助推作用对大口径铝合金薄壁管数控弯曲壁厚减薄和回弹的影响

Effects of pressing die's boosting function on wall thinning and springback in NC bending process of thin-walled tube with large diameter

以有限元软件Dynaform为平台,建立了大口径薄壁管数控弯曲及回弹的有限元模型,分析了压块助推速度和压块与管子之间的摩擦系数对壁厚减薄和回弹角的影响规律。结果表明,压块与管子之间没有摩擦或者压块的助推速度为0.9、助推速度为1.0且压块和管子间摩擦系数为0.1的条件下,管子壁厚减薄超过航空标准中允许的最大减薄量0.4375mm。在压块的助推速度不变的条件下,压块与管子之间摩擦系数从0.1增加到0.3,能够有效地降低管外侧的壁厚减薄,但是回弹角也会明显增大。当压块与管子之间的摩擦系数为定值时,助推速度从1.0增加到1.2,对管外侧壁厚减薄的改善作用不大,回弹角没有明显变化。

Based on FEM code Dynaform, an FEM model of the NC bending and springback process of thin-walled tube with large diameter has been established. The effects of velocity of pressing die and the friction between pressing die and tube on thinning and spring back angle in NC bending process of thin-wall tube with large diameter were studied. The results show that the wall thinning of the tube will exceed the allowable value 0. 4375mm according to the aerial criterion if the tube is formed under the following conditions, there is no friction between the tube and the pressing die, the boosting velocity is 0.9, the boosting velocity is 1.0 and the friction coefficient between pressing die and tube is 0. 1. Given fixed value of boosting velocity, as the friction coefficient between pressing die and tube increases to 0. 3 from 0. 1, the wall thinning can be lessened effectively, but the spring back angle can be increased dramatically. Given fixed value of the friction coefficient between pressing die and tube, the increase in the boosting velocity from 1.0 to 1.2 won＇t make any obviously improvement in the wall thinning or make any difference in the spring back angle.