Finite element simulation of superplastic punch forming with a thickness control ring

Abstract

The analysis of superplastic punch forming process is studied by the use of the finite element method to obtain the optimum punch speed and the related deformed shapes. The punch forming has an advantage of guaranteeing the desired accuracy inside a product and controlling the thickness of a deformed sheet more accurately than blow forming. In the formulation, the large inelastic behavior of the superplastic material is described as incompressible, nonlinear, viscous flow. In punch forming processes, a punch velocity control algorithm is combined in the analysis for optimization of the forming time, which is indispensable to minimize the relatively long forming time. The algorithm deals with the maximization of the strain rate sensitivity and the consistency of the desired strain rate. The numerical analysis demonstrates that a thickness control ring shaped prominence effects the thickness distribution in a deformed sheet so that a desired thickness distribution can be obtained with the proper location of a thickness control ring.