U形件弯曲加载压边力的有限元模拟

Finite element simulation with loading blank-holder force in bending forming for U-shaped parts

由于平板弯曲成U形件后要发生回弹,对此在弯曲模上增加压边装置能显著地减少回弹。可是,目前加载多大的压边力并没有相应的计算公式而是凭经验估算。压边力过小,模具结构紧凑,但抑制回弹效果不大;压边力过大,抑制回弹效果明显,但弹性元件尺寸变大,模具结构庞大,闭合高度过高,冲压作业取件困难。因此,我们将弯曲顶件力作为加载压边力的参照值进行有限元模拟,结果显示:压边圈施加的压边力数值并非越大越好。压边力数值小于等于顶件力数值,回弹变化较大;压边力数值大于等于顶件力数值,回弹值或回弹形状的变化趋于平稳,抑制了回弹。

A U-shaped part bent from sheet-metal blank can induce springback,which can be obviously reduced by installing a blank-holder on bending die.However,there is no calculation formula to figure out the blank-holder force loaded and only empirical estimation is resorted to at present.If the blank-holder force is excessively small,the die structure will be compact,which will have an undesirable effect on inhabiting springback.If the blank-holder force is excessively large,it is apparent to inhabit springback,but the enlarged elastic element dimensions,together with the enormous die structure,will result in excessive size in shut height,and difficulty in stamping operations.Therefore,it is plausible to conduct finite element simulation of the blank-holder force with ejecting force of bending die as referencevalue.The results show that the greater the blank-holder force is not always the better.When the bank-holder force is no greater than the ejecting force in force value,spring-back varies greatly.When the blank-holder force is no less than the ejecting force in force value,the resilience value tends to be stable with moderate changes,and springback is inhabited.