On a finite-strain viscoplastic law coupled with anisotropic damage: theoretical formulations and numerical applications

Abstract

Based on a dissipation inequality at finite strains and the effective stress concept, a Chabochetype infinitesimal viscoplastic theory is extended to finite strain cases coupled with anisotropic damage. The anisotropic damage is described by a rank-two symmetric tensor. The constitutive law is formulated in the corotational material coordinate system. Thus, the evolution equations of all internal variables can be expressed in terms of their material time derivatives. The numerical algorithm for implementing the material model in a finite element programme is also formulated, and several numerical examples are shown. Comparing the numerical simulations with experimental observations indicates that the present material model can well describe the primary, secondary and tertiary creep. It can also predict the anisotropic damage modes observed in experiments correctly.