Hydromechanical deep-drawing of aluminium tailor welded blanks

Tailor welded blanks (TWBs) offer many benefits for the automotive industry. They can not only reduce the car body weight, but also save manufacturing costs and improve the product's performance. However, former studies have shown that TWBs made of aluminium have a reduced formability, due to the properties and quality of the weld line area.; In this thesis, a model is presented in order to investigate the formability of aluminium TWBs and the effect of a hydraulic counter pressure on the deep-drawing process. For the simulation, DYNAFORM is used as pre-processor, and LS-DYNA, as solver. The aluminium alloys AA5182 and AA6016 are investigated in different material and thickness combinations.; A counter pressure of 100bar is demonstrated to decrease the weld line movement and to allow deeper draw depths to be reached as with the conventional process, since less thickness reduction takes place. As the counter pressure is further increased, the weld line movement can be further decreased, and even deeper draw depths can be reached. Since the blankholder is segmented, the possibility of applying a different blankholder force on each side of the tailored blank is also investigated, and shown to also be successful at reducing the weld line movement. However, a compromise between the magnitude of the counter pressure and the maximum value of the blankholder force on the thinner side is needed in order to not exceed the available ram force.; A tool die design is presented, which allows conventional and hydromechanical deep-drawing of tailored blanks, since both, the sealing and the step issues are solved through tool die modifications.