Tool design for the tubular press forming of a rear suspension member with the finite element analysis

Tool design is carried out for a press forming of a tubular axle in the rear suspension assembly based on the result of the finite element analysis. The analysis incorporates a three-dimensional elasto-plastic finite element method with the explicit time integration scheme by using LS-DYNA3D. The analysis simulates the two-stage stamping process and it fully evaluates the deformation mechanism by forming and springback. With the trial tool shape, simulation is performed in order to investigate failure by wrinkling, shape inaccuracy and the local deformation. This paper identifies such unfavourable mechanism in the tubular press forming and proposes a new tool design with a guideline for modification in the design of the process and sequential tool shapes. The finite element analysis result with the improved tool design confirms that the proposed design not only reduces the possibility of failure, but also improves the quality of a formed product.