A novel model to predict U-bending springback and time-dependent springback for a HSLA steel plate

In this paper, a novel model which considers initial strain related to the material's yielding stress, the combination of stretch and bending strain and isotropic hardening rule is introduced to predict U-bending springback and time-dependent springback behaviors for a high strength and low alloy (HSLA) steel plate. It is noteworthy that time-dependent springback is associated with plastic strain hardening for the HSLA steel plate. The results obtained from the performed analysis show that the hardening exponent, bending radius and thickness ratio, friction coefficient, and blank holder force have great influences on the springback angle and stress level. Based on this novel model, the prediction of HSLA steel plate's springback is done in the stage of tool design and hence, the accuracy of drawn part is increased.