Describing the non-saturating cyclic hardening behavior with a newly developed kinematic hardening model and its application in springback prediction of DP sheet metals

A recently proposed non-saturating kinematic (NSK) Swift model is verified by modeling the advanced high-strength sheet metal DP600, of which the cyclic loading is typically featured by the non-saturating hardening and permanent offset phenomenon along with other classical characteristics. Good performances are also presented to describe the further cyclic hardening behavior in different strain ranges. Noticeably only the tension data are used to determine the model parameters for this material due to the appropriate control function. Then the non-saturating kinematic (NSK) Swift model is applied to the simulation of the automobile underbody cross member in Numisheet 2005 Benchmark 2, where only the tension data is available for the material constant determination while the cyclic loading occurs in the forming process. Nice agreements are achieved between the measured data and the numerical results of the springback and the thickness prediction for two DP sheet metals (DP600 and DP965). Both the theoretical importance of the control functions in material modeling and practical significance of the obtained non-saturating kinematic (NSK) Swift model can be implied through the constitutive verification and the industrial application.