利用断裂力学理论建立了钢轨踏面斜裂纹扩展寿命预测模型; 以CRH2型动车组为研究对象, 计算了轮轨接触时钢轨内部的应力分布, 然后利用预测模型估算了钢轨踏面斜裂纹的扩展寿命, 并分析了摩擦因数、裂纹倾斜角、钢轨磨损率等因素对钢轨踏面斜裂纹扩展寿命的影响。结果表明: 倾斜角在30°~40°时, 斜裂纹扩展寿命随摩擦因数的增大而降低; 裂纹倾斜角增加到50°~60°时, 斜裂纹扩展寿命先增加后减小; 随裂纹倾斜角的增大, 斜裂纹扩展寿命先增后减; 斜裂纹扩展寿命随磨损率增大先缓慢增加, 当磨损率达到一定值后急剧增加; 实际使用数据间接证明了模型预测的准确性。

The prediction model of propagation life of oblique crack on rail′s surface was established by the fracture mechanics theory. Taking CRH2 train-set as research object, stress distribution in the internal of rail when wheel and rail contacted was calculated, and then the propogation life of oblique crack on rail surface was estimated by using above modle. Furthermore, the effects of friction factor, inclination angle and wear rate on the propagation life of rail surface oblique crack were analyzed. The results show that the oblique crack propagation life decreased with the increase of friction factor when the inclination was 30°-40°, and the oblique crack propagation life first increased then decreased when the inclination angle was 50°-60°. With the increase of inclination angles, the oblique crack propagation life increased, then decreased. The oblique crack propagation life increased slowly with the increase of wear rate, and then increased rapidly when the wear rate up to a constant value. Fact data could prove indirectly the accurate of prediction.