Variation of elastic modulus during plastic deformation and its influence on springback

Inelastic recovery behavior of TRIP steels during unloading has been investigated by uniaxial tensile tests. Unloading stress–strain curves obtained under different plastic strain indicated that the percentage of inelastic recovery to the total recovery increased with plastic deformation. An empirical expression describing the relation of elastic modulus with plastic strain has been proposed. Then the expression was implemented into LS-DYNA software to simulate U-channel springback. Comparison showed that springback simulation with a varied elastic modulus was more precise than that with a constant elastic modulus. Inelastic recovery needs be considered in order to improve springback simulation precision.