Numerical investigations on a framework for fracture prediction in metal forming with a material model based on stress-rate dependence and non-associated flow rule

In this paper, the proposed framework for fracture prediction during sheet metal forming is explained and some numerical investigations are presented to demonstrate the effectiveness of this method. In particular, the role of parameters that affects the forming limit curves, which are represented by the initiation of local bifurcation in each stress rate, are examined; namely, anisotropic parameters and the K_C value, which means a stress-rate dependence, and other material properties. The newly proposed concept of forming limit diagram is used to evaluate the formability of the concerned material and working process.