Springback prediction of magnesium alloy sheet with nonlinear combined hardening

Springback is regarded as one of the main defects that occur in sheet-metal forming processes. Therefore, improving its prediction accuracy, especially under highly nonlinear conditions, is important for researchers. In this paper, constitutive equations that consider the isotropic hardening, kinematic hardening, and distortional hardening are proposed for magnesium alloy sheet. The work hardening and springback behaviors of 0.8-mm-thick AZ31B magnesium alloy sheet were investigated and simulated. The AZ31B specimen was subjected to a bending process after the pre-tension deformation, which aided in the observation of its springback behavior under nonlinear loading paths. Simulations were conducted using ABAQUS-Explicit (Vumat) and ABAQUS-Implicit (Umat). Comparisons between the experimental and numerical results demonstrate the strong influence of the kinematic hardening on the springback prediction of magnesium alloy sheet.