钢轨裂纹疲劳与磨损耦合关系的研究
Research of the coupling relationship between rail crack fatigue and wear

采用有限元分析软件ANSYS结合疲劳与磨耗耦合模型,分析钢轨裂纹疲劳与磨损的竞争机制。10 t轴重车轮以纯滚动方式滚过初始长度为100 μm,扩展角度为30°的钢轨表面裂纹,计算出各个阶段的等效应力强度因子Keff。研究结果表明,钢轨的破坏形式以疲劳破坏为主;随着裂纹长度增加,其扩展速率先增加后减小,当裂纹长度为600时,其扩展速率最快;在裂纹初始扩展阶段,裂纹扩展方向基本与行车方向一致;当裂纹长度大于600 μm后,裂纹扩展角度超过90°,裂纹沿着与起始阶段相反的方向扩展,形成鱼钩型裂纹。
Fatigue and wear coupling model based on the finite element method software ANSYS was used to analyze the competition mechanism between fatigue and wear. The equivalent stress intensity factor Keff of the crack tip was obtained for the initial crack with 100μm and 30° under the pure rolling state and ten tons axle load, and then the equivalent stress intensity factor Keff of different length crack was obtained. The results show that, the major damage of rail is wheel/rail contact fatigue. The stress intensity factor KI increases firstly, and then decreases with the increase of crack length. In the initial extension stage of crack, the extending direction of crack is the same of the driving direction. When the crack length is more than 600 microns, the extending direction transforms into the opposite of driving direction, and forming the crack which looks like a fishhook