Finite Element Simulation of Stamping a Laser-Welded Blank

In order to achieve higher assembly accuracy for automotive body, increased body rigidity, and decreased stamping and assembly costs in car body manufacturing, a new method of sheet metal stamping has been developed, in which several blanks of different strength and thickness are integrated using CO₂ laser-welding.

The stamping formability of the laser-welded blank is limited compared with that of the conventional single blank. It is very difficult to predict the exact decrease in formability for different positions of the weld line and for different matching of materials. Because experimental estimations were indispensable for stamping die designers to evaluate formability at the stage of planning dies, many man-hours were spent conducting actual experiments. Therefore, the elastic-plastic finite element method, commercial code “JNIKE3D”, has been improved to obtain high accuracy results by considering the planar anisotropy of the materials using the biquadratic yield function and by considering the initial pressure distribution on the blankholder. Using the improved code, the formability of stretch and shrink flanging laser-welded blanks influenced by the weld line position has been predicted.