Simulation Technique for Pre-forming of AHSS Edge Stretching

Edge cracking in advanced high strength steels (AHSS) is one of the main failure modes in many sheet metal stamping processes. Pre-forming into a wave (or scallop) shape at the edge is a common technique used to gain material at high edge stretch regions in preparation for the subsequent edge stretch processes. The accurate simulation of this multi-stage forming process remains a challenging task since these edges experience complicated forming processes including bending, unbending, and stretching deformations. In this study, a simulation variable study is performed and the effect of various material models, hardening rules and solvers on the simulation results is also investigated. A simulation technique is established for this multi-stage forming process. Simulation results are compared to experimental data and reasonable agreement is achieved. Different failure criteria are also evaluated and discussed for use in this type of application.