金属板材回弹与曲率关系的研究

Research on the relationship between the springback of sheet metal and curvature

目前主要采用位移量来评估板材冲压后的回弹,这种评估方法不能直接地反映回弹是由于弹性应变能释放而引起的曲率改变的物理本质,从而给回弹补偿和模面修改带来一定的困难。根据塑性弯曲理论,将膜力和弯矩引起的回弹分别用高斯曲率和平均曲率表征,并对双曲率片回弹后的高斯曲率和平均曲率的分布情况进行了分析。实验结果表明,用曲率评估方法可以较好地体现回弹的成因,有助于准确地预测回弹趋势,对实际生产加工中的修模、试模过程具有一定的指导意义。

The springback of sheet metal after press forming is now usually evaluated by the displacement.However,the method cannot directly reflect the physical nature of springback that the curvature change is caused by the release of elastic strain energy.It is difficult to compensate the springback and modify the die surface.According to the plastic bending theory,the springback caused by membrane force and moment can be respectively indicated by the Gaussian curvature and the mean curvature,which distribution after springback of double curvature is analyzed.The results show that the curvature-based springback evaluation method can truly reflect the causes of springback and hence bring more precise springback prediction.It is helpful for engineer to modify the die and test the die in the process of die machining.