全滑动状态下轮轨接触热弹性应力

Thermoelastic Stresses Due to Wheel-Rail Contact in Pure Sliding State

用有限元法建立了轮轨接触热-机械载荷耦合计算模型.在传热模型中考虑了轮轨间非稳态热传导以及轮轨与环境的热对流和热辐射.着重分析因全滑动磨损轮轨接触斑扩大过程中的温度场和应力场,磨损速度对热弹性应力场的影响,以及轮轨在热-机械载荷共同作用下材料最易发生破坏的位置.计算结果表明,磨损速度对磨损过程中温度场和应力场的影响很大,轮轨接触表面附近的最大剪应力和剪应变平面与滑动方向所成夹角约为50°和140°.

A finite element method was applied to establish a thermal-mechanical coupling model for wheel-rail contact in pure sliding state. The non-steady heat conduction between the contacting surfaces of wheel-rail, heat-convection and radiation between the wheel-rail and the ambient were considered. Analysis emphases were put on thermal and stress fields in the expansion process of contact patch due to wear of pure sliding, the effect of expansion rate of contact patch on thermoelastic stresses, and on failure locations of wheel-rail under the thermal-mechanical loads. Calculation results show the expansion of the contact patch significantly affects temperature and stress distributions, and the planes of maximum shear stress and shear strain are at angles about 50° and 140°with respect to the sliding direction.