Forming limit analysis of aluminum tailor-welded blanks

This paper presents an investigation on forming limits of tailor-welded blanks (TWBs) made of 5754-O aluminum sheets using both experimental and numerical approaches. A TWB is composed of two or more welded flat metal sheet of different thicknesses, shapes or mechanical properties. Due to the existence of weldment and the individual configurations of parent blanks, a TWB should be considered as heterogeneous in its structure. The mechanical properties of those parent metals and weld metal required for the simulation were measured individually. With the aid of the acquired data, finite element simulations for analyzing the forming process of TWBs were carried out using a general purpose finite element package, LS-DYNA. A localized necking criterion based on the vertex theory is employed to predict forming limit strains and failure locations of the aluminum TWBs. The theoretical predictions were satisfactorily validated with those obtained from the experiments.