Résumé
The nucleation of cracks during welding process is of main importance in order to assess the lifetime prediction of the component that is made. Due to the complexity of the loading of the material during the process, a two scale numerical model is developped. The two scales are (i) the structural level and (ii) the microstructural level. A macroscopic criteria is developped and a simultion is performed to look at the influence of the process parameters (initial temperature, input energy, thermal boundary conditions,...). Then a microstructural ¯nite element model is developped.