函数型摩擦系数条件下轮轨滚动和滑动接触的热机耦合分析

Thermal Mechanical Coupling Analysis of Wheel Rail Rolling and Sliding Contacts under Functional Friction Coefficient

以直径为860mm的LMA型踏面轮对和60kg.m-1钢轨为例,在考虑轮轨间热传导以及轮轨与环境间的热传导和热辐射基础上,采用非线性有限元分析软件ABAQUS提供的mixed Lagrangian-Eulerian方法建立轮轨接触的热机耦合有限元模型,并采用隐式和显式相结合的方法分析轮轨滚、滑动接触工况下的热机耦合问题。结果表明:轮轨滚动接触时,轮轨间的摩擦温升较小、不影响轮轨表面的材料性能,工程上可以忽略其温度对轮轨接触特性的影响;轮轨滑动接触时,轮轨间的摩擦温升足以改变轮轨表面的材料性能,进而影响摩擦系数,且不同摩擦系数对轮轨接触热机耦合特性影响也较大,因此采用与相对滑动速度、温度和载荷等因素相关的函数型摩擦系数可以准确分析轮轨滑动接触的热机耦合特性。

With the diameter of 860 mm LMA tread wheelset and 60 kg. m-1 rail as examples, considering the heat conduction between wheel and rail, the heat conduction and thermal radiation between wheel/rail and environment, the thermo-mechanical coupled finite element model of wheel-rail contact was established using mixed Lagrangian-Eulerian method provided by nonlinear finite element analysis software ABAQUS. The thermo-mechanical coupling problems under wheel rail rolling and sliding contact conditions were ana- lyzed by combining the implicit method with explicit method. The results show that, under the condition of wheel-rail rolling contact, the friction temperature rise between wheel and rail is smaller, which does not affect the material properties of wheel/rail surface, and the influence of temperature on wheel-rail con- tact characteristics can be ignored in engineering. Under the condition of wheel-rail sliding contact, the friction temperature rise between wheel and rail is enough to change the material properties of wheel/rail surface then affect friction coefficient. And different friction coefficients have great influence on the thertoo-mechanical coupling characteristics of wheel-rail contact. Therefore, the thermo-mechanical coupling characteristics of wheel-rail sliding contact can be accurately analyzed by adopting the functional friction coefficient related to such factors as relative sliding velocity, temperature and load, etc.