变径管内高压成形送料区壁厚分布规律

Thickness distribution in the guiding zone of hydroforming of tube with variable cross sections

通过力学分析和全量本构方程,推导出了变径管内高压成形送料区壁厚增厚的解析公式。该公式反映了送料区初始长度、摩擦系数、内压等参数与送料区两端壁厚差之间的定量关系,并与数值模拟获得的规律一致。结果表明,送料区两端壁厚差受送料区初始长度、摩擦系数及内压的影响,随着送料区初始长度、摩擦系数和内压的增加,送料区两端壁厚差会越来越大,即靠近送料区外端点的壁厚增加会更加明显。因此保证内高压成形得到的变径管送料区壁厚增加不明显的措施是:尽量减小送料区初始长度、减少摩擦,选择较低的成形内压。

The analytic formula of the feeding zone thickness distribution in hydroforming of variational cross-section tube is derived by using the total strain theory.The formula shows the effect of initial length of feeding zone,friction coefficient,and internal pressure,on the thickness difference between two ends of feeding zone quantitatively,and the analytic results have good agreement with the FEM.The results show that with the increasing of initial length,friction coefficient and internal pressure,the thickness difference between two ends of feeding zone increased,namely the thickening of outer end increased.The thickening of feeding zone prevention can be realized by shorting the initial length of feeding zone,decreasing the friction coefficient and choosing low internal pressure.