Influence of inhomogeneous constitutive properties of weld materials on formability of tailor welded blanks

In the current work, the local constitutive properties of three different laser welded beads were used in finite element (FE) models of tailor welded blanks (TWBs). Based on these FE models, the influence of the weld property inhomogeneity on TWB formability was evaluated by performing Erichsen cupping tests numerically and experimentally. Comparative studies of the predicted crack onsets, punch load–stroke profiles, punch/blank contact areas, plastic strain evolution and major/minor in-plane strain distributions were conducted based on the FE models with and without the incorporation of the inhomogeneous weld properties. The results revealed that with the implementation of inhomogeneous hardening data of weld materials in simulation, more accurate results can be predicted especially for TWBs made from identical base sheets. Moreover, the inhomogeneous properties of weld materials affect the formability of TWBs made from identical base materials more significantly than those made from dissimilar ones. This fact is associated with crack patterns and weld line movements in the TWB forming process.