Finite-element analysis and design of binder wraps for automobile sheet metal parts using surface boundary condition

The forming of automobile sheet metal parts in a draw die consists of clamping a blank by binders to form a binder wrap and drawing the blank into the final part. This paper proposes a numerical method to calculate the binder wrap. A blank is composed of two regions: the contact region with the die face and the noncontact region of the die cavity. In this study, surface boundary condition is suggested for calculating the configuration of the binder wrap. Surface boundary condition means that the three-dimensional geometric data of the die face are used as the base for the displacement boundary condition of the finite-element analysis. To verify the validity of the proposed method, the binder wraps of complicated automobile parts, including a front fender and a trunk lid, are analyzed.