Application of new VBHF optimization strategy to improve formability of automobile panels with aluminum alloy sheet
(1. School of Materials Science and Engineering, Shanghai University, Shanghai 200072, China;
2. Shanghai Key Laboratory of Digital Autobody Engineering, School of Mechanical Engineering,
Shanghai Jiao Tong University, Shanghai 200240, China;
3. State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China)
2. Shanghai Key Laboratory of Digital Autobody Engineering, School of Mechanical Engineering,
Shanghai Jiao Tong University, Shanghai 200240, China;
3. State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, Shanghai 200240, China)
Abstract: A VBHF (Variable Blank Holder Force) optimization strategy was employed to determine the optimal time-variable and spatial-variable BHF trajectories, aiming at improving the formability of automobile panels with aluminum alloy sheet. The strategy was implemented based on adaptive simulation to calculate the critical wrinkling BHF for each segmented binder of the Numisheet’05 deck lid in a single round of simulation. The thickness comparison of the stamped part under optimal VBHF and constant BHF shows that the variance of the four sections is decreased by 70%, 44%, 64% and 61%, respectively, which indicates significant improvement in thickness distribution and variation control. The investigation through strain path comparison reveals the fundamental reason of formability improvement. The study proves the applicability of the new VBHF optimization strategy to complex parts with aluminum alloy sheet.
Key words: deep drawing; variable blank holder force; aluminum alloy sheet; formability