Ductile Shear Damage Model for Porous Materials

Abstract

Based on a pre-existing yield function, an extended version of the well-known Gurson-Tvergaad-Needleman (GTN)isotropic hardening model is presented in this investigation. The yield function of the proposed constitutive model possesses the distinctiveness to be more accurate for arbitrary void volume fraction and especially to explicitly depend upon the third stress invariant. As a numerical example, the presented constitutive model and, for the purpose of comparison, the GTN model, are used to analyse the necking of a round tensile bar and the two-dimensional simple dynamic shearing problem. The numerical results highlight similarities, good agreement as long as softening initiation of specimen is not reached, and discrepancy as soon as failure of specimen starts, between the proposed model and the GTN model.