A study on the analytical modeling for warm hydro-mechanical deep drawing of lightweight materials

The warm hydroforming process has become an emerging technology in recent years to reduce the weight of automotive body structure and minimize the number of process steps. In this study, analytical models were developed to investigate the effects of process conditions such as temperature, hydraulic pressure, blank holder force and forming speed. The analytical model under hydro-mechanical deep drawing (HMD) condition was developed based on experimental results in the literatures. FE models were also developed to validate the analytic models. Then, the analytic model was validated through comparisons with both existing experimental results and FE results. The analytical model provided rapid and reasonably accurate results for the design of warm hydroforming process. Based on this analytic model, several parametric studies were performed regarding to the temperature, hydraulic pressure, blank holder force, and punch speed conditions. It was demonstrated that the process windows for a successful part forming could be rapidly predicted with a reasonable accuracy by the analytic model compared to lengthy and costly thermo-mechanical FEA or experimental trial and error.