Identification of advanced constitutive model parameters through global optimization approach for DP780 steel sheet

In recent years, in order to improve the precision of the springback prediction, many advanced material constitutive models have been developed to describe the complex material behavior of sheet metal upon load reversals. The Yoshida-Uemori (Y-U) and the homogeneous yield function-based anisotropic hardening (HAH) models are typical models which are able to predict the Bauschinger effect, transient hardening and permanent softening phenomena. The heavy identification efforts raise to be one main chanllenge before their application due to the numerous parameters. Appropriate tests and robust optimal methods are needed to calibrate parameters. In this work, cyclic stress-strain curve of DP780 steel sheets are obtained by tension-compression tests, and then the parameters of modified Y-U and HAH model are identified through global optimization approach. The identified parameters are verified by the comparison between springback results of U-shape draw-bending process and simulation.