Phase Transformation and Damage Elastoplastic Multiphase Model for Welding Simulation

The article is dedicated to the study of the introduction of damage concept in the multiphasic behaviour which occurs during by welding process. Attention is paid to coupling between ductile damage, small strain elasticity, finite visco-plasticity and phase transformation. Based on the theory of thermodynamics and continuum damage mechanics (CDM), we built constitutive equations to describe damage growth and crack appearance during and after welding. The thermodynamics of irreversible processes with state variables is used as a framework to develop the phase coupling model. The related numerical aspects concern both the local integration scheme of the constitutive equations and the global resolution strategies. The models are implemented in CASTEM 3M finite element code. Based on the finite element program, some examples and applications are presented to forecast the damage induced by welding and validate the models.