Study on formability of AISI 304 steel sheet using M-K model and GTN damage criterion

In this research, response surface methodology (RSM) was used to rank the parameters of GTN damage criterion in the order of significance in the study of metallic sheets formability, so as to select a limited number of the most significant parameters to have the GTN criterion calibrated. A total of 7 GTN parameters were selected for this purpose. Then, considering a suitable range for each parameter, a total of 143 experiments were designed using RSM. In these experiments, the minimum limit strain obtained from the forming limit diagram (FLD0) of AISI 304 steel sheet was taken as response. In order to calculate the FLD0, M-K model was simulated using Abaqus finite element (FE) software. In these simulations, GTN criterion was used to predict fracture in the defect zone of the M-K model. Upon performing analysis of variance (ANOVA) on the data obtained using the FE simulations, the GTN criterion parameters were ranked in the order of significance. Furthermore, using the calibrated values of the GTN parameters, forming limit diagram of AISI 304 sheet was obtained completely at an acceptable accuracy.