An explicit integration algorithm for the unified rate-dependent elastoplastic damage model applied to high-rate dynamics

Abstract The main purpose of this work is to present an explicit integration algorithm for the unified rate-dependent elasto-plastic damage model. In the new integration algorithm, the plastic correction is solved by the following two assumptions: Constant equivalent strain rate; the direction of the deviatoric stress tensor remains unchanged if no plastic strain occurs. When the stress tensor at the initial moment is on the yield surface, both the plastic multiplier and the equivalent plastic strain increment obtained by the plastic correction method proposed in this paper is the same as that obtained by the plastic flow method. It indirectly proves the rationality of the plastic correction method. Then, both the traditional return mapping algorithm and this new integration algorithm are applied to the modified Johnson-Cook constitutive model and Cowper-Symonds model. Simulation of the Split Hopkinson pressure bar (SHPB) experiments using the modified Johnson-Cook constitutive model and Cowper-Symonds model, respectively. The stress error and the accumulated stress error are introduced to evaluate the accuracy of the plasticity integration algorithm. Numerical simulation results show that the accuracy of the new integration algorithm is higher than the traditional return mapping algorithm.