Numerical and Experimental Comparison of Fractural Characteristics of 316L Stainless Steel

The fracture of a 316L stainless steel was investigated, both experimentally and numerically, by using two well-known ductile fracture criteria: Gurson-Tvergaard-Needleman (GTN) and Johnson-Cook (J-C). Tensile tests were modeled using the Ls-Opt of Ls-Dyna in order to determine the damage parameters of both models. The limit strains at various states of stress were further obtained by Forming Limit Diagram (FLD) experiments, and the fracture limits at different stress triaxialities were determined using the tensile test specimens with various notch sizes. Both of the used damage models predicted the fracture behavior very close to that of the experiments for the left side of the FLD. However, the prediction of the right side of the FLD by the models was found quite different from each other. The J-C damage model predicted the left side of the FLD with an error of 11.85% and the right side of the FLD with an error of 5%. The average error was 8.82% all over the FLD. On the other side, the errors for the GTN damage model were calculated 4.55 and 40% for the left and right side of the FLDs, respectively and 20% for all over the FLD curve.