普速铁路钢轨滚动接触疲劳裂纹萌生研究和检验

以普速铁路京九线不同曲线半径为研究对象,建立车辆-轨道动力学模型、磨耗和裂纹萌生预测模型;计算60N廓形在不同曲线半径条件下的轮轨接触状态,预测了不同曲线条件下磨耗发展率、裂纹萌生位置与寿命,并与京九线现场观测结果进行对比验证。研究结果表明:随着疲劳损伤的累积,不同曲线半径下钢轨的阶段磨耗发展率呈下降的趋势,其中曲线半径小(600 m)的磨耗发展率降低最快,随着曲线半径的增大,平均磨耗发展率降低趋势减缓;不同曲线半径下钢轨裂纹萌生位置均在钢轨表面以下1～3 mm处,横向位置在距离轨顶中心15～20 mm范围内,曲线半径600 m外轨裂纹萌生寿命大约为2.64×10⁵次,内轨裂纹萌生寿命约为4.86×10⁵次,与现场观测较为符合。

Research and Validation on Rolling Contact Fatigue Crack Initiation in Existing Common Speed Railway

Beijing-Jiulong Railway,an common speed railway,is the engineering background.A vehicle-track dynamic model,a wear and RCF(rolling contact fatigue)crack prediction model were established with consideration of different curve radius.The wheel rail contact state of 60N profile with different curve radiusi were calculated.The wear growth rate,the crack initiation location and life were predicted.Based on the comparison of calculation and measured data,it shows that the track wear development rate at each stage is decreased as the accumulation of fatigue damage.In particular,the decrease rate of the wear development rate of 600 m-radius curve is the greatest.As the curve radius increases,the decrease tendency of average wear development rate is alleviated.The track crack initiation location is generally-3 mm below rail surface and the lateral location is 15~20 mm away from the centerline of the track top.The crack initiation lives in the high and low rails in the 600 m-radius curve are about 2.64×10^5 and 4.86×10^5 wheel cycles.The prediction is consistent with the field observation results.