A new methodology for ductile fracture criteria to predict the forming limits

The main objective of this study was to develop an improved method for an application of ductile fracture criteria to predict forming limit diagram (FLD) of the sheet metals. Neck initiation was studied experimentally and numerically for a tensile test. Based on the results, a new methodology regarding the ductile fracture criteria was proposed to estimate forming limits. The new methodology states that the fracture criteria constant could be calculated at a thickness strain in the range of 20-25%, and be considered as a critical value of the ductile fracture criteria for strain localization. The new proposed methodology was successful in predicting the left side of the FLD and more refinement is needed to predict the right side of the FLD.