Analysis and design of hydroforming process for automobile rear axle housing by FEM

An FEM program, HydroFORM-3D, for the analysis and design of tube hydroforming processes, has been developed by modifying and adding some subroutines to the previous rigid-plastic finite element program, and then applied to the hydroforming process for an automobile rear axle housing. This paper includes the theoretical background of the program development. Through a numerical simulation, an optimum process is proposed to meet the practical requirements, which shows the efficiency of the numerical simulation. Two types of hydroforming dies are analyzed by numerical simulation. The sliding-type die has the drawback of a possibility of buckling, whereas the fixed-type die causes bursting failure. The thickness distribution of the final product is affected not only by the types of die, but also by the loading paths. The potential failure site for rear axle housing predicted by the numerical simulation is consistent with the experimental results. The values of maximum axial compression force for the first and second hydroforming processes are also in good agreement with experimental data. To manufacture a sound automobile rear axle housing without failure, it is better to use the sliding-type die and it is also critical to maintain a suitable hydraulic pressure level.