Numerical study of the influence of microstructure on subsequent yield surfaces of polycrystalline materials

This study deals with modelling of the elastoplastic behaviour of a polycrystalline material, subjected to complex loading programmes, using a self-consistent scheme based on scale transition techniques. The influence of microstructure evolution on the elastoplastic response of the material is analysed. A brief introduction to the self-consistent modelling is presented. The comparison of the numerical results with the experimental data available from literature reveals a good agreement between the calculated and measured evolution of yield surface. From the three parameters describing the internal structure of the material, the grain shape evolution is neglected in this study. The remaining two are internal stresses and crystallographic texture. The influence of these parameters on subsequent yield surfaces is analysed. When compared with the second-order residual stresses, the role of crystallographic texture in hardening of polycrystals appears to be insignificant. The influence of the intragranular microstructure, or third-order internal stresses, is addressed indirectly by appropriate simulations involving the hardening matrix of individual crystals.