A novel finite element simulation of hot stamping process of DP780 steel based on the Chaboche thermomechanically hardening model

Advanced high-strength steels (AHSS) despite excellent properties with low weight and high strength have the concern of high springback occurrence. The amount of springback can be reduced by hot forming process. In this paper, the influence of temperature rises on the springback quantities generated potentially during a hot stamping process of the DP780 steel is investigated. To obtain a proper description for hardening behavior, a type of the Chaboche thermomechanically constitutive model has been used in conjunction with an anisotropic Yld2000-2D yield criterion. Since the elastic modulus of the AHSS during loading and unloading stages can make considerable influences on the springback, consideration of Young's modulus as a function of equivalent plastic strain is necessary. Moreover, the process is simulated via ABAQUS software implementing UMAT and VUMAT user-defined subroutines as well as the forward Euler explicit integration scheme is applied to calculate the stress and strain at the end of time increments. The results demonstrate the efficiency of the novel temperature-dependent Chaboche model to predict the level of stresses and temperature during and after hot stamping process.