Numerical simulation for local plastic instability and wrinkling of sheet metal forming

A Mindlin shell element model of elastic-plastic large deformation based on a virtual power principle is proposed. On the theoretical basis of Hill' s so-called bifurcated sufficiency condition on elastic plastic materials, the flange wrinkling with respect to the deep-drawing with square punch and cylinder punch, and the side-wall wrinkling with respect to the deep-drawing with circular cone punch are successfully simulated. The flange wrinkling models, for example, the number, shape and location of the wrinkling are very coincided with experimental ones. Finally, using 3D laser life-object modeling technique and imitating movement technique, the occurring and developing of the wrinkling processes are displayed.