摘要
轮轨滚动接触下,钢轨表面会产生典型的鱼钩形剥离掉块,其形成机理目前暂未明确。为了探究轮轨滚动接触下钢轨表面裂纹扩展机理,基于最大周向拉应力准则,建立轮轨滚动接触疲劳计算模型,提出裂尖扩展路径预测方法,并对不同初始角度裂纹的扩展路径进行预测。结果表明,钢轨表面微裂纹为I-II复合型裂纹,随着裂纹长度增加,K;先增加后减小,而K;呈现持续增加的变化趋势。当裂纹尖端扩展至一定深度时,裂尖扩展的驱动力由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剥离掉块。钢轨表面萌生的微裂初始角度对剥离掉块的路径影响较为明显,但对剥离掉块深度影响较小。本文研究成果可为钢轨表面打磨维修规程的制定提供理论依据。
Under the wheel/rail rolling contact force, the rail surface will produce typical fishhook shaped spalling defect, and its formation mechanism is not clear at present.In order to explore the propagation mechanism of rail surface cracks under the wheel/rail rolling contact force, the fatigue calculation model of wheel/rail rolling contact was established and the prediction method of crack propagation path was proposed based on the maximum circumferential stress criterion.The results show that, the surface microcracks of the rail belong to the I-II mixed cracks.With the increase of crack length, the stress intensity factor K;increases firstly and then decreases.However, the K;shows a trend of continuous increase.When the crack grows to a certain depth, the driving force of crack propagation changes from K;to 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 angle of initial crack on rail surface has an obvious influence on the path of the spalling defect, but has little influence on the depth of the spalling defect.The research results of this paper provide a theoretical basis for the formulation of maintenance regulations for rail surface grinding.
作者
孟睿君
MENG Rui-jun(School of Architectural Engineering,Zhengzhou University of Industrial Technology,Zhengzhou 450001,China)
出处
《计算力学学报》
CAS
CSCD
北大核心
2022年第2期257-262,共6页
Chinese Journal of Computational Mechanics
基金
河南省科技攻关(2021002210226)资助项目。
关键词
钢轨
剥离掉块
应力强度因子
最大周向拉应力准则
扩展路径
rail
spalling defect
stress intensity factor
maximum circumferential stress criterion
propagation path
