Computational implementation of stress integration in FE analysis of elasto-plastic large deformation problems

In this paper, we compare different numerical implementation algorithms for the rate type constitutive equation and present an integration scheme base d on the physical meaning of the stress. Numerical implementation of variou s schemes is investigated in conjunction with the return mapping algorithm and the conditions to maintain plastic consistency. Jaumann and Truesdell r ates are taken as the objective stress rates in the constitutive equation. An alternative numerical treatment for rate of deformation tensor D-ij is p resented and is shown to maintain incremental objectivity. Numerical exampl es included a single element under rigid body rotation, a necking bifurcati on of a bar in tension and a punch indentation process. It is shown that th e use of Truesdell stress rate with specific numerical integration procedur e gives more accurate results than other procedures presented. (C) 2000 Els evier Science B.V. All rights reserved.