关键工艺参数对铝合金斜法兰非轴对称盒形件充液成形的影响

Influence of critical process parameters on hydroforming for aluminum alloy non-axisymmetric box with oblique flange

铝合金斜法兰非轴对称深腔盒形件成形过程中受力变形复杂。通过理论分析计算、有限元分析软件Dynaform的数值模拟及试验,对成形工艺进行了优化。针对该零件充液拉深过程易出现的破裂、起皱现象,研究了预胀形高度、预胀形液室压力、液室压力加载路径对零件法兰最高处D侧与最低处B侧凸模圆角区域在板料成形过程中壁厚变化的影响。结果表明,预胀形高度越高或预胀形液室压力过大,零件B侧与D侧凸模圆角在成形后壁厚减薄越严重;预胀形高度过低也会导致D侧凸模圆角在成形后发生严重减薄。预胀形结束后,液室压力加载过快,易发生褶皱,达到临界液室压力后,可以有效抑制板料壁厚过度变薄。

The stress and deformation during sheet hydroforming process of aluminum alloy non-axisymmetric box with oblique flange were complicated,and the forming process was optimized by theoretical analysis and calculation,numerical simulations using software Dynaform and experiments. Based on cracking and wrinkling easily occurred in the hydrodynamic drawing process,the influences of pre-bulging height,pre-bulging cavity pressure,and loading path of cavity pressure on wall thickness variation at punch fillet of the highest corner D and the lowest corner B were investigated. The results indicate that the minimum wall thickness at punch fillet of corner B and corner D reduces with the increase of pre-bulging height or the oversize of pre-bulging pressure. Too low pre-bulging height also causes the wall thickness at punch fillet of corner D to thin excessively. Wrinkling easily occurs if the cavity pressure is loaded too fast after pre-bulging.After the critical cavity pressure is reached,the wall thickness of the sheet can be effectively restrained to thin excessively.