Evolution of in-plane stresses induced fracture behaviors of Tailor Welded Blanks subjected to non-uniformly distributed load

•Non-uniformly distributed forming load could improve deformation uniformity of TWBs without sacrificing the limit bulge height.•Strain components captured by DIC system were introduced into Levy-Mises law to quantitatively evaluate stress states of TWBs.•In-plane stresses of TWBs when subjected to non-uniformly distributed forming load was responsible to the improved formability.•Correlation between stress states and fracture behavior of TWBs was presented to clarify the failure mechanism of TWBs.