A novel analytical model to predict springback of DP780 steel based on modified Yoshida-Uemori two-surface hardening model

Advanced high strength steels are widely used in the automotive industry due to their appropriate strength to weight ratio. This alloy has unique hardening behavior. In this paper, a novel analytical model is introduced to predict springback in U-shaped bending process of as-received and pre-strained DP780 dual phase steel specimens. This model is based on the Hill48 yield criterion and plane -strain condition. The effect of sheet thinning and the motion of the neutral surface is taken into account on the springback. The modified Yoshida-Uemori two surface hardening model is applied to investigate the effect of work hardening stagnation. This novel model is examined on the Numisheet 2011 benchmark 4. The effects of the blank holder force and work hardening stagnation are studied on the sheet springback phenomenon. By comparison of the present model with previous alternate models, obtaining the more accuracy is tangible. Also, it is demonstrated that the springback parameters have more changes with increasing the blank holder force. Also, the parameter of the work hardening stagnation has more effect on the pre-strained specimen as compared to the as-received sample.