U-channel forming analysis with an emphasis on springback deformation

Today apart from CAD/CAM activities, engineering simulation tools based on the finite element method are employed regularly in the design of stamping dies for sheet metal parts in automotive industries. With the increased use of FE simulations in tooling departments, the forming analyses of sheet metals components are used more frequently in the design feasibility studies of production tooling. These computer tools allow the design engineer to investigate the process and material parameters controlling the material flow over the die surfaces. Nevertheless, the reliability of predicted formability and the accuracy of the estimated deformed geometry for a given stamping part depend on the selected computational modeling approach. In this paper, a kinematic hardening plasticity model based on an additive backstress form is described in order to improve the predicted sheet metal deformation response. The performance of the model in the forming analyses of sheet metals is investigated, and the FE analysis of Numisheet’93 U-channel benchmark is performed using implicit FE analyses based on the kinematic hardening plasticity model. A comparison of the U-channel geometry after springback, predicted with present model, indicates a significant improvement with respect to geometry computed using the isotropic hardening plasticity model.