摘要
为了探究钢轨表面鱼钩形剥离掉块形成机理,基于接触单元法和最大周向拉应力准则,建立轮轨滚动接触疲劳计算模型,提出裂纹扩展路径预测方法,并对轮轨接触状态及多裂纹等条件下的扩展路径进行预测。结果表明,钢轨表面初始微裂纹为I-II复合型裂纹,并逐渐倾向于90°方向扩展。当裂尖扩展至一定深度时,扩展驱动力将由K向K转变,此时裂尖在K的驱动下发生约70°的转折,倾向于向上扩展而导致鱼钩形剥离掉块。轮轨切向荷载特征对剥离路径影响较大,其中牵引条件下的剥离深度最大可至1.76 mm。当钢轨表面存在多个裂纹时,中间裂纹的滑开型驱动效应会被加强,并与相邻裂纹交汇而形成剥离掉块病害。
In order to investigate the formation mechanism of fishhook shaped spalling defect on rail surface, the fatigue calculation model of wheel/rail rolling contact was established and the prediction method of crack propagation path was proposed based on the contact element method and maximum circumferential tensile stress criterion. And the influence of wheel/rail contact state and multiple cracks on crack propagation path were analyzed. The results show that, the initial rail surface microcrack is an I-Ⅱ mixed crack, and gradually tends to propagate in the 90° direction. When the crack grows to a certain depth, the driving force of crack propagation changes from Kto K. At this point, the crack tip will turn about 70° under the drive of K, and tends to propagate upward and leads to fishhook shaped spalling defect. The characteristics of wheel/rail tangential loads have a great influence on the spalling path, and the maximum depth of spalling defect can be up to 1.76 mm under the traction condition. When there are multiple cracks on the rail surface, the sliding driving effect of the middle crack will be strengthened. Finally, the intersection between adjacent cracks will form, and accelerates the formation of spalling defect.
作者
孟睿君
赵瑞
魏晓刚
MENG RuiJun;ZHAO Rui;WEI XiaoGang(School of Architectural Engineering,Zhengzhou University of Industrial Technology,Zhengzhou 450001,China;Zhengzhou University of Aeronantics,Zhengzhou 450001,China)
出处
《机械强度》
CAS
CSCD
北大核心
2022年第4期1002-1008,共7页
Journal of Mechanical Strength
基金
河南省科技攻关项目(202102310240)资助。
关键词
钢轨
剥离掉块
最大周向拉应力准则
扩展路径
Rail
Spalling defect
Maximum circumferential tensile stress criterion
Propagation path
