胀管机夹爪静力分析及结构优化

Structure Optimization and Static Analysis on Clamping Claw of Pipe Expander

通过对国内外与夹爪相关的结构优化方式进行调研,结合国外的胀管机夹爪结构,建立有限元模型并进行分析。考虑夹爪断裂部位应力水平对疲劳寿命的影响以及夹爪夹持铜管能力的大小,选择了夹爪的接触面圆角半径、高度等结构参数,研究了单因素对夹爪的等效应力以及与铜管之间接触应力的影响规律,确定了正交优化试验因素以及相应的水平选择。在正交试验中,设计了夹爪L9(34)三因素三水平正交试验,并对模拟试验结果进行方差分析,得出最优组合为A3B2C1,即在接触面开3个防滑槽、接触面高度为3.8 mm同时夹爪背面无圆角的优化结构,优化后夹爪结构最大等效应力减少了3.5%,平均摩擦力增大了24.5%,提高了夹爪寿命以及夹爪稳定夹持铜管的能力。

Based on the investigation of the structure optimization methods related to clamping claw at home and abroad,combined with the clamping claw structure of foreign pipe expander, the finite element model is established and analyzed.Considering the influence of stress level on fatigue life and the ability of gripping copper tube, the structure parameters such as fillet radius and height of gripping copper tube are selected. The influence of single factor on equivalent stress of gripping jaw and contact stress between gripping jaw and copper tube is studied. The orthogonal optimization test factors and corresponding level selection are determined. In the orthogonal test, the three factors and three levels orthogonal test of claw L9(34) is designed, and the range and variance analysis of the simulation test results are carried out. The optimal combination is A3B2C1, that is, the optimized structure with three anti-skid grooves on the contact surface, the height of the contact surface is 3.8 mm, and the back of the claw is not rounded. After optimization, the maximum equivalent stress of the claw structure is reduced by 3.5%, the average friction force increases by 24.5%, which improves the life of the gripper and the ability of the gripper to hold the copper tube stably.