Springback prediction and compensation for the third generation of UHSS stamping based on a new kinematic hardening model and inertia relief approach.

Ultrahigh-strength steel (UHSS), such as DP980, has been widely used in automotive structural components to further reduce the weight of the autobody and improve the crashworthiness performance. However, UHSS sheets demonstrate more obvious kinematic hardening, which results in severe springback. In the present work, the kinematic hardening of typical Quenching and Partitioning steel, QP980, which is the typical steel of third generation of UHSS, is tracked by using a nonsaturating kinematic (NSK) Swift model in order to simulate the loading process more accurately. For unloading process, inertia relief is adopted as a new control approach in springback calculation. The experiment results show that the NSK Swift model improves the springback prediction accuracy greatly compared with that predicted by isotropic hardening model, and the inertia relief is validated as an accurate and efficient springback calculation method. Moreover, springback compensation based on the NSK Swift model can reach acceptable tolerance as ±0.5 mm through the iterative compensation method in LS-Dyna. [ABSTRACT FROM AUTHOR]