MULTI-STEP NUMERICAL SIMULATION OF BULK METAL FORMING PROCESSES BASED ON DEFORMATION THEORY OF PLASTICITY

The bulk metal forming processes are calculated and analyzed by using a multistep finite element method (FEM) based on deformation theory of plasticity. In this method, FEM solution is implemented to minimize approximated plastic potential in static equilibrium by constraint variation principle, for incompressible rigid-plastic materials. The multi-step simulation deals with the fictitious sliding constraints for intermediate configurations and iterations step by step along the deformation path, considering the contact and deformation history, which could provide rapid analysis for more complicated bulk forming problems. The one-step and multi-step forward simulations of several typical bulk metal forming problems are performed by this method, the calculated results of which are compared with those obtained by incremental FEM. The results indicate: multi-step FEM simulation of the bulk metal forming processes could give the reasonable answers with a small amount of computing time, the errors of which are less 10% compared with those of incremental FEM.