Papers by Keyword: Incompressibility

Abstract: For several years, modeling hyperelasticity has been focused on and leaded to a large choice of strain energy potential forms. Since then, many advances have been made in constitutive modeling of rubber like materials. These models are nowadays widely used in many applications like constitutive modeling of soft tissues in biomechanics problems or plastic thermoforming simulation. In this work, constitutive modeling of TPO sheets for thermoforming application is considered. Experimental measurements have shown that the material is transversely isotropic. To take into account this anisotropy, we implemented some new transversally isotropic hyperelastic constitutive models in Abaqus software with the help of user subroutines. Furthermore, different particular forms of the strain energy potential are investigated and their hyperelatic constants are fitted to the measurement data from tensile tests performed in different directions. Based on the results of these investigations, a transversely isotropic form of the energy potential derived from the Yeoh constitutive model is adopted and several tests are analyzed for validation purpose. The chosen model is a good compromise that achieves accurate predictions with limited amount of tests and limited identification efforts. Another key finding of this work is the influence of the anisotropy on the thermoformed parts.

Abstract: One-dimensional process of formation and the subsequent motion of a plane transverse shock wave is studied on the basis of solutions of the corresponding nonlinear evolutionary equation. This equation defines behaviour of the solution in front area of wave process and follows from inner series of a matched asymptotic expansions method. A comparative analysis of the volume deformation and forming processes will be carried out and their basic differences are specified. In the capacity of model examples solutions of some concrete boundary value problems of a dynamic shear deformation are observed.

Abstract: Based on the strain energy function proposed by GAO Y C and the theory of finite deformation dynamics, the question about the cavity dynamic formation and bifurcation of the incompressible homogeneous solid sphere under a suddenly applied uniform tensile dead-load was studied. The condition under which a dynamic bifurcated solution exists was examined. The relationship between the dead-load and the cavity radius, the critical load, the stress distributions after the cavity formation, the vibration phase diagram of the cavity radius and the approximate vibration period were also determined.