Influence of Yoshida-Uemori Model on Springback Prediction

Today, the advanced hardening Yoshida-Uemori model is recommended for an improved springbackSpringback prediction in stamping numerical simulation. This model is a combined hardening model coupled with the elastic evolution modulus8Modulus which depends on the equivalent plastic strain. It is implemented in the most used FEAFinite element analysis (FEA) stamping codes with occasionally some variations. In order to provide materialMaterials cards for the FEAFinite element analysis (FEA) stamping codes, ArcelorMittal has at one’s disposal the equipment to perform reverse shear tests and hysteresis loops. An in-house methodology has been developed to identify the Yoshida-Uemori adjusting parameters. The developed identification protocol leadsLead to a set of materialMaterials parameters improving the springbackSpringback prediction compared to a purely isotropic hardeningIsotropic hardening model. The results analysis shows that the elastic modulusModulus evolution has an influence on springbackSpringback prediction of the same order as the combined hardening. A solution is proposed here to improve the elastic modulusModulus evolutive model according to the final stress state after springbackSpringback.