轮轨滚动摩擦温升分析

Coupling Analysis of Wheel/Rail Frictional Temperature

利用有限元法,考虑轮轨间非稳态热传导、与环境的热对流以及热辐射的影响,建立了轮轨滚动接触热耦合计算模型来模拟轮轨滚滑摩擦温升;在模拟轮轨纯滑动条件下,计算分析了由磨损引起的滑动接触斑的尺寸增大对轮轨温度场的影响;在模拟轮轨接触斑部分滑动工况时,针对不同蠕滑率、摩擦系数以及轴重对轮轨温度场的影响进行了相应的计算分析.结果表明:接触斑材料的磨损速度只影响磨损过程中的温度场分布,其稳态温度场分布基本一致;热载荷随着纵向载荷、蠕滑率以及摩擦系数的增大而增大,进而影响轮轨滚动接触热疲劳.

Temperature rise due to wheel/rail friction greatly affects rolling contact failure of wheel/rail,such as wear, flatting, checking and so on. Complexity and particularity of wheel/rail in rolling contact make it very difficult to measure directly. Heat coupling model of rolling/sliding of wheel/rail was proposed to calculate the temperature rise by finite element method. Non-steady heat conduction between the contacting surfaces of the wheel/rail, heat-convection and radiation between the wheel/rail at ambient condition was taken into consideration. Effect of the expansion rate of contact patch, due to wear of material, on the frictional temperature was analyzed in pure slide of wheel on rail. Under the wheel rollingsliding at high speed, the effects of creepages, frictional coefficients and wheel loads on the temperature were also investigated. It is found that all factors as showed above were closely related to temperature distribution and thermal fatigue of wheel/rail in rolling contact at high speed.