NUMERICAL MODELLING OF THE DAMAGE-TO-FRACTURE TRANSITION IN A DUCTILE MATERIAL

The present work aims at the numerical treatment of the crack propagation throughout structures made of engineering metals and alloys whose failure results from ductile damage. The challenge consists in reproducing numerically within a unified numerical methodology the successive steps of diffuse damage, strain localisation and crack propagation leading to the ultimate ruin of the structure. This requires the definition of physics motivated criteria and the introduction of specific kinematics with the passage from one step to the other as compatible as possible. In this purpose, we are studying here the ability of the cohesive zone model (CZM) approach to ensure the connection between diffuse damage dealt with in the context of the standard finite element method (FEM) and crack propagation treated in the context of the extended finite element method (X-FEM).