车门内板拉延开裂分析与讨论

Analysis and discussion on cracking in drawing for automobile door inner panel

以某车型前车门内板为研究对象,为解决零件在拉延工序出现的开裂和暗裂缺陷,首先对模具及零件生产现状进行分析,针对成形缺陷提出添加刺破刀的改善方案;然后,利用有限元仿真模拟对刺破刀形状和刺破高度进行多组合对比,得到了最优的刺破刀方案:压边力为1200 kN、刺破刀形状为D形、刺破高度为15 mm;最后,通过冲压实验验证了添加刺破刀的效果。冲压实验方案的破口宽度与仿真计算结果存在一定误差,这是因为冲压实验存在二次成形过程,材料在二次成形过程中的回复和软化对冲压实验结果有较大影响。这种冲压方法可以作为破口宽度趋势性分析的依据,但无法精确量化分析。

For the front door inner panel of a certain type of automobile, in order to solve the crack and dark crack defects of parts in the drawing process, firstly, the production status of die and parts was briefly analyzed, and according to the forming defects, the improvement plan of adding piecrcing knife was put forward. Then, the shape of piercing knife and the piercing height were compared in multiple combinations by finite element simulation, and the optimal piecrcing knife scheme was obtained as the blank holder force of 1200 kN, the piercing kinfe shape of D-type and the piercing height of 15 mm. Finally, the effect of adding piercing knife was verified by stamping test. And there was a certain error of the break width results between the stamping test scheme and the simulation calculation. It is because that there is secondary forming process in stamping test, the recovery and softening of the material in the secondary forming process have a great impact on the stamping test results. This stamping method could be used as the basis for the trend analysis of break width, but it could not be accurately quantitative analysis.