轨底坡对曲线线路钢轨疲劳裂纹萌生寿命的影响  

Effect of Rail Cant on Fatigue Crack Initiation Life of Curve Rail

作　　者：周宇[1] 王少锋[2] 张杰[1] 姜俊楠[1] 

机构地区：[1]同济大学道路与交通工程教育部重点实验室,上海201804 [2]华东交通大学轨道交通学院,江西南昌330013

出　　处：《中国铁道科学》2015年第1期25-32,共8页China Railway Science

基　　金：国家自然科学基金资助项目(50908179;51378395);国家科技支撑计划项目(2013BAG20B01);中央高校基本科研业务费基金资助项目(20113153)

摘　　要：考虑轮轨蠕滑接触关系,以及普通货车两轴转向架的导向轮对和非导向轮对分别作用在曲线两股钢轨轨头上的应力、应变,建立基于临界平面法的钢轨疲劳裂纹萌生寿命预测模型,研究不同轨底坡对曲线线路钢轨疲劳裂纹萌生寿命的影响。结果表明：在各种轨底坡下外轨疲劳裂纹均主要由导向轮引起,而内轨疲劳裂纹在轨底坡为1∶40-1∶25时主要由导向轮引起,在轨底坡为1∶20-1∶10时主要由非导向轮引起;线路曲线半径越小,导向轮作用下的内外轨疲劳裂纹萌生越早,反之则非导向轮作用下的内轨疲劳裂纹萌生越早;磨耗型新轮与75kg·m^-1新轨接触时,在曲线半径≤1000m条件下采用1∶20的轨底坡,在曲线半径〉1000m条件下采用1∶40的轨底坡,可以延长钢轨疲劳裂纹萌生寿命;选取不同的轨底坡,可以改变轮轨接触斑的位置、面积和黏着—滑动区的分布及蠕滑力,进而影响到钢轨疲劳裂纹萌生寿命,但改变轮轨接触斑位置的范围有限,不同轨底坡时接触斑移动距离在外轨上小于10.2mm,在内轨上小于3.0mm。The rail rolling contact fatigue（RCF）crack initiation life prediction model based on the theory of critical plane method was established considering the wheel-rail creep contact as well as the stress and strain on the rail heads of curve rails by the leading and trailing wheelsets in the two-axle bogie of a commonly used freight train respectively.The effects of different rail cants on the RCF crack initiation life of curved track were researched.The results show that all the RCF cracks in the high rails under various rail cants were mainly caused by the leading wheels.Under the rail cants of 1∶40-1∶25and 1∶20-1∶10,the RCF cracks in the low rail were mainly caused by the leading and the trailing wheels respectively.The smaller is the curve radius of the track,the earlier of RCF cracks initiated in both the high and low rails under the leading wheels.Contrariwise,the earlier of RCF cracks initiated in the low rail under the trailing wheel.Considering the worn-type new wheel over the 75kg·m^-1 new rail,the rail cants of 1∶20and 1∶40on the curves with the radius of R≤1000 mand R〉1000 mrespectively can prolong the RCF crack initiation life.Different rail cants can influence the RCF crack initiation life by changing the position and area of the wheel/rail contact patch,the distribution of adhesion-slide area and creep force.But the range for changing the position of wheel/rail contact patch is limited.The moving distances of the wheel/rail contact patch are less than 10.2 mm on the high rail and less than 3.0 mm on the low rail under different rail cants.

关 键 词：钢轨 轨底坡 铁路曲线 疲劳裂纹 寿命预测 临界平面法 轮轨关系 

分 类 号：U213.42[交通运输工程—道路与铁道工程]