Investigation on Mechanisms of Rolling Contact Fatigue Occurring on Low Rails of Sharp Curves on Heavy Haul Railway Line
Severe rolling contact fatigue(RCF)and the resulting spalling have been observed on the low rails of sharp curves on a heavy haul railway line in China,especially on the inner rail shoulder.In order to reveal its initiation mecha-nism,a dynamic model was developed for the typical heavy haul train running on the line,for which observations and measurements of wheels and rails were considered together with design parameters of the locomotives and wagons.The surface RCF index and the damage function were employed to isolate the main influencing factors of the RCF numerical-ly.The results show that the predicted RCF zones,crack direction and their severity are all in great agreement with field observations,and the worn rail profile is found to be the root cause of two RCF zones occurring on the inner and outer shoulders of the low rails.The RCF on the inner shoulder of the low rail is dominated by the passing locomotives,with most significant RCF contribution by the middle wheelset of the"Co-Co"type bogie.The leading wheelsets of locomo-tives and the wagons determine the RCF on the outer shoulder of the low rails.With the increase of the curve radius,the dynamic wheel-rail interaction weakens,causing decreasing severity of RCF on the low rails,with the inner and outer RCF zones moving towards the center of the rail top,until eventually merging into one RCF zone on curves with a radius of about 1 000 m,with spalling tending to disappear.
heavy haul railwayrail rolling contact fatiguelow railsvehicle dynamicsdamage functionsurface rolling contact fatigue index
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