Stress based forming limit diagram for formability characterization of 6061 aluminum

Two numerical criteria of forming limit diagram (FLD) criterion and ductile fracture criterion (DFC) are presented for FLD prediction of 6061 aluminum. The numerical results are compared with the experimental FLD and also punch's load-displacement curve of experimental samples. Experimental FLD of this study is calculated using hemispherical punch test of Hecker. Experimental FLD is converted to FLSD and imported to the Abaqus software to predict necking of samples. Numerical results for FLSD prediction were compared with experimental FLSD. Results show that ductile fracture criterion has higher accuracy for FLD and FLSD prediction of 6061 aluminum. Comparison of numerical and experimental results for force-displacement curve of punch shows that numerical results have a good agreement with experiment.