A simple model for viscous regularization of elasto-plastic constitutive laws with softening

Abstract

An overlay-type rheological model is presented, which is used to introduce viscosity in inviscid elasto-plastic material laws with softening, in order to reduce the mesh-dependency of Finite Element solutions. This model is intended to be an alternative to the well-known visco-plastic formulations of Perzyna and Duvaut-Lions. A time integration algorithm for the visco-elastic model component is presented, being demonstrated in the paper, that it is unconditionally stable and oscillation-free. The algorithm is tested in a problem with slip driven softening (von Mises material) and in a problem with decohesion driven softening (Cam-Clay model). Figures showing the capability of the algorithm to regularize the solution are presented. Copyright © 2004 John Wiley & Sons, Ltd.