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

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.

Key words:rail; wheel-rail contact; rolling contact fatigue; wear; track geometry irregularity