Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Mechanical Design and Production

A tailor-welded blank (TWB) is comprised of two or more separate pieces of sheet metal welded together prior to stamping. TWBs allow the welding of materials with different grades, thickness or corrosion coatings together to achieve desired properties in different areas. However, several process defects appear during the forming of TWBs such as springback, reduced formability due to welding, and weld-line movement (WLM). The present work studies the effect of different process parameters on springback and WLM through an integrated experimental and numerical analysis of U-bending process of the TWB. The analysis of draw-bending process shows that, under constant BHF schemes, weld-line moves under all BHF levels considered. WLM occurs at the early stage of punch travel. This problem has been successfully solved via the use of variable blank holding force (VBHF) schemes that eliminates WLM

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