Investigating effective yield surface of porous metals exhibit different hardening behaviors by cell models with randomly distributed spherical voids

This study focuses on the development of effective yield surface of porous metals, which is characterized with the two constitutive parameters (i.e., q 1 and q 2 ) in the widely used Gurson–Tvergaard–Needleman (GTN) model. It was found that the influence of q 1 and q 2 on the mechanical responses may be masked by adjusting the two failure parameters ( f c and f F ), yielding a set of GTN parameters deviated from the actual situation and leading to the errors in failure predictions. Therefore, the two constitutive parameters should be carefully calibrated according to the hardening behavior of matrix. Further investigations on the void density and distributions proved that cubic cells containing 100 randomly distributed non‐intersecting spherical voids are sufficient in characterizing the homogenization. On this basis, effective yield surface of porous metals with a wide range of void volume fractions (from 0.4% to 20%) was investigated, and a correlation between the constitutive parameters and the power‐law hardening behavior of matrix was established. Finally, experimental verifications were conducted on low alloy steel SA508, indicating the q 1 and q 2 from this study can yield more accurate mechanical response predictions then the previously suggested values. The influence of constitutive parameters on the failure predictions were discussed. Effective yield surfaces of porous metals with f range from 0.4% to 20% were investigated. Correlation between the constitutive parameters and power‐law hardening was established. Experimental verifications were conducted on low alloy steel SA508.