Formability of Tailor Welded Blanks Based on the Improved Rule of Mixture Considering the Welding Residual Strain and Stress
In this paper, the rule of mixture, which is often used to derive the weld properties from the uniaxial tension test of a subsize welded specimen, was improved by taking the residual welding strain/stress into account and assuming iso-strain increment across the welded specimen. Based on this improved method, hardening data of two different tailor welded blanks were determined. Erichsen cupping tests were performed experimentally and numerically to evaluate the effects of welding residual strain and stress on TWB formability. The results indicate that: (1) the residual strain and stress affect the formality of TWBs to some extent and (2) neglecting the welding residual strain and stress may predict a delayed crack onset and relatively large values in the maximum punch load and Erichsen index.