A finite element formulation is derived for the incremental analysis of the superplastic sheet metal forming process. The formulation is associated with a contact algorithm for the blow forming process and the male forming process. In the formulation, the large inelastic behavior of the superplastic material is described as incompressible, nonlinear, viscous flow.
The finite element code developed is applied to a class of male forming processes for the diaphragm with initial thickness distribution. The superplastic forming is usually carried out with the blow forming process, but is sometimes carried out with the male forming process for the accuracy inside the formed part. The numerical simulation produced many interesting and fruitful results and provided the design criterion for the preform in the punch forming of the diaphragm with initial thickness distribution.
