考虑轨道几何不平顺的钢轨裂纹萌生与磨耗共存预测

Prediction of Rail Rolling Contact Fatigue Crack Initiation and Wear Growth Considering Track Geometry Irregularity

摘要:

在钢轨裂纹萌生和磨耗发展共存预测方法的基础上，考虑了轨道几何不平顺对轮轨接触位置分布、磨耗和疲劳损伤的影响，引入轮轨接触点在钢轨上的分布概率，分散了钢轨的磨耗和疲劳累积.分析结果表明：考虑轨道几何不平顺的情况下，轮轨接触点的分布范围和概率随着磨耗和型面变化而变化，钢轨表面磨耗和内部疲劳损伤分布范围均加宽，而损伤速率降低.预测得到800 m曲线半径外轨在裂纹萌生前的平均磨耗发展率为3.813 1 μm?万次-1，相较未考虑不平顺的结果降低了15.92%.裂纹萌生寿命预测结果为318 292次，相较未考虑不平顺的预测结果增大了14.66%.裂纹萌生点的位置比未考虑不平顺时略远离钢轨中心.

Abstract:

Based on the prediction method for the coexistence of the rail rolling contact fatigue (RCF) crack initiation and wear growth, the influence of track geometric irregularity on wheel-rail contact position distribution, rail wear, and fatigue damage were taken into consideration. The distribution probabilities of wheel-rail contact positions on the rail were introduced to disperse the wear and fatigue damage accumulation in the rail. The conclusion shows that the distribution range and probabilities of the wheel-rail contact positions will change with the wear growth and profile evolution influenced by the track geometry irregularity. Then the scope of the wear on the rail surface and the fatigue damage inside the railhead will widen and the damage rate will be reduced. For the 75 kg/m rail as the high rail in the curve of 800 m radius in heavy-haul railway, the growth rate of the average wear is 3.813 1 μm? 10-4 cycles before RCF crack initiates and the crack initiation life is 318 292 cycles. The growth rate of the average wear and the crack initiation life predicted by the above method are about 15.92% lower and about 14.66% higher than those predicted by the method without considering the track geometry irregularity respectively. Moreover, the crack initiation position is a little farther away from the rail center.