Numerical simulations and experimental validations of a proposed ductile damage model for DIN1623 St12 steel

In this research, first DIN1623 St12 steel is selected because of its remarkable formability and wide application in metal forming industries. As the main contribution and objective of the current study, a ductile damage model is proposed and calibrated for the selected material. For this goal, then damage parameters and fracture locus of the material are experimentally and numerically determined. Various convenient tensile tests on flat-grooved, pure tension and shear-tension specimens are employed, as the novelty of the investigation. Based on the experimental and numerical results, a relation between equivalent fracture strain and stress triaxiality is obtained. Finally, in order to validate the fracture locus, the determined damage parameters, and the damage model, extra tensile tests are experimentally performed on notched specimens and compared with numerical simulations. Comparison of the numerical results and observation tests reveals good conformity. Therefore, it is concluded that the presented ductile damage model can successfully and reliably predict damage initiation, propagation, and fracture of the material in metal forming processes.