徐忠伟　吴圣川　康国政　王习术

摘要：

基于断裂力学理论对含表面撞击坑高铁车辆空心车轴进行疲劳断裂安全性分析.考虑车轮与车轴、齿轮与车轴的过盈配合效应，在压装部引入残余压应力，根据车轴实物撞击坑形貌和尺寸建立仿真模型；采用385 km/h高铁车轴实测动应力，经变换获得一维七级载荷谱.分析结果表明：对于深度为300 μm的撞击抗，缺陷最深处的应力强度因子约为0.75 MPa·m1/2，远小于BS79102005标准规定值，据此认为带有单个深度为300 μm撞击坑的空心车轴在正常服役期内不会发生裂纹萌生和扩展.研究结果可为我国高速列车检修规程和无损检测周期的制定提供参考.

关键词：

高速列车； 空心车轴； 损伤容限； 撞击坑； 疲劳裂纹； 有限元

中图分类号： U270.33；O346.1；O242.21

文献标志码： B

Abstract：

Based on the fracture mechanics theory， the fatigue crack safety is analyzed for a highspeed railway vehicle hollow axle with surface impact pits. Considering the interference fit effect of wheelaxle and gearaxle， the residual compressive stress is introduced into the press fits and the simulation model is built by the profile and size of the actual impact pits on axle surface. The 1D sevenstage load spectrum is obtained from the transformed measured dynamic stress of a 385 km/h highspeed train hollow axle. It is identified that， as to a single pit with a depth of 300 μm， the stress intensity factor of the node with the largest stress is about 0.75 MPa·m1/2， which is far smaller than that in BS79102005， and so a single crater with a depth of 300 μm can not lead the crack initiation and propagation of hollow axle which is in normal operation. The safety of axles can be ensured. The research result provides important theoretical reference and scientific support for the articles of the maintenance of the China highspeed train.

Key words：

highspeed train； hollow axle； damage tolerance； impact pit； fatigue crack； finite element

0引言

当前，我国高铁列车运行速度不断提升，运营总里程近2万km，已位居世界前列.高铁列车普遍使用空心车轴，这可确保在车轴截面力学性能基本不变的前提下，尽可能地减少材料消耗，大幅度降低簧下质量.但是，目前基于材料力学的无限寿命设计方法没有考虑车轴在设计和制造中引入的内部缺陷或者裂纹，忽略由此带来的局部应力集中，从而给出过于保守的设计结论.另一方面，高铁列车车轴在服役过程中可能出现意外的表面擦划伤、撞击坑、腐蚀坑等缺陷.这些经常出现的微小缺陷极有可能导致整轴的损伤累积和疲劳破坏.调研发现，车轴失效破坏中有近2/3是由交变载荷引发……