Implementation and validation of a polycrystalline model for a bi-phased steel under non-proportional loading paths

The aim of the present paper is to propose a polycrystalline approach in order to model the elastic–plastic behavior of an austenitic–ferritic stainless steel. In order to take into account the specific character of the steel, the multi-scale polycrystalline approach proposed by Cailletaud–Pilvin [Pilvin, P., 1990. Approches multiéchelles pour la prévision du comportement anélastique des métaux, PhD Thesis, Université Pierre et Marie Curie; Cailletaud, G., 1992. A micromechanical approach to inelastic behavior of metals. International Journal of Plasticity 8, 55–73; Cailletaud, G., Pilvin, P., 1994. Utilisation des modéles polycristallins pour lecalcul par éléments finis. Revue Européenne des Eléments Finis 3 (4), 515–541] is extended to bi-phased material. In particular, two interaction laws and two local behaviors, based on the crystallographic slip and the dislocation density evolution, are simultaneously considered. After an identification of the model parameters on simple tests (monotonous tension, tension-compression), we propose an evaluation of the predictive capabilities of the multi-scale approach for non-proportional loading paths. A good agreement is observed between simulation and experimental data.