Previous research papers presented methods for joining different aluminium or steel sheets of the same thickness using the friction stir welding process with flat tools. A novel variant of the friction stir welding process has been developed by the Materials Testing Institute of the University of Stuttgart, enabling the joining of aluminium and steel sheets of different thicknesses in order to further increase the lightweight potential of sheet metal components. Compared to the conventional welding method, the difference of this method relates to the stir welding tool used, which consists of a stepped welding pin and allows combined lap-and-butt joints to be produced. In this context, this paper aims to demonstrate the lightweight potential and the crash performance of Tailor Welded Blanks (TWBs) made from DX54(1 mm) and AL6016 - T4 (2 mm). For this purpose, the first step was to identify possible parts of car body structures that could be replaced by components made from these TWBs. Subsequently, these parts were constructively integrated into the selected structures, which were finally used to perform crash simulations with front and side impacts. To demonstrate the benefits of the new joining technology, the calculated crash results were compared with those of the conventional car body structures and the advantages of the used TWBs were highlighted. Concretely, the friction stir welded TWBs enabled the vehicle weight to be reduced while providing comparable properties to those of currently used components, thus lowering CO2 emissions during car use.
