Formability Analysis of Auto Panel Stamping Based on Inverse Numerical Simulation

Based on the inverse analysis principle, a novel numerical simulation approach has been developed to predict initial blank shapes and forming defects in complex-shaped auto panel stamping. Two new techniques are included in this approach. Firstly, to correctly describe blank deformation behavior, a kind of modified membrane finite element with bending effect is introduced. Secondly, with regard to the boundary condition definition, non-plane binders with variable blank holder force are classified and studied, the punch and die actions are replaced by a resultant force situated on the contact surface, and the work done by drawbead is evaluated at the nodes concerned according to an equivalent restraining force model, in taking into account the bending-unbending and friction. The rapid calculation method provides an easy process of part formability determination. The numerical results of example confirm its accuracy for design of auto panel stamping process.