Computational modeling of superplastic sheet metal forming processes

A computational model for the superplastic forming of sheet metal is presented. The numerical results are tested against a physical model of the superplastic forming process. The physical model provides a convenient laboratory method for verification of the kinematics equation. Incompressible rubber material is used to simulate superplastic sheet metal being formed, with pressure applied through the pulling vacuum in a plexiglass die. The model is compared with the deformation of rubber sheets in a square box. The depth at various points is compared with the experimental values in various stages of deformation. The computed values are in agreement with the data in stage I. The model does not predict the surface as accurately in stages II and III, particularly in corner regions. An assumption of uniform thickness does not seem to be correct