Evaluation of Effective Paramters on Formability of TWB

Formability of automotive friction stir welded TWB (tailor welded blank) sheets isnumerically investigated in biaxial stretching based on hemispherical dome stretch (HDS) test infour automotive sheets of Aluminum alloy 6111-T4, 5083-H18, 5083-O and DP590 steel, havingdifferent thicknesses. The effects of the weld zone modeling and the thickness ratio on formabilityare evaluated. In order to carry out the numerical simulations, mechanical properties areconsidered according to Chung et al. [11] experimental results. von-Mises and Hill’48 quadraticyield functions are used to compare the isotropic and anisotropic behaviors of the used sheets. Inorder to simplify the problem, the anisotropy of the weld zone is ignored. The FEM results arecompared with experimental results of [11]. Anisotropic assumption for base materials and varyingthickness for the weld zone give more accurate prediction. Numerical results are in goodagreement with the experimental results. Failure onset locations and patterns are accurate. Sincethe formability is dependent on the stress concentration, asymmetric distribution of strength andcomplexity of weld zone properties, the thickness ratio in TWB affect formability.