In the present paper, a finite element nonlinear coupled thermoelasticity formulation is presented for analysis of the wave propagation, reflection, and mixing phenomena in the finite length isotropic solids. The governing equations are derived based on the second Piola-Kirchhoff stress and the full form of Green’s strain-displacement tensors to account for the large deformations and finite strains. In contrast to the available researches, the assumption of very small temperature changes compared to the reference temperature is released in the present research. Galerkin’s method, a weak formulation, and cubic elements are employed to obtain the time-dependent non-linear finite element governing equations. The proposed solution procedure to the resulting highly nonlinear and time-dependent governing equations employs an updating algorithm and Newmark’s numerical time integration method. The wave propagation and reflection phenomena are investigated for both the mechanical and thermal shocks and time variations of distributions of the resulting displacements, temperature rises, and stresses are illustrated graphically and discussed comprehensively. Furthermore, the effects of the non-linear terms are discussed comprehensively. Results reveal that in the non-linear analysis, no fixed speed of wave propagation can be defined. تفاصيل المقالة

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. تفاصيل المقالة

In this paper, a nonlinear finite element formulation is presented for analysis of the stress, displacement, and temperature distributions of thermo hyperelastic hollow spheres subjected to mechanical and thermal forces. It is assumed that the hollow sphere is made of functionally graded and temperature-dependent material. The coupled nonlinear equations are derived from the concept of multiplicative decomposition of the deformation gradient. Mechanical and thermal parts are considered for studying the thermo-hyperelastic behavior.An appropriate strain energy function is considered and by exchange the invariants of strain tensors in the modified model, the governing equations are extended to an incompressible model. The governing equations are found by considering Mooney-Rivlin hyperelastic model. Distribution of displacement, stress components, and temperature through the thickness of the hollow sphere are plotted for different constitutive, temperature dependency, and inhomogeneity parameters. The obtained results indicate that the temperature dependency of the material and inhomogeneity properties have a considerable influence on displacement, stress components, and temperature distribution along the radial direction. تفاصيل المقالة