Numerical comparison of isotropic hypo- and hyperelastic-based plasticity models with application to industrial forming processes

Abstract

Industrial forming processes are usually characterized by large plastic strains and rotations of material elements. This emphasizes the importance of reliable finite strain elastoplasticity models in corresponding finite element simulations. The aim of this work is to review and numerically compare two inherently different types of formulations of finite strain elastoplasticity, namely hypoelastic- and hyperelastic-based plasticity models, with special reference to their applicability in forming processes. Both models allow for nonlinear isotropic and kinematic hardening of Voce and Armstrong–Frederick type and were implemented as user material subroutines (UMAT) into ABAQUS/Standard. Several numerical tests were conducted to assess their respective capabilities. Interestingly enough, although both models led to remarkably different results in shear-dominated single element deformation tests, the structural simulations of a deep drawing, draw bending and thermoforming process delivered nearly congruent results. This suggests that both models are well-suited for modeling elastoplastic materials in common industrial forming processes.