Relevance of Incorporating Cavity Shape Change in Modelling the Ductile Failure of Metals

Abstract

The purpose of this paper is to assess the relevance of considering the cavities shape change in the context of physically based modelling of the ductile rupture in metals. Two thermomechanical models have been used in this study: the GTN model, developed by Gurson, Tvergaard, and Needleman for spherical cavities keeping their shape unchanged during loading, and the GLD model, proposed by Gologanu, Leblond, and Devaux for ellipsoidal cavities that can change their shape. The GTN and GLD models have been extended to take into account material thermal heating due to plastic dissipation. These two constitutive laws have been implemented into the commercial finite element code Abaqus/Explicit in order to simulate the necking of a round bar and the failure of a sheet deep drawing. The results showed the importance of incorporating the shape effects of the cavities for a correct description of the material failure.