简谐激励下轮轨非稳态滚动接触的蠕滑力特性

轮轨非稳态滚动接触是指接触斑内的质点在滚动接触过程中,接触斑的外形和其他参数产生快速变化的过程,这时运动波长L与接触斑纵轴半径a处于同一数量级。本文使用Kalker三维滚动接触理论计算轮轨蠕滑率、法向力、钢轨轨面接触几何简谐激励时的非稳态蠕滑力,并与由稳态滚动接触理论计算的结果进行比较。其结果表明:在小蠕滑状态下,非稳态滚动接触的蠕滑力随L/a(简称波长比)的增长而产生明显的幅值衰减和相位滞后。在蠕滑率和钢轨轨面接触几何简谐激励时,非稳态蠕滑力的变化规律可用波长比L/a的传递函数描述,而法向力情况却不能。对于短波波磨等非稳态滚动接触行为,应使用非稳态滚动接触理论进行分析。

Properties of Wheel-rail Creep Forces in Non-steady States under Sinusoidal Excitation

The non-steady state wheel-rail rolling contact is a process in which one or more of contact parameters are changing significantly during the passage of a particle through the contact patch.In the non-steady state,the motion wavelength L and the contact semi-axis a in the rolling direction are in the same magnitude.This paper focuses on the property of the wheel-rail creep force in the non-steady state in which the contact parameters vary as sinusoidal waveforms.The creep forces under sinusoidally varying creepages,normal forces and vertical irregularities are computed respectively by the Kalker 3D rolling contact theory and are compared with results of the steady rolling contact theory.Calculation results show as follows: Under small creep conditions,the fluctuating part of the unsteady creep force decreases in amplitude and lags in phase along with growing of the wavelength ratio L/a;the creep force under sinusoidally varying creepages and vertical irregularities can be described as the transfer functions of the dimensionless frequency a/L,but it is hard to find the similar transfer functions for the case of the normal force;the wheel-rail rolling contact problems such as the rail short-pitch corrugation should be solved with the non-steady state theory.