pressure drop is increased about 2.5 times. Manuscript profile
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      382 - Drilling of Engineering Ceramics using Combination of Ultrasonic Vibrations and Diamond Slurry
      seyed hoseini
      Engineering ceramics due to high-strength-to-weight ratio, wear and corrosion resistance, and high strength temperatures, in the industries especially in aerospace, automobile, electronics and computers are used widely. In attention to the  increasingly usage process of More
      Engineering ceramics due to high-strength-to-weight ratio, wear and corrosion resistance, and high strength temperatures, in the industries especially in aerospace, automobile, electronics and computers are used widely. In attention to the  increasingly usage process of these material, applying of conventional machining methods  for producing  machined into complex and desired shapes or making hole with  high production ratio and adequate accuracy, are not suitable and it commonly has not enough output. Ultrasonic machining is a modern mechanical machining method that is appropriate to create holes in hard and brittle materials by means of an ultrasonically vibrating properly-shaped tool that exciting vertically on the workpiece and abrasive slurry.  In this article modal analysis is used to choose the best shape for wave amplitude magnification and concentration. A desktop CNC milling machine is used to create feed motion control on ultrasonic head on a ceramic sample.  Effects of input factors: power, abrasive grit size, slurry concentration and feed rate are analyzed by Taguchi method on the material removal rate (MRR), tool wear rate (TWR) and hole over size (HOS). The results imply that among input parameters, power has the most effect on MRR, also grit size and feed rate have the most effects on TWR and HOS. Manuscript profile
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      383 - Effects of Mechanical Alloying on microstructure and microhardness of Nanocrystalline Ni–50at.% Ti Shape Memory Alloy’
      Morteza Ghadimi Ali Shokuhfar
      In this work, nanostructured NiTi shape memory alloy with equal atomic percentage was produced through mechanical alloying. The result exhibited that after 60 h of mechanical alloying of high purity elemental powder mixtures of nickel and titanium by a planetary high-en More
      In this work, nanostructured NiTi shape memory alloy with equal atomic percentage was produced through mechanical alloying. The result exhibited that after 60 h of mechanical alloying of high purity elemental powder mixtures of nickel and titanium by a planetary high-energy ball mill, the Ti dissolved into Ni lattice and NiTi (B2) phase with was obtained. The XRD investigations, SEM observations, TEM examinations and microhardness results concluded that this method is a powerful and high productive process for preparing NiTi shape memory alloy with nanocrystalline structure and appropriate morphology. Manuscript profile
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      384 - Evaluation of γ-Al2O3/n-decane Nanofluid Performance in Shell and Tube Heat Recovery Exchanger in a Biomass Heating Plant
      Navid Bozorgan Maryam Shafahi
      The performance of a γ-Al2O3/n-decane nanofluid shell-and-tube heat exchanger in a biomass heating plant is analyzed to specify the optimum condition based on the maximum heat transfer rate and performance index for wide range of nanoparticle volume fraction (0&nd More
      The performance of a γ-Al2O3/n-decane nanofluid shell-and-tube heat exchanger in a biomass heating plant is analyzed to specify the optimum condition based on the maximum heat transfer rate and performance index for wide range of nanoparticle volume fraction (0–7%). Compared with pure n-decane, the obtained results in this research show that by using γ-Al2O3/n-decane nanofluid as coolant at optimum values of particle volume concentration for maximum heat transfer rate (ϕ=0.021) and for maximum performance index (ϕ=0.006), the heat transfer rate and pumping power increased by 10.84%, 13.18% and 6.72%, 2.3%, respectively. Increasing particles concentration raises the fluid viscosity, decreases the Reynolds number and consequently decreases the heat transfer coefficient. As a result, determining the optimum value of the particle volume fraction of nanofluid as the working fluid, can improve the performance of shell-and-tube heat exchangers. Manuscript profile
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      385 - Automated detection of inner surface defects in pipes using image processing algorithms
      turaj azizzadeh Mir saeed safizadeh
      This paper presents a new methodology for the automated inspection of pipes. Standard inspection systems are based on closed-circuit television cameras which are mounted on remotely controlled robots and connected to remote video recording devices. The main problems of More
      This paper presents a new methodology for the automated inspection of pipes. Standard inspection systems are based on closed-circuit television cameras which are mounted on remotely controlled robots and connected to remote video recording devices. The main problems of such camera-based inspection systems are: 1) the lack of visibility in the interior of the pipes and 2) the poor quality of the obtained images because of difficult lighting conditions. The focus of this research is the automated detection and location of defects in the internal surface of pipes. The proposed optical system is an assembly of a CCD camera and a laser diode to create a ring-shaped pattern. The camera obtains images of the light projections on the pipe wall. A novel method for extracting and analyzing intensity variations in the obtained images is described. The image data analysis is based on image processing algorithms. Finally, an image of the pipe wall is generated by extracting the intensity information existing in the pipe pictures. Defects and anomalies can be detected using this extracted image. Manuscript profile
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      386 - An Experimental/Numerical study on the effect of forming parameters in sheet hydrodynamic deep drawing
      behrooz zareh Abdolhamid Gorji Mohammad Bakhshi Salman Nourouzi
      There are many parameters that affect the sheet hydroforming process such as fluid pressure, material properties, interfacial friction between blank and tool surfaces, etc. In this paper, a FEM-based Taguchi method is used to determine the effects of forming parameters More
      There are many parameters that affect the sheet hydroforming process such as fluid pressure, material properties, interfacial friction between blank and tool surfaces, etc. In this paper, a FEM-based Taguchi method is used to determine the effects of forming parameters on the quality of part formability in the process of hydrodynamic deep drawing assisted by radial pressure. Four important forming parameters, fluid pressure, friction coefficient at blank/punch interface, die entrance radius and the amount of gap between die rim block and blank holder are considered in this investigation. In order to have more comprehensive study, three different workpieces are used as the case studies. Three-dimensional FE models are developed for simulating the forming process. After experimental validation, these models are used for performing the set of experiments designed by Taguchi’s  orthogonal array. The signal-to-noise (S/N) ratio and the analysis of variance (ANOVA) techniques are used to calculate the contributions of each of the mentioned parameters to the output characteristic. The results indicate that fluid pressure in the die cavity and friction coefficient at blank/punch interface are the most influential parameters. Also, die entrance radius and the amount of gap between die rim block and blank holder have considerable effect on the part formability. The obtained results may provide useful guidance on determining forming parameters. Also, further optimization of the forming parameters can be done based on the degree of importance of the parameters on the sheet hydroformability.   Manuscript profile
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      387 - Design of a New Anti-Lock Braking System for Motorcycles
      M. Shamsmohammadi M Soheili S. Nasiri M. J. Rajabirad M. Torabi N. Javam
      A new anti-lock braking system (ABS) for motorcycles is proposed in this study. It functions by processing the speed of the motorcycle tire in contact with the ground relative to the speed of the motorcycle itself and by calculating the slip ratio (λ) of the tire slippi More
      A new anti-lock braking system (ABS) for motorcycles is proposed in this study. It functions by processing the speed of the motorcycle tire in contact with the ground relative to the speed of the motorcycle itself and by calculating the slip ratio (λ) of the tire slipping on the ground while braking, and reducing it to a minimum which leads to increased controllability of the motorcycle and reduction of the stopping distance, especially when the ground is slippery. The design of the new ABS and its pilot model comprises mechanical parts, hydraulics, and an electrical circuit. The pilot model providing the testing facility for the brake system functioning in a fixed place is in fact a simulation of the movement of a motorcycle on the ground. When the electric motor is turned on, and its flywheel reaches the desired speed, a controllable load is applied to the flywheel by the motorcycle tire which is a modelling of the weight of the motorcycle and the rider. Then, by turning the electric motor off, the throttle is released and the brake is activated. In this state, without the tire being locked, it will stop within a shorter time and distance than the non-ABS, because the new system keeps the tire in the threshold state of slipping relative to the ground, which is the maximum friction coefficient and the maximum brake force. The results show that the stoppage time for the new ABS is about 40% less than that is the non-ABS type. Manuscript profile
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      388 - Aging Influence on Charpy Impact Behavior of Basalt Fiber Reinforced Epoxy Composites
      S. Mohammad Reza Khalili R. Eslami Farsani V. Daghigh
      Changes in moisture content and temperature can perturb both stiffness and strength and as such the impact resistance of composite structures. In this paper, the pre-notched basalt fibre reinforced epoxy (BFRE) composite specimens are studied under Charpy impact loads i More
      Changes in moisture content and temperature can perturb both stiffness and strength and as such the impact resistance of composite structures. In this paper, the pre-notched basalt fibre reinforced epoxy (BFRE) composite specimens are studied under Charpy impact loads in order to investigate the changes in impact energy absorption (fracture toughness) with different kinds of aging conditions. To create three types of aggressive environmental conditions, the specimens were frozen in dried air at T= -18 °C, frozen in tap water at T= -18 °C and kept in tap water at T= 30 °C and the results were compared with the specimen without aging influence (T= 25 °C). Water used for this examination has a high percentage of precipitation (70-80%) which causes high corrosion and consequent decrease in mechanical properties. The outcomes illustrated that the long-term exposure to tap water (T= 30 °C), dried air (T= -18 °C) and frozen in tap water (T= -18 °C) were all affected on energy absorption of BFRE composites, however, freezing effect in water was more intense. To study the nature of the failure mechanisms, all failed specimens were inspected by Scanning Electron Microscopy (SEM) photographs. Manuscript profile
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      389 - Design and Manufacturing the Torque Gauge of ICaSbot and Implementing its Data Transfer Protocol
      Moharam Habibnejad korayem A. Tajik H. Tourajizadeh
      In this paper, a new approach to modify cable tension measuring mechanism is described; furthermore, the constructed boards which amplify load cell output are introduced. This approach has some advantages including of providing feedback for motors, evaluating the robot’ More
      In this paper, a new approach to modify cable tension measuring mechanism is described; furthermore, the constructed boards which amplify load cell output are introduced. This approach has some advantages including of providing feedback for motors, evaluating the robot’s ultimate load carrying capacity, improving the motor control system and estimating the vibrating deflections of the end effecter final position. Close loop control of the robot and improvement its accuracy are of the objectives of this work. In addition, a new approach to transfer data from load cell to PC for a six Degree of Freedom (DOF) cable robot called ICaSbot is investigated. With neglecting cable mass, the value of cable length variation is estimated using cable tension theory in the specific path. The mechanism, the designed board and the sensors’ output and calibration equation are validated by the aid of a comparison study with simulation results of MATLAB for two different predefined paths Manuscript profile
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      390 - Flow and Heat Transfer over two Bluff Bodies from Very Low to High Reynolds Numbers in the Laminar and Turbulent Flow Regimes
      Amin Etminan
      Flow structure and heat transfer characteristics around two-equal in-tandem square cylinders in the two dimensional laminar and turbulent flow regimes are simulated numerically for Reynolds and Prandtl numbers, Re=1-1×105, Pr=0.71, respectively. The investigation is bas More
      Flow structure and heat transfer characteristics around two-equal in-tandem square cylinders in the two dimensional laminar and turbulent flow regimes are simulated numerically for Reynolds and Prandtl numbers, Re=1-1×105, Pr=0.71, respectively. The investigation is based on an implicit finite volume scheme for integrating the unsteady Navier-Stokes equations and use of standard κ-ε model to Reynolds stresses and scalar fluxes terms modelling. In this study, the instantaneous and mean streamlines, vorticity and isotherm patterns for different Reynolds numbers and distance between the cylinders are presented and discussed. In addition, the global quantities such as drag coefficients, RMS lift and drag coefficients, Strouhal number and Nusselt number are determined. An interesting phenomenon has been observed in the flow patterns depending upon the Reynolds number and the distance between the cylinders. A switch over in the nature of the fluctuations of the lift and drag coefficients has been also observed with the increase of Reynolds number and the distance between the cylinders. The numerical results are in good agreement with the experimental and numerical data available in the literature Manuscript profile
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      391 - Experimental Investigation of the Aerodynamic of a Car Model
      vahid barzanooni
      In this study, the time-average velocity in the near wake of a two-dimensional Notch-Back car model that located in the wake of a trailer has been investigated. The present experiments were carried out in an open circuit low-speed wind tunnel made by Fara Sanjesh Saba L More
      In this study, the time-average velocity in the near wake of a two-dimensional Notch-Back car model that located in the wake of a trailer has been investigated. The present experiments were carried out in an open circuit low-speed wind tunnel made by Fara Sanjesh Saba Ltd, in Iran and was used to simulate uniform air flow. Results show: at the close spacing, time- average velocity profile at the behind of car only has a maximum peak due to the interaction of the jet fluid with the wake of car, so that with increasing vehicles spacing, the jet fluid effect at the create velocity maximum pick gradually pale. In additional with increasing the vehicle spacing we see that the velocity in the wake of car started to grow from the lower height. To measure the drag coefficient it was preferred to use wake–survey method and also the equation recently derived by Van Dam. The dimensionless distance between vehicles derived based on the length of the front one ranges from 0.1 to 3. It was observed that the value of car drag coefficient experiences a rising trend in the beginning and then a descending one along dimensionless distance of 0.1 to 1.3 compared to individual condition. In further distances it will be less than the individual condition. Manuscript profile
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      392 - Analytical solutions for buckling of functionally graded circular plates under uniform radial compression by using Bessel function
      abbas heydari
      The current study presents a new analytical method for buckling analysis of circular plates with constant thickness and Poisson’s ratio, made of functionally graded material subjected to radial load. Governing equations are based on energy method for thin plates. The bo More
      The current study presents a new analytical method for buckling analysis of circular plates with constant thickness and Poisson’s ratio, made of functionally graded material subjected to radial load. Governing equations are based on energy method for thin plates. The boundary conditions of the plate are assumed to be simply supported and clamped. The stability equations were obtained by using conservation of energy. The critical buckling load and first mode shape in terms of Bessel function of the first kind were obtained using Variational Calculus method. Increase in buckling capacity and improvement in the behavior of functionally graded plates in comparison to homogenous plates have been investigated Manuscript profile
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      393 - Simulation and Research on deep rolling process parameters
      kianoush alasvand
      Deep rolling is a kind of mechanical surface treatments that can improve surface quality, dimensional accuracy and mechanical properties of the parts. Compressive residual stresses generated by the process reduce the tensile stresses during loading into the workpiece. T More
      Deep rolling is a kind of mechanical surface treatments that can improve surface quality, dimensional accuracy and mechanical properties of the parts. Compressive residual stresses generated by the process reduce the tensile stresses during loading into the workpiece. The distribution of residual stress induced by deep rolling can be influenced by rolling parameters; such as overlap of the rolling tracks, friction coefficient between roller and target plate, deep rolling force and deep rolling mechanical tools. In the present research, the effects of these parameters are studied by finite-element simulations. The results indicate that: (I) increasing overlap results in increasing magnitude of the maximum residual stress.  (II) Increases in the coefficient of friction results in decrease magnitude of the maximum residual stress and for coefficient of friction more than 0.1 the effect of friction can cause contraction. (III) Increase in the force intensity results in increase magnitude of the maximum residual stress. (IV) The deep rolling with mechanical tools and spring force provides a higher residual stress than the roller with constant force mode. Manuscript profile
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      394 - Triaxiality factor and Lode angle effects on failure of a steel considering plastic anisotropy
      Giuseppe Mirone Arash Keshavarz Rahmatollah Ghajar
      X-100 steel is one of the most recently developed materials for production of gas transportation pipelines. This material is severely anisotropic. Smooth and notched round bars with different notch radius and flat notched specimens with different notch radius and notch More
      X-100 steel is one of the most recently developed materials for production of gas transportation pipelines. This material is severely anisotropic. Smooth and notched round bars with different notch radius and flat notched specimens with different notch radius and notch depth in tension are tested to characterize the failure of this material under quasi-static loading condition.Triaxiality factor that embodies the effect of mean stress and Lode angle are the parameters that affect the failure. Lode angle is a recently introduced parameter in the fracture of ductile materials and contains the effect of third invariant of deviatoric stress tensor. The load-displacement curves and pictures taken by 2 photo camera are used to study the effects of anisotropy, triaxiality factor and Lode angle on the failure of this material. Finally an experimental failure criterion is developed to model the failure of this material. In this failure criterion, strain at fracture initiation is a function of X and TF. Models that take into account the effect of Lode angle, Triaxiality factor and anisotropy in plasticity and damage are the current state of the art in the research of ductile materials. Manuscript profile
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      395 - Experimental and Numerical Study of Through Thickness Residual Stresses Distribution in Sheet Metals Produced by ECAR
      Mohammad Sedighi Masoud Mahmoodi
      Abstract:The equal channel angular rolling (ECAR) is one of the severe plastic deformation processes, which can develop a shear deformation into a sheet metal. In this process, internal stresses are created due to the different strain levels experienced in different loc More
      Abstract:The equal channel angular rolling (ECAR) is one of the severe plastic deformation processes, which can develop a shear deformation into a sheet metal. In this process, internal stresses are created due to the different strain levels experienced in different locations at the same time. The incremental hole drilling method is an effective technique for the evaluation of the through-thickness residual stress distribution in the metal sheets processed by the ECAR. In this work, the residual stresses as the macro stresses have been considered by the help of the incremental method and FEM for numerical calculation of the calibration coefficients. In addition, the FE simulation has been used to investigate the residual stress profile through the thickness. It was observed that the ECARed sample was compressive at the top surface while it was in tension at the bottom surface and the stress profile was not uniform through the material thickness. A comparison between the hole drilling measurements and the FE simulation results showed a good agreement. Manuscript profile
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      396 - Experimental Examination of Intact and CFRP Retrofitted RC Beams under Monotonic and High Cycle Fatigue Loadings
      Mohammad Zaman Kabir Ata HojjatKashani
      The aim of this research is to investigate the effect of Carbon Fiber Reinforced Polymer (CFRP) composite fabric on monotonic and fatigue behaviors of reinforced concrete beams. To control the failure occurrence, a small notch was induced at the middle span in bottom su More
      The aim of this research is to investigate the effect of Carbon Fiber Reinforced Polymer (CFRP) composite fabric on monotonic and fatigue behaviors of reinforced concrete beams. To control the failure occurrence, a small notch was induced at the middle span in bottom surface for all of the studied RC specimens. Totally 12 beams were tested from which 6 beams tested under monotonic and 6 other tested under fatigue cyclic loading. Every 6 tested beams consisted of 3 intact and 3 CFRP retrofitted RC beams. The specimens were 150×150×1000 mm in dimensions and  a 150 mm-deep notch was cut at the center. The experimental examination was conducted to study stresses distributed throughout the critical regions in reinforced concrete and carbon fiber reinforced plastic (CFRP) strengthened RC beams. Fundamentally, these critical regions are cracked zones in CFRP-retrofitted RC beams. Results from monotonic and fatigue tests were compared to each other. In the monotonic test, shear stress distribution and stiffness measurements were carried out until the failure of specimens. In the fatigue test, the ceiling of applied load was considered at the level of design service load for bridges. In addition, strain measurements led to the calculation of interfacial shear stresses between concrete substrate and the CFRP layer. The variation of such stresses through load cycles will be presented and discussed. Load–deflection curves, strain responses and propagation of tension cracks would provide an insight on the performance of the CFRP strengthened beams subjected to different cycles of fatigue loading. Manuscript profile
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      397 - Effect of Mandrel, Its Clearance and Pressure Die on Tube Bending Process via Rotary Draw Bending Method
      Reza Jafari Nedoushan
      One of the most prominent industries is bending, while using rotary draw bending method is known to be the most conventional approach for thin wall tube bending. Pressure die is one effective tool which boosts the tube during the process and eventually improves the bend More
      One of the most prominent industries is bending, while using rotary draw bending method is known to be the most conventional approach for thin wall tube bending. Pressure die is one effective tool which boosts the tube during the process and eventually improves the bending quality. Other effective parameters are mandrel and the amount of clearance between tube and mandrel. In the present study, the process was modeled by finite element method and comparing practical results, the precision of the model was validated. Following this, using the validated model, the effects of pressure die movement and the mandrel and its clearance were investigated. Specifically, the force vicissitudes and bending quality respect to mandrel clearance and pressure die movement were evaluated. It was shown that reducing the clearance between mandrel and tube, results in force increase while the bending quality was improved. Also it was indicated that the pressure die movement has less effects on process forces and flattening of the tube. Manuscript profile
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      398 - Developments in Conventional Machining of Aluminum Matrix Composite Material: A Review
      VINOD SAINI Zahid A. Khan Arshad Noor Siddiquee
      Aluminium matrix composites (AMCs) materials are continuously displacing traditional engineering materials because of their advantages of high stiffness and strength over homogeneous material formulations. Properties of AMCs can be tailored to the demands of different i More
      Aluminium matrix composites (AMCs) materials are continuously displacing traditional engineering materials because of their advantages of high stiffness and strength over homogeneous material formulations. Properties of AMCs can be tailored to the demands of different industrial applications by suitable combinations of matrix, reinforcement and processing route. Presently, several grades of AMCs are manufactured by different methods. The hard ceramic component that increases the mechanical characteristics of AMCs causes quick tool wear and premature tool failure in the machining operations. Therefore the solution of the machining problems is one of the prerequisites for a widespread industrial application of AMCs. This paper provides a review of various research activities and various developments in the field of conventional machining of AMCs. Researchers have explored a number of ways to improve machining efficiency by traditional methods. This paper presents an overview of AMC material that reveals the roles of the reinforcement particles on the machinability of AMCs and provides a useful guide for a better control of their machining processes. Manuscript profile
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      399 - Experimental Investigation on the Influence of Cutting Parameters on Surface Quality obtained in SPDT of PMMA
      Ketan Jagtap
      Manufacturing of an optical lenses demand a specialized technology and thus needs sophisticated precision manufacturing process. PMMA is one of the most used optical polymer for manufacturing of optical lenses, the shaping of which into the required precision and accura More
      Manufacturing of an optical lenses demand a specialized technology and thus needs sophisticated precision manufacturing process. PMMA is one of the most used optical polymer for manufacturing of optical lenses, the shaping of which into the required precision and accuracy is a challenging task. The focus of the present paper is to understand the effect of machining parameters on the surface characteristics especially flatness obtained in single point diamond turning (SPDT). The experiments were conducted according to Taguchi L9 design. The machining parameters chosen are feed rate, spindle speed, depth of cut and cutting environment. Analysis of results reveals that the spindle speed is more influential on the surface flatness generated by the SPDT. All the flatness measurements were done by the non contact type of measurement. It is observed that the minimum PV value produced is 0.837 µm. Manuscript profile
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      400 - Application of Pulsed eddy current technique to stress and residual stress measurement
      Abbas Habibalahi M. S. Safizadeh
      Stress and residual stress are the main problems in the operating performance of materials. They are the principal causes of material failure and can affect life time of component. However measurement or predictions of them are typically difficult. Two common non-destru More
      Stress and residual stress are the main problems in the operating performance of materials. They are the principal causes of material failure and can affect life time of component. However measurement or predictions of them are typically difficult. Two common non-destructive methods, X-ray diffraction and ultrasound are not reliable methods for subsurface residual stress measurements and destructive hole-drilling method is not absolutely precise and safe. In this study, the PEC method was applied to the qualitative and quantitative measurements of stress in aluminum alloy specimens. PEC is a high performance non-destructive testing technique but its application in stress and residual measurement is unknown. In this study a qualitative and quantitative approach for measuring residual stress by PEC technique was developed. Results indicated that pulsed eddy current responses are sensitive to stress and showed PEC method is capable of residual stress measurements. Manuscript profile
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      401 - Developing a 3D Multi-Body Model of the Scoliotic Spine with Lateral Bending Motion for Comparison of Ribcage Flexibility
      khatereh Hajizadeh Ian Gibson Gabriel Liu
      In this paper, a fully discretized bio-fidelity simulation model for bio-mechanical (kinematic) analysis of scoliosis for various patients was developed to analyze forces on vertebrae, loads acting on the intervertebral disc, corresponding angles between vertebrae, and More
      In this paper, a fully discretized bio-fidelity simulation model for bio-mechanical (kinematic) analysis of scoliosis for various patients was developed to analyze forces on vertebrae, loads acting on the intervertebral disc, corresponding angles between vertebrae, and tension in the spine muscles during lateral bending. It was further developed to study the movement limitation and muscle activation of a scoliotic subject. This system was built by using the commercial software LifeMOD. The whole spine (pre-defined by the software) was discretized into individual vertebra segments with rotational joints representing intervertebral discs. In this study, two female subjects (with 40±1.0 kg weight and 154±3 cm height), one with normal spine and the other one with scoliotic spine, were asked to do lateral bending and bend as far as they can. Motion capture data of these two subjects was obtained. Next, motion capture data was assigned to the model using a motion agent set and the inverse dynamics simulation was performed to simulate the complicated multi-body motion of lateral bending. The mobility of the ribcage, activity of muscles which are important in the lateral motion of body, as well as joint angles were analyzed using the developed simulation model. According to the obtained results, the mobility of the ribcage in scoliosis model was less than that of the normal model with the same anthropometric data. This finding is in direct agreement with the qualitative experimental results done by other researchers Manuscript profile
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      402 - The effect of carbon nanotubes on buckling analysis of embedded oil pipes resting on elastic medium
      Hassan Rahimipour Afshin Manouchehrifard
      The theoretical and experimental investigation on the thermo-mechanical properties of carbon nanotube (CNT) as reinforcer for oil and gas pipes has increasingly become a hot research area for many engineers and material scientists in recent years. This is mainly due to More
      The theoretical and experimental investigation on the thermo-mechanical properties of carbon nanotube (CNT) as reinforcer for oil and gas pipes has increasingly become a hot research area for many engineers and material scientists in recent years. This is mainly due to the advent of the new composite material systems that exhibit exotic material and mechanical properties as compared to the traditional, carbon fiber-reinforced composite structures. In this study, the effect of carbon nanotube (CNT) on the buckling of the embedded sea lines is investigated. The sea lines are simulated with isotropic cylindrical shell subjected to thermal and mechanical loads. The sea line is reinforced by armchair carbon nanotubes (CNTs) where characteristics of the equivalent nanocomposite being determined using Mori-Tanaka model. The elastic medium is modelled using Pasternak foundation. The governing equations are obtained based on strain-displacement, stress-strain and energy relations as well as Hamilton's principal. The influences of volume percent of CNTs in sea lines, geometrical parameters, elastic medium constants, temperature change and poison ratio on the buckling load of the system are investigated. Results indicate that the buckling load of the sea line increases with increasing volume percent of CNTs in sea lines. Hence, the CNTs are very useful as reinforcer for sea lines in order to increase of the buckling load of the system. Manuscript profile
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      403 - A Finite-Volume Method in General Curvilinear Coordinates for Simulation of Blood Flow Past a Stenosed Artery
      Sina Zanousi Ruzbeh Shafaghat Qadir Esmaili
      In this study, flow characteristics through symmetric stenosis artery are investigated. The shape of eccentricity for stenotic flows is limited by circular-cross sections and plaques are usually assumed as to be oriented concentrically. ThegoverningequationsaretheusualNav More
      In this study, flow characteristics through symmetric stenosis artery are investigated. The shape of eccentricity for stenotic flows is limited by circular-cross sections and plaques are usually assumed as to be oriented concentrically. ThegoverningequationsaretheusualNavier-Stokesequationsandare numericallysolved by using finite volumemethod in arbitrary orthogonal curvilinear coordinates. In addition, three-dimensional elliptic grid is presented which the generating system is based on solution of a system of partial differential. To prevent serious distortion or overlapping of mesh lines, grid regularity is verified by some controlling parameter like Skewness value and maximum grid aspect ratio (MAR).The main objective of the present study is to investigate different degrees of the stenosis (45%, 55%, 65% and 75% by area reduction) and finding the critical one which play a significant role in the development of forming sediment in the wall of vessel. It is shown that the magnitude of inlet Reynolds number have strong relationship with the velocity, pressure and wall shear stress (WSS) distributions as expected. The most important conclusion obtained from our model is the high WSS and pressure drop which is exerted near the stenosed point and formation and development of large recirculation regions which found in the downstream of the stenosis, especially in the case of severe stenosis could create many pathological diseases Manuscript profile
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      404 - Vibration Analysis of Laminated Composite Plates Carrying Rotating Circular Mass
      Reza Alibakhshi Reza Akbari Alashti
      In this paper, the free vibration response of a laminated composite rectangularplate supporting a rotating circular patch mass is studied. The two variable refined platetheory that employs only two unknown functions as against three in the case of simpleshear deformatio More
      In this paper, the free vibration response of a laminated composite rectangularplate supporting a rotating circular patch mass is studied. The two variable refined platetheory that employs only two unknown functions as against three in the case of simpleshear deformation theory is applied to define the third order displacement field of acomposite rectangular plate. The plate is considered to have simply supported boundaries.The equations of motion for the rectangular plate are obtained by calculus of variation. Dueto significance of the fundamental frequency of the plate, its variation with respect to thenon-dimensional geometrical parameters such as aspect ratio of the plate, size and locationof the rotating patch mass, is investigated. It will be shown herein that the proposed theoryis simple in solving the free vibration problems of plates with patch masses. Manuscript profile
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      405 - Optimization of suspension system of sport car in three dimensional reactions space
      Reza Kazemi Mohsen Raf'at Hadi Zolghadr
      Suspension system as one of the most important key elements of vehicle has always been considered by research centres and auto makers over the world and this issue is more important on sport cars which have special sensitive working conditions and even the smallest defe More
      Suspension system as one of the most important key elements of vehicle has always been considered by research centres and auto makers over the world and this issue is more important on sport cars which have special sensitive working conditions and even the smallest defect can strongly affect their performances. In this study, optimization of effective handling parameters of a sport car with three optimization indices is favourable cover racetrack at the shortest possible time. For this purpose a sport car model simulated in ADAMS/car software has been used and all test steps have been implemented in this environment. At the end of reaching optimum solution in different racetrack conditions, Pareto solution set optimization method has been used and in this problem, optimization indices have been examined which is covered distance in standard constant radius test with three different radii. so, by implementation of these experiments at different levels of optimization parameters, all solution sets are collected in a three dimensional diagram called performance space whose coordinates axes are optimization indices values, then using LP norm idea, possible optimum solutions are selected from among other solution and in order to find optimum solution in a special racetrack, a new idea has been proposed, through this, weighted coefficients related to each optimization indices for a special racetrack are determined and optimum solutions appropriate for that track is selected from pareto solution set. Manuscript profile
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      406 - Feasibility study on aluminum alloys and A441 AISI steel joints by friction stir welding
      Hamed Aghajani Majid Elyasi Morteza Hoseinzadeh
      In this paper, welding feasibility between AA1100, AA5050 and AA6082 aluminum alloys and A441 AISI steel by friction stir welding has been studied. Mathematical analysis of the heat generation during process showed that the maximum temperature produced in AA6082 aluminu More
      In this paper, welding feasibility between AA1100, AA5050 and AA6082 aluminum alloys and A441 AISI steel by friction stir welding has been studied. Mathematical analysis of the heat generation during process showed that the maximum temperature produced in AA6082 aluminum alloy and A441 AISI joint but heat distribution in AA1100 aluminum alloy was higher than the other alloys. The investigation on joints windows concluded that the connecting link between AA1100 and A441 AISI steel was without any defect. Because of improper heat production and distribution in other joints, small tunnel was formed in the joints lower zones. Due to the softness of aluminums rather than steels, in tensile tests all joints were broken from the aluminum base metals. Strongest weld belonged to AA5050 aluminum alloy and A441 AISI steel joint that was about 84% of the aluminum base metal strength. Maximum joint efficacy based on A441 AISI has its place to AA6082 to A441 weld. Microhardness tests shows that welding line between AA1100 aluminum alloy and A441 AISI steel is harder that other joints. Manuscript profile
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      407 - Finite Element Analysis of Automotive Disk Brake and Pad in Frictional Model Contact
      Ali Belhocine
      The object of this work is to present a study of the thermomechanical behavior of the automobile disc brake for the prediction of their resistance to fatigue. Then, a study of purely mechanical dry contact between the disc and pads is developed with a good prediction be More
      The object of this work is to present a study of the thermomechanical behavior of the automobile disc brake for the prediction of their resistance to fatigue. Then, a study of purely mechanical dry contact between the disc and pads is developed with a good prediction becomes a major stake for the industrialists while modeling the loading and the boundary conditions around the disc.We used the same computer code to visualize displacements,  total deformations in the disc, shear stresses, Von Mises stresses and, the tools of contact pads. We also studied the case of thermoelasticity while interpreting the various exits results during this simulation. ¶¶ Manuscript profile
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      408 - Frequency Response of AFM Nano Robot in Liquid by considering the effect of Cantilever's dimension and Environmental Parameters
      Saeed Sami Moharam Habibnejad Korayem
      Dynamic analysis and study of Atomic force microscope in liquid environment is the main goal of this research. Hydrodynamic and squeeze forces act on Cantilever of Atomic force microscope which works in liquid environment, so. In this paper the effect of different envir More
      Dynamic analysis and study of Atomic force microscope in liquid environment is the main goal of this research. Hydrodynamic and squeeze forces act on Cantilever of Atomic force microscope which works in liquid environment, so. In this paper the effect of different environmental and physical factors had studied on frequency response diagrams. The importance of frequency response analysis is studying the possibility of occur a phenomenon which causes disturbance and decreases accuracy of imaging. Timoshenko beam model and finite element method had been used in order to simulation. Meanwhile interaction forces between sample and tip point in gas and liquid environment were also considered in simulations. Achieved results had showed that in comparison with gas, resonance frequency has decreased considerably in liquid environment which is due to additional mass of liquid and also amplitude is decreased in liquid environment that’s because of additional damping due to presence of liquid. Meanwhile several studies in repulsion and attraction area with more and less distance from equilibrium distance, had showed that in repulsion state, stimulation frequency is more than attraction area, that the reason is related to more hardness in repulsion area, and also the presence of interaction forces had caused that in zero excitation frequency, amplitude isn’t zero. Manuscript profile
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      409 - Multiobjective Constrained Optimization of a Newly Developed Needle Driving Mechanism in the Sewing Machine for Improvement of the Mechanical Performance
      Saeed Ebrahimi Iman Hajizadeh Pedram Payvandy
      Sewing is one of the most commonly used manufacturing processes in the world. In the textile industry, development of sewing machines with optimal mechanical performance is very important. Obviously, the quality of sewing, the increase of the needle transmission force a More
      Sewing is one of the most commonly used manufacturing processes in the world. In the textile industry, development of sewing machines with optimal mechanical performance is very important. Obviously, the quality of sewing, the increase of the needle transmission force and the optimal mechanical advantage are greatly dependent on the design criteria of the needle driving mechanism. Unfortunately, despite the importance of this topic, very limited number of researches has been carried out in this regard. Therefore, in this paper, first a newly developed needle driving mechanism of a sewing machine is introduced. Then, the concepts of transmission angle and mechanical advantage are described. Next, the multiobjective constrained optimization process of this mechanism using the genetic algorithm is explained. For this purpose, some objective functions are presented to reduce the needle generated heat by minimizing the needle velocity in the penetration zone, to reduce undesirable vibrations by minimizing the needle jerk, and to increase the mechanical performance by maximizing the mechanical advantage and minimizing deviations of the transmission angle from its ideal value. Results confirm improvement of the required design criteria of the newly developed mechanism in this study Manuscript profile
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      410 - Investigating the effect of temperature on mechanical behavior of rubber compounds embedded in composite structure of pneumatic tires
      Moslem Namjoo Hossein Golbakhshi Meisam Mohammadi
      Owing to elastic and viscous characteristics embedded rubber compounds, the dissipated energy from periodic deformation is converted into heat generation and consequently, the tire may have different body temperatures for different operating conditions. In most performe More
      Owing to elastic and viscous characteristics embedded rubber compounds, the dissipated energy from periodic deformation is converted into heat generation and consequently, the tire may have different body temperatures for different operating conditions. In most performed investigations, just temperature distribution is considered and the mechanical behaviour of rubber parts which are highly temperature-dependent is ignored. In this study a 3D finite element model is used for evaluating the effects of loading conditions and rubber temperature on mechanical behaviour of tire. Comparing with related published works, the results of presented study have a great accuracy and can provide a comprehensive analysis to avoid the temperature related failure. Manuscript profile
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      411 - Experimental Bending Analysis of Strip Sandwich and Laminated Composite Plates
      Iraj Rajabi S.M.R. Khalili M. Shariyat
      There exist simple theories to predict the strain of sandwich structures under a bending load and specific support conditions. Although theoretical predictions are highly effective, but the role of testing in validation of these theories and their progress is undeniable More
      There exist simple theories to predict the strain of sandwich structures under a bending load and specific support conditions. Although theoretical predictions are highly effective, but the role of testing in validation of these theories and their progress is undeniable. The main goal of the present paper is to prepare a test instruction in order to minimize the error of data acquisition and their analysis. The effects of specimen thickness, place of strain gauge installation and kind of strain gauge was investigated. Characterization of mechanical properties of test specimens are another focus of the present study. Classic theories are used to validate the results of the tests. Based on the large number of tests conducted on the samples, the results show that an important source of error in between experimental and theoretical results may be incorrect installation of the strain gauge. A method to find this out, is to obtain the results of loading and unloading. The method of using the gauge factor of the strain gauge on the package gives better results. Using a circuit with three wires omits the error of wire resistance. The results of the tests on composite specimens obtained by TML Company strain gauges showed small differences with the results obtained by BLH Company strain gauges. The error between experimental and theoretical results in sandwich specimens increases by increasing the core thickness. The measurements obtained by strain gauge in compression is not reliable. An important result obtained was that a half-bridge installation of the strain gauge decreases the error so much. Manuscript profile
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      412 - Intermetallic phase formation during combustion synthesis of mechanically activated Ni-Ti alloy
      Seyed Khatiboleslam Sadrnezhaad Shahin Katiraei Abbas Ghasemi
      Intermetallic phase formation and oxidation reaction during combustion synthesis (CS) of Ni-Ti equiatomic mixture are affected by mechanical activation (MA) and pre-heating conditions. Important parameters are ignition time, reaction duration, temperature rise, microstr More
      Intermetallic phase formation and oxidation reaction during combustion synthesis (CS) of Ni-Ti equiatomic mixture are affected by mechanical activation (MA) and pre-heating conditions. Important parameters are ignition time, reaction duration, temperature rise, microstructural change, titanium oxidation and intermetallic phase formation. Superelasticity and shape memory effects are influenced by two-stage austenite-rhombohedral and rhombohedral-martensite transformations detected by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) of the combusted samples. Tension tests indicated superelastic behavior after 1 h, production of Ni3Ti after ½ h and delayed superelastic/thermoelastic behavior after 2 h MA. Results indicate that pre-combustion heating fosters mono-phase formation and titanium oxidation; while mechanical activation lowers ignition-start-time, synthesis-duration and Ni3Ti formation. Manuscript profile
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      413 - Modeling and Optimal Control of a Sport Utility Cable Suspended Robot
      Hami Tourajizadeh Moharam Habibnejad Korayem Mahdi Yousefzadeh
      A new mechanism is presented in this paper for simulating the athlete performance and training the sportsman’s exercises, using a closed loop six degrees of freedom (DOFs) cable suspended robot. This robot cancels the necessity of presence of a sport coach for training More
      A new mechanism is presented in this paper for simulating the athlete performance and training the sportsman’s exercises, using a closed loop six degrees of freedom (DOFs) cable suspended robot. This robot cancels the necessity of presence of a sport coach for training the sportsman. Using the proposed robot, it is possible to program the robot for training the athlete limb (arm, leg and etc.) within a predefined trajectory corresponding to his special sport performance. The limb of the sportsman which is involved in the game and should be trained could be attached to the end-effector of the cable robot. Since in many sports a large environmental space needs to be covered by the athlete movement, ordinary robots are not capable to be employed for this application while cable robots are applicable since a large dynamic workspace can be covered by them. Moreover, training the sportsman limb requires a precise movement of the mentioned end-effector on a predefined trajectory. This importance could not be satisfied without using a proper closed loop controlling system since a variable external disturbing force applies on the end-effector as a result of the weight of the sportsman limb and its dynamic movement. Studio cams and automatic brancard for carrying the damaged sportsman out of the field are also of other applications of the presented closed loop cable robot. So required dynamic and control formulation of the end-effector of the cable robot is derived for handling the athlete limb on a predefined trajectory in a closed loop way. Simulation on using the MATLAB confirms the possibility of the mentioned claim for simulating the sportsman training. Finally the efficiency of the proposed mechanism in training the athletes’ limb is also proved by conducting experimental test on Iran University of Science and Technology (IUST) cable robot (ICaSbot). Manuscript profile
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      414 - Surface Characteristics Improvement of AZ31B Magnesium by Surface Compositing with Carbon Nano-tubes through Friction Stir Processing
      M. Soltani M. Shamanian B. Niroumand
      In this research, the compositing of the surface of AZ31B magnesium alloy with CNT was studied by FSP. The parameters under study were rotational speed (500-1500 rpm), transverse speed (12-44 mm/min), number of passes (1-4), and CNT weight fraction (0-2%). Microhardness More
      In this research, the compositing of the surface of AZ31B magnesium alloy with CNT was studied by FSP. The parameters under study were rotational speed (500-1500 rpm), transverse speed (12-44 mm/min), number of passes (1-4), and CNT weight fraction (0-2%). Microhardness testing, optical metallography, FESEM, and EDS analysis were employed for the characterization of the samples. The suitable limits for the transverse speed and rotational speed were 12-24mm/min and 870-1140 rpm, respectively. The highest hardness in the FSP without compositing was assigned to the transverse speed of 24 mm/min and rotational speed of 870 rpm with a hardness of about 60 Vickers and the stir region grain size of less than 5 microns. The Zener-Holman parameter was calculated for computation and the least value was related to the conditions of the transverse speed of 12-24 mm/min and rotational speed of 870 rpm; as a result, the samples with the finest grain size were theoretically and experimentally specified. The most homogenous structure with the highest hardness was related to the three-pass state with a hardness of 69 Vickers. The best rate was the CNT weight percentage with a %2 weight enjoying the highest hardness. The FESEM images confirmed the suitable distribution of CNTs in the background after the performance of the three-pass processing. Manuscript profile
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      415 - Prediction of Residual Stresses by Radial Basis Neural Network in HSLA-65 Steel Weldments
      M. Heidari
      This paper investigates the residual stress fields in the vicinity of weld bead in HSLA-65 steel weldments using a neural network. This study consists of two cases: (i) the experimental analysis was carried out on the measurement of residual stresses by XRD technique. M More
      This paper investigates the residual stress fields in the vicinity of weld bead in HSLA-65 steel weldments using a neural network. This study consists of two cases: (i) the experimental analysis was carried out on the measurement of residual stresses by XRD technique. Many different specimens that were subjected to different conditions were studied. The values and distributions of residual stresses occurring in welding of HSLA-65 plate under various conditions were determined. (ii) The mathematical modeling analysis has proposed the use of radial basis (RB) NN to determine the residual stresses based on the welding conditions. The input of RBNN are welding current, welding voltage, welding heat input, travel speed of welding, wire feed speed and distance from weld. The best fitting training data set was obtained with 18 neurons in the hidden layer, which made it possible to predict residual stresses with accuracy of at least as good as the experimental error, over the whole experimental range. After training, it was found that the regression values (R2) are 0.999664 and 0.999322 for newrbe and newrb functions respectively. Similarly, these values for testing data are 0.999425 and 0.998505, respectively. Based on the verification errors, it was shown that the radial basis function of neural network with newrbe function is superior in this particular case, and has the average error of 7.70% in predicting the residual stresses in HSLA-65. This method is conceptually straightforward, and it is also applicable to other type of welding for practical purposes. Manuscript profile
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      416 - Optimizing the Parameters Contributing to Riveting Quality Using Imperialist Competitive Algorithm and Predicting the Objective Function via the Three Models MLR, RBF, and ANN-GA
      Abbas Fadaei Allahyar Gorbanpour Amir Salarpour
      The metal sheets play an important role in the mechanical design, particularly in the aerospace structures. The rivet connections are frequently used to connect these sheets. The riveting quality greatly influences the rupture of the rivet and the sheet. The various par More
      The metal sheets play an important role in the mechanical design, particularly in the aerospace structures. The rivet connections are frequently used to connect these sheets. The riveting quality greatly influences the rupture of the rivet and the sheet. The various parameters affect the quality of this operation. In this paper, the optimization of the parameters contributing to the riveting quality in order to minimize the value of the maximum tangential stress in the sheets is addressed. To this end, the tolerance of the hole diameter in the top and the bottom sheets, the friction coefficient, and the tolerance of the rivet diameter and the rivet length were considered as the parameters influencing the riveting quality. A total of 64 models were obtained by the permutations of the parameters two at a time. The outputs were determined using the finite element method. The objective function for the optimization is the maximum tangential stress for which there is no analytical relation. Thus, three methods including the multivariable linear regression (MLR), the artificial neural network model of the radial basis function (RBF) type, and the hybrid model of the artificial neural network and the genetic algorithm (ANN-GA) were employed to model this function. Further, the performance of the three models was compared and the most suitable one was selected to model the objective function. The regression model was used to model the values of the height and the diameter after riveting. The imperialist competitive algorithm is utilized to solve this optimization problem. The obtained value for the maximum tangential stress using the imperialist competitive algorithm is 16368 pounds per square inches. After modification, this value increased to 23440 pounds per square inches using the finite element method. . The 0.07689 inches and 0.18524 inches were obtained for the height and diameter of the rivet after riveting, respectively. Manuscript profile
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      417 - Experimental investigations of microstructure of Al 1100 alloys welded by friction stir welding process
      vahiid zakeri Ahad Gholipoor Parviz asadi
       In this paper, hardness and tensile properties of welded zone of aluminum 1100 alloys by friction stir welding process was investigated and the effects of rotational and traverse speeds of tool on these parameters was studied. Also the fracture cross-section of welded More
       In this paper, hardness and tensile properties of welded zone of aluminum 1100 alloys by friction stir welding process was investigated and the effects of rotational and traverse speeds of tool on these parameters was studied. Also the fracture cross-section of welded samples was investigated. According the results of this paper, the hardness of weld material is higher than base material and is increased by decreasing the rate of rotational speed to traverse speed. The yields strength of weld material is 70% of base material in best conditions due to the weak thermo mechanically affected zone around weld nugget, although in some samples the tensile strength of weld material is equal to base material. Also the SEM images of fracture cross-section of welded samples showed a ductile fracture during tensile test.  Manuscript profile
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      418 - Study of the Resonant Frequency of Unimorph Triangular V-shaped Piezoelectric Cantilever Energy Harvester
      Rouhollah Hosseini Mohsen Hamedi
      Abstract: The main aim of the vibration energy harvesters is to locally power autonomous devices such as wireless sensors. Generally, power levels are low and the environmental benefit of the technology is to replace batteries rather than saving energy per se. Piezoelec More
      Abstract: The main aim of the vibration energy harvesters is to locally power autonomous devices such as wireless sensors. Generally, power levels are low and the environmental benefit of the technology is to replace batteries rather than saving energy per se. Piezoelectric vibrational energy harvesters are usually inertial mass based devices, where a cantilever beam with a piezoelectric outer layer is excited into resonance by a mechanical vibration source at the root of the cantilever beam. However, the geometry of a piezoelectric cantilever beam will greatly affect its vibration energy harvesting ability. This paper deduces a remarkably precise analytical formula for calculating the fundamental resonant frequency of unimorph V-shaped cantilevers using Rayleigh-Ritz method. This analytical formula, which is convenient for mechanical energy harvester design based on piezoelectric effect, is then validated by ABAQUS simulation. This formula raises a new perspective that, among all the unimorph V-shaped cantilever beams and in comparison with rectangular one (the simplest tapered cantilever), can lead to the highest resonant frequency and maximum sensitivity.Keywords: Mechanical Energy harvester, Piezoelectric, Unimorph V-shaped Cantilever, Resonant frequency, Finite Element Manuscript profile
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      419 - Analysis of Off-road Performance for a Tracked Vehicle
      MohamadReza Elhami
      Suspension system is one of the most important factors in provision of ride comfort and dynamic stability in any vehicle. However, the suspension system for the tracked vehicle has more particular specifications in compare with the other vehicles. Due to its continuous More
      Suspension system is one of the most important factors in provision of ride comfort and dynamic stability in any vehicle. However, the suspension system for the tracked vehicle has more particular specifications in compare with the other vehicles. Due to its continuous track, these specifications can help the tracked vehicles possess an improved dynamic stability in off-road maneuvers compared to the vehicles with discrete tiers. In this paper, off-road performance of the tracked vehicle has been thoroughly investigated. In this regard, firstly the mathematical model of a tracked vehicle suspension system with governing dynamic equations are derived and the state-space representation are represented. After on, the off-road inputs such as hill inputs, passing over Belgian block and irregular terrain are applied to the dynamic model and the system outputs, especially body hull vertical acceleration as one of the most important criteria of stability, are reviewed. The results show that the responses are in range of acceptable overshoot and there suggest the related critical speed of the vehicle. Furthermore, for model validation the results are compared with ACMP reference model in response to the standard off-road inputs and the results are satisfactory. Manuscript profile
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      420 - Optimal Trajectory Planning for Flexible Mobile Manipulators under Large Deformation Using Meta-heuristic Optimization Methods
      Habib Esfandiar Moharam Habibnejad Korayem Mohammad Haghpanahi
      In present paper, a point to point optimal path is planned for a mobile manipulator with flexible links and joints. For this purpose, a perfect dynamic modeling is performed for mobile manipulators considering large deformation in links, shear effects, elastic joints, e More
      In present paper, a point to point optimal path is planned for a mobile manipulator with flexible links and joints. For this purpose, a perfect dynamic modeling is performed for mobile manipulators considering large deformation in links, shear effects, elastic joints, effect of gravitation, and non-holonomic constraints. To study large deformation of links, non-linear relation of displacement-strain and Green’s strain tensor are used. Optimal path is planned based on direct methods and applying meta-heuristic optimization methods. In order to get an optimal path profile, maximum load carried by manipulator and minimum transmission time are considered as the objective functions for optimization problem. To provide the parameters of optimization problem, parametric optimization problem is solved using Harmony Search (HS) and Simulated Annealing (SA) efficient methods. In order to investigate the efficiency of the proposed method, simulation studies are performed considering two-link flexible manipulator with wheeled base. The results indicate that the proposed method has a suitable power and performance when facing dynamics non-linear system. Moreover, the results of path planning for manipulators by small and large deformation models are also compared. The effect of flexibility in joints is studied when planning a point to point path. Manuscript profile
    • Open Access Article

      421 - Non-linear Analysis of Adhesive Joints in Composite Structures
      Ehsan Selahi
      This paper presents a novel formulation and numerical solutions for adhesively bonded composite joints with non-linear (softening) adhesive behaviour. The presented approach has the capability of choosing arbitrary loadings and boundary conditions. In this model adheren More
      This paper presents a novel formulation and numerical solutions for adhesively bonded composite joints with non-linear (softening) adhesive behaviour. The presented approach has the capability of choosing arbitrary loadings and boundary conditions. In this model adherends are orthotropic laminates that obey classical lamination theory. The stacking sequences can be either symmetric or asymmetric. Adhesive layer(s) is (are) homogenous and isotropic material. They are modeled as continuously distributed non-linear (softening) tension/compression and shear springs. In this method by employing constitutive, kinematics and equilibrium equations, sets of differential equations for each inside and outside of overlap zones are derived. In the inside of overlap zone, the set of differential equations is non-linear, that is solved numerically. By solving these equations, shear and peel stresses in adhesive layer(s) as well as deflections, stress resultants and moment resultants in the adherends are determined. Most of adhesives have non-linear behavior, therefore unlike previous methods, in which the adhesive layers are modeled as linear materials, in the presented approach the non-linear behavior is assumed for the adhesive layer and can be used to analyze the most of adhesive joints. The numerical results reveal that in the inside of overlap zone, magnitudes of shear forces are considerably large due to high rate of variation in the bending moments. The developed results are successfully compared with those obtained by finite element analysis using ANSYS. The comparisons demonstrate the accuracy and effectiveness of the aforementioned methods. Manuscript profile
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      422 - Buckling analysis of cracked columns by XFEM
      Mohammad Reza Shirazizadeh Hossein Shahverdi Ali Imam
      This paper focuses on using the recently developed extended finite element model for buckling analysis of edge cracked columns under concentric axial load. The effect of crack depth and its location on the carrying capacity of columns is studied. The effect of different More
      This paper focuses on using the recently developed extended finite element model for buckling analysis of edge cracked columns under concentric axial load. The effect of crack depth and its location on the carrying capacity of columns is studied. The effect of different boundary conditions is also investigated. Numerical examples are offered to show the efficiency and effectiveness of the proposed method. The presented results are compared with analytical and experimental works available in the literature. Good agreement with experiment is shown, although the difference with analytical results is considerable for columns with deeper cracks. The reason of this difference is discussed.  It is shown that the proposed method is more accurate than the analytical methods which are developed based on rotational spring models. Manuscript profile
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      423 - Analysis and Interpretation of Bearing Vibration Data Using Principal Component Analysis and Self - Organizing Map
      Raj Patel V. K. Giri
      Induction motor bearing is one of the key parts of the machine and its analysis and interpretation are important for fault detection. In the present work vibration signal has been taken for the classification i.e. bearing is Healthy (H) or Defective (D). For this purpos More
      Induction motor bearing is one of the key parts of the machine and its analysis and interpretation are important for fault detection. In the present work vibration signal has been taken for the classification i.e. bearing is Healthy (H) or Defective (D). For this purpose, clustering based classification of bearing vibration data has been carried out using Principal Component Analysis (PCA) and Self Organising Map (SOM). From the vibration signal, twelve statistical features have been extracted from both the healthy and the defected condition of the bearing. Further, these data are subjected to PCA to extract significant features relevant to cluster structure. It is observed that out of twelve features only four features are found significant which is feed to the SOM model.  The SOM based classification is able to achieve an accuracy of 100%. This cluster-based method of feature reduction and classification could be useful in assessing the induction motor incipient bearing fault detection with large data set.  Manuscript profile
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      424 - Investigation of The Effects of Process Parameters on The Welding Line Movement in Deep Drawing of Tailor Welded Blanks
      Ali Fazli
      In this paper, the deep drawing process of tailor welded blanks is simulated using the finite element modelling and verified using the experimental results available in the literature. Then the effect of die and material properties on the welding line movement is invest More
      In this paper, the deep drawing process of tailor welded blanks is simulated using the finite element modelling and verified using the experimental results available in the literature. Then the effect of die and material properties on the welding line movement is investigated. It is seen that the most effective material parameters on weld line movement are different between sheet metal thicknesses and strength coefficient of two welded sheets. Also it is seen that the most effective die parameter on weld line movement is the friction coefficient between punch and blank. Finite element simulations show that in the wall section of the drawn cup, the welding line moves toward the material with smaller thickness and lower strength coefficient while in the bottom of the drawn cup, the welding line moves toward the material with larger thickness, and higher strength coefficient. Based on the results, increasing the friction coefficient between blank and die, decreases the welding line movement considerably. Manuscript profile
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      425 - Accuracy Improvement of Upper Bound Analysis of Bimetallic Rods Extrusion Using a New Velocity Field
      Hamed Afrasiab Mojtaba Qasemi-Mahallekolaei
      In this paper, the direct extrusion process of bimetallic rods in conical dies is analyzed by an improved upper bound method. The deformation zone is subdivided into six smaller zones and by considering a non-spherical entrance boundary to the deformation zone, a veloci More
      In this paper, the direct extrusion process of bimetallic rods in conical dies is analyzed by an improved upper bound method. The deformation zone is subdivided into six smaller zones and by considering a non-spherical entrance boundary to the deformation zone, a velocity field is presented which is different from velocity fields employed in previous studies. The total power consumption of the process including internal, shear and frictional powers is obtained using this velocity field, and then the forming force is calculated by employing the upper bound theory. The superior accuracy of the proposed analysis is demonstrated by comparing the computed force with available experimental data and results of an upper bound analysis in the literature. Finally, the developed model is employed to study the effect of some process parameters on the forming load. It is observed that there is an optimal die angle that minimizes the extrusion force. The value of this optimum angle increases with friction coefficient. Manuscript profile
    • Open Access Article

      426 - Free Vibration Analysis of Nanoplates using Differential Transformation Method
      Sayed Hassan Nourbakhsh Mohsen Botshekanan Dehkordi Amir Atrian
      In this paper, a free vibration of nano-plates is investigated considering the small scale parameter. The used rectangular nano plate is thin and under different boundary conditions. In order to obtain the natural frequencies of the nano-plates, classical plate theory o More
      In this paper, a free vibration of nano-plates is investigated considering the small scale parameter. The used rectangular nano plate is thin and under different boundary conditions. In order to obtain the natural frequencies of the nano-plates, classical plate theory on the basis of non-local theory is used. The governing equation is solved using a semi-analytical method DTM[1]. The results for free vibration of those plates are compared with the theoretical data published in the literature. Results show that DTM is a powerful, simple, accurate and fast method for solving equations in comparison with other methods. Non-local parameter is very effective in vibration of nano-plates and its influence is different in various boundary conditions. Influence of this parameter in simply supported-clamp boundary condition is higher than other boundary conditions. Manuscript profile
    • Open Access Article

      427 - The Impact of Die Corner Radius and Friction Coefficient on Bulge Forming of T-Shaped Copper Tubes using Finite-Element Method and Experimental Analysis
      M. Ahmadpour Omid Ghahraei
      In this paper, the effects of various parameters on the process of T-shaped copper tube bulge forming have been investigated. This evaluation is based on the properties of the copper tubes, properties of polyurethane rod and practical conditions of a bulge forming proce More
      In this paper, the effects of various parameters on the process of T-shaped copper tube bulge forming have been investigated. This evaluation is based on the properties of the copper tubes, properties of polyurethane rod and practical conditions of a bulge forming process such as the friction coefficient between die and tube, between tube and rod, boundary conditions and their constraints. The effect of each condition on a T-shaped copper tube has been explicitly simulated using the Abaqus software. The experimental results have been validated by conducting a series of experiments. After simulating the process, the effect of other parameters such as die corner radius, friction coefficient, thickness of the tube and counterpoise can be evaluated and used in practical experiments. Then, the simulation results have been compared with the obtained results from the experiments. Once the accuracy of the simulation results has been endorsed, the optimal values of different parameters have been determined using simulations. The optimal values for die corner radius, friction coefficient and counterpoise are 5 mm, 0.05 and 200 N, respectively. The findings shows the positive effect of utilization of optimal value for die corner radius, optimal value for counterpoise and lubricate on optimize forming process properties. Manuscript profile
    • Open Access Article

      428 - Experimental Study and Modeling of Friction Stir Welding Process of Aluminum 1100 Alloys, using Artificial Neural Network with Taguchi Method
      V. Zakeri Mehrabad Ali Doniavi A. Gholipoor
      In this paper, the temperature distribution in workpiece and microstructure of welded zone in friction stir welding of aluminum 1100 alloys and the effect of the tool rotational speed on these parameters have investigated experimentally. Also feed forward back propagati More
      In this paper, the temperature distribution in workpiece and microstructure of welded zone in friction stir welding of aluminum 1100 alloys and the effect of the tool rotational speed on these parameters have investigated experimentally. Also feed forward back propagation neural network has been used to predict the temperature of the workpiece during the welding process by considering the process time and tool rotational speed as input parameters of the neural network. For this purpose, the Taguchi design of experiments has been used and the network with minimum mean squared error was selected. This way of neural network selection is very formal and effective than the existing methods. The selected network mean squared error with this approach is 0.000388, its most differences with experimental inputs is 0.770997ºC and its regression R values is 0.99113. Also according to experimental results, increasing tool rotational speed leads to higher plastic deformation in materials and also causes increasing the friction between tool and workpiece which leads to higher workpiece temperature. Manuscript profile
    • Open Access Article

      429 - Attitude Control of Unmanned Aerial Vehicle Based on Sliding Mode Technique with Parameter Estimation
      A. A. Akbari* S. Amini
      An adaptive robust controller for nonlinear and coupling dynamic of aerial vehicle has been presented. In this paper an adaptive sliding mode controller (ASMC) is integrated to design the attitude control for the inner loops of nonlinear coupling dynamic of Unmanned Aer More
      An adaptive robust controller for nonlinear and coupling dynamic of aerial vehicle has been presented. In this paper an adaptive sliding mode controller (ASMC) is integrated to design the attitude control for the inner loops of nonlinear coupling dynamic of Unmanned Aerial Vehicle (UAV) in the presence of parametric uncertainties and disturbances. In the proposed scheme, the adaptation laws can estimate the unknown uncertain parameters and external disturbances, while the sliding mode control is used to ensure the fast response and robustify the control design against unmodeled dynamics with a small control effort.The synthesis of the adaptation laws is based on the positivity and Lyapunov design principle. In comparison with other sliding mode approaches, the approach does not need the upper bound of parametric uncertainty and disturbances. The navigation outer loops of small UAV instead is based on PIDs to control altitude and heading. Simulation results demonstrate that the proposed controller can stabilize the nonlinear system and also it has stronger robustness with respect to the model uncertainties and gust disturbance. Manuscript profile
    • Open Access Article

      430 - Effect of Rotational Speed on Wear Behavior and Mechanical Properties of Friction Stir Welded AA6061+15%Al2O3p Metal-Matrix Composite
      Moslem Paidar Mojtaba Jafarian Mohsen Salehi Mohammad Saeed Khakpash
      The main objective of the present work was to investigate the effect of tool rotational speed on the mechanical and microstructural properties of aluminum based metal matrix composites (AA 6061 alloy reinforced with 15% of Al2O3 particles). The welds were produced by va More
      The main objective of the present work was to investigate the effect of tool rotational speed on the mechanical and microstructural properties of aluminum based metal matrix composites (AA 6061 alloy reinforced with 15% of Al2O3 particles). The welds were produced by varying the rotational speed from 630 to 1250 r/min while the chosen welding speed was 80 mm/min for analysis. It was found from the analysis of the microstructure that the changing of the rotational speed leads to variation of the grain size and also the fragmentation and improvement of Al2O3 particles distribution in nugget zone. Moreover, the obtained results clearly depicted that increasing rotational speed from 630 to 1250 r/min resulted in improvement of the wear resistance and also decreases the fluctuations of friction coefficient which can be attributed to the presence of Al2O3 particles which acted as barriers and restricted the grain growth in nugget zone. The lowest wear rate was achieved at welds produced at rotational speed of 1250 r/min. It was seen from the hardness results that the highest tensile strength value was obtained for 1250 r/min rotational speed with an average value of about 320 MPa (equivalent to 82% that of the base metal). Manuscript profile
    • Open Access Article

      431 - Mechanical Behavior of Al-SiCnp Nanocomposite Fabricated by Hot Extrusion Technique
      A. Atrian S. H. Nourbakhsh
      In this paper, fabrication and characterization of Al-SiC nanocomposites is investigated. The Al matrix is reinforced with different amounts of SiC nano-particles using mechanical milling, cold pressing, and, hot extrusion techniques. To get the best quality of the samp More
      In this paper, fabrication and characterization of Al-SiC nanocomposites is investigated. The Al matrix is reinforced with different amounts of SiC nano-particles using mechanical milling, cold pressing, and, hot extrusion techniques. To get the best quality of the samples, the extrusion process is optimized firstly. With this regard, hot extrusion parameters such as the rate of extrusion, temperature, the extrusion ratio, lubrication, and the die set dimensions are experimentally studied. Finally, the nanocomposites with relative density more than 99% could be successfully fabricated under extrusion ratio of 8.5:1. As-extruded billets were then used to prepare standard tensile test specimens based on ASTM-E8. Afterwards, relative density, tensile behaviour, and micro-hardness of the samples were determined. The results show about 50% improvement for both the tensile strength and micro-hardness and near 1% reduction of relative density as the content of SiC reinforcement increases to 3 vol%. Therefore, specimens with higher strength-to-weight ratio which is a key parameter in aerospace and automotive applications can be produced using current techniques. Manuscript profile
    • Open Access Article

      432 - Numerical Investigation on Heat Transfer and Performance Number of Nanofluid Flow inside a Double Pipe Heat Exchanger Filled with Porous Media
      Ehsan Aminian Babak Ahmadi
      Two common methods to augment heat transfer are the application of nanofluids and porous inserts. In the present work, heat transfer inside a double tube heat exchanger filled with porous media is analyzed numerically using two phase mixture model for the nanofluid flow More
      Two common methods to augment heat transfer are the application of nanofluids and porous inserts. In the present work, heat transfer inside a double tube heat exchanger filled with porous media is analyzed numerically using two phase mixture model for the nanofluid flow and the Darcy-Brinkman-Forchheimer model for the flow inside porous media. Basically, porous media improve heat transfer at the expense of increasing pressure drop. A new PN (Performance number) -defined as the ratio of heat transfer to pressure drop on the base state (without porous media and nanoparticles)- is introduced to better judge the first law’s performance of configurations. Results indicated that by keeping and increasing Reynolds number from 500 to 2000, an increase of 56.09% was observed in the performance number. Furthermore, maintaining Reynolds number at Re=500 and changing from 0.0001 to 0.1, results in an increase of 138%. For pressure drop, by keeping and increasing Reynolds number from 500 to 2000, it is 40 times. Furthermore, maintaining Reynolds number at Re=500 and changing from 0. 1 to 0.0001, the pressure drop is 250 times. Besides, adding 3% nano particles to the base fluid enhances the performance number by about 50% and increase pressure drop by about 20%. Manuscript profile
    • Open Access Article

      433 - Experimental Investigation on Fatigue Evaluation of Orthopaedic Locking Compression Plate
      Saenoddin Mohajerzadeh Khalil Farhangdoost Pedram Zamani Kamal Kolasangiani
      Locking compression plate (LCP) is a common orthopedic instrument for internal fixation and healing of bone trauma. It is important to study on mechanical behavior and failure investigation of LCP because its failure leads to lots of cost and pain to the patient. In thi More
      Locking compression plate (LCP) is a common orthopedic instrument for internal fixation and healing of bone trauma. It is important to study on mechanical behavior and failure investigation of LCP because its failure leads to lots of cost and pain to the patient. In this paper, fatigue life of an eight-hole tibia LCP is evaluated under flexural loading. A four-point bending jig is manufactured and fatigue tests are performed for different compression loads. Fatigue life cycles are investigated for compression loads of 500, 600, 700, 800, 900 and 1000 N and relation between compression load and life cycles is estimated. 125 walking days is estimated for the patient during treatment period according to life cycle results. Post failure analysis results on fracture surface revealed that the crack initiated from the edge of compression hole and propagated from lower to the upper surface of LCP according to beach marks. Finally, Scanning electron microscopy (SEM) on the fracture surface revealed striations as a proof of fatigue crack growth. The striation spacing near the crack initiation site is found to be smaller than this spacing far from the initiation zone. The fatigue crack propagation life is estimated as 1600 cycles according to the number of striation spacings. Manuscript profile
    • Open Access Article

      434 - Evaluation of ANN and ANFIS Methods in Study of the Motion of a Bubble in A Combined Couette-Poiseuille Flow
      Morteza Bayareh Amireh Nourbakhsh
      10.30495/admt.2021.1895407.1180
      The equilibrium position of a deformable bubble in a combined Couette-Poiseuille flow is investigated numerically by solving the full Navier-Stokes equations using a finite-difference/front-tracking method. The present approach is examined to predict the migration of a More
      The equilibrium position of a deformable bubble in a combined Couette-Poiseuille flow is investigated numerically by solving the full Navier-Stokes equations using a finite-difference/front-tracking method. The present approach is examined to predict the migration of a bubble in a combined Couette-Poiseuille flow at finite Reynolds numbers of 5, 10, and 15. The related unsteady incompressible full Navier-Stokes equations are solved using a conventional finite-difference method with a structured staggered grid. The purpose of this study is to evaluate ANN and ANFIS methods in study of the lateral migration of the bubble. Evaluation criteria of accuracy in test set derived from ANFIS demonstrates that estimated values of correlation coefficient (r), Mean Absolute Error (MAE), and Root Mean Square Error (RMSE) are 0.97, 0.001, and 0.0014, respectively. The ANN model with RMSE of 0.0007, MAE of 0.0004 and r of 0.99, is better than ANFIS model. It is also demonstrated that the bubble position estimated by the ANN and ANFIS models closely follows the one achieved from front tracking method. Manuscript profile
    • Open Access Article

      435 - A Surrogate Reduced Order Free Vibration Model of Linear and Non-Linear Beams using Modified Modal Coefficients and HOSVD Approaches
      Mohammad Kazem Moayyedi
      In the present work, two low-dimensional models are presented and used for vibration simulation of the linear and non-linear beam models. These models help to compute the dynamical responses of the beam with fast computation speed and under the effects of different cond More
      In the present work, two low-dimensional models are presented and used for vibration simulation of the linear and non-linear beam models. These models help to compute the dynamical responses of the beam with fast computation speed and under the effects of different conditions. Also the obtained results can be used in the conceptual and detailed design stages of an engineering system overall design. First, a finite element analysis based on Euler-Bernoulli beam elements with two primary variables (deflection and slope) at each node is used to find static and dynamic responses of the considered linear and non-linear beams. Responses to three different static load cases are obtained and applying them as initial conditions, the time responses of the beam are calculated by the Newmark's time approximation scheme. A low-dimensional POD model which was extracted from the ensemble under the effect of an arbitrary loading is reconstructed. To apply the model to simulate the response of beam under the effect of other loads, POD modal coefficients are updated due to change of initial condition. This modification is performed based on the recalculation of the eigenvalues due to a new initial condition. Also, another low-dimensional model is constructed which is developed based on an ensemble under the effect of several parameters. To apply the model to simulate the response of the beam under the effect of other loads and variations of beam thickness, POD-HOSVD modal coefficients are updated due to the change of desired parameters. The results obtained from the low-dimensional model are showing good agreement to the benchmark data and proving high level accuracy of the model. Manuscript profile
    • Open Access Article

      436 - Development of Thermal and Structural Deformation Model to Predict the Part Build Dimensional Error in Fused Deposition Modeling
      K. Chockalingam M. Karthic N. Jawahar
      The most common extrusion based technology in rapid prototyping is Fused Deposition Modeling (FDM). In FDM process, widely used materials are Acrylonitrile Butadiene Styrene (ABS) and Polycarbonate. In this study ABS-P430 material is considered. During the part build pr More
      The most common extrusion based technology in rapid prototyping is Fused Deposition Modeling (FDM). In FDM process, widely used materials are Acrylonitrile Butadiene Styrene (ABS) and Polycarbonate. In this study ABS-P430 material is considered. During the part build process, the rapid heating and cooling is happening on the build part which leads to high thermal gradient. This thermal gradient causes thermal stress; it will lead to deformation of build parts. In this paper a three dimensional transient thermo-mechanical Finite Element Analysis (FEA) had been used to find out the maximum principal stress and deformation of the build part. This FEA analysis is called as thermal and structural deformation model or 3D FEA model. In this model, the novel technique called Element birth/death is used in ANSYS11 to mimic the FDM process. The most influencing parameters of FDM process called orientation and layer thickness have been considered in a 3D FEA model to calculate the deformation of a part. To validate the work, a standard design which is considered in 3D FEA model is fabricated using dimension 1200es FDM machine using same orientation and layer thickness and deformation is measured. From the results it was observed that the relative error between 3D FEA model and actual fabricated model is found to be 3-6%. This 3D FEA model would be helpful for RP machine users to find the deformation of the build part before making the products. Manuscript profile
    • Open Access Article

      437 - Preliminary Analysis of the Cladding Mechanical Behavior of a Nuclear Superheat Boiling Water Reactor
      Majid Bahonar Gholamreza Jahanfarnia Morteza Gharib
      In the present study, investigation of mechanical behaviour of the fuel cladding material for a nuclear superheat Boiling Water Reactor with annular fuel rods, is carried out. In this design, each annular fuel element is cooled internally by steam and externally by wate More
      In the present study, investigation of mechanical behaviour of the fuel cladding material for a nuclear superheat Boiling Water Reactor with annular fuel rods, is carried out. In this design, each annular fuel element is cooled internally by steam and externally by water. For the fuel cladding material, radiation embitterment and irradiation-assisted stress corrosion cracking (IASCC) are the most important issues that have to be taken into account. Hence, for cladding, two materials are considered. Preliminary thermal expansion and stress analysis have been done for a fresh (begin of cycle) ASBWR (Annular-fuelled Superheat Boiling Water Reactor) fuel element. The purpose of these analysis is to investigate the stress distribution and thermal expansion of the cladding in the initial phase of operation. The results show that there is a noticeable difference in the axial expansion between the inner and outer claddings. For T91 (modified 9Cr-1Mo steel) cladding, the maximum axial thermal growth of the inner cladding is 22.12 mm, which is about 9.7 mm more than the outer cladding. For Inconel 718 cladding, the results are 27.8 mm and 13.4 mm, respectively. Manuscript profile
    • Open Access Article

      438 - Investigating the Reason for Compressor Gearbox Gear Failure in Arfa Iron and Steel Company using Analytical and Fracture Studies
      Mahdi Ebrahimzadeh Ali Galehdari
      Given the application of gears in various industries including steel industries, studying the reasons for facture in gears before reaching the end of their lifetime is of great importance. In this study, a gearbox was investigated which included a gear and a pinion. Aft More
      Given the application of gears in various industries including steel industries, studying the reasons for facture in gears before reaching the end of their lifetime is of great importance. In this study, a gearbox was investigated which included a gear and a pinion. After four years of use, the teeth of gear and pinion along with the shaft attached to the gear were fractured. The fracture had occurred suddenly and with a lot of noise. The fracture in gear and pinion were in the teeth while the fracture in shaft occurred in the keyway. At the beginning of the study, shaft and gear design equations were used to evaluate the suitability of each of the parts in the system using theoretical equations and then fracture type was determined using fracture studies and the accuracy of analytical results were determined. In the analytical study, the results showed that the fracture is due to improper design for the gear shaft leading to more than one million unites of load on the shaft leading to cracks in the keyway and misalignment between gears causing fracture. In the fracture studies, the fracture type (ductile and brittle) was determined and the accuracy of analytical results was confirmed. In the numerical results, the distribution of static strain in the fractured shaft and a redesigned shaft are investigated. Manuscript profile
    • Open Access Article

      439 - Steady State Creep Characteristics of a Ferritic Steel at Elevated Temperature: An Experimental and Numerical Study
      Roozbeh Alipour Ali Farokhi Nejad Hamid Nilsaz Dezfouli
      Prediction of creep life for a ferritic steel plate is significant in the context of its application as an element of steam generating systems. In this paper, the issue of elevated temperature creep in 2.25Cr–1Mo steel was investigated in detail, including the mec More
      Prediction of creep life for a ferritic steel plate is significant in the context of its application as an element of steam generating systems. In this paper, the issue of elevated temperature creep in 2.25Cr–1Mo steel was investigated in detail, including the mechanism and the compatibility of hyperbolic sine modeling methodology for the description of steady state creep behavior of this alloy. Creep rupture tests were conducted on the thin foil samples at an elevated temperature ranging from 973 to 1073 K at various stresses between 90 to 210 MPa. A hyperbolic sine model is then used to fit the experimental creep data and the corresponding best fit parameters are provided. Using these parameters, a finite element analysis employing ABAQUS was carried and the reliability of the hyperbolic sine model was investigated in relation to the creep curve and creep life in the steady state creep area. The main outcome of the current study is creep characterisation of 2.25Cr–1Mo steel foils at extreme elevated temperature and to propose a finite element model for simulating this condition which is not reported so far. The results of experimental, constitutive analysis and finite element simulation were compared to each other and it was shown that they are in a good agreement. Manuscript profile
    • Open Access Article

      440 - Thermal-hydraulic Analysis of Helical Coil Steam Generator of The Multi-Application Small Light Water Reactor (MASLWR) Test Loop Using Drift Flux Model
      Mansour Talebi Valiyolah Ghazanfari
      The Multi-Application Small Light Water Reactor (MASLWR) test loophas been built as a proof of concept for SMRs that is scaled down in size and has electric heater rods instead of a nuclear core. In this paper with using Drift-Flux Model (DFM), the thermal-hydraulic ana More
      The Multi-Application Small Light Water Reactor (MASLWR) test loophas been built as a proof of concept for SMRs that is scaled down in size and has electric heater rods instead of a nuclear core. In this paper with using Drift-Flux Model (DFM), the thermal-hydraulic analysis of helical steam generator in MASLWR under steady-state conditions is simulated. This simulation is performed using the finite volume method. To ensure the accuracy and stability of solutions, User Defined Function (UDF) is written in C programming language. Distributions of velocities, local void fractions, temperature and pressure in the steam generator are calculated in different heights. To validate this simulation,the calculated primary side and secondary bulk fluid temperature are compared with experimental data. The experimental data have been provided by series of measurements of parameters of heat-transfer agent at Oregon State University. The calculated data are in good agreement with measured data and consequently the accuracy of this simulation is satisfied. Accuracy of the prediction shows that it is possible to use the DFM for thermal-hydraulic analysis in advanced models in nuclear power plant and other industries. Manuscript profile
    • Open Access Article

      441 - Combining Magnetic Flux Leakage and Optical Inspection Technique for Identification of Nearby Pittings
      Turaj Azizzadeh Mir Saeed Safizadeh
      Magnetic Flux Leakage (MFL) is an indirect measurement technique. Therefore, calibration curves are generally used to estimate the depths of the defects from the measured MFL signals. This has been shown to give good results on varying degrees of the single defects. How More
      Magnetic Flux Leakage (MFL) is an indirect measurement technique. Therefore, calibration curves are generally used to estimate the depths of the defects from the measured MFL signals. This has been shown to give good results on varying degrees of the single defects. However due to the interaction between the leakage fluxes, nearby pittings can-not be discriminated and properly assessed using the conventional MFL technique. In order to ensure reliable measurement for this case, the MFL technique is combined with the optical inspection technique. The main contributions of this study are to develop a new calibration method based on the defect depth, defect area as well as the amplitude of the corresponding MFL signal and propose a novel combined approach for detection and identification of the nearby pittings. MFL and optical inspection techniques are applied to a test specimen containing the nearby pittings. The results obtained from the experimental tests demonstrate the efficacy of the proposed approach. Manuscript profile
    • Open Access Article

      442 - Theoretical Predictions on Mechanical Properties of Functionally Graded Epoxy/Clay Nanocomposites
      Mahdi Karami Khorramabadi
      In this paper, the theoretical predictions of mechanical properties of functionally graded and uniform distributions Epoxy/clay nanocomposites are presented. The specimens were prepared for uniformly distribution of nanoclay with different nano particles weight percent More
      In this paper, the theoretical predictions of mechanical properties of functionally graded and uniform distributions Epoxy/clay nanocomposites are presented. The specimens were prepared for uniformly distribution of nanoclay with different nano particles weight percent (pure, 3 wt%, 5 wt% and 7 wt%) and functionally graded distribution. The distribution of nanoparticles has been investigated by Field Emission Scanning Electron Microscopy (FESEM). For uniformly distribution of nanoclay, it is shown that there is no sign of the agglomerates found via FESEM imaging which can address well the distribution of nanoclay particles in epoxy. In addition, for functionally graded distributions, it is found that dispersion of nanoclays vary smoothly and continuously from one surface to the other one. The mechanical properties have been determined by simple extension tests. The results of extension tests show that elastic modulus begins to increase up to 5 wt% of nanoclay and then decreases. So, for functionally graded distribution, the elastic modulus is generally larger than the corresponding values for uniform distribution of nanoclay. The theoretical predictions of Young’s modulus for functionally graded and uniform distributions nanocomposites are calculated using a genetic algorithm procedure. The formulation for Young modulus includes the effect of nanoparticles weight fractions and it is modified for functionally graded distribution. To investigate the accuracy of the present theoretical predictions, a comparison is carried out with the experimental results. It is found that the results obtained from the theoretical predictions of genetic algorithm procedure are in good agreement with the experimental ones. Manuscript profile
    • Open Access Article

      443 - Numerical Investigation of Forced Convection Heat Transfer for Different Models of PPFHS Heatsinks
      Soheil Sadrabadi Haghighi hamidreza goshayeshi Iman Zahmatkesh
      10.30486/admt.2022.1957347.1348
      In his research article, several models of heatsink were optimally designed in fin length, width and height along with pin placement which consists of 4 pin fin heatsink models heatsink (including square with different pin angles, circular, truncated cone, and cone pin More
      In his research article, several models of heatsink were optimally designed in fin length, width and height along with pin placement which consists of 4 pin fin heatsink models heatsink (including square with different pin angles, circular, truncated cone, and cone pin heatsinks and one model of the plate-fin heatsink (PFHS)) in order to achieve better thermal performance as well as less energy consumption and were numerically investigated under high air velocity and heat fluxes. Different parameters such as peak temperature, Nusselt number, heat resistance, pressure drop, and energy consumption were compared. The results show that the square PPFHS with the pin angle of 45 degrees has the highest thermal performance compared to the rest of the models while also having the highest pressure drop and energy consumption between the models consuming more than 255 and 358 percent more energy in order to have the same air velocity in the pathway, while the truncated and the fully formed cone model despite having 25% and 30% less thermal performance, have the least pressure drop between the pin models of the heatsinks and therefore consume the least energy out of the PPFHS. Manuscript profile
    • Open Access Article

      444 - Investigation of The Effect of Notch Tip Radius on Fracture Energy of Charpy in 7075 Aluminium Alloy
      Ali Hossein zadeh Mohammad Reza Maraki Mohsen Sadidi
      In the present study Charpy impact tests on a 7075-T651 aluminium alloy with full size (55×10×10 mm) with different notch tip radius (range of 0.19 to 0.40 mm) were conducted and the fracture energy was measured. The experimental results showed that the rela More
      In the present study Charpy impact tests on a 7075-T651 aluminium alloy with full size (55×10×10 mm) with different notch tip radius (range of 0.19 to 0.40 mm) were conducted and the fracture energy was measured. The experimental results showed that the relationship between the fracture energy (E) and the notch tip radius of the Charpy samples (r) for the tested Aluminium is E=18.052r+1.741. Using this relationship, the Charpy energy can be determined for this Aluminium for any notch tip radius. Fracture surfaces revealed an intergranular failure for base metal in longitudinal direction, that a predominately brittle failure (cleavage) with some insights of ductile characteristics was observed. Moreover, with increasing notch tip radius, cracked particles were observed and some microvoids were nucleated, i.e., ductile fracture. Changes in the primary crack notch cause a change in the stress intensity factor adjacent to the crack tip, where the fracture energy in the Charpy Impact Test is subjected to the primary crack notch. Manuscript profile
    • Open Access Article

      445 - Efficiency Estimation of Olefin Furnaces in Order to Provide Methods for Increasing the Efficiency
      Jamaledin Binanejad Amir Homayoon Meghdadi Isfahani
      Despite the growing trend in the petrochemical industry in the country, the industry has faced challenges and accomplishments. One of the most important challenges in the petrochemical industry is energy management in the refinery. Fajr Jam refinery is designed to refin More
      Despite the growing trend in the petrochemical industry in the country, the industry has faced challenges and accomplishments. One of the most important challenges in the petrochemical industry is energy management in the refinery. Fajr Jam refinery is designed to refine part of sour gas produced from Phase 6 of South Pars gas field in Iran and the nominal capacity of gas refining at this site, to determine the factors affecting energy consumption in the ophthalmic furnaces, 104 and 109 kilns were selected and the following were monitored scientifically: monitoring of furnace wall temperature with thermography, furnace feed analysis, steak gas analysis and energy efficiency of furnaces. The results of this study showed that in the furnace 104, the design efficiency and real efficiency was 92.98 and 84.67, respectively and for the furnace 109, the design efficiency and real efficiency was 94.98 and 71.18, respectively. As a result, the amount of energy loss is high and should save energy consumption in these furnaces and improve efficiency: replacement of refractory refractories is also a replacement of insulation. Manuscript profile
    • Open Access Article

      446 - Design and Manufacturing Optimization of Abrasive Water Jet Machining using Expert System
      Morteza sadegh amalnik
      This paper addresses the concept of the expert system for abrasive waterjet machining. For optimization of abrasive waterjet machining, computer based concurrent engineering environment is used. The design specification is acquired through a feature based approach. The More
      This paper addresses the concept of the expert system for abrasive waterjet machining. For optimization of abrasive waterjet machining, computer based concurrent engineering environment is used. The design specification is acquired through a feature based approach. The expert system links with feature base library. The expert system links with material database which holds attributes of more than 20 type of materials. It also links with abrasive data base which hold attributes of 8 types of abrasive, and also 4 type and size of machine. expert system also links with machine database which hold machine parameters. For each design feature, the expert system provides information needed for optimization of design and manufacturing. The expert system can be used as an advisory system for optimization of design and manufacturing. It can be used as a teaching program for new abrasive waterjet machining operators. For each design feature, the expert system provides information such as machining cycle time and cost and cutting rate. By changing machine parameters, we can optimize machining cycle time and cost and cutting rate. Comparison results of the expert system and experimental CNC Abrasive waterjet results for different design feature shows that machining time and cost of expert system is 10% less than experimental. Manuscript profile
    • Open Access Article

      447 - Experimental Investigation of Pool Boiling of Single Wall Carbon Nanotubes (SWCNTs) with Different Grooved Surfaces
      Amir Vasei Moghadam Hamid Reza Goshayeshi
      The enhancements in boiling heat transfer can bring immediate benefits to improve the efficiency and cost of heat energy transfer. In this study, heat transfer coefficient in pool boiling of single wall carbon nanotube-water (SWCNTs) at a concentration of 0. 05, 0. 1 an More
      The enhancements in boiling heat transfer can bring immediate benefits to improve the efficiency and cost of heat energy transfer. In this study, heat transfer coefficient in pool boiling of single wall carbon nanotube-water (SWCNTs) at a concentration of 0. 05, 0. 1 and 0. 15 vol. % on smooth and grooved surfaces has been investigated experimentally at atmospheric pressure. The effect of some shapes namely circular groove, square groove and straight groove on the boiling heat transfer has been also investigated. The experimental results indicated that making different grooved surfaces and also using (SWCNTs)-water enhanced the boiling heat transfer coefficient. The highest increase in heat transfer coefficient was seen in circular grooved, which is 76% higher than the base fluid water on the smooth surface. The heat flux has been changed from 0 to 140 kW/m2. By comparing the results, the circular groove with 0.15% concentration of SWCNTs has higher heat transfer coefficient for the boiling heat transfer. Based on pool boiling surfaces, a new type of grooves pool pooling surface was designed and constructed, which is consisted of inclined circular groove at angle of 45°. Outcome of the present work definitely indicates that the inclination of the circular groove could be excellent option for the increasing of pool boiling heat transfer. Cornwel-Houston correlation has been modified to take care of the effect of grooved surfaces for correlating the Nusselt number as a function of Reynolds number and Prandtl number in pool boiling. This new correlation agrees with the experimental data from the augmented surface satisfactory. Manuscript profile
    • Open Access Article

      448 - Investigating Effects of Vertical Baffles on Damping of Shallow Water Sloshing using a 3D Model
      Rahim Shamsoddini Bahador Abolpour
      10.30486/admt.2023.1968678.1385
      Liquid sloshing is a common phenomenon in the transporting of liquid tanks. A safe liquid transporting needs to control the entered fluctuating forces to the tank walls, before leading these forces to large forces and momentums. Using predesigned baffles is a simple met More
      Liquid sloshing is a common phenomenon in the transporting of liquid tanks. A safe liquid transporting needs to control the entered fluctuating forces to the tank walls, before leading these forces to large forces and momentums. Using predesigned baffles is a simple method for solving this problem. Smoothed Particle Hydrodynamics is a Lagrangian method that has been widely used to model such phenomena. In the present study, a three-dimensional incompressible SPH model has been developed for simulating the liquid sloshing phenomenon. This model has been improved using the kernel gradient correction tensors, particle shifting algorithms, turbulence model, and free surface particle detectors. The results of the three-dimensional numerical model are compared with an experimental model, showing a very good accuracy of the three-dimensional numerical method used. This study aims to investigate vertical baffle effects on the control and damping of liquid sloshing. The results of the present investigation show that in this particular case, by using baffles, it is possible to reduce more than 50% of the maximum value of pressure fluctuations in the slashing phenomenon. Manuscript profile
    • Open Access Article

      449 - Comparison of Neural Networks and Fuzzy System for Estimation of Heat Transfer Between Contacting Surfaces
      Shayan Fathi Mohammad Eftekhari Arman Adamian
      Neural networks can be used in various subjects, such as the discovery of relationships, identification, system modelling, optimization and nonlinear pattern recognition. One of the interesting applications of this algorithm is heat transfer estimation between contactin More
      Neural networks can be used in various subjects, such as the discovery of relationships, identification, system modelling, optimization and nonlinear pattern recognition. One of the interesting applications of this algorithm is heat transfer estimation between contacting surfaces. In the current investigation, a comparison study is done for temperature transfer function estimation between contacting surfaces using Group Method of Data Handling (GMDH) neural networks and ANFIS (Adaptive Neuro Fuzzy Inference System) algorithm. Different algorithms are trained and tested by means of input–output data set taken from the experimental study and the inverse solution using the Conjugate Gradient Method (CGM) with the adjoint problem. Eventually, the optimal model has been chosen based on the common error criteria of root mean square error. According to the obtained results among different models, ANFIS with gaussmf membership function has the best algorithm for identification of TCC between two contacting surfaces with 0.1283 error. Also, the inverse method has the lowest error for thermal contact conductance estimation between fixed contacting surfaces with root mean square error of 0.211. Manuscript profile
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      450 - Fatigue Crack Growth in Thin-Wall Pipes Subjected to Bending
      MohammadMahdi Amiri
      In this paper, a circumferential external surface flaw in a metallic round pipe under cyclic bending loading is considered. Because of very rapid changes in the geometrical parameters around the crack front region, the mesh generation of this region must be done with gr More
      In this paper, a circumferential external surface flaw in a metallic round pipe under cyclic bending loading is considered. Because of very rapid changes in the geometrical parameters around the crack front region, the mesh generation of this region must be done with great care. The analysis of the fatigue crack growth is done in accordance with Paris law. The spread lane of the exterior defect is achieved from the graph of “α” vs. “relative crack depth”. The growth of fatigue crack is also analyzed (the comparative crack depth against loading runs diagram) with various initial crack “α” beneath periodic loading. Fatigue shape growth of primarily semi-elliptical peripheral surface flaws is shown. The weight of the Paris exponent (material constant) on fatigue crack propagation is presented as well. Furthermore, the “fatigue crack growth” progression of several specimens is evaluated experimentally by employing a manually-constructed experimental setup. Conclusively, the experimental results achieved by periodic bending loading tests are compared with the numerical results. Fatigue shape development of initially semi-elliptical external surface defects is illustrated. The effect of the Paris exponent (material constant) on fatigue crack propagation is shown as well. Moreover, the fatigue crack growth of several specimens is assessed experimentally using a manually-constructed experimental set up. Finally, the experimental results obtained by cyclic bending loading tests are compared. Manuscript profile
    • Open Access Article

      451 - Implementation of the Quasi-Brittle Damage Model for 2024 Aluminum Alloy under Periodic Loading
      Sadegh Ghorbanhosseini saeed yaghoubi
      Damage mechanics is one of the most important parts of mechanical engineering that determines the time life for different mechanical elements. The most various models that have been provided so far in damage mechanics, are related to ductile or brittle damage. Nowadays, More
      Damage mechanics is one of the most important parts of mechanical engineering that determines the time life for different mechanical elements. The most various models that have been provided so far in damage mechanics, are related to ductile or brittle damage. Nowadays, the investigation of materials by ductile-brittle damage behavior has been considered by researchers. Kintzel quasi-brittle damage model is one of the best damage models in this field. Therefore, in this paper, due to the application of 2024 Al alloy in different industries especially aerospace and the ductile-brittle damage behavior of this alloy, the implementation of the Kintzel quasi-brittle damage model is presented. For this purpose, by writing an explicit user subroutine VUMAT in finite element software (ABAQUS), a test sample under periodic loading has been modeled. The results of this research showed that the complete failure occurs after the 12th cycle under a periodic loading. Also, 2024 Al alloy showed a good ultimate tensile strength (about 400 MPa) under periodic loading. The magnitude of ductile and brittle damage variables are 0.23 and 0.38, respectively. Manuscript profile
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      452 - The Effect of Type and Location of a Phase Change Material (PCM) Layer in a Building Wall on Energy Consumption using Numerical Simulation
      Arezoo Soleimani Dashtaki Afshin Ahmadi Nadooshan Afshin Abedi
      Phase Change Materials (PCMs) have been the subject of many researches in recent years due to the storage and release of energy at low temperature ranges. PCMs store or releasing a large amount of energy at a constant temperature range leads to saving energy. In this pa More
      Phase Change Materials (PCMs) have been the subject of many researches in recent years due to the storage and release of energy at low temperature ranges. PCMs store or releasing a large amount of energy at a constant temperature range leads to saving energy. In this paper, the numerical modelling of a multilayer composite wall including PCM located on the southern side of a building is carried out using an implicit method. The data correspond the fifteenth day of each month in Tehran. The governing equations are discretized by the implicit Crank Nicolson method and solved by iteration method using MATLAB software. Finally, the location and volume fraction of PCM in the wall of the building are studied to achieve maximum efficiency. The results show that the effect of latent and sensible heat results in a reduction in the input heat flux and thermal load to the building. The optimum location for the PCM layer is the middle layer of the composite wall to reduce the heat transfer rate inside the building. In addition, it is found that the PCM volume fraction in gypsum does not have a significant effect on the thermal performance of the multi-layer composite wall. Hence, low volume fraction reduces the costs without affecting the thermal performance of the building. Manuscript profile
    • Open Access Article

      453 - Studying the Behavior of a Variable Pitch “Hydro Screw” Micro Hydro Turbine, Numerical Analysis and Experimental Investigation
      ali hosseini moghdam omami yousef yassi ahmad Nourbakhsh
      Hydro screw is an axial micro hydro turbine of Archimedean origin. Due to ever-increasing need for clean fuel based and environmentally clean electric power, a research project was undertaken at IROST. In this study, the effect of spiral variable pitch on hydro screw tu More
      Hydro screw is an axial micro hydro turbine of Archimedean origin. Due to ever-increasing need for clean fuel based and environmentally clean electric power, a research project was undertaken at IROST. In this study, the effect of spiral variable pitch on hydro screw turbine has been studied numerically. Based on the results, it was found that the turbine had the best efficiency with a spiral pitch of 1.5. Accordingly, the small model of this turbine was made and tested in the laboratory. The results indicate that the numerical results of the calculations are in good agreement with experimental result, and therefore they can be used safely in the course of subsequent turbine studies. In summary, the results indicate that the maximum turbine output is between 62% and 68% which is about 30% higher than the constant pitch blade turbine. Manuscript profile
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      454 - Experimental Study of the Effect of Variable Pitch in Indexable Cutting Tool on AISI4140 Steel Surface Finish in Milling
      Behrouz Mahdikhani Mehrdad Javadi
      10.30495/admt.2020.1890458.1166
      Chatter is one of the most limitations that cause undesirable effect on improving productivity and part quality. In this paper, an experimental method has been used for analysing the effect of changing pitch in the indexable cutting tool in milling. For this purpose, th More
      Chatter is one of the most limitations that cause undesirable effect on improving productivity and part quality. In this paper, an experimental method has been used for analysing the effect of changing pitch in the indexable cutting tool in milling. For this purpose, the cutting forces of machining in three different directions were investigated and a comparison was made between tools with equal and unequal pitches. Milling of AISI 4140 has been performed with two different depths of cut (0.5&1mm) and the machining surface finish were examined. Furthermore, by using accelerometer sensors, the machining vibrations and machining forces by using dynamometer were measured. According to the findings, as well as the reduction of vibrations of machining about 50 %, machining forces reduction between 15% and 30% and surface finish improvement more than 200%were observed. In this regard, utilizing tools with different pitches leads to improvement in machining efficiency, reducing energy consumption, manufacture of high quality parts and it will ultimately reduce costs. Manuscript profile
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      455 - A Novel Approach for Optimization of Vehicle Noise Insulators
      S.Hamed Tabatabaei Saeed Moradi Haghighi Kasra Ghasemian Amir Hossein Kiani
      10.30495/admt.2020.1883494.1161
      Development of effective sound insulators for interior noise reduction of vehicle cabin is an essential phase of the process of vehicle manufacturing. One of the main issues in this process is the space limitations for packaging the firewall insulators. In this paper, a More
      Development of effective sound insulators for interior noise reduction of vehicle cabin is an essential phase of the process of vehicle manufacturing. One of the main issues in this process is the space limitations for packaging the firewall insulators. In this paper, a new approach in sound insulator optimization will be used, in which the space limitation has been considered. The insulator consists of a Micro-Perforated Plate (MPP) and a limp porous layer. MPP layer is suitable for use in vehicles due to low weight and flexibility in design. The main goal of this study was to reach better performance and less weight and volume in a specific thickness. So, a mathematical model of this sound package has been developed and validated by experimental data and SEA software. The simulation results illustrate the high performance of the optimized sound package in practical application, particularly at higher frequencies. On the other hand, the weight and thickness of the optimized sound package are less than the conventional sound packages. These qualities provide an optimized design that has better compatibility with the automotive industry. Manuscript profile
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      456 - Numerical Study of Microbeam with Geometric Discontinuity Under Electrostatic Load using Strain Gradient Theory
      Hadi Hamidizadeh Mahmoud Mousavi Mashhadi Younes Mohammadi
      In this work, the pull in analysis of microbeam with geometric discontinuity for two different boundary conditions has been investigated. Boundary conditions are considered as Clamped-Free (CF) and Clamped-Clamped (CC). The governing equations are transformed into non-d More
      In this work, the pull in analysis of microbeam with geometric discontinuity for two different boundary conditions has been investigated. Boundary conditions are considered as Clamped-Free (CF) and Clamped-Clamped (CC). The governing equations are transformed into non-dimensional form and then solved using Differential Quadrature method (DQ). The conductive polymer length scale parameter was also obtained. The effects of different parameters and pull in voltage on microbeam are studied. Most of the microbeams analyzes were made of Gold, Nickel or Silicon, but we used variety of conductive polymers in this paper. The results show that conductive polymer microbeams can be a suitable substitute for expensive metals. The results can be used to design and improve the performance of Micro-Electromechanical System (MEMS) devices. Manuscript profile
    • Open Access Article

      457 - Studying the Effect of Pulse Shape on Dynamic Stress Intensity Factor at the Finite Crack Tip using Displacement Fields
      Hossein Rahmani Mohammad Ahmadi Balootaki
      In analytical studies, step (Heaviside) function is used to simulate an impact load. However, in real behaviour of materials, loading and unloading take a short time. The present study discusses analytically the effects of pulse shape and rising time of an impact load o More
      In analytical studies, step (Heaviside) function is used to simulate an impact load. However, in real behaviour of materials, loading and unloading take a short time. The present study discusses analytically the effects of pulse shape and rising time of an impact load on dynamic stress intensity factor. Firstly, a pulse load with positive slip (linear and non-linear) is applied on a cracked plate and the amount of dynamic stress intensity factor on the crack tip is obtained. Then the effects of pulse time are discussed. Results show that increasing the rise time decreases the stress intensity factor because of reduction of inertia effects. Moreover, the duration of rise time plays the main role in dynamic stress intensity factor changes and how the variations are not matter. Manuscript profile
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      458 - The Case Examination of Detection of Structural Damages on a Plate using Wavelet Transform
      Ali Mohammad Rousta Peyman Beiranvand Farzad Akbarinia Mehdi Hooshmand
      Sometimes, suddenly or gradually structural or nonstructural damages are created in structure’s members due to natural or unnatural reasons like earthquake or corrosion. One of the methods used from the early in last decade to recognize damage is wavelet transform More
      Sometimes, suddenly or gradually structural or nonstructural damages are created in structure’s members due to natural or unnatural reasons like earthquake or corrosion. One of the methods used from the early in last decade to recognize damage is wavelet transform method. In this method, instead of examination of natural frequencies and the rate of its changes, vibration response or static response of a structure in various points of a structure is recorded at the same time, which in fact is a place-domain signal. In this paper, some factors have been investigated on a plate such as the effect of crack depth reduction, effect of changing support conditions, and the effect of approaching two rectangular cracks; and the responses obtained from finite element analysis, have been studied and the following results are gained: the ability of wavelet method to recognize the locality and severity of cracks, identification of tiny cracks up to 0.5mm depth and increasing the intensification of cracks’ effect on plate by reducing their distance from each other. Manuscript profile
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      459 - Studying the Effect of Different Vortex Generator Geometries and Arrangements on Heat Transfer Performance of Heat Sinks
      Mohsen Motahari-Nezhad Shayan Fathi Mohammad Eftekhari Armen Adamian
      10.30495/admt.2020.1870924.1126
      In this paper, different geometries and arrangements of vortex generators for improving the heat transfer performance of heat sinks have been studied. The effect of different parameters including the inclination angle of vortex generators and the distance between them a More
      In this paper, different geometries and arrangements of vortex generators for improving the heat transfer performance of heat sinks have been studied. The effect of different parameters including the inclination angle of vortex generators and the distance between them are also investigated on heat transfer performance of heat sinks. Numerical computations are done based on the finite volume method and they have been validated with available experimental data which were in accurate compatible with each other with RMSE error of less than 6%. According to the obtained outcomes, between rectangular, triangular and symmetrical NACA0012 vortex generator, heat sink with NACA0012 vortex generator has the best thermal performance. On the other hand, heat sink with rectangular vortex generator has the highest fluid flow pressure drop. So, using rectangular vortex generator with heat sink needs a fan with the highest power. Also, the results show that thermal resistance of the heat sink decreases with Reynolds number increase. Also, heat sink pressure drop increases with Re number enhancement. Meanwhile, the pressure drop rate is more sensible in higher Reynolds numbers. Manuscript profile
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      460 - Design of Structure for a Heavy Duty Mineral Tow Machine by Evaluating the Dynamic and Static Loads
      Mehdi Akhondizadeh Meysam Atashafrooz
      10.30486/admt.2023.1962820.1365
      The present manuscript gives the description of findings which took importance during the design and analysis of the structure of heavy duty hauler machine ordered by Gol-e-Gohar iron ore complex in Iran. Stress and deformation analysis was indeed the heart of the proje More
      The present manuscript gives the description of findings which took importance during the design and analysis of the structure of heavy duty hauler machine ordered by Gol-e-Gohar iron ore complex in Iran. Stress and deformation analysis was indeed the heart of the project and the key of its success. The challenging problem of evaluation of value and behaviour of active loads was taken under consideration precisely and all participated external forces were included in analysis. Since the present case is a moving structure, the loading evaluation should be included in all critical experienced conditions through the operation. The inertial forces due to acceleration and road bump have the governing role and have been evaluated and considered in analysis. After precise and complete evaluation of external loads and applying the correct boundary conditions, the simulations for stress analysis have been performed in ANSYS. The main findings of the present study were the optimized decision for the geometry of several important load carrying elements and appropriate reinforcement of the risky positions which was the result of the correct knowledge of the mechanics of problem. Finally, the structure was manufactured with the total weight of about 38 ton and load carrying capacity of 120 ton including the dynamic effects. After succeeding in the initial loading, the operational loading in real conditions in mine ramp has been carried out gradually and the machine is currently working in desired predicted form. Manuscript profile
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      461 - Analytical and Numerical Study of Pre-Stress Effect in Piezoelectric Sandwich Type Ultrasonic Transducer
      Hamidreza Nadri Mahdi Shaban Abbas Pak
      10.30495/admt.2021.1904847.1204
      In this paper, the effect of pre-stress condition on the resonance frequency of the transducer is studied by using numerical and analytical methods. To compare the obtained results, two sandwich-type transducers with nominal frequency of 25 kHz and 30 kHz are considered More
      In this paper, the effect of pre-stress condition on the resonance frequency of the transducer is studied by using numerical and analytical methods. To compare the obtained results, two sandwich-type transducers with nominal frequency of 25 kHz and 30 kHz are considered. Experimental determination of pre-stress value in transducer is described and measured. Then resonance frequency of transducers in the presence of pre-stress is determined by impedance analyser. Numerical analysis is conducted by modelling three-dimensional transducer in details at ABAQUS software. The resonance frequency is determined with and without pre-stress. The FE results show that by applying pre-stress on the transducers, the resonance frequency of transducers decreased. Furthermore, the FE results are very close to experimental results. Furthermore, a systematic analytical solution is presented based on one-dimensional wave propagation. The resultant displacement for each sub-section of the transducer is calculated and then all of them are assembled and solved by considering the continuity conditions of displacement and force components. It is found that pre-load condition that is produced by central bolt reduces resonance frequency of the transducer. The obtained analytical results provide fast and reliable model for predicting resonance frequency of transducer. Manuscript profile
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      462 - Design and Analysis of Bicycle Helmet Made of PETg and ABS with Honeycomb Structure Against External Impacts using Abaqus Software
      sajjad pakzad ahad shah hoseini Maryam Dehghani amir bahador khalkhali
      10.30495/admt.2021.1896746.1185
      The bicycle helmet has a significant role in reducing and preventing impact because of reducing the deceleration of the skull, spreading the area over which the forces of the impact reach them and preventing direct contact between the skull and the impacting object. Hon More
      The bicycle helmet has a significant role in reducing and preventing impact because of reducing the deceleration of the skull, spreading the area over which the forces of the impact reach them and preventing direct contact between the skull and the impacting object. Honeycomb structure, due to its elastic properties, extends the energy absorption time of the whole structure and also increases the ability of the whole structure to absorb energy. Therefore, it can be used in the liner designing of a helmet to reduce velocity, energy, and acceleration in impacts. In this paper, intending to identify the minimum stress transmitted to the helmet during an impact, we used Rhino software to model a helmet with honeycomb liner and outer shell and then analyzed it in Abaqus software. Due to the fact that the size of various parts of the head is different in people, so for more comfort and safety, the use of customized-helmet is emphasized. To design and make a customized-helmet, the materials used in designing the helmet are ABS and PETg filaments, which can be used in 3D printing. These two materials have been analyzed with four compositions for the liner and the shell of the helmet. The results show that the best combination of the helmet with Minimum stress transmission and appropriate plastic strain due to impact is the helmet case with honeycomb liner of PETg and a shell made of ABS. Manuscript profile
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      463 - The Inverse Method of Damage Detection using Swarm Life Cycle Algorithm (SLCA) via Modal Parameters in Beam Like Structures
      Alireza Arghavan Ali Ghoddosian Ehsan Jamshidi
      10.30495/admt.2021.1921979.1248
      The Non-destructive vibration based structural damage detection techniques have been developed in the recent decades. They are usually converted into a mathematical optimization problem that should be solved using optimization algorithms. In this paper, a new hybrid alg More
      The Non-destructive vibration based structural damage detection techniques have been developed in the recent decades. They are usually converted into a mathematical optimization problem that should be solved using optimization algorithms. In this paper, a new hybrid algorithm, using a particle swarm - genetic optimization, is proposed that is called Swarm Life Cycle Algorithm (SLCA). Additionally, Modified Total Modal Assurance Criterion (MTMAC) that is modal based and involved natural frequencies and mode shapes, is used as an objective function. A cantilever beam is modelled and simulated using finite element method as a numerical case study with several different damage scenarios. To compare the effectiveness of the proposed algorithm with GA and PSO, they are applied to detect the locations and severities of damages of numerical cases separately. To assess the robustness of them, the effects of environmental noise, coordinate and mode incompleteness on the accuracy of damage detection have investigated. For experimental validation of the proposed method, empirical studies of single and double crack aluminium cantilever beams were conducted. The numerical and experimental results show that the proposed algorithm has great potential in crack identification. It is observed that SLCA is able to detect the location and extent of damage irrespective of the noise level and perform well in the presence of mode and coordinate incompleteness. Manuscript profile
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      464 - Evaluation of Mixed-Mode Center Crack SIF in a Curved Plate Repaired by Stop Holes, Composite Patch, and Hybrid Methods
      Sirvan Mohammadi sadegh daryaei
      10.30486/admt.2022.1947527.1329
      In this research, using the 3D finite element method and considering different materials for a composite patch, the effect of separate and simultaneous use of stop holes and composite patch (one-sided and two-sided) on reduction of SIF in a curved plate including mixed- More
      In this research, using the 3D finite element method and considering different materials for a composite patch, the effect of separate and simultaneous use of stop holes and composite patch (one-sided and two-sided) on reduction of SIF in a curved plate including mixed-mode crack is investigated. Glass-epoxy, graphite-epoxy, carbon-epoxy, and boron-epoxy are used for repair patches. For the one-sided patch, the effects of different geometric parameters on the efficiency of the repair are investigated. For all four composite patches, as the thickness of the patches increases, KI and KII decrease, but with increasing the patch length, KI and KII increase. The research results also show that with increasing the width of the glass-epoxy patch, KI and KII almost do not change, but for other patches, as the patch width increases, the SIF increases. The effect of the radius of curvature of the plate on the efficiency of various repair methods is also investigated. In all repair methods studied, SIF decreases with increasing radius of curvature of the curved plate. Different repair methods are compared and the best method with the highest efficiency is introduced. The best repair mode is the hybrid repair method (stop-holes and two-sided boron-epoxy patch), which reduces KI and KII by 84.50 and 86.6%, respectively. Finally, the effect of adhesive thickness used for patch bonding on hybrid repair method efficiency and durability is investigated. for all four materials of patches understudy, KI and KII increase with increasing the thickness of the adhesive, but on the other hand, as the thickness of the adhesive increases, the maximum Von Mises stress in the adhesive decreases. Manuscript profile
    • Open Access Article

      465 - Numerical Study of the Flow Field and Heat Transfer of a Non-Newtonian Magnetic Nanofluid in A Vertical Channel Affected by A Magnetic Field
      amireh nourbakhsh amirreza sadeghi
      10.30486/admt.2022.1939334.1312
      The present paper examines thermal and hydrodynamic behavior of the incompressible laminar flow of a non-Newtonian magnetic nanofluid in a vertical rectangular channel numerically using two-phase mixture model, Carreau model, and finite volume method. The non-uniform tr More
      The present paper examines thermal and hydrodynamic behavior of the incompressible laminar flow of a non-Newtonian magnetic nanofluid in a vertical rectangular channel numerically using two-phase mixture model, Carreau model, and finite volume method. The non-uniform transverse magnetic field is created by an electric current-carrying wire located along the channel. The Schiller-Naumann model is employed to calculate the slip velocity between the solid and liquid phases. The flow pattern and nanofluid temperature is assessed by changing effective parameters such as Reynolds number, the magnetic field strength, flow rate, mean axial temperature, and channel heat transfer. It is observed that the transverse secondary flow increases by increasing the magnetic strength due to Kelvin force. The hot fluid is transferred more from the sidewall to the center of the channel and the cold fluid moves from the center of the channel towards the wall, leading to an increase in heat transfer. Also, at low Reynolds numbers, more fluctuations occur in the velocity profile due to the dominance of Kelvin force over inertial force. Manuscript profile
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      466 - Vibration Behavior of the Planetary Gear System by Considering the Fixed Output
      Ali Shahabi Amir Hossein Kazemian
      10.30486/admt.2022.697460
      This work studies on analytical model of the single–stage spur planetary gear in form of lumped–parameter model. It includes key nonlinear factors of planetary gear vibration such as mesh stiffness and backlash of meshing gears. The planetary gear set is mod More
      This work studies on analytical model of the single–stage spur planetary gear in form of lumped–parameter model. It includes key nonlinear factors of planetary gear vibration such as mesh stiffness and backlash of meshing gears. The planetary gear set is modeled as a set of lumped masses and springs and dynamic model of the planetary gear set is presented. Nonlinear equations of motion are presented for each component and each component has three degrees of freedom in planar motion. We have numerically evaluated a set of linear and nonlinear equations to obtain natural frequencies and analysis of vibration behavior of the system under nonlinear factors and fixed output. In previous researches, natural frequencies of planetary gears were evaluated from two points of view: the first one considered fixed output for planetary gears and the second one consists of free rotational output. In this research, the influence of the output flexibility is evaluated on natural frequencies of the planetary gear. Meanwhile, by considering the fixed output, vibration behavior of the nonlinear system is investigated. Results show that the most important effect of the output flexibility is on the principal natural frequency. Because of chaotic phenomenon, vibration behavior of components in translational directions is different. Manuscript profile
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      467 - Investigation of the TiO2/SiC/SiO2 Coating Effect On the Wear Rate of Needle Graphite Electrode by using Electrical Discharge Machining
      Hossein Alian Moghadam majid jabbari Saeed Daneshmand Saeid Rasouli Jazi Arezoo Khosravi
      10.30495/admt.2021.1923176.1251
      Needle graphite electrodes are one of the main parts used in electric arc furnaces. These electrodes have a significant impact on melt quality and product quality, and their consumption is one of the most important parameters of steel production cost in EAF furnaces. Th More
      Needle graphite electrodes are one of the main parts used in electric arc furnaces. These electrodes have a significant impact on melt quality and product quality, and their consumption is one of the most important parameters of steel production cost in EAF furnaces. Therefore, reducing the consumption of needle graphite electrodes in these furnaces is very important. The main reasons for continuous use of needle graphite electrodes in arc furnaces are oxidation of the sidewalls and sublimation of their tips, and many solutions have been proposed to reduce them. In the present study, the effect of coating consisting of TiO2/SiC/SiO2 elements on the wear rate of the needle graphite electrode in the sublimation state is investigated using EDM (Electrical Discharge Machining- Spark device). For this purpose, the effect of voltage, current, pulse on time and pulse off time on the electrode wear rate are investigated and in this regard, Taguchi design method has been used to reduce the number of experiments. Based on the test results, TiO2/SiC/SiO2 coating reduces the wear rate of the needle graphite electrode due to sublimation. Manuscript profile
    • Open Access Article

      468 - Evaluating the Effect of the Second Invariant of Deformation Tensor in The Axial and Azimuthal Shear Deformations
      Amir Ghafouri Sayyad Ali Imam Shahram Etemadi Haghighi
      10.30486/admt.2021.1928399.1275
      The purpose of the present paper is to investigate the effect of the second invariant of the deformation tensor on the axial and azimuthal shear deformation of an incompressible hyperelastic solid with various strain energy functions. To this end, the axial shear deform More
      The purpose of the present paper is to investigate the effect of the second invariant of the deformation tensor on the axial and azimuthal shear deformation of an incompressible hyperelastic solid with various strain energy functions. To this end, the axial shear deformation of an incompressible cylinder with the modified Gent-Thomas, Gent-Thomas, Gent-Gent, and Carroll strain energies subjected to an axial shear traction is considered, where the displacement field is determined analytically for the first three models and numerically for the fourth model. The phenomenon of strain hardening at large elastic deformations, predicted either by the limiting chain extensibility condition for the modified Gent-Thomas and Gent-Gent models or phenomenologically by the Carroll model, is observed and it is shown that the second invariant of deformation increases the strain hardening experienced by such materials. Next, the azimuthal shear deformation of an incompressible annular wedge with the modified Gent-Thomas, Gent-Thomas, Gent-Gent, and Carroll models is considered, where the annular wedge is subjected to a controllable azimuthal shear deformation and the angular displacement is determined analytically for all the above models. Again, the second invariant of the deformation tensor is shown to have a significant effect on the azimuthal shear deformation as reflected in the increase of the strain hardening of the material in such deformation. In addition, the annular wedge with the modified Gent-Thomas and Carroll models is shown to have a higher resistance in azimuthal shear deformation than the other models mentioned above. Manuscript profile
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      469 - Free Vibration of Defective Nanographene using Molecular Dynamics Simulation and Differential Quadrature Method
      Hossein Golestanian ali khodadadi mahmoud haghighi
      10.30495/admt.2021.1928536.1276
      In this paper, the free vibration of defective nanographene is investigated using Molecular Dynamics Simulation (MD) and Differential Quadrature Method (DQM). The equations of motions and the related boundary conditions are derived based on the differential constitutive More
      In this paper, the free vibration of defective nanographene is investigated using Molecular Dynamics Simulation (MD) and Differential Quadrature Method (DQM). The equations of motions and the related boundary conditions are derived based on the differential constitutive relations in conjunction with the classical plate theory via Hamilton’s principle. Then, DQM is used to investigate free vibration of the nanographene with various boundary conditions. At first, in order to determine natural frequencies more realistically, nanographene mechanical properties are determined using MD simulations. The effects of defects are investigated by analyzing pristine and defective nanographenes containing Stone Wales, vacancy, and Adatom defects. According to the results, the non-dimensional fundamental natural frequency parameter converges to the analytical value for N=10×10. Results indicate that graphene with CCCC boundary conditions has the maximum natural frequency. The minimum value corresponds to the graphene with SSSS boundary conditions. In addition, Non-dimensional fundamental frequency parameter of the nanoplate increases with increasing nanoplate aspect ratio. Finally, defects reduce density, position ratio and elastic moduli of nanographene, which causes a decrease in natural frequency. Stone Wales and vacancy defects decrease nanographene natural frequencies by about 8 and 25 percent, respectively. Manuscript profile
    • Open Access Article

      470 - Development of A New Correlation for Estimating Pressure Gradient of Oil- Water Two Phase Flow in A Horizontal Pipe
      yasha hasanzade seyed ali AlaviFazel zoha azizi seyed mohsen peyghambarzadeh alireza azimi
      10.30495/admt.2021.1928725.1279
      Pressure gradient of a two phase mixture in a horizontal pipe were experimentally investigated for water/super viscose oil mixtures. The mixture contained oil having a viscosity of 67 cp and density of 0.872 g/cm3, and pure water, flowing through an acrylic pipe having More
      Pressure gradient of a two phase mixture in a horizontal pipe were experimentally investigated for water/super viscose oil mixtures. The mixture contained oil having a viscosity of 67 cp and density of 0.872 g/cm3, and pure water, flowing through an acrylic pipe having a length and diameter of 6 m and 20 mm, respectively. A high speed digital camera has been used to record visual information. Superficial velocities of water and oil were in the range between 0.18–1.2 m/s and 0.18–0.95 m/s, respectively. The experimental pressure gradient has been compared to the Al-Wahaibi correlation and two-fluid model. The absolute average error for the “two-fluid model” and Al-Wahaibi correlation have been calculated for 30% and 12%, respectively. In this investigation, a new modified correlation is developed on the basis of the Al-Wahaibi correlation, that predicts the values of pressure gradient with an absolute average error of about 9%. The pressure gradient correlation was validated extensively against 11 independent data sources. To our knowledge, this is the best pressure gradient furmola that is published for oil–water flow which includes wide range of operational conditions including fluid properties, pipe diameters and pipe materials. One of the advantages of the new proposed formula is that it also performs well for super viscosity oils. Manuscript profile
    • Open Access Article

      471 - Numerical Study on Forced Convection of Slip Flow in A Microchannel with Smooth and Sinusoidal Walls
      Afshin Ahmadi Nadooshan DAriush Bahrami Akram Jahanbakhshi
      10.30495/admt.2021.1926613.1265
      The micro-scale equipment has many advantages, including high thermal performance, high surface-to-volume ratio in heat transfer, small size, low weight, low required fluid and high design flexibility. In this study, fluid flow inside a microchannel is modeled under the More
      The micro-scale equipment has many advantages, including high thermal performance, high surface-to-volume ratio in heat transfer, small size, low weight, low required fluid and high design flexibility. In this study, fluid flow inside a microchannel is modeled under the assumption of laminar, incompressible, and two-dimensional flow under symmetric boundary conditions. The slip boundary condition is applied to the walls and the flow in the channel output is assumed to be fully developed. The effect of sinusoidal wall with the domain of 0.1 on the hydrodynamic and thermal behavior of the fluid is investigated and the results are compared with the results of smooth wall. The results show that for a constant Reynolds number, the maximum velocity decreases in the microchannel center by increasing the slip coefficient. Also, the comparison between the results of the wavy-wall microchannel and the microchannel with a smooth wall indicates that the heat transfer in the smooth microchannel is less than that in wavy-wall one. Considering the boundary conditions, the thermal behavior of the fluid is approximately the same for two cases in which both walls are sinusoidal and the only upper wall is sinusoidal. Manuscript profile
    • Open Access Article

      472 - Stress Wave Propagation in 2D Functionally Graded Media: Optimization of Materials Distribution
      Parham Rajabi Hossein Rahmani Alireza Amiri
      10.30495/admt.2021.1908681.1216
      In this paper, the analysis and optimization of the effect of the materials distribution on the behavior of 2D functionally graded media subjected to impacted loading has been investigated. First, it is assumed that there are two cases for distributing the components in More
      In this paper, the analysis and optimization of the effect of the materials distribution on the behavior of 2D functionally graded media subjected to impacted loading has been investigated. First, it is assumed that there are two cases for distributing the components in the FG material. In the first case, the power law is considered for materials distribution, and in the second case, the volume fractional changes of the components are made by third degree interpolation. Considering the elastodynamic behavior of the FG materials under loading, the general governing equations of the wave propagation are extracted for the case of properties variation in two dimensions and then the equations are solved using the finite difference method. Finally, an optimization has been made using a single objective genetic algorithm. The results show that the materials distribution has a considerable effect of stress wave propagation in FGMs. Manuscript profile
    • Open Access Article

      473 - Removing Residual Stress and Increasing Fatigue Life by Ultrasonic Method
      Ali Moarefzadeh
      10.30495/admt.2021.1907388.1213
      In this paper, a new method is introduced for evaluating effects of residual stress on fatigue life. The ability of ultrasonic method using longitudinal wave with critical angle of refraction or LCR wave in measuring and removing residual stresses due to welding was use More
      In this paper, a new method is introduced for evaluating effects of residual stress on fatigue life. The ability of ultrasonic method using longitudinal wave with critical angle of refraction or LCR wave in measuring and removing residual stresses due to welding was used. Two plates of alloy 2024-T351 were welded to each other. To measure their residual stress field acoustoelastic property was used and the changes in the speed of ultrasonic propagation of elastic waves when passing through the residual stress fields was investigated. In order to exert the effects of residual stress on fatigue life, the relations between the coefficients of effective stress intensity (SIF) and Fatigue Crack Propagation (FCP) rate in a state that the parts were welded together with residual stress under cyclic loading were obtained. Finally, ultrasonic waves with a certain frequency were used to remove the residual stresses. Also, the relationships between stress intensity factor and fatigue crack propagation rate were modified to predict fatigue life after removal of residual stresses. This method resulted in a 31% increase in fatigue life. The main reason for the increase in life was the plastic area created by the ultrasound wave. Therefore, it can be said that introduced method are suitable for using to remove residual stress due to welding. Manuscript profile
    • Open Access Article

      474 - The Application of the Extended Isogeometric Analysis (XIGA) with K-Refinement Approach for the Prediction of Fatigue Life in Linear Elastic Fracture Mechanic
      Ata Fardaghaie Shahram Shahrooi Mohammad Shishehsaz
      10.30486/admt.2021.1927025.1271
      This study investigates the fatigue life of a cracked plate subjected to cyclic load under linear elastic fracture mechanics, using a numerical method of extended isogeometric analysis (XIGA) with a K-refinement approach. XIGA is applied to simulate discontinuity proble More
      This study investigates the fatigue life of a cracked plate subjected to cyclic load under linear elastic fracture mechanics, using a numerical method of extended isogeometric analysis (XIGA) with a K-refinement approach. XIGA is applied to simulate discontinuity problems without meshing and without the necessity for element boundaries to be aligned to crack faces. In this method, the crack faces are simulated by discontinuous Heaviside functions, whereas the singularity in the stress field at the crack tip is simulated by crack tip enrichment functions. The stress intensity factors for the cracks are numerically calculated using the interaction integral method. Paris law of fatigue crack growth is utilized for predicting the fatigue life of a cracked plate. In the standard finite element analysis, there is no refinement method similar to k-refinement. The effect of the k-refinement on the accuracy of the values stress intensity factor and fatigue life is investigated. To achieve this, the order of Non-uniform rational B-Splines (NURBS) basic function is considered as linear, quadratic, and cubic. It is observed that as NURBS orders are increased in k-refinement, results are improved, and the error is lower compared with the analytical solution. The results show that values of stress intensity factor and fatigue life obtained using XIGA are more accurate compared to those obtained by the finite element method. In addition, and they are closer to the results of the analytical solution, and the XIGA method is more efficient. Manuscript profile
    • Open Access Article

      475 - Magnetic Field Effect on Ferro-Nanofluid Heat Transfer in a Shell and Tube Heat Exchanger with Seven Twisted Oval Tubes
      Mansour Talebi Mehran Tabibian
      10.30486/admt.2022.1937049.1300
      This article investigates the effect of magnetic field on the performance of a special shell-and-tube heat exchanger using ferro-nanofluid. The heat exchanger comprises seven twisted oval tubes with triangular array mounted on a hexagonal cross section. Water/iron oxide More
      This article investigates the effect of magnetic field on the performance of a special shell-and-tube heat exchanger using ferro-nanofluid. The heat exchanger comprises seven twisted oval tubes with triangular array mounted on a hexagonal cross section. Water/iron oxide nanofluid with a volume ratio of 4% is used as hot fluid in tubes and water is employed as cooling fluid in the shell. The flow regime is laminar and calculations are performed at different Reynolds numbers and various magnetic fields. The governing equations include continuum, momentum, energy, and magnetic field equations that are solved using a finite volume method. It is demonstrated that the wall temperature of the tubes at the output is lower when the magnetic field is present compared to the case in which the magnetic field is not applied. Applying the magnetic field to the ferro-nanofluid leads to an increase in the Nusselt Number by about two times, leading to an increase in thermal efficiency of the heat exchanger. Also, the effect of the magnetic field was quite different with respect to the geometry and position of the tubes relative to the flow field. The effect of increasing the Nu in the first half of the twisting of the tube is approximately equal to the rate of reduction in the second half of the tube, resulting in a reduction in the impact of the magnetic field intensity. Manuscript profile
    • Open Access Article

      476 - Design, Numerical and Experimental Investigation of High Swirling Flow in an Annular Combustion Chamber
      Zahra Ghahramani Masoud Zareh Hossein Pourfarzaneh Farshad Pazooki
      10.30495/admt.2021.1919786.1238
      In this study, an annular combustion chamber of a turbojet engine with a net trust of 1650N is designed. Kerosene is considered as fuel in this study. The design consists of evaluation of the reference quantities, calculation of the required dimensions, estimation of ai More
      In this study, an annular combustion chamber of a turbojet engine with a net trust of 1650N is designed. Kerosene is considered as fuel in this study. The design consists of evaluation of the reference quantities, calculation of the required dimensions, estimation of air distribution and pressure drop, estimation of the number and diameter of air admission holes, as well as aerodynamic considerations. The design process is accompanied by Computational Fluid Dynamics (CFD) based on RANS simulation. Three-dimensional simulation of the reacting process within the combustion chamber is carried out based on the finite volume method. The RNG turbulent model and the finite rate/eddy dissipation combustion model are considered in the present study. Finally, the (atmospheric test) AT rig of the combustion chamber is explained. The Turbine Inlet Temperature (TIT) of combustion chamber is measured at different operating conditions. The TIT values in the numerical simulation and experimental measurement are 1191.1K and 1227 K, respectively, in the design point. The SN and the angle of the RZ are equal to 0.9955 and 35.26 degree, respectively. The temperature, velocity and pressure fields of RZ, air-fuel mixture, combustion turbulence are then presented in image outputs and graphs. The results indicate that the temperature distribution at the outlet of combustion chamber is relatively uniform. Manuscript profile
    • Open Access Article

      477 - A Comprehensive Study on the Effects of the Boundary Conditions on the Elastic Buckling Capacity of a Perforated Plate
      Sadegh Ghorbanhosseini Saeed Yaghoubi Mohammad Reza Bahrambeigi
      10.30495/admt.2021.1914605.1227
      Nowadays, different industries are using sheets, plates, and shells as important parts of their components. Because of their small thickness compare to other dimensions, their structural safety requires more attention. Therefore, increasing their strength and intensifyi More
      Nowadays, different industries are using sheets, plates, and shells as important parts of their components. Because of their small thickness compare to other dimensions, their structural safety requires more attention. Therefore, increasing their strength and intensifying their resistance against any kind of failure type could be introduced as an important problem for enhancing the structural safety. Buckling is one of the most significant failure type that should be considered in the stability of any parts such as sheet metals. Thus, investigation of the buckling capacity of the sheet metals is remarkable. On the other hand, the existence of discontinuity like holes and notches in sheet metals can decrease their buckling capacity, significantly. In current study, based on Finite Element Method (FEM), ABAQUS/Explicit has been employed to determine the elastic buckling capacity in a perforated rectangular sheet metal with different boundary conditions on its edges. Afterward, the effect of the hole position and the plate aspect ratios (plate length/plate width) on the buckling capacity of sheet metal was studied. Finally, in order to enhance the sheet metal buckling capacity, two different types of stiffeners were used. The outcomes showed that the maximum buckling coefficient is related to the sheet metal which have four clamped edges. Moreover, For all boundary conditions, the buckling coefficient does not change significantly for the sheet metals with aspect ratio of more than 4. Also, stiffener type 2 increased the buckling capacity of sheet metal up to 83%. Manuscript profile
    • Open Access Article

      478 - Fuzzy Tracking Control of the 3PRR Parallel Rehabilitation Robot
      Moosarreza Shamsyeh Zahedi Zahra Fathipour Majid Anjidani
      10.30486/admt.2022.1962069.1363
      In this study, a couple of 3PRR parallel robot is used for the rehabilitation process of a patient to eliminate a walking disability and leads to his treatment. The 3PRR robot has three degrees of freedom, provided by three prismatic actuators. Also using a couple of th More
      In this study, a couple of 3PRR parallel robot is used for the rehabilitation process of a patient to eliminate a walking disability and leads to his treatment. The 3PRR robot has three degrees of freedom, provided by three prismatic actuators. Also using a couple of them, can quickly rehabilitate and provide the rehabilitation movements of a patient in the walking process. In this study, the extraction of kinematic and dynamic Equations of the robot was investigated, and a fuzzy-logic-based controller is performed. This controller has the ability to repel unwanted disturbances to follow the desired path. All modelling was simulated by MATLAB software. The simulation results show that using the mathematical model and controller, it is easy to go any desired path in the workspace; and this controller will be able to repel environmental disturbances like the sudden movement of patients. Manuscript profile
    • Open Access Article

      479 - Experimental and Numerical Study of In-Plane Loading of Thin-Walled Tubes with Different Section Shapes and Wall Thickness
      sajjad dehghanpour Ali Alavi Nia
      10.30486/admt.2022.1948255.1330
      In this paper, deformations and energy absorption capacities of thin-walled tubes with different section geometries (circle, square, rectangle, hexagon and triangle) under quasi-static in-plane loading are investigated. The tubes have the same material properties, mass, More
      In this paper, deformations and energy absorption capacities of thin-walled tubes with different section geometries (circle, square, rectangle, hexagon and triangle) under quasi-static in-plane loading are investigated. The tubes have the same material properties, mass, volume, lengths and average section area and the loading conditions are similar for all of the specimens. In order to investigate the behaviour of the tubes, more than 100 tests are carried out and numerical simulations are performed. The numerical results are in good agreement with experimental data and show that the section geometry has an important effect on energy absorption capacity so that the circular and square sections have the least and the most capability of energy absorption, respectively. Furthermore, for a specific tube, the absorbed energy increases with the wall thickness. The first peak load in load-displacement curves has the greatest and the smallest values for rectangular and circular sections, respectively. Manuscript profile
    • Open Access Article

      480 - Dimensional and Geometrical Tolerance Analysis of Two Flexible Curved Sheet Metal Parts Assembly
      Parisa Omidvar Maryam Saryazdi
      10.30486/admt.2022.1934277.1295
      Sheet metal assemblies are widely used in the automobile, aerospace, and shipbuilding industries. Sheet metals deform during the manufacturing and assembly process due to their high flexibility. Traditional tolerance analysis approaches were developed for rigid assembli More
      Sheet metal assemblies are widely used in the automobile, aerospace, and shipbuilding industries. Sheet metals deform during the manufacturing and assembly process due to their high flexibility. Traditional tolerance analysis approaches were developed for rigid assemblies; however, new approaches of tolerance analysis and variation simulations have been proposed for flexible (compliant) assemblies using FEM. In this paper, a new method called Interactive Worst Case (IWC) is introduced for tolerance analysis of flexible assemblies, which demands a few FEM simulations and is based on traditional Worst Case (WC) method. IWC method guarantees that all the parts will assemble accurately and have proper function. The case study of this paper is two flexible sheets in the form of quarter cylinders, joined together by six spot welding to form a half-cylinder assembly. The accuracy of IWC is verified by comparing the results to uniform MIC. The results of MIC are also compared to the results of the Monte-Carlo simulation (MCS). Manuscript profile
    • Open Access Article

      481 - Application of Improved Blocked-Off Method to Simulate the Interacting Influences of Obstacle Shape and Wall Velocity on the Turbulent Mixed Convection Flow in a Trapezoidal Cavity
      Meysam Atashafrooz
      10.30486/admt.2022.1952976.1341
      In the current research, interaction influences of obstacle shape and top wall velocity on the hydrothermal behaviours of the turbulent mixed convection flow in a trapezoidal cavity are numerically simulated. To achieve this goal, three different shapes of the obstacles More
      In the current research, interaction influences of obstacle shape and top wall velocity on the hydrothermal behaviours of the turbulent mixed convection flow in a trapezoidal cavity are numerically simulated. To achieve this goal, three different shapes of the obstacles including semicircular, triangular, rectangular are considered. Dimensions of these obstacles are chosen so that the environment around all three of them is same. The RNG model is chosen to simulate the turbulent flow. To model the inclined or curved walls of trapezoidal cavity and obstacles, the improved blocked-off method is applied. Results show that the obstacle shape and top wall velocity have a significant influence on the thermal and hydrodynamic behaviours. In fact, the highest magnitude of heat transfer rate along the bottom wall occurs in the cavity with the rectangular obstacle and for the highest magnitude of top wall velocity; whilst its lowest magnitude is related to the pure free convection and for the cavity with the semicircular obstacle. Besides, the lowest and highest magnitudes of temperatures fields occur for the cavities with rectangular and triangular obstacles, respectively. Manuscript profile
    • Open Access Article

      482 - Function Generation Synthesis of the Four-bar Linkage Based on Four and Five Precision Points using Newton-HCM
      Seyyed Mojtaba Varedi-Koulaei
      10.30486/admt.2023.1962704.1364
      The length values selection for a determined type of linkage to achieve the necessary task, dimensional synthesis, is classified into three classes based on the mechanism’s task: function generation, path generation, and motion generation. The case considered in t More
      The length values selection for a determined type of linkage to achieve the necessary task, dimensional synthesis, is classified into three classes based on the mechanism’s task: function generation, path generation, and motion generation. The case considered in this study, Function generation synthesis, aims to create a relation between the angular motions of the input and output links of the mechanism. For this problem, a semi-analytical method called the Newton-HCM is used for numerical solutions, which combines Newton’s method with the semi-analytical Homotopy Continuation Method (HCM). Function generation synthesis of a planar four-bar linkage for four and five precision points is the main challenge of the current study, which is highly nonlinear and complicated to solve. Numerical examples of the function generation problem for a four-bar linkage with four and five precision points are presented and authenticate the excellent performance of the proposed algorithm. Manuscript profile
    • Open Access Article

      483 - Vibration Analysis of Rotating Disk Carrying Annular Concentrated Masses in Turbo-pump System
      Behrooz Shahriari Mostafa Nazemizadeh A. M. Shirvani
      10.30486/admt.2023.697496
      Vibration analysis of rotating disks is one of the most important problems in turbomachines. In this study, a new method has been presented which analyzed the radial vibration of a turbo-pump rotating disk carrying two annular concentrated masses located on the disk and More
      Vibration analysis of rotating disks is one of the most important problems in turbomachines. In this study, a new method has been presented which analyzed the radial vibration of a turbo-pump rotating disk carrying two annular concentrated masses located on the disk and at its end. Natural frequencies have been calculated in different rotating speeds; then results have been compared with each other. The effects of concentrated masses position and intensity on natural frequencies have been investigated. The results show that concentrated masses always have been decreased the value of first natural frequency, but in the case of second and third natural frequencies, depending on the mass concentration magnitude and its position, the magnitude of natural frequency has been increased or decreased. The vibration of the rotating disk without considering the concentrated mass, was examined. Then the resulting solution was generalized for two connected disks in internal concentrated mass location. The effect of concentrated masses, one on the disk body and the other on the outside of the disk, is considered as boundary conditions in the two disk Equations. The results show that increasing in angular velocity of rotating disk reduces the natural frequency. Concentrated masses always reduce the first natural frequency. At the second and third natural frequencies, concentrated masses may increase or decrease the natural frequency, which depends on the value and position of concentrated mass. Concentrated mass has the most impact when it is in a position that has the most radial displacement. Manuscript profile
    • Open Access Article

      484 - Numerical Analysis of The Crater Diameter and Penetration Depth of The Target Due to The Impact of Short-Rod Segmented Projectiles at High Velocity
      Behnam Yasemi Hamid Soleimanimehr Hossein Khodarahmi sadegh rahmati Najmeh khazraiyan
      10.30486/admt.2022.1925663.1260
      This paper deals with the numerical simulation of segmented projectiles. A segmented projectile is a subset of kinetic energy projectiles. The segmented projectile is made of tungsten and the target is semi-infinite and is made of 4340 steels. Due to the disadvantages o More
      This paper deals with the numerical simulation of segmented projectiles. A segmented projectile is a subset of kinetic energy projectiles. The segmented projectile is made of tungsten and the target is semi-infinite and is made of 4340 steels. Due to the disadvantages of segmented projectiles with, the simulation of segmented projectile with is discussed. Projectiles with aspect ratio greater than one are known as short-rod projectiles. This aspect ratio range forms both the primary and secondary phase of penetration. Numerical simulation was performed by AUTODYN software with Smoothed Particle Hydrodynamic (SPH) method. The use of SPH approach is most consistent with the experimental results. In order to have effective segmented projectiles, greater speeds were used in the simulations. In this range of velocity, due to the hydrodynamic penetration and complete erosion of the rods, the maximum penetration depth is obtained. After a relatively good correlation between the simulation results and the experimental and Hydrocode results, the numerical analysis of the segmented projectiles is performed. The results show an increase in the penetration depth of segmented projectile relative to the continuous type. In the following, the relationship between velocity increase and penetration depth and crater diameter of this type of projectile is investigated. An increase in penetration depth of 40 to 60% has been observed in this type of projectile compared to the continuous projectiles. An increase in penetration depth and crater diameter is observed with increasing impact velocity. Manuscript profile
    • Open Access Article

      485 - Effect of Inter-Cavity Spacing and Heat Treatment in Friction Stir Processing/Welding (FSP/FSW) Al7075 Composites Containing Al2O3 and Graphene Nanomaterials using Charpy Impact Test
      Ali Hosseinzadeh Mahmoud Shariati Danial Ghahremani-moghadam Mohammad Reza Maraki
      10.30486/admt.2022.1943233.1321
      In this research, the friction stir process by adding Al2O3 and graphene nanoparticles at two different distances have been investigated. Nanoparticles are inserted in cavities with a diameter of 2 mm and a depth of 3 mm. Nanoparticles of Al2O3, graphene, and equal comp More
      In this research, the friction stir process by adding Al2O3 and graphene nanoparticles at two different distances have been investigated. Nanoparticles are inserted in cavities with a diameter of 2 mm and a depth of 3 mm. Nanoparticles of Al2O3, graphene, and equal compositions of Al2O3 and graphene, each with two cavity spacings of 8 and 10 mm, have been performed in six different groups of friction stir process. From each group, Six Charpy specimens were separated. Charpy impact test was performed on six samples, three of which were heat-treated after the friction stir process. Charpy impact test has shown that the specimens have higher fracture energy after heat treatment. Also, in all cases, the fracture energy at the distance between the two cavities are10 mm more than the distance of 8 mm, this is since nanoparticles do not accumulate at a more distance. Also, to observe the resulting microstructures using optical microscopy and scanning electron microscopy on the friction welding process and the fracture surface of Charpy impact specimens were performed. The results show that the nanoparticles are accumulated in some samples and well dispersed in the materials in others. Manuscript profile
    • Open Access Article

      486 - Minimum Stiffness and Optimal Position of an Intermediate Elastic Support to Maximize the Fundamental Frequency of a Vibrating Timoshenko Beam using Finite Element Method and Multi-Objective Genetic Algorithm
      Hossein Ebrahimi Farshad Kakavand Hasan Seidi
      10.30486/admt.2022.697492
      This paper explores the optimal position and minimum stiffness of two intermediate supports to maximize the fundamental natural frequency of a vibrating cantilever Timoshenko beam with tip mass using Finite Element Method (FEM) and a multi-objective genetic algorithm (G More
      This paper explores the optimal position and minimum stiffness of two intermediate supports to maximize the fundamental natural frequency of a vibrating cantilever Timoshenko beam with tip mass using Finite Element Method (FEM) and a multi-objective genetic algorithm (GA). After validating the results by comparison to previous works, the effects of the mass ratio and the position and stiffness of intermediate elastic support on the fundamental frequency are investigated. The numerical results demonstrated that as mass ratio increases, the optimal position moves toward the tip mass, and minimum stiffness increases. In many practical applications, it is not possible to place intermediate support in the optimal position; therefore, the minimum stiffness does not exist. In order to overcome this issue, a tolerance zone is considered, and design curves are proposed. The simultaneous optimization of the first and second natural frequencies of the beam with two intermediate supports was carried out using the genetic algorithm (GA) and the multi-objective GA. It was found that the optimization of the first and second natural frequencies did not require the two supports to have the same and high stiffness. The stiffness and optimal positions of the two supports differ at different mass ratios. Moreover, to optimize the first natural frequency, the second support should be stiffer, while the optimization of the second natural frequency requires the higher stiffness of the first support. Manuscript profile
    • Open Access Article

      487 - Evaluation of Critical Buckling Load in FG Plate using Analytical and Finite Elements Methods
      Hossein Ahmadi Rashid AMIR GHIASVAND Maziar Mahdipour Jalilian Mahdi Kazemi
      10.30486/admt.2022.1904716.1203
      In this paper, analytical and finite element solutions of mechanical buckling of a thick Functionally Graded (FG) plate have been investigated. Boundary conditions have been assumed as simply supported at all edges and three different loadings have been applied. In anal More
      In this paper, analytical and finite element solutions of mechanical buckling of a thick Functionally Graded (FG) plate have been investigated. Boundary conditions have been assumed as simply supported at all edges and three different loadings have been applied. In analytical section the procedure of developing the critical buckling force by third order shear theory has been presented and then the stability Equations have been reduced from 5 to 2. In continue, the problem has been solved using numerical simulation by ABAQUS. To validate the FEM, results have been compared and validated with analytical solution. The results show that the bi-axial compression loading case with the loading ratio of R to one and R to zero are the most possible and most unlikely case in buckling occurrence, respectively. Manuscript profile
    • Open Access Article

      488 - Experimental Investigation and Modeling of Bubble Departure Frequency for Nucleate Pool Boiling Heat Transfer of Pure Liquids on Flat Heater
      Samane Hamzekhani Farhad Shahraki Davood Mohebi- kalhori Mohammad Reza Fardinpour
      10.30486/admt.2023.1960198.1354
      In the present study, the response surface methodology is used to predict the bubble departure frequency of pure liquids using experimental data. Water, ethanol and methanol pure liquids were used as the testing fluid. The effects of vapor and liquid density difference, More
      In the present study, the response surface methodology is used to predict the bubble departure frequency of pure liquids using experimental data. Water, ethanol and methanol pure liquids were used as the testing fluid. The effects of vapor and liquid density difference, vapor and liquid viscosity, surface tension, thermal conductivity, heat flux on the vapor bubbles departure frequency on the heat transfer of boiling pool of pure liquids were investigated by response surface methodology. The results showed that the output of the Response surface methodology had a good overlap with the data of bubbles departure frequency of pure liquids. Also, the results for the bubble departure frequency show a good overlap between the models presented by the researchers and the experimental data and have good accuracy. In this research, a new model for the prediction of vapor bubble departure frequency, based on the Buckingham theory, in nucleate boiling is proposed, which predicts the experimental data with a satisfactory accuracy (9%). Manuscript profile
    • Open Access Article

      489 - Modeling of Turbulent Flow Around a Square Obstacle using a Generated Mesh by Image Processing Method
      Bahador Abolpour Rahim Shamsoddini
      10.30486/admt.2023.1962376.1362
      The mesh generation process as a time-consuming and computational effort in the numerical methods always has been paid attention to by researchers to provide more accurate and fast methods. In this study, an accurate, fast, and user-friendly method of mesh generation ha More
      The mesh generation process as a time-consuming and computational effort in the numerical methods always has been paid attention to by researchers to provide more accurate and fast methods. In this study, an accurate, fast, and user-friendly method of mesh generation has been developed by combining the image processing method with Computational Fluid Dynamics (CFD). For this purpose, a turbulent flow around a single square as a bluff body is simulated by homemade code using MATLAB software as a test case to illustrate the mentioned method. The conservative Equations have been discretized using the finite volume method based on the Power-la scheme. Utilizing useful filters on the imported gray-scale digital image provides edge detection of the obstacle in the computational domain. After the edge detection step, an orthogonal, structured, and staggered mesh is generated. Manuscript profile
    • Open Access Article

      490 - Nd:YAG laser processing of thick NiTi wires to locally alter ‎transformation properties towards achieving multiple memory ‎shape memory alloys
      Mahmoud Kadkhodaei Amin  Alipour Ehsan  Foroozmehr
      Every commercial NiTi (Nitinol) Shape Memory Alloy (SMA) has its own transformation temperatures, which may cause limitations in ever-growing demands for the application of these alloys in novel engineering design. Among various methods proposed to achieve multiple func More
      Every commercial NiTi (Nitinol) Shape Memory Alloy (SMA) has its own transformation temperatures, which may cause limitations in ever-growing demands for the application of these alloys in novel engineering design. Among various methods proposed to achieve multiple functional characteristics, laser processing offers effective solutions in locally controlling the transformation properties of NiTi parts. The current work describes the application of laser technique followed by post processing to locally alter transformation temperatures and impose phase transition for thick NiTi wires. To this end, various laser parameters are applied, and the influences of peak power and pulse width on the functional, microstructural and mechanical properties of laser processed samples are studied. A four-sided laser processing protocol is proposed to process almost the whole cross section of thick Nitinol wires. It is also shown that post-processing heat treatment is required to recover the shape memory properties of as-processed Nitinol specimen. The transformation temperatures of final processed Nitinol wire increase by about 50 °C compared to those of the unprocessed base material. Manuscript profile
    • Open Access Article

      491 - A Study on The Effects of Different Pad Materials on Brake System Performance of a High-Capacity Elevator by FEM Simulation
      Mohammad  Sajjad Mahdieh Farshad Nazari Ali Riyadh  Khairullah
      The brake system must be reliable and display unchanging action throughout its use, as it guards the health and life of many people. Properly matched friction pair, a drum, and a brake pad have a great impact on these factors. The brake pads are far more complex compone More
      The brake system must be reliable and display unchanging action throughout its use, as it guards the health and life of many people. Properly matched friction pair, a drum, and a brake pad have a great impact on these factors. The brake pads are far more complex components. New technologies make it possible to develop materials with various compositions and different proportions and connect them permanently in fully controllable processes. This elaboration shows that all these factors have a greater or lesser impact on the coefficient of friction, resistance to friction wear and high temperature, and the brake pad’s operating life. The friction materials are required to provide a stable coefficient of friction and a low wear rate at various operating speeds, pressures, temperatures, and environmental conditions. The aim of this work is therefore to investigate the possibility of using a Finite Element Analysis (FEA) approach to evaluate the braking performance of a heavy-duty elevator with different non-conventional pad materials including Composite Carbon fiber reinforced, Composite Epoxy SMC and SiC (silicon carbide). The results show that the performance of SiC (silicon carbide) is better than two other materials. In the braking system with SiC, the required time for stoppage of the system is lower than two other materials. Manuscript profile

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