基于非线性有限元的网套补偿器轴向刚度特性及计算方法研究

网套补偿器在航天管路系统中广泛使用，补偿器的轴向刚度是其基本力学参数，然而其复杂的微结构特征使得轴向刚度呈现强烈的非线性。为实现对网套补偿器轴向拉伸全过程的仿真计算，从钢丝网套入手，基于钢丝的螺旋梁模型，分析了轴向长度、螺旋角及网套直径对轴向刚度的影响，结果表明轴向长度和螺旋角将显著影响轴向刚度；分析了边界条件的影响，结果表明在计算轴向刚度时固定边界与约束径向位移的循环边界可以互换。结合网套刚度分析的结论，提出了基于接触关系的子网套刚度分析方法，解释了拉伸时轴向刚度非线性变化原因，进一步建立了2/N波纹管-螺旋梁复合模型以及2/N单波-单锭螺旋梁复合模型用于不同刚度阶段的有限元计算。算例结果表明，仿真获得的力-位移曲线与试验曲线一致性较好，高刚度阶段的轴向刚度误差为3.40%。

Research on Mesh Sleeve Compensator Axial Stiffness Characteristics and Calculation Methods Based on Nonlinear Finite Element Analysis

The mesh sleeve compensator is widely used in aerospace pipeline systems, and the axial stiffness of the compensator is its basic mechanical parameter. However, its complex microstructure characteristics make the axial stiffness exhibit strong nonlinearity. To achieve simulation calculation of the entire axial stretching process of the mesh sleeve compensator, this article starts with the steel wire mesh sleeve and analyzes the influence of axial length, helix angle, and mesh sleeve diameter on axial stiffness based on the spiral beam model of the steel wire. The results show that axial length and helix angle will significantly affect axial stiffness; The influence of boundary conditions was analyzed, and the results showed that the fixed boundary and the cyclic boundary of constrained radial displacement can be interchanged when calculating axial stiffness. Based on the conclusion of the stiffness analysis of the mesh sleeve, a sub mesh sleeve stiffness analysis method based on contact relationship was proposed, explaining the nonlinear changes in axial stiffness during stretching. A 2/N corrugated pipe spiral beam composite model and a 2/N single wave single spindle spiral beam composite model were further established for finite element calculation at different stiffness stages. The results of the example show that the force displacement curve obtained from simulation is in good agreement with the experimental curve, and the axial stiffness error in the high stiffness stage is 3.40%.