圆筒形件拉深工艺的有效压边力研究

Valid Blank Holding Force for Deep Cylindrical Cup

采用高阶厚向异性屈服准则及经典塑性理论,推导出圆筒形件拉深过程中的应力应变计算公式,获得了避免拉深破裂的上限压边力解析表达式.运用能量法研究了突缘产生起皱的能量变化情况,推导出抑制突缘起皱的下限压边力解析表达式.在上限压边力和下限压边力解析表达式的基础上,给出圆筒形件拉深工艺成功的有效压边力区间,并通过试验对理论计算结果进行了验证.理论计算和试验结果均表明:在拉深过程中,若压边力小于下限压边力,则拉深件起皱;若压边力大于上限压边力,则拉深件破裂;若压边力位于下限压边力和上限压边力之间,则拉深件能顺利成形.

The stress and strain expressions of the flange section in deep drawing are obtained on the basis of classic plasticity theory and the anisotropic yield criterion with a high exponent, and the expressions of the maximum blank holding force free of fracture are deduced. The flange wrinkling is investigated by means of energy method to obtain the expression of the minimum blank hol.ding force free of flange wrinkling. According to the maximum and minimum blank holding force, the valid range of blank holding force can be sought out. The numerical results coincide the experiments well. It is concluded that fracture and wrinkle appear if the blank holding force is beyond its maximum or below the minimum, and the deep drawing operation can be successfully performed if the blank holding force gets between the maximum and the minimum.