Damage Prediction and Evolution using Uncoupled Elastoplastic-Damage Lemaitre’s and Vaz’s Models

Abstract

This paper presents the two uncoupled elastoplastic-damage models; uncoupled Lemaitre’s and Vaz’s damage models. The two models are implemented into the finite element ABAQUS software using user routine UMAT to analyze and predict damage and damage evolution. In the context of von-Mises yield criteria, damage variable and fracture indicator are predicted, in addition to the von-Mises stress and the effective plastic strain. Both the elastoplastic tangent operator and the return mapping procedure are formulated using the consistent formulation. Two cases have been analyzed; the first one is an axisymmetric notched bar, while the second case is a plane strain doubled notched plate. In addition to the aforementioned predictions, a parametric study is carried out to explore the effect of the damage denominator and damage exponent on the damage behavior. It is concluded that the two models succeeded in the prediction of the point of fracture, while the uncoupled Lemaitre's damage model gives a more efficient description of the damage band.