List of articles (by subject) advanced manufacturing technology
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Open Access Article
1 - Data-based Probe for Bearing Balls using Design Expert with Biodegradable Media
Saurabh MalpotraThis paper discusses about the lapping process for both metallic and non-metallic materials. The experiments were carried out based on the RSM design of experiments (DOE) approach to investigate the effect of their parameters on the lapping quality of ball bearing, for MoreThis paper discusses about the lapping process for both metallic and non-metallic materials. The experiments were carried out based on the RSM design of experiments (DOE) approach to investigate the effect of their parameters on the lapping quality of ball bearing, for predicting the new results. This study explored the modification for fine finishing of bearing balls through Biodegradable medium (Aloe Vera) and silicon carbide (SiC) powder as an abrasive in addition of conventional oil-based media having an advantage like Antioxidant, antibacterial, non–toxic, good compression, and shear stresses. Spindle speed (rpm), Time (minutes), Force (N), Abrasive concentration were considered as the input process variables while the PISF, MRR and surface Roundness was considered as the process response. The result shows the most significant parameter for maximum PISF of 82.3%, 7.6 mg/min MRR and 9.05μm roundness was achieved with 672 rpm at 7.5 N force, 37.5% abrasive concentration, 165 minutes experimental run time, was achieved. Manuscript profile -
Open Access Article
2 - Study of the Early Development Factors of Failure in Valves of Reciprocating Compressors by Experimental and Numerical Simulation
Mostafa Sayahbadkhor Ali Mozafari Alireza Naddaf OskoueiNowadays most of reciprocating compressors have one - way valves that act by difference pressure between behind and front of valves. In this article, experimental and numerical studying of one - way valves in reciprocating compressors was done. In this experimental test MoreNowadays most of reciprocating compressors have one - way valves that act by difference pressure between behind and front of valves. In this article, experimental and numerical studying of one - way valves in reciprocating compressors was done. In this experimental tests, one – way valve with two different materials for rings; stainless steel with the material number 1.5022 and sign 38si6, and carbon-peek composite, were used. Numerical simulation for one-way valves with identical characteristics of experimental tests was done by CFX 5.7.1 and Ansys workbench 9.1. Experimental tests showed that life of carbon-peek composite ring was more than stainless steel. The most important cause of failure in the stainless steel ring was inappropriate distribution of forces due to the springs below the ring. Another common cause of failure in these valves was the stresses on walls in the location of springs that approved by numerical simulation. Difference in reaction of one - way valves in opening and closeing was another cause of failure because they were different in thermal expansion coefficient, thickness and diameter of carbon-peek composite and stainless steel rings. Appropriate thickness of rings determined by flow equation. The results obtained from numerical simulations have a good agreement with experimental tests. Manuscript profile -
Open Access Article
3 - Investigating the Performance of Coated Carbide Insert in Hard Steel Helical Milling
Navid Molla Ramezani Behnam Davoodi Mojtaba Rezaee HajidehHelical milling is an alternative hole-making machining process which presents several advantages when compared to conventional drilling. In the helical milling process, the tool proceeds a helical path while rotates around its own axis. Due to its flexible kinematics, MoreHelical milling is an alternative hole-making machining process which presents several advantages when compared to conventional drilling. In the helical milling process, the tool proceeds a helical path while rotates around its own axis. Due to its flexible kinematics, low cutting forces, tool wear, and improved borehole quality may be achieved. In this study, a new helical milling process to create holes in hardened steel with a hardness of HRC 52 was used. Carbide inserts with PVD TiN coating were applied. Input parameters including cutting speed and feed rate were considered in 4 and 2 levels, respectively. In order to increase the reliability of the results, experiments were repeated 4 times and the total of 32 tests were performed. Other cutting parameters, such as axial and radial depth of cut were constant. Machining process was performed in dry state and without any lubricant. Output characteristics were tool wear, surface roughness, cutting force, machining time and material removal rate. Tool wear, surface roughness and forces, were measured by tool maker microscopy, roughness tester and dynamometer, respectively. The results showed that increasing the cutting speed on this type of hardened steel, decreases the surface roughness, machining forces and machining time. However, increasing the cutting speed and the feed rate enhances the tool wear and material removal rate considerably. Cutting speed and Feed rate of 50 m/min and 0.05 mm/tooth, offered the best mechanical properties of the Machining. Manuscript profile -
Open Access Article
4 - Design and Analysis of Two Pass Rolling Dies
siva prasad kondapalli VISHNU KANDULASheet metal forming is widely used in automotive and aerospace industry. In this paper analysis of sheet metal forming process by deep drawing was discussed. Static analysis on the deep drawing operation was carried out to find the stresses, strains and total deformatio MoreSheet metal forming is widely used in automotive and aerospace industry. In this paper analysis of sheet metal forming process by deep drawing was discussed. Static analysis on the deep drawing operation was carried out to find the stresses, strains and total deformation of deep drawing cup. CAD models are generated using CATIA from the dimensions obtained by theoretical calculations and analysis is carried out using ANSYS software. The force required to develop the cup, deformation and defect like tearing, wrinkles etc. can be obtained through simulation. By using this method it is easy to make stress and strain analysis for different materials. From the analysis, it is observed that Titanium has the maximum stress with standing ability when compared to copper and Aluminum. Manuscript profile -
Open Access Article
5 - The Effect of Focal Distance and Type of Auxiliary Gas on Cut Width in CO2 Laser Cutting of Stainless and Mild Steel Sheets
Hossein Taheri Hamid Zarepour Firouzabadi Majid HashemzadehLens focal distance and auxiliary gas type utilized in CO2 laser cutting are two important parameters affecting process measures such as cuts width and quality at desired cutting speeds. This research work focuses on cuts width and quality in CO2 laser cutting with a po MoreLens focal distance and auxiliary gas type utilized in CO2 laser cutting are two important parameters affecting process measures such as cuts width and quality at desired cutting speeds. This research work focuses on cuts width and quality in CO2 laser cutting with a power of 4000W on two types of steel sheets at different focal distance values and using different types of auxiliary gas. The effect of focal distances of 5” and 7.5” as well as utilizing oxygen and nitrogen as auxiliary gas on cut width and quality in 304L stainless steel and St37 steel sheets were investigated. The size of cut widths was measured using an optical microscopy. The results demonstrate that cuts performed at the focal distance of 7.5” are wider than those created at the focal distance of 5”. It is also observed that with increased workpiece thickness, the use of focal distance of 7.5” is more feasible because cuts are faster; need lower laser power, and use less amount of auxiliary gas. When using oxygen as auxiliary gas, the main factor affecting the cutting efficiency is the oxidation reaction, whereby oxidation energy is added to laser power which results to an increased energy level in the cutting region. This means that using oxygen as auxiliary gas makes it possible to cut thicker sheets at higher cutting speeds as compared to that of nitrogen. However, when using oxygen as auxiliary gas, the quality of cuts appears to be lower and their width larger as compared to cuts performed by nitrogen auxiliary gas. Manuscript profile -
Open Access Article
6 - Application of the Relevance Vector Machine for Modeling Surface Roughness in WEDM Process for Ti-6Al-4V Titanium Alloy
Abolfazl Foorginejad Nader Mollayi Morteza TaheriCutting the Titanium alloys is a complicated task which cannot be performed by traditional methods and modern machining processes, such as Wire electro-discharge machining (WEDM) process which are mainly used for this purpose. As a result of the high price of the Ti-6Al MoreCutting the Titanium alloys is a complicated task which cannot be performed by traditional methods and modern machining processes, such as Wire electro-discharge machining (WEDM) process which are mainly used for this purpose. As a result of the high price of the Ti-6Al-4V alloy, proper tuning of the input parameters so as to attain a desired value of the surface roughness is an important issue in this process. For this purpose, it is necessary to develop a predictive model of surface roughness based on the input process parameters. In this paper, The Taguchi method was used for the design of the experiment. According to their effectiveness, the input parameters are pulse-on time, pulse-off time, wire speed, current intensity, and voltage; and the output parameter is surface roughness. However, a predictive model cannot be defined by a simple mathematical expression as a result of the complicated and coupled multivariable effect of the process parameters on the surface roughness in this process. In this study, application of the relevance vector machine as a powerful machine learning algorithm for modeling and prediction of surface roughness in wire electro-discharge machining for Ti-6Al-4V titanium alloy has been investigated. The predicting result of model based on the root means square error (RMSE) and the coefficient of determination (R2) statistical indices, prove that this approach provides reasonable accuracy in this application. Manuscript profile -
Open Access Article
7 - Investigating the Effect of Rotation Speed and Ultrasonic Vibrations in the Incremental Forming Process
Saeed Amini Farshad Nazari Mohammad Baraheni Amir Hossein GhasemiIncremental forming is one of the forming methods that is considered because of no need to specific die, especially for rapid prototyping. In this study, the incremental forming process is carried out by using a rotating tool and assisted ultrasonic vibration. Purpose o MoreIncremental forming is one of the forming methods that is considered because of no need to specific die, especially for rapid prototyping. In this study, the incremental forming process is carried out by using a rotating tool and assisted ultrasonic vibration. Purpose of this research is to investigate the effect of rotation speed and ultrasonic vibrations in the incremental forming process. According to the obtained results, mean and maximum values of forming force reduced by using a rotating tool and applying ultrasonic vibrations. The results of surface roughness tests demonstrated that by increasing rotational speed, the surface roughness improved 44% and applying ultrasonic vibrations with tool rotation can reduce surface roughness about 74%. Applying ultrasonic vibrations lead to increase micro-hardness up to 84%, but, by increasing rotational speed, surface hardness slightly reduces. Results of straight groove test determined ultrasonic vibrations with the rotating tool can increase stretching limit up to 41.79% due to the affect on the sheet plasticity behavior. Manuscript profile -
Open Access Article
8 - Incremental Forming of Polymeric Sheet Printed by Fused Deposition Modeling
Saeid Esmaeili Mohsen Loh-Mousavi Sayyed Ali EftekhariSingle point incremental forming (SPIF) and fuseddeposition modeling 3D printing (FDM) are two methods of rapid prototyping. Each method has its own pros and cons. using SPIF method can provide an accurate forming process to shape sheets fabricated by 3D printing with t MoreSingle point incremental forming (SPIF) and fuseddeposition modeling 3D printing (FDM) are two methods of rapid prototyping. Each method has its own pros and cons. using SPIF method can provide an accurate forming process to shape sheets fabricated by 3D printing with their special characteristics. In this study, single-point incremental forming of Poly Lactic Acid (PLA) sheets fabricated by FDM 3D printer was investigated by experiments. The formability process was evaluated by two different experiments. In the first experiment, a lubricant was used at ambient temperature and SPIF was investigated and for the second experiment hot air and lubrication were employed to achieve better formability. In addition, the effects of sheet thickness and strategy of layering of printed sheets by FDM were also studied on SPIF formability. The results showed that the incremental forming of printed PLA sheets in hot air is a more successful state to produce dome shapes parts and ruptures are less and this forming method can be used for some applications such as making partial curve of skull as a medicine solution in surgeries. Also, it was shown that the best layering strategy to print the PLA sheets used for better forming of SPIF is triangular pattern strategy against with rectangular strategy. It was found that thickness of 2mm printed sheet has better formability and less rupture versus 3mm of thickness. Manuscript profile -
Open Access Article
9 - Recycling of Magnesium Machining Chips via Shear Consolidation Processing
Reza Abdi Behnagh Peyman Mashhadi Keshtiban Hadi AbdollahiIn this research, the feasibility of solid-state recycling of pure magnesium (Mg) chips is investigated by applying a synthesis technique called shear consolidation processing (SCP). During the SCP, machining chips are first loaded into the container and slightly compac MoreIn this research, the feasibility of solid-state recycling of pure magnesium (Mg) chips is investigated by applying a synthesis technique called shear consolidation processing (SCP). During the SCP, machining chips are first loaded into the container and slightly compacted, and then a rotating tool with a designated diameter is plunged into the Mg chips at a selected spindle rotation speed and feed rate. Due to the huge amount of heat generation, the softened materials are compressed and synthesized to form a consolidated part eventually. The results show that the SCP process is a feasible solution for producing a void-free consolidated material directly from Mg chips in a single step. The microstructure analysis using optical microscopy (OM) and scanning electron microscopy (SEM) shows a significant grain refinement in the produced part compared with the base material (from around 900 µm to 11 µm). The recycled specimen has a much higher hardness (at least 100% increase) than the parent material and also exhibits better wear resistance. This improvement is attributed to the resulting fine-grained microstructure due to severe plastic deformation during the SCP process. Manuscript profile -
Open Access Article
10 - Experimental Investigation of the Formability Improvement of Brass 260 and Al5182-O in Various Strain Rate using Hydrodynamic and Electrohydraulic Forming Methods
َAmin Ashrafi Tafreshi Mehdi ZohoorStudying the formability of the sheet metals have been the subject of many researches during the last decades. A number of experimental and numerical approaches were implemented to derive the formability diagrams of different materials. In this study, the formability of MoreStudying the formability of the sheet metals have been the subject of many researches during the last decades. A number of experimental and numerical approaches were implemented to derive the formability diagrams of different materials. In this study, the formability of two mostly used alloys, Brass 260 and Al5182-O as low and moderate formability materials, were investigated respectively. The forming limit diagrams of both materials were determined by using three experimental approaches such as Nakazima quasi-static as low strain rate method, hydrodynamic forming method as the moderate strain rate method and Electrohydraulic Forming process as high strain rate method. Three experimental results of forming limit diagram with the various strain rate were compared graphically. The results have shown that both of the materials could withstand higher strains when the electrohydraulic forming method was applied on the specimens and consequently, the forming limit diagrams for Brass 260 and Al5182-O shift up by 11% and 14%, respectively. In addition, it was concluded that the hydrodynamic forming method improves the formability of the materials by 4% and 6% for Brass 260 and Al5182-O, respectively. The outcomes of this study indicated that the formability of both materials was improved significantly by increasing the strain rate. Manuscript profile -
Open Access Article
11 - Thermal Loads and Surface Quality Evaluation in Machining of Hardened Die Steel under Dry and Cryogenic Machining
Farshid Jafarian Emad MohseniAISI H13 die steel is widely used in different industries because of its especial properties. During the machining of hard materials, some of the mechanical properties of the material are changed due to the generation of intensive thermo-mechanical loads and plastic def MoreAISI H13 die steel is widely used in different industries because of its especial properties. During the machining of hard materials, some of the mechanical properties of the material are changed due to the generation of intensive thermo-mechanical loads and plastic deformation into the workpiece. Controlling these intensive changes in machined surfaces is an important task and significantly affects the performance of the machined part. In addition, surface roughness is one of the aspects of surface texture and affects the fatigue life of the material. Since machining of hard materials is a difficult procedure and it is confronted with several limitations, new methods in machining processes are essential to be developed. One of these methods is using cryogenic coolant where the machining temperature may be considerably reduced by spraying liquid nitrogen on the cutting region. Based on this, at the present study, the variation of thermal loads and surface roughness at different machining parameters were evaluated under dry and cryogenic conditions. To do this, a thermal infrared camera and liquid nitrogen delivery system was used during the machining of hardened AISI H13 steel. Compared with dry condition, the effectiveness of the cryogenic coolant on surface roughness and thermal loads were analysed and discussed at different cutting speed, feed rate, and depth of cut. Finally, it was found that, applying cryogenic coolant in machining of AISI H13 die steel can be very effective to enhance performance and quality of the machined component in terms of surface roughness and thermal loads. Manuscript profile -
Open Access Article
12 - Experimental Study on Manufacturing of Tailor Friction Stir Welded Aluminium Blanks
Farhad Teimouri Hamid Montazerolghaem Mahmoud FarzinToday, in sheet metal forming processes, a new concept of fabricating consolidated sheets or in other words Tailor Welded Blanks emerged. Friction Stir Welding is one method for manufacturing TWBs and has numerous advantages over fusion welding methods for joining alumi MoreToday, in sheet metal forming processes, a new concept of fabricating consolidated sheets or in other words Tailor Welded Blanks emerged. Friction Stir Welding is one method for manufacturing TWBs and has numerous advantages over fusion welding methods for joining aluminum sheets. In the present study, TWBs made by friction stir welding of 6061-T6 and 5754-O aluminum alloys were studied. The effects of different tool rotational speeds and welding speeds on the mechanical properties and microstructural characteristics of dissimilar joints were evaluated. The results showed that in an appropriate range of speeds combinations, an optimum rotational speed exists at which maximum strength is achieved. Regarding welding speed, greater strength is attained at higher speeds. The microstructural analysis confirms that an increase in welding speed will result in grain size reduction and consequently higher tensile strength. It is observed that above the optimum rotational speed, the grain size of the nugget zone increases which results in decreasing tensile strength. With regard to elongation, it is found that despite the grain growth of the nugget zone at a higher ratio of tool rotational speed to welding speed, the elongation improved due to the dominant material existing in the weld zone. Positioning Al 6061 on the advancing side of the dissimilar joints leads to improved mechanical properties compared with positioning on the retreating side. It is notable that the degree of such improvement in ductility is much more remarkable than strength, which is valuable regarding formability concerns. Manuscript profile -
Open Access Article
13 - Determination of Material Properties Components used in FEM Modeling of Ultrasonic Piezoelectric Transducer
Abbas PakUltrasonic transducers have found new applications such as ultrasonic assisted micromachining, micro forming, surface treatment, welding, etc. Apart from the transducer’s shape and size, the resonant frequencies and amplitude are seriously affected by materials pr MoreUltrasonic transducers have found new applications such as ultrasonic assisted micromachining, micro forming, surface treatment, welding, etc. Apart from the transducer’s shape and size, the resonant frequencies and amplitude are seriously affected by materials properties used for transducer components. A further problem with the material is that their properties may vary from batch to batch and may also depend on the size of the raw stock. In this work using modal analysis, the material properties are calculated based on the frequency response method, which is more accurate than the nominal one. The finite element modelling was employed for both 2D and 3D FEM analysis to observe the behaviour of the cylindrical test rods and two sandwich-type piezoelectric transducers with the nominal frequency of 20 kHz and 30 kHz to find the validity of these properties. The obtained results showed that the modal analysis method could accurately determine the bar speed, Poisson's ratio and elastic modulus of the ultrasonic transducer components. The accuracy of this method increases by considering more vibration mode. Based on the results, obtained errors for FEM modelling of two ultrasonic transducers with the frequency of 20 kHz and 30 kHz are 0.15% and 0.33%, respectively. Manuscript profile -
Open Access Article
14 - Investigation of Magnitude and Position of Maximum von Mises Stress in The Cylindrical Contact Problems
Hasan Heirani Reza NaseriIn the analysis of contact mechanics problems, determination of stress field in mechanical elements is essential. Between the stress components the von Mises stress is more important, because it is used in the investigation of yield criteria and fatigue fracture of elem MoreIn the analysis of contact mechanics problems, determination of stress field in mechanical elements is essential. Between the stress components the von Mises stress is more important, because it is used in the investigation of yield criteria and fatigue fracture of elements. The aim of this study is to present formulas for determining the magnitude and position of maximum von Mises stress. For this purpose, the effect of various material properties, element geometries and loading conditions on these two parameters are investigated. By applying Hertzian contact stress and von Mises relations, the magnitude and position of maximum von Mises stress are determined. The von Mises stress is assumed to be a function of material properties, geometry of the element and loading conditions and finally two formulas are presented for the calculation of the magnitude and position of maximum von Mises stress. The results of these presented formulas are in close agreement with the literature. The error is less than 1% for depth prediction and less than 6% for stress value prediction, which confirms the accuracy of the presented formulas. Manuscript profile -
Open Access Article
15 - Influence of Tool Offset Distance on Microstructure and Mechanical Properties of the Dissimilar AA2024–AA7075 Plates Joined by Friction Stir Welding
Hossain Soleimany kamran amini Farhad GharaviIn the present study, the effect of tool offset on microstructure and mechanical properties of dissimilar friction stir welding of Al2024 and Al7075 alloys were investigated. In this regard, base metals were welded by FSW under different tool offsetting conditions, 1.5 MoreIn the present study, the effect of tool offset on microstructure and mechanical properties of dissimilar friction stir welding of Al2024 and Al7075 alloys were investigated. In this regard, base metals were welded by FSW under different tool offsetting conditions, 1.5 and 2 mm shifted into Al2024 and Al7075 alloys, respectively, in addition to constant rotation rates and traverse speeds named as 710 rpm and 28 mm/min respectively. The microstructure of different welding zones and fracture surface were investigated by an Optical Microscope (OM) and Scanning Electron Microscopy (SEM), respectively. The results showed that by tool offsetting from the weld center through Al2024, an onion-shaped area has been created and mixture happens completely. However, by tool off-setting towards Al7075, onion-shaped microstructure fails to be formed in the stirred area. From the results of the tensile test, it is presented that maximum tensile strength is obtained in samples with a tool offsetting into the Al7075. With 1.5 mm tool offsetting into Al2024, first, joint tensile strength increases by 22.2 % in comparison to non-offset condition, and then, with more tool offset as much as 2 mm, tensile strength decreases by 22.2 %. In addition, by tool offsetting towards Al7075 by 1.5 and 2 mm, joint tensile strength decreases by 4.5 and 28.5 %, respectively. It is also concluded that in the offset samples towards the 7075 alloy, the microhardness in the HAZ area decreased compared to the microhardness of the offsets samples towards the 2024 alloy. Finally, the best mechanical behavior and microstructural properties were obtained in the sample with the tool offset of about 1.5 mm towards the welded Al2024 base metal (70215 samples) alloy. Manuscript profile -
Open Access Article
16 - Effect of MIG Welding Parameters on Mechanical Properties of Dissimilar Weld Joints of AISI 202 and AISI 316 Steels
Venkatratnam Dirisala KESAVA RAO V.V.SIn the present work dissimilar joints of AISI 202 and AISI 316steels are produced using Metal Inert Gas (MIG) welding. Welding current, wire feed rate, flow rate of gas and edge included angle are considered as input parameters and tensile strength, Impact strength and MoreIn the present work dissimilar joints of AISI 202 and AISI 316steels are produced using Metal Inert Gas (MIG) welding. Welding current, wire feed rate, flow rate of gas and edge included angle are considered as input parameters and tensile strength, Impact strength and Maximum bending load are considered as output responses. Response Surface Method (RSM) is adopted using Central Composite Design (CCD) and 31 experiments were performed for 4 factors and 5 levels. Analysis of Variance (ANOVA) is carried out at 95% confidence level and coefficient of determination (R2) of 0.94 is obtained for all the output responses. Effect of welding parameters on output responses are studied by drawing main effect plots. Dominating parameters are identified using contour plots and surface plots are drawn to find the optimal solution. Optimal weld parameters are identified using Response optimizer. Manuscript profile -
Open Access Article
17 - Experimental Correlation Between Microstructure, Residual Stresses and Mechanical Properties of Friction Stir Welded 2024-T6 Aluminum Alloys
Majid Farhang Mohammadreza Farahani Mohammad Nazari O. Sam DaliriFriction stir welding was performed on AA2024- T6 aluminum plates using different rotation and traverse speeds with the objective of improving the mechanical strength and microstructure properties. The influence of the traverse and rotation speed on the microstructures, MoreFriction stir welding was performed on AA2024- T6 aluminum plates using different rotation and traverse speeds with the objective of improving the mechanical strength and microstructure properties. The influence of the traverse and rotation speed on the microstructures, mechanical properties and residual stresses of the welded Aluminum plates were investigated. By increasing the rotation speed, stirred zone grain size became larger. Besides, the homogenous second phase distribution was obtained. Furthermore, by increasing both rotational and traverse speeds, hardness of the thermo-mechanically affected zone and the stirred zone increase to base metal hardness. These welded plates that were fractured at advancing side have a maximum tensile strength equal to 71% of base plate strength which was obtained at 31.5 mm/min traverse speeds and 1120 rpm rotational speed. The longitudinal residual stress was diminished with decreasing of rotational speed by 1120 rpm at a constant traverse speed. In this conditions and by increasing the traverse speed by 31.5 mm/min, the maximum tensile strength was obtained as many as 48%. It was attributed to more plastic deformation and minimum grain size in the weld zone due to higher traverse speed. Manuscript profile -
Open Access Article
18 - Design Construction and Evaluation of a Ring-like Karbandi Structure
Ahad Shahhoseini sajjad pakzad Mohammad Mehdi Ranjbar Malek ShahiDue to the gold price increases in the Iranian market, the desired buyers have been attracted to LGJ (Lightweight Gold Jewelry). Meanwhile, because of the strength decreases in structure in LGJ., we investigated a structural solution in this research. The proposed solut MoreDue to the gold price increases in the Iranian market, the desired buyers have been attracted to LGJ (Lightweight Gold Jewelry). Meanwhile, because of the strength decreases in structure in LGJ., we investigated a structural solution in this research. The proposed solution was Karbandi as a supporting lattice-ordered structure in Iranian architecture. We used five types of primary Iranian architecture arches and a perfectly logical Karbandi plan to create ring-like structures. Arches and ring-like structures were compared based on maximum mises stress, strain, and weight using FEM analyses. The applied load and approximate area of it in analyses, according to the female mean Tip-pinch and the mean of minimum, thumb, and index finger width were chosen. Based on analyses results, a ring-like Karbandi structure was chosen for construction. The models were constructed in four alloys category based on sterling silver standard with Cu-nanoparticles as an admixture. A practical test was done to investigate the mean deformation time for each alloy's model category. A weight was used to investigate the observable deformation time-based capacity of the models. Results showed that the lowest mises max stress value was observed in the 1st arch, although the 3rd arch had the minimum strain among arches. In ring-like Karbandi structures made from 1st and 3rd arches, the minimum value of mises max stress and strain was related to the Karbandi. In the physical load applying process, the category that did not contain cu-nanoparticles had the highest deformation meantime among all categories. Manuscript profile -
Open Access Article
19 - Numerical Analysis of Heat Transfer and Temperature Distribution in Direct Metal Laser Sintering Method
Farshid Rajabi Arman Maroufi Cyrus Aghanajafi Mohammad Mehdi KasaeiIn this research, the thermal analysis of additive fabrication by DMLS method has been investigated. In the DMLS method, the metal powder is melted by a laser heat source and finally a solid three-dimensional piece is formed. This analysis was performed by finite elemen MoreIn this research, the thermal analysis of additive fabrication by DMLS method has been investigated. In the DMLS method, the metal powder is melted by a laser heat source and finally a solid three-dimensional piece is formed. This analysis was performed by finite element method in Abaqus software. Laser heat distribution is considered Gaussian. The mechanical and thermal properties of the powder are considered as a function of melting temperature. Finally, the results obtained by the finite element method are compared with previous researches. The effects of laser speed and power on temperature distribution have also been investigated. Manuscript profile -
Open Access Article
20 - Prediction of Material Removal Rate in Ductile–Mode Micro Ultrasonic Machining
Hamid ZarepourThis paper presents a model to predict Material Removal Rate (MRR) in Micro Ultrasonic Machining (micro-USM). The proposed model is developed based on the ductile-mode of material removal in micro-USM process. The correlation between ductile material removal rate and pr MoreThis paper presents a model to predict Material Removal Rate (MRR) in Micro Ultrasonic Machining (micro-USM). The proposed model is developed based on the ductile-mode of material removal in micro-USM process. The correlation between ductile material removal rate and process parameters including frequency and amplitude of the ultrasonic vibration, particle size, and slurry concentration is presented. The proposed predictive model is verified by performing micromachining experiments using two types of workpiece materials including silicon and quartz at various process parameters levels. The results show that the MRR increases with a rise in vibration amplitude for both silicon and quartz materials. The experimental MRR values follow a trend similar to that of predicted MRR values. However, the predicted MRR values are higher than the measured MRR values for both silicon and quartz materials. The measured MRR values for ductile removal mode were found to have a considerable increase at vibration amplitudes of 2 mm and 2.4 mm for silicon and quartz, respectively, which is in favour of increasing the accuracy of the model prediction. Manuscript profile -
Open Access Article
21 - Experimental Study on the Effects of Friction Stir Spot Welding Process Parameters on AL2024T3 Joint Strength
Majid Farhang Mohammadreza Farahani Moein EnamiIn this study, effects of process parameters of Friction Stir Spot Welding were investigated on Al2024T3 which has poor weldability. Several spot welds were performed by the FSSW process on the 2mm aluminium sheets. The effects of main process parameters such as tool Ro MoreIn this study, effects of process parameters of Friction Stir Spot Welding were investigated on Al2024T3 which has poor weldability. Several spot welds were performed by the FSSW process on the 2mm aluminium sheets. The effects of main process parameters such as tool Rotational Speed (RS), Normal Plunge Depth (NPD), and Dwell Time (DT) on the joint strength were investigated. By increasing the tool rotational speed, the joint strength increased, consequently. The mean failure load improved 52% when the tool rotational speed increased from 800 rpm to 1120 rpm, whereas increasing the rotational speed from 1120 to 1600 did not have significant effect on the failure load. The results showed, increasing the normal plunge depth from 1.5 to 1.75 millimetre led to an increase in the failure load of spot welds by about 1.62 times. Also, the 3 seconds dwell time showed higher failure load compared to 2 and 5 seconds dwell time. Manuscript profile -
Open Access Article
22 - Experimental and Numerical Investigation of Injection Molding Main Parameters’ Effects on Shrinkage and Warpage of a Thin Sheet Made of HDPE
Ali Massah Nathan Jafarian Jam Ehsan SouryInjection molding is one of the common processes for producing plastic parts. In this process, the mold is filled immediately and then the part and mold will be cooled down during the packing time. In the end, the part will be ejected from the mold. In this study, the e MoreInjection molding is one of the common processes for producing plastic parts. In this process, the mold is filled immediately and then the part and mold will be cooled down during the packing time. In the end, the part will be ejected from the mold. In this study, the effects of the most important processing parameters such as packing time, melt and mold temperature have been investigated on shrinkage and warpage of the products experimentally and numerically. According to previous reports, a thin sheet is defined by a length to thickness ratio of at least 100. MOLDFLOW software has been utilized to obtain the numerical results. For the empirical study, 64 specimens have been produced in different production conditions. These samples have been scanned by a 3D scanner and results have been analyzed by CATIA software. The findings show that increasing melt and mold temperature decreases the warpage amount and rises the shrinkage in the specimens. Also increasing the packing time up to 2 seconds increases the warpage and decreases the shrinkage noticeably but in longer packing times the variations will be less remarkable. Moreover, findings show that the general trend in simulated and experimental results are similar in all reported values of shrinkage and warpage, in which the maximum calculated errors for both of them are approximately 10%. Manuscript profile -
Open Access Article
23 - Investigation of In-Situ Compressive Strength of Fiber-Reinforced Mortar and the Effect of Fibers on the Adhesion of Mortar/Steel
Ali Saberi Varzaneh Mahmood NaderiThe proper connection between mortar and steel is one of the crucial issues in civil engineering. This paper has investigated the effect of polypropylene fibbers on the bond between cement mortar and steel, using “Twist-off” and “pull-off” tests. MoreThe proper connection between mortar and steel is one of the crucial issues in civil engineering. This paper has investigated the effect of polypropylene fibbers on the bond between cement mortar and steel, using “Twist-off” and “pull-off” tests. Moreover, in order to assess the in-situ mechanical properties of fibre-reinforced mortars, the correlation of records obtained from semi-destructive methods of “Twist-off” and “pull-off” with those of laboratory tests was determined, and calibration curves were provided, using the regression analyses. The mentioned tests were modelled with the ABAQUS software to evaluate the distribution of stresses and cracks developed during the semi-destructive tests. The results show that the addition of polypropylene fibbers reduces the shrinkage of mortars by about 13% and this has a direct effect on the bond between the mortar and steel. So that the shear and tensile bond of fibre-reinforced mortars at 90 days is 75% and 94% higher than conventional mortars, respectively. The reason for this is the effect of fibbers on the process of hydration of mortars and also to prevent excessive opening of cracks, which is shown by SEM. According to the results, instead of using an expensive and imported pull-off device, a cheap and internal twist-off device can be used to measure adhesion. Also, to evaluate the compressive strength of mortars, twist-off and pull-off tests can be used by placing the readings obtained in the equations y = 0.156x + 0.329 and y = 0.055x-0.001 instead of x, respectively, to evaluate the compressive strength of mortars. Manuscript profile -
Open Access Article
24 - Investigating the Effect of Electrical Discharge Process Input Parameters on Mechanical Properties of Aluminum Surface
Hadi Eivazi bagheri Hamid Gorji Mohammad Reza Shabgard mohamad Bakhshi-JooybariOne of the important parameters in electrical discharge machining is the presence of micro cracks on the workpiece surface (recast layer). Therefore, the aim of this study was to investigate the possibility of increasing the mechanical properties of aluminum surface by MoreOne of the important parameters in electrical discharge machining is the presence of micro cracks on the workpiece surface (recast layer). Therefore, the aim of this study was to investigate the possibility of increasing the mechanical properties of aluminum surface by alloying elements (copper and nickel) diffusion to the recast layer and thus removing surface micro cracks. For this purpose, pulse on time and pulse current in with and without ultrasonic vibration have been considered as input parameters and the presence of surface micro cracks has been investigated using microscopic images. Also, the yield stress of the surface layer was calculated using the surface micro hardness. Based on the obtain results, surface without micro cracks has been created on the aluminum surface due to the diffusion of copper and nickel into the workpiece surface which increased aluminum surface yield strength from 90MPa to 280MPa without ultrasonic vibrations and to 310MPa while applying ultrasonic vibrations. In other words, ultrasonic vibrations cause an average of 20% increase in surface layer yield strength. In addition, according to the wear test, in the case of using ultrasonic vibration, improving the mechanical properties of the surface has caused thinner grooves on the aluminum surface. Manuscript profile -
Open Access Article
25 - Simulation of Friction Stir Extrusion using Smoothed Particle Hydrodynamics (SPH)
Mostafa Akbari Mansour Hakimollahi parviz Asadi Hossein Rahimi AsiabarakiThis research aims to construct a three-dimensional numerical model for modeling friction stir extrusion using the completely Lagrangian method, smoothed particle hydrodynamics (SPH). For extrusion simulations, the Finite Element Method (FEM) is extensively utilized; ho MoreThis research aims to construct a three-dimensional numerical model for modeling friction stir extrusion using the completely Lagrangian method, smoothed particle hydrodynamics (SPH). For extrusion simulations, the Finite Element Method (FEM) is extensively utilized; however, it has limitations due to excessive element deformation. Because the particle-based method eliminates the usage of volumetric elements, SPH can be a viable alternative. The performance of the SPH model was evaluated using different particle sizes. The results showed that the smaller particle size improves the temperature results as well as the shape of the wire produced. Then the mechanical and microstructural properties of the produced wires were investigated. The results show that the grain size in the center of the wire is larger than its perimeter due to the lower strain rate in this area. Increased strain reduces grain size in the produced microstructure by increasing nucleation sites during recrystallization, as is well known. The wire microhardness in the centre is 121 HV, whereas it is 129 HV in the periphery. Grain size is the main reason of increased hardness near the sample's periphery. Manuscript profile -
Open Access Article
26 - Investigating the effect of nanosilica on the compressive strength of hard concrete by considering Atomic Force Microscopy (AFM) examinations
seyed mohammad mahdi shafiei mahboobeh pirizadeh Ebrahim ZolgharneinThis study investigated the compressive strength of hardened concrete and the formation of Calcium Silicate Hydrate (C-S-H) with the addition of nanosilica (SiO2). Compressive strength testing was performed using ASTM C496 to determine stress-strain curves and compressi MoreThis study investigated the compressive strength of hardened concrete and the formation of Calcium Silicate Hydrate (C-S-H) with the addition of nanosilica (SiO2). Compressive strength testing was performed using ASTM C496 to determine stress-strain curves and compressive strength of the materials. The hydration process and formation of C-S-H and Calcium Hydroxide (CH) was examined using Atomic Force Microscopy (AFM) and Fourier Transform Infrared Spectroscopy (FTIR). Results indicate an increase in compressive strength using 1, 3 and 5% of nanosilica to concrete replacement by volume in comparison to the control mix (without nanosilica). The optimum concrete replacement to yield maximum strength was of the 5% nanosilica content. Comparing the 56 day results for the 3 and 5% of nanosilica replacement samples, notice the same percentage of C-S-H formation of 83 and 85%, respectively Manuscript profile