基于多层级有限元方法的钢丝网套轴向刚度研究

Research on Axial Stiffness of Wire Braid Based on Multi-level Finite Element Method

航天增压输送管路中广泛应用的钢丝网套具有复杂的非线性力学特性,本文研究了其轴向力学行为机理和仿真建模方法。利用多股并排管状编织结构建模方法建立了网套三维几何模型,基于周期性理论建立了网套细观尺度的柱面编织单胞模型。使用单胞模型对网套内部无/有芯轴两种边界下的轴向拉伸工况进行了仿真模拟计算,结果表明两种边界条件下的网套轴向刚度差异极大。在文中,还提出了网套简化分析螺旋梁模型,对比了螺旋梁模型和单胞模型的结果差异,基于刚度等效原则提出了螺旋梁模型的修正方法。仿真算例表明,经过修正后的螺旋梁模型计算得到补偿器加内压后的轴向反力和试验结果一致性较好,相比未修正的螺旋梁模型误差大大降低。螺旋梁模型和修正方法为网套补偿器进一步的力学分析提供了基础。

Wire braid which is widely used in aerospace pressurized transport pipelines has complex nonlinear mechanical properties,and its axial mechanical behavior mechanism and simulation modeling method are investigated in this paper.The wire braid's three-dimensional geometric modeling is achieved using the multi-strand side-by-side tubular braiding structure modeling method.At a fine scale,the columnar braiding single-cell model of the wire braid is established based on the periodicity theory.The single-cell model simulates the axial tensile working condition of the wire braid with and without a mandrel under two boundaries.The calculation results indicate a significant difference in the axial stiffness of the wire braid under the two boundaries.A simplified analytical model of a wire braid is proposed to compare the differences between the results of the spiral beam model and the single-cell model.A correction method for the spiral beam model is proposed based on the principle of stiffness equivalence.The simulation example demonstrates that the corrected spiral beam model accurately calculates the axial reaction force of the compensator with internal pressure,with good agreement with the test results.The error is significantly reduced compared to the uncorrected spiral beam model.The helical beam model and correction method provide a reference for further mechanical analysis of sleeve expansion joints.