钢轨滚动接触疲劳裂纹萌生和磨耗共存预测方法验证

Verification of Prediction Method for Coexistence of Rolling Contact Fatigue Crack Initiation and Wear Growth in Rail

摘要:

采用小比例轮轮滚动接触疲劳试验再现钢轨裂纹萌生和磨耗过程，根据钢轨裂纹萌生和磨耗共存预测方法结合试验条件建立相应的预测模型，分别对试验和仿真预测的钢轨试样磨耗、裂纹萌生寿命和启裂角度等进行比对，从而验证钢轨裂纹萌生和磨耗共存预测方法。研究发现：当试样萌生裂纹时，有53.8%的试样经历了2个磨耗阶段，平均磨耗发展率约为5.83 μm·10^-4次^-1；预测的试样在萌生裂纹前经历了2次磨耗阶段，平均磨耗发展率约为5.18 μm·10^-4次^-1，较试验结果低约11.1 %；试验中试样裂纹萌生寿命在6×10⁴ ~ 14×10⁴次范围内，且裂纹长度在荷载循环次数在11×10⁴ ~ 12×10⁴次时达到极大值，预测的裂纹萌生寿命为11.1×10⁴次，基本与试验结果中裂纹萌生时出现极大值的试样所对应的荷载作用次数接近。试验观测到试样表面裂纹开口与滚动方向的角度平均值约为45°；仿真预测的裂纹开口与滚动方向的角度平均值基本与观测到的裂纹开口与滚动方向的角度一致。

Abstract:

A small-scale wheel-wheel rolling contact fatigue （RCF） experiment was applied to reproduce the rail RCF crack initiation and wear growth process. Then， according to the experimental conditions， the prediction model was established based on the method for the coexistence of rail rolling contact fatigue(RCF） crack initiation and wear growth. The wear， crack initiation life and the angle of the RCF crack in the rail specimens of the experiment and simulation were compared to verify the method. The result shows that when the crack initiated in the specimen surface during the experiment， 53.8 % of the specimen experiences two wear phases. The average wear growth rate is about 5.83 μm·10^-4 cycles^-1. In the simulation， there are also two wear phases when the crack was initiated. The average wear growth rate is about 5.18 μm·10^-4 cycles^-1 which is about 11.1 % lower than the experimental results. In the experiment， the crack initiation life is about 6×10⁴ to 14×10⁴ cycles. Moreover， the crack length reaches its maximum value when the loading cycles is about 11×10⁴ to 12×10⁴ cycles. In the simulation， the predicted crack initiation life is about 11.1×10⁴ cycles， which is close to that of the specimen with the maximum crack length in the experiment. It is observed that the average value of the angle between the crack mouth and the running direction along the specimen surface is about 45°which is close to that of simulation.