Journal of Simulation and Analysis of Novel Technologies in Mechanical Engineering
Volume:7 Issue: 2, 2014

In this paper، analysis of linear and nonlinear buckling of relatively thick orthotropic graphene sheets is carried out under mechanical load based on elasticity theories. With the help of nonlocal elasticity theory، the principle of virtual work، first order shear theory and Von-Karman nonlinear strain، the dominant relationship in terms of obtained displacements has been obtained، and the method of differential quadrature (DQ) with non-uniform distribution points (Chebyshev -Gauss-Lobato) has been used. To check the validity، the obtained results have been compared with other resources، and the effects of nonlocal coefficient، thickness، radius and elastic base on the dimensionless buckling loads were calculated and investigated. Moreover، the results of analysis using nonlocal and local theory were compared together. It can be noticed that the dimensionless buckling loads on graphene sheets increased more with a decrease in flexibility as far boundary condition is concerned. Additionally، with an increase in the sheet radius، the variation between nonlocal and local analysis results will be more.

In this work, the melting process of compounds containing nanoparticles of NePCM in a square hole with different angles affected by two pairs of well-spring heat source on horizontal walls was numerically investigated. Four different configurations of elements were employed to investigate the effect of changes in the position of elements on the horizontal walls of the well-spring landscape on the ratio of liquid fraction. In the first case, the springs and wells have been located on horizontal walls separately. The environmental condition in the second case is that the spring-well elements have been set on the horizontal walls alternatively. In the third case, springs are on the left of well elements, and ultimately in the fourth case, spring and well elements are all set at the bottom of horizontal walls. Results show that in the first arrangement, using 2%weight of Al2O3 nanoparticles, compared to other cases, the highest ratio of liquid fraction is obtained.

Perforated discs have many applications in different parts of industry. By making such disks of functionally graded materials, more capabilities can be obtained from them. Vibration analysis of these kinds of disks can help us make them more efficient. In this paper, modeling and evaluation of disk vibration of functionally graded materials with regard to thickness were carried out using Abaqus software. Since no certain element has been defined regarding functionally graded materials for the design and analysis of a particular element in Abaqus software, molding of such materials has been used in this application. In order to verify the results, the results obtained from ABAQUS analysis have been compared with those available in the literature. The obtained results show that by defining more layers with regard to changes in properties, the obtained results approach the exact solutions.

In this study, the elastic bending of sector graphene sheet has been studied based on elasticity using Eringen Nonlocal Elasticity Theory. In order to do this, the balance equations governing the sector graphene sheet have been solved in terms of displacements with regard to nonlocal relationship of stress, shear theory of the first order, and obtained linear strains using developed Kantorovich method. In this method, the obtained partial differential equations are converted into two categories that can be solved using analytical and numerical methods. Developed Kantorovich method is a method with a high rate of convergence, in which the expected convergence is achieved with just three to four repetitions. With regard to the fact that no research has yet been conducted in this regard, the results, considering the nonlocal coefficient equal to zero, have been compared with other articles in order to check the validity. In the end, the effect of nonlocal coefficient variations on the results in terms of thickness, boundary conditions, hardness of elastic base and difference between nonlocal and local elasticity analysis has been studied.

In this paper,fluidity onset analysis in FG thick-walled spherical tanks under concurrent pressure loading and heat gradient has been presented. Designing thick-walled spherical tanks under pressure as tanks holding fluids under heat loads with high heat gradients require new approaches. Under high internal pressure and high temperature, the tank enters the plastic stage in a part of its thickness; hence, for designing, a tank, which necessitates the onset of fluidity, is required for pressure study and heat gradient. Elasticity module, tensile yield, heat flow coefficient and heat expansion coefficient change gradually and, according to the power model, along radial direction. In order to describe the material behavior in the plastic area in the FG thick-walled spherical tank under internal pressure and heat gradient, Treska yield index has been used, and materials’ behavior has been assumed to be in elastic-plastic form.

Because of their wide application in industries requiring high pressure and temperature, manufacturing square and rectangular pipes have attracted more attention than ever before. There are various methods such as extrusion, tensile and stress for manufacturing square pipes. Another method on which studies have focused in recent years is the re-forming of round pipes in order to turn them into square or rectangular ones. The methods suggested in these researches are all applicable for the manufacture of square pipes without the possibility of manufacturing rectangular pipes. The method introduced in this paper consists of filling the pipe with bismuth and rolling it in three successive stages. In this research, first, the intended process is simulated in Abaqus software, and then a real sample is manufactured by an experimental test. The manufactured sample is checked with regard to its dimensions and is compared with the results obtained from the simulation. The results of the study show that the method of filling the pipe with bismuth and moving it through three rollers is an appropriate method for the manufacture of thin-walled pipes with rectangular cross-section.

The need for simulation of human foot mechanism has made researchers and engineers move towards different patterns to describe this movement. In this regard, optimal solutions such as energy consumption, accuracy, etc. are of utmost importance. In this paper, efforts have been made to present a new solution by designing a fully two-dimensional six-bar mechanism with one degree of freedom so that it has the least error with regard to human foot while walking. Meanwhile, the findings of this paper present a process for the optimization of multi-bar mechanisms so that they can be employed in any other field such as making human foot prosthesis. Here, the particle swarm optimization algorithm was used. The results from the optimization were compared with experimental data regarding human feet. The results show that while optimizing many motor parameters, the proposed six-bar mechanism is able to simulate the movement of the human foot very well.

In this paper, buckling of cylindrical grooved shells under axial load has been examined by theoretical and experimental methods. The shell is made of USA/API – X42 5L steel standards. This material is one of the most common materials used in gas, oil and petrochemical industries. The effect of spiral grooves on cylindrical shell was analyzed, and the results obtained from the Abaqus software were compared with experimental results. Theoretical and experimental results were in good agreement. Hence, the numerical results can be used as well. It was also found that the number of grooves on the critical buckling load has an important role so that the critical buckling load decreases with an increase in critical load groove.