Application of the radial return method to compute stress increments from Mroz's hardening rule

It is well known in the literature that the isotropic hardening rule in pla sticity is not realistic for handling plastic deformation in a simulation o f a full sheet-metal forming process including springback. An anisotropic h ardening rule proposed by Mroz is more realistic. For an accurate computati on of the stress increment for a given strain increment by using Mroz's rul e, the conventional subinterval integration takes excessive computing time. This paper proposes the radial return method to compute such stress increm ent for saving computing time. Two numerical examples show the efficiency o f the proposed method. Even for a sheet model with more than 10,000 thin sh ell elements, the radial return method takes only 40 percent of the overall computing time by the subinterval integration.