Comparison of elastic-plastic and rigid-plastic implicit FEM simulations in sheet forming applications

Abstract

A general formulation for numerical finite element simulation of complex sheet forming processes with arbitrary tools is briefly introduced. An incremental displacement (“solid”) approach is assumed. Special attention is drawn to the choice of material models. The performance of the reviewed elastic-viscoplastic and rigid-viscoplastic algorithms is documented and the numerical results are compared to the experimental measurements. Test problems as well as deep drawings with complex irregular die geometries are simulated. Direct comparisons of the results obtained for identical tool-sheet sets from elastic-plastic and rigid-plastic models are presented and discussed. Provided that the overall numerical model is properly derived, it is shown that both approaches are accurate for many typical applications in sheet forming. Consequently, additional criteria to aid in the choice of material models are proposed and discussed. These include robustness, efficiency, and type of resulting information sought.