Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering: 4 (2)

Open Access Article

1 - Study of the Effects of Various Boundary Conditions on the Acoustical Treatments of Double-Panel Structures Lined with Poroelatic Materials
محمدحسن شجاعی فرد روح ا... طالبی رضا احمدی مائده امیرپور ملا

In this paper, the acoustical treatment of double-panel structures lined with poroelatic materials is predicted using analytical method in order to study the effective usage of the various boundary conditions of porous layer and to identify the effective parameters on t More

In this paper, the acoustical treatment of double-panel structures lined with poroelatic materials is predicted using analytical method in order to study the effective usage of the various boundary conditions of porous layer and to identify the effective parameters on the transmission loss of the multilayer systems. Therefore, inertia and viscous coupling along with thermal and elastic coupling should be considered in transfer stress dynamic and stress-strain relationships for an elastic porous material based on Biot theory. Then, the governing equations of the wave propagation in an elastic porous material are briefly considered and the general forms for the stresses and displacements within the porous material are given. Applying various boundary conditions and solving these equations with Matlab code simultaneously, the transmission loss of these structures is calculated. The results from the analytical method are compared with the SEA madel and the experimental data with excellent agreement is observed. Finally, the influence of effective parameters of this structure with various boundary conditions on the transmission loss of the multilayer systems is studied. The results have been shown that the transmission loss of double-panel structures lined with a layer of porous material can depend critically on the method of mounting the porous layer to the facing panel. Manuscript profile

Open Access Article

2 - A Survey on Buckling and Vibrations of a Viscoelastic Beam under Distributed Lateral and Axial Loads
حمید رضا ایپک چی حمیده صدیقی

In this paper, based on Kelvin and Linear Standard Solid models, dynamic response and the buckling load of a viscoelastic beam under lateral and axial loads have been determined. The governing equations have been extracted using Euler and Timoshenko theories and their a More

In this paper, based on Kelvin and Linear Standard Solid models, dynamic response and the buckling load of a viscoelastic beam under lateral and axial loads have been determined. The governing equations have been extracted using Euler and Timoshenko theories and their analytical solutions have been obtained by using the eigenfunctions expansion method. Buckling load have been calculated by using the Euler and Timoshenko beam theories based on Kelvin and standard models. The results have been compared with the elastic case. The results show that the simulation of a viscoelastic beam with an elastic case, is not a reasonable approximation for moderately high damping. Also, the damping parameter has not been appeared explicitly in the buckling load determination, even though the buckling load of a viscoelastic beam is 50% more than an elastic beam. Manuscript profile

Open Access Article

3 - Using the Ultrasonic Nondestructive Methods for Prediction of Mechanical Properties of AISI 4140 Alloy Steel
محمد حمیدنیا فرهنگ هنرور

Achieving the mechanical properties of steels after various manufacturing and heat treatment processes is significant and essential. In production lines, after producing the specific and standard samples, mechanical properties have been measured by destructive processes More

Achieving the mechanical properties of steels after various manufacturing and heat treatment processes is significant and essential. In production lines, after producing the specific and standard samples, mechanical properties have been measured by destructive processes which cause waste of cost and time. In addition, destructive techniques cannot detect the miniscule changes made in mechanical properties of steel during heat treatment processes. In this paper, the ultrasonic nondestructive method is used for accurate measuring the elastic properties of AISI 4140 steel samples which are heat treated at different levels. Each sample has its specific microstructure and hardness due to the heat treatment process it has gone through. The elastic properties of each sample are obtained by measuring the velocities of longitudinal and shear waves in each sample. On the other hand, for detecting the error resources and evaluation of precision of measuring method, uncertainty analysis is performed. A good agreement is noted between results obtained from ultrasonic measurements and available information in reference tables and it was shown that the ultrasonic technique can measure the elastic properties of AISI 4140 samples with high accuracy. In sum, achieved results show that the maximum value of mechanical properties belongs to the microstructure with higher hardness and with decreasing the hardness these properties, also, decline. Manuscript profile

Open Access Article

4 - Optimum Die Design in Drawing of Square Section Rod from Round Bar
حشمت‌اله حقیقت سید بابک الهویسی

Drawing of square section rod from round bar can be done with two die shapes. In the first die shape, deformation starts from corners of the square and in second die shape, deformation starts from sides of square. This article has compared the drawing force for both die More

Drawing of square section rod from round bar can be done with two die shapes. In the first die shape, deformation starts from corners of the square and in second die shape, deformation starts from sides of square. This article has compared the drawing force for both die shapes and as a result optimum die shape was determined. Due to complexity of metal flow inside the die, analyzing of actual process was difficult and upper bound approach has applied based on equivalent axisymmetric curved die. In equivalent process, in each position on the die axis, perpendicular cross sections on both actual and the equivalent die have the same area. By determining the profile of the equivalent curved die, a velocity field inside the die was presented. Then, internal, shearing and frictional powers were calculated and relative mean draw stress was estimated by equating the summation of these powers with required external power. As a final result, the die shape which required less force was introduced as optimum one Manuscript profile

Open Access Article

5 - Surface Effect on Nonlinear Free Vibration Analysis of Nanotubes
جعفر اسکندری جم یاسر میرزایی بهنام قشلاقی

In this work,The free nonlinear vibrations of nanotubes using the Euler-Bernoulli beam theory along with the von Kármán geometric nonlinearity in presence of surface effects has been investigated. Natural frequencies of a simply-supported nanotube in terms More

In this work,The free nonlinear vibrations of nanotubes using the Euler-Bernoulli beam theory along with the von Kármán geometric nonlinearity in presence of surface effects has been investigated. Natural frequencies of a simply-supported nanotube in terms of the Jacobi elliptic functions are obtained by using the free vibration modes of the corresponding linear problem. The numerical results describe the imperative influence of surface effect, mode number, vibration amplitude, and the length and thickness of the nanotubes on the vibrational characteristics of the nanotubes. In addition the influence of surface effects on the system phase trajectory is considered. Finally, it is observed that the surface effects diminish by increasing in the dimension of nanotubes. The present study may be used to improve the design of different types of micro-nano sensors. Manuscript profile

Open Access Article

6 - Analysis of Free Vibration Sector Plate Based on Elastic Medium by using New Version of Differential Quadrature Method
مسلم محمدی مصطفی غیور علی فرج پور

The new version of differential quadrature (DQ) method is extended to analyze the free vibration of thin sector orthotropic plates on the Pasternak elastic foundation with various sector angles and elastic parameters. Detailed formulations are given. Comparisons are mad More

The new version of differential quadrature (DQ) method is extended to analyze the free vibration of thin sector orthotropic plates on the Pasternak elastic foundation with various sector angles and elastic parameters. Detailed formulations are given. Comparisons are made with existing analytical and/or numerical data. Numerical results indicate that convergence can be achieved with increasing in number of grid points. The accurate results could be obtained with 9x9 or even higher grid. It is found that the results are influenced by grid spacing and for obtaining the accurate and reliable result non-uniform grid should be used. Manuscript profile

Open Access Article

7 - Optimization of Reduction Settings and Inter-stand Tensions for Tandem Cold Mills using Genetic Algorithm
فرشید آقاداوودی حسین گلستانیان نوید نگهبانی

Cold rolling process is a complicated process which can be optimized by changing in variables and settings. This paper presents a set-up optimization system developed to calculate reductions and inter-stand tensions for each stand of a five stand tandem cold mill. The More

Cold rolling process is a complicated process which can be optimized by changing in variables and settings. This paper presents a set-up optimization system developed to calculate reductions and inter-stand tensions for each stand of a five stand tandem cold mill. The main objective in this optimization is minimization of power consumption. First, by using the analytical method, the equations of roll force and roll torque have been determined. The Genetic algorithm has been used to find out the optimum reduction setting and inter-stand tension which minimized the power consumption in five roll stands. The results have been compared with experimental data. Finally, the influence of effective parameters such as lubricants and strength of plates is studied. The results have been shown a similar pattern in reduction setting. Manuscript profile

Open Access Article

8 - Evaluation of Tool Performance With Nanocrystalline Multilayer Coatings on the Machinability of Superalloy Inconel 718
رسول مختاری همامی بهروز موحدی ایرج لیرابی مهدی بازرگان حقیقی

In this paper, the performance of the cutting tool with nanocrystalline multilayer coatings (TiN+TiAlN) for machining of superalloy Inconel 718 in the dry and wet conditions was studied. The multi layer TiN and TiAlN with nanocrystalline structure was applied by physica More

In this paper, the performance of the cutting tool with nanocrystalline multilayer coatings (TiN+TiAlN) for machining of superalloy Inconel 718 in the dry and wet conditions was studied. The multi layer TiN and TiAlN with nanocrystalline structure was applied by physical vapor deposition technique (arc evaporation) on the WC-Co inserts. The results of the ball on disc wear test and the machining of superalloy Inconel 718 in wet and dry conditions indicated that the nanocrystalline coatings could produce better performance of tools in turning. Abrasion and adhesive wear resistance improved by nanocrystalline and modified Aluminum composition in TiAlN coating as well as toughness and thermal stability. Manuscript profile

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