Investigation on determination of loading path to enhance formability in tube hydroforming process using APDL

During tube hydroforming (THF) process, failure modes such as buckling, necking and bursting may occur because axial feeding and internal pressure are imposed simultaneously. Therefore, the suitable loading condition in THF with regard to internal pressure and axial feeding should be designed to improve formability and to avoid failure modes on the final hydroformed product. This study deals with the procedure for the determination of the loading path in THF for improving the formability of the final product after the THF. The suitable loading path is based on the adaptive method using ANSYS parametric design language (APDL). This proposed procedure is demonstrated via a sub-frame model of an engine cradle module in an automobile to be able to satisfy the specifications required after hydroforming, such as excessive thickness thinning phenomena, and the results have been proved to be successful on its effectiveness and feasibility. Consequently, it is shown that the approach proposed in this study will provide a valuable method to satisfy the increasing practical demands for designing the process conditions in THF.