Control of defects in the deep drawing of tailor-welded blanks for complex-shape automotive panel

With the development of lightweight vehicles, tailor-welded blanks (TWBs) are being increasingly used in the automotive industry. Splitting and wrinkling are the main defects occurring during the deep drawing of TWBs. Accordingly, in this paper, a new method to control the forming defects is introduced in the forming process of TWBs. The microstructure and mechanical properties of TWBs are characterised by metallography and tensile tests. Finite element analysis is conducted for an automobile rear door inner panel made of TWBs to analyse the deep drawing. Edge and notch cutting are introduced to address forming defects and reduce the number of stamping tools. The thinning index, thickening index and minimum distance between the material draw-in and trimming lines are defined as the measurable index to analyse the numerical results. Orthogonal experiments, numerical simulations and multiobjective experiments are conducted to optimise the forming parameters. The proposed method and optimised parameters are verified through experiments, the results of which are essentially consistent with the numerical simulation. Indeed, the proposed method can provide guidance in controlling defects associated with the deep drawing of TWBs for complex-shape automotive panels.