柱面扁壳形状不良的实验研究

为控制覆盖件成形中的形状不良缺陷，以矩形柱面扁壳为模型，研究其拉深件及切边后曲面方向的形状不良，分析了形状不良的形成机制及成形条件及切边对形状不良的影响．结果表明：回弹诱发了柱面扁壳的形状不良，形状不良基本成对称分布，在曲面方向随距板面中心点距离的增加而增加，切边后由于残余应力释放，使形状不良程度增大；形状不良随板料厚度的增加、压边力的增加、屈服强度的降低、凸模曲率半径的减小而减小．

Study on shape defect of cylinder shallow shells

In order to improve the shape defects of auto-body panels, the shape defect is studied through the experiment of drawing parts before and after trimming for the rectangle cylinder shallow shell. The mechanism of shape defect and the effect of forming condition and trimming on shape defect are analyzed. The results show that the spring-back induces the shape defect of cylinder shallow shell. The shape defect of curve direction displays approximately the central symmetry, and it increases with increasing of the distance to the panel centre. Residual stress after trimming was released make the shape defect increased. The shape defect is decreased with increasing sheet thickness, increasing binder force, decreasing yield strength, and decreasing curvature radius.