Evaluation of Effective Paramters on Formability of TWB

Document Type: Research Paper

Authors

Department of Mechanical Engineering, Shiraz University, Shiraz, Iran

Abstract

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

Keywords