Application of response surface methodology to drive GTN model parameters and determine the FLD of tailor welded blank

► In this study, we predicted the forming limit diagram (FLD) of a tailor welded blank. ► The Gurson–Tvergaard–Needleman model was applied as failure criterion. ► Desired parameters were determined by application of response surface methodology. ► Proper agreement between predicted and experimental FLDs was observed. Tailor welded blanks (TWBs) have found great usage in auto industries; however there are some drawbacks, low formability and weld line movement, which hinder their applications. Prediction of their formability through forming limit diagrams (FLDs) enables one to consider the effects of forming parameters on forming behavior of TWBs. Different numerical approaches have been applied to predict the experimental FLD of these blanks. In the present research Gurson–Tvergaard–Needleman (GTN) model was applied as failure criterion. The parameters of GTN model were firstly derived for both thin and thick monolithic blanks of studied TWB by application of response surface methodology. Then experimental method of obtaining FLD was simulated and FLD of transversely welded TWB was predicted using Abaqus software. The results indicate that the FLD of studied TWB is lower than those related to the parent sheets and there is an appropriate agreement between the predicted and experimental FLDs of the studied TWB.