重载铁路钢轨疲劳裂纹萌生影响因素

基于临界平面理论的钢轨疲劳裂纹萌生预测模型,建立轮轨三维瞬态滚动接触有限元模型;模拟重载铁路的轮轨接触状态;分析不同轨底坡(分别为1∶40,1∶30,1∶20,1∶10)和不同摩擦系数(分别为0.25,0.30,0.35,0.40,0.50)对轮轨接触状态和钢轨疲劳裂纹萌生的影响。结果表明:轨底坡为1∶40时,采用以上钢轨预测模型得到的钢轨疲劳裂纹萌生位置与现场观测结果基本吻合;轨底坡对轮轨接触斑的位置及应力状态影响较大,LM型踏面车轮与75 kg·m^-1钢轨在轨底坡为1∶20时更为匹配;随着轨底坡增大,钢轨疲劳裂纹萌生时的通过总重先增大后减小,轨底坡为1∶20时达到最大;随着摩擦系数增大,钢轨疲劳裂纹越容易萌生。

Factors Influencing Fatigue Crack Initiation of Rail for Heavy Haul Railway

Based on the rail fatigue crack initiation prediction model of critical plane theory,the wheel-rail threedimensional transient rolling contact finite element model was established to simulate the wheel-rail contact state of heavy haul railway.The effects of different rail cants(1:40,1:30,1:20 and 1:10,respectively)and different friction coefficients(0.25,0.30,0.35,0.40 and 0.50,respectively)on wheel-rail contact state and rail fatigue crack initiation were analyzed.Results show that when the rail cant is 1:40,the position of fatigue crack initiation obtained by the above rail prediction model is basically consistent with field observation results.The rail cant has a great influence on the location of the wheel-rail contact patch and the stress state.The LM-type tread wheel and 75 kg·m^-1 rail are more matched when the rail cant is 1:20.With the increase of the rail cant,the traffic gross weight of the rail fatigue crack initiation increases first and then decreases,and it reaches the maximum when the rail cant is 1:20.As the friction coefficient increases,the fatigue crack of the rail is more likely to initiate.