变压边力控制与矩形件拉深成形特性的相关性研究

通过采用DYNAFORM软件进行数值模拟试验,确定出在定常压边力曲线控制下矩形件拉深成形压边力变化安全区的取值范围,然后根据该试验结果以及相关资料,选取出12种典型变压边力控制曲线进一步进行数值模拟。变压边力数值模拟试验结果表明,采用变压边力控制矩形件拉深成形过程时,变压边力对矩形件拉深成形特性影响显著。对试验所获得的矩形件最大增厚量和最大减薄量进行数据分析,变压边力对最大减薄量的影响较对最大增厚量的影响更为显著。根据试验结果比较所选取的12种典型变压边力控制曲线可知,改善矩形件拉深成形性能最优的变压边力曲线为曲线L,最差的变压边力曲线为曲线I。最后,分别采用曲线L,曲线I以及定常曲线A进行物理模拟试验,以验证数值模拟的试验结果。物理模拟试验结果表明,其最大减薄量的试验结果与数值模拟所获得的试验结果十分吻合。因此,通过数值模拟可以有效地进行变压边力曲线的预测和控制研究。

Study on the relativity of the variable blank holder force control and the formability of rectangular box drawing

In the paper,at first,the series of the simulation tests were used to find the forming critical conditions of rectangular box drawing during the rectangular box drawing processing when applying constant blank holder forces. According the test results,the reasonable alteration scope of initiative variable blank holder forces (VBHF) was obtained as 1.9t～2.3t. Then,based on the studying on the test productions of blank holder force,applied twelve typical VBHF curves to having the simulation tests by DYNAFORM. The simulation test results obviously showed that VBHF had great effects to drawing formability of hot-galvanized sheet steel during the rectangular box drawing. However,the different VBHF curves were applied to control the whole drawing,it would get great different effects. According the simulation test results,the VBHF had great effects to the maximum thick thinning ratio,but had little effect to the maximum thick incrassation ratio. So,reasonably applied the VBHF would greatly decrease the fractures occurring. When the VBHF profile was as curve L would get the best effect of drawing formability,when it was as curve I would get contrary effect,when it was as the other types of curves would get effects between above two types of VBHF curves. Finally,the actual tests were applied to prove the validity of the simulation tests. The results were shown that the FEM simulation tests were good tools for predicting and optimizing of VBHF.