JOURNAL OF SIMULATION AND ANALYSIS OF NOVEL TECHNOLOGIES IN MECHANICAL ENGINEERING (JOURNAL OF SOLID MECHANICS IN ENGINEERING)
Year:2008 | Volume:1 | Issue:3|Papers Count:8

Many researchers content themselves with the 2D simulation of welding process instead of the 3D simulation, because of the time and the cost factors of the latter. In this research, the number of elements and nodes are reduced by an initiative plan (defining an equivalent model) for the simulation of welding. The welding process has been simulated by an uncoupled thermal-mechanical finite element model in three steps. Thermal history was determined from thermal analysis, and then the distribution of the metallurgical phase on the fusion and heat affected zones were calculated by a certain code. Afterward, the stress distribution was computed from mechanical analysis, where the material property was defined element by element according to the second step. One of the most important objectives of this simulation is to study the residual stresses of welding. Comparisons between the thermal analysis results and the metallographic and laboratory results of this research show acceptable accuracy of the proposed method.

In this paper at first introduced constituent equations for piezoelectric and then by the help of this equations, internal energy of hinged-hinged piezoelectric multilayer beam was computed. Then by the principle of minimum potential energy and Rayleigh -Ritz method the bending curvature equation of hinged-hinged piezoelectric multilayer beam under concentrated moment, concentrated force, uniform pressure load and applied electrical voltage with satisfaction of boundary conditions are guessed. Unknown coefficients are determined by the principle of minimum potential energy. Thereinafter obtained equations have simplified for hinged-hinged unimorph and bimorph beam. Electrical load and voltage produced in unimorph and bimorph beam as sensor are calculated. In order to verify the derived equations for a hinged-hinged piezoelectric multilayer bending beam, the analytical calculation compared with ANSYS 10 results by some finite element examples.

Bending analysis of FGM plates under uniform and sinusoidal loaded result in forth order partial differential equation. In this paper the analytical solution is based on the extended Kantorovich iterative procedure. The differential equations for the iterative procedure is derived using the Galerkin method. The solution was develope based on the classical plate’s theory (CLPT). The reliability of the present analytical method for FGM, under different boundary condition, was verified and approved when comparing Navier solution and finite element results with ANSYS solution. Since the FGM modeling is impossibility at ANSYS, a macro has used for modeling and analysis. The results show a high accuracy and the iterative process converges very rapidly. It was also found that the final form of the generated solutions is independent of the initial trial function.

In this study, dynamic behavior of safety mechanism of a mechanical controller is investigated using 3D-FE simulation. This paper is concentrated on controller of a high acceleration projectile. The controller is located in the top of the projectile. Safety mechanism is divided to deformable and rigid parts. Deformable and rigid parts are simulated in Abaqus and Adams commercial soft wares; respectively. The goal of this study is to investigate the safety mechanism operation includes plastic deformation of safety ring, rotor rotation and the required time for this operation. Also, some important parameters of safety mechanism such as, determination of required time and angular velocity for plastic deformation of safety ring, exit of safety pin, and the angular velocity correspondent to rotor rotation, when the axis of needle and guide hole are aligned, are studied.

Modeling of crack propagation by a finite element method under mixed mode conditions is of prime importance in the fracture mechanics. This article describes an application of finite element method to the analysis of mixed mode crack growth in linear elastic fracture mechanics. Crack - growth process is simulated by an incremental crack-extension analysis based on the maximum principal stress criterion which is expressed in terms of the stress intensity factor. In this paper a procedure is employed to correct direction of crack propagation to ensure that a unique final crack path is achieved for different analysis of a problem by using different increments of crack. For each increment of crack extension, finite element method is applied to perform a single - region stress analysis of the cracked structure. Results of this incremental crack – extension analysis are presented for several geometries.

In this research a final element model for simulating three dimensional deformation in rolling of flat product is modeling in ABAQUS and further developed to study the frictional effects on spread and bulge. To predict the magnitude of bulging, the rolling process is approximated by successive forging steps. The elongation or the average spread at each step from the previous calculations are used in the model. The theoretical results of the model is in a good agreement with the experimental values given by other investigation.

The available fatigue theories have been examined using simple specimens subjected to bending or tension-compression loads. Therefore, the stress fields have been generally one or two dimensional. Anti-roll bar is a component belongs to the suspension system of the vehicles. In spite of having simple circular section, due to the having several curvatures, this component experiences a three-dimensional stress field.  This component is usually under alternating bending and torsion loads and the fatigue phenomenon is the main cause of its breakage and failure. In the present paper, employing the finite element method and the prepared computer code, the accumulated fatigue damage analysis of the mentioned component is accomplished based on the modified version of the well-known critical plane- type theories for three-dimensional stress fields. Results of the proposed theories are compared with the experimental fatigue results.

The objective of this paper is path planning of a 3 DOF planer robot with hydraulic actuator using genetic algorithm. First the geometric and kinematic parameters of robot were established. The equations of motion are derived by Lagrange method. We proposed the model for proportional valve and hydraulic actuators. Then using the genetic algorithm we minimized the hydraulic energy consumption as a fitness function during the mechanism motion between two specified points.