A Novel Approach for Formability Prediction of Tailor Welded Blank

Formability of Tailor Welded Blank (TWB) is an important parameter which limits this kind of blanks usage. A forming criterion for tailor welded blank is presented based on the analytical model in this research. This criterion suggests Limit Strength Ratio (LSR) and Limit Thickness Ratio (LTR) for forming limit of TWB. When thickness ratio or strength ratio in tailor welded blank is greater than LTR or LSR, formability will be limited and necking will happen sooner. The influence of thickness ratio on the formability of TWB has been investigated by experimental tests and Finite Element (FE) simulations, but strength ratio has just been studied by simulation. All the simulation and experiment results indicate that by the increase of thickness ratio and strength ratio, the formability will decrease and weld line movement will increase. The obtained results of the present study indicate that fracture happens in the thinner side of TWB and near to the weld line. Moreover, fracture line is parallel to weld line and the fracture position moves farther than weld line by thickness ratio decreasing. Simulation results have a good agreement with experimental results as well.