基于名义应力法的弹性链型接触网疲劳寿命预测

Fatigue life prediction of elastic stitched catenary based on nominal stress method

针对高速铁路弹性链型接触网进行接触线疲劳寿命预测分析.利用ANSYS,采用直接积分法对弓网耦合系统进行动态仿真,得到接触线的应力时程;运用雨流计数法得到离散的应力循环,采用应力修正算法得到平均应力为零的疲劳应力谱;通过简化方法估算获得材料S-N曲线,从而计算得到疲劳破坏次数;最终运用线性累积损伤理论预测接触线的疲劳寿命.对比分析接触线不同位置的疲劳寿命值,结果表明:接触线每跨疲劳寿命趋势一致;每跨在吊弦处和定位点处疲劳寿命较低,其中寿命最低值出现在左侧第一根吊弦处,疲劳寿命最低值为20 a左右.结果可为高速铁路弹性链型接触网接触线的实际施工维护和更换周期的确定提供参考.

As to the elastic stitched eatenary on high-speed railway, the fatigue life of the contact wire is predicted. The pantograph catenary coupling system is dynamically simulated by direct integration method using ANSYS and the time history of the contact wire stress is obtained. The discrete stress cycles are obtained by rain-flow counting method, and the fatigue stress spectrum of which the mean stress is zero is obtained by stress modification algorithm. The S-N curve of the material is estimated by a simplification method and the number of the fatigue damage is calculated. Finally, the fatigue life of the contact wire is predicted with the linear cumulative damage theory. The fatigue life values of contact wire in different positions are compared and the result shows that, the fatigue life change trend of the contact wire in every span is the same; the positions of the lower fatigue life in every span occur around the hanger and the support point, and the lowest fatigue life that is about 20 a occurs around the first hanger on the left side. The results can provide reference for the actual construction and maintenance and the replacement periodof the contact wire of elastic stitched catenary on high-speed railway.