A general cyclic plasticity model taking into account yield surface distortion for multiaxial ratchetting

Most of the theoretical studies devoted to multiaxial ratchetting are focused on the location of the macroscopic yield domain in order to predict the correct direction of plastic strain rate, since normality of the plastic strain rate to the yield surface is usually assumed. To the authorsʹ knowledge, the shape of subsequent yield surfaces was always kept constant in these models for simplicity reasons but unlike experimental observations. In a previous paper [J. Eng. Mater. Technol. 124(4) (2002) 402], the authors have explained the need to take into account yield surface distortion in macroscopic modeling and have therefore proposed such a constitutive model but only for biaxial loadings. In the present paper, the generalization of this distortional model is proposed for any loading paths. The model is then identified and validated on a large data base obtained firstly with an efficient polycrystalline model that can predict multiaxial ratchetting as well as yield surface distortion, and secondly with the experimental results of complex tests realized on a type 316L stainless steel.