多边形条件下高铁车轴裂纹扩展寿命计算及检查间隔制定方法研究

Study on the Crack Propagation Life of High Speed Train Axle with Wheel Polygons and the Method to Determine Inspection Intervals

文章调研了目前关于车轴材料属性和载荷条件离散性对剩余寿命的影响的处理方法并进行了简要总结;建立了车辆系统刚柔耦合动力学模型,提取了车轮20阶多边形条件下各工况车轴危险截面应力-时间历程,进行了应力谱的编制;基于小试样裂纹扩展试验数据拟合得到了NASGRO方程裂纹扩展参数,计算得到车轴卸荷槽部位裂纹深度为2~40 mm的剩余寿命;考虑材料属性和载荷条件离散性来制定车轴剩余寿命计算的安全系数;结合剩余寿命计算结果、超声波检测裂纹检出概率曲线和车轴失效概率制定了车轴合理的检查间隔。结果表明,车轮多边形条件下,车轴剩余寿命为38.5万km,考虑材料属性和载荷条件离散性的安全系数分别为1.26和1.33,得到车轴检查间隔为3.8万km。

This article investigates and briefly summarizes the current method of handling the impact of the material properties and the discreteness of load conditions on the residual life of the axle;builds the rigid-flexible coupling dynamic model of the car system,extracts the stress-time processes of the dangerous sections of the axle in different working states in the 20th-order polygonal condition of the wheel and establishes the stress spectrum.It fits the data of crack growth test of small samples to get the crack growth parameters with the NASGRO equation and works out the residual life of the axle when the crack in the unload groove is 2~40 mm deep.Considering the material properties and the discreteness of load conditions,it defines the safety factor for calculating the residual life of the axle.In combination with the calculation result of the residual life,the crack detection probability curve by ultrasonic test and the axle failure probability,it establishes a reasonable inspection interval for the axle.The result shows that in the polygonal condition of the wheel,the residual life of the axle is 385,000 km,and considering the material properties and the discreteness of load conditions,the safety factor is 1.26 and 1.33 respectively,so the inspection interval of the axle is 38,000 km.