1 Two forming simulations are performed. An exploded view of the initial configuration used in the first simulation is shown in Figure 2. The quarter-symmetry model consists of a blank holder, a punch, and a blank. The blank holder and punch are treated as rigid bodies. The blank is discretized with 2414 shell elements and is considered to be an orthotropic, elastic-plastic material.
Contact is modeled between the punch and the blank and between the blank and the blank holder.
Symmetry boundary conditions are specified on the appropriate edges of the blank. The punch is displaced vertically to form the box, while the blank holder remains fixed. The large wrinkle that extends from the corner of the box downward to the blank holder makes this part unacceptable. Increasing the hydroforming pressure might suppress the formation of this wrinkle. To suppress wrinkling of the box, a rigid draw cap is added to the model, as shown in Figure 3.