Simulation numérique par éléments finis d'agrégats polycristallins soumis à des chargements thermomécaniques issus du soudage

Numerical simulations of polycrystalline aggregates were made for an austenitic stainless steel submitted to cyclic thermomecanical loading resulting from a multipass welding operation. The constitutive behavior is based on crystalline plasticity mechanisms for f.c.c. single crystal, with temperature dependent elastoplasticity. Numerical procedures were developed for boundary conditions transfer at local scale and for normal and tangential stress computation at grain boundaries. Such simulations allow to study the variation of stress distribution for different crystallographic or morphologic textures. Mots clefs: simulation elements finis, plasticite cristalline, thermomecanique, anisotropie