在车辆稳态通过小半径曲线和直线的条件下,建立由轮对一钢轨一轨枕弹簧组成的系统有限元弹性振动模型.在模型中,假设轮轨蠕滑力饱和且等于法向力与摩擦系数的乘积.钢轨和车轮在饱和蠕滑力作用下产生动力学耦合,当耦合关系比较强时,轮轨系统会出现弹性黏一滑振动.应用有限元软件ABAQUS分析该模型的运动稳定性,发现在一些条件下轮轨系统存在严重的频率不大于150Hz的黏一滑弹性振动.振动模态显示,在轮轨发生黏一滑振动时,车轮相对钢轨发生横向滑动,而轮轨系统的低频黏一滑振动是引起车轮多边形磨耗的原因之一.应用本文方法可预测在小半径曲线和直线线路运行的车轮的多边形磨耗.计算结果发现,当正确选择轨枕支撑弹簧刚度或当控制轮轨摩擦系数不大于0.27时,可抑制甚至消除车轮多边形磨耗.%The finite-element (FM) elastic vibration model of the wheelset-track system consisting of a wheelset, two rails and a series of sleeper support springs is established under the condition that a vehicle negotiates a tight curve or runs on a straight line in a steady state.In the model, the creep forces between the wheels and rails are assumed to be saturated and equal to the normal contact forces multiplied by the friction coefficient.The motion of rails is coupled with the motion of wheels under the action of saturated creep forces.When the coupling is strong, self-excited vibration of the wheel-rail system occurs.The motion stability of the model is analyzed using the ABAQUS package.The results show that there are serious propensities of unstable self-excited vibrations whose frequencies are not more than 150 Hz under certain conditions.The mode shapes demonstrate that wheels slide against rails in the lateral direction when these unstable vibrations occur.The self-excited vibration of the wheel-rail system is a possible mechanism to cause polygonal wear of railway wheels.The present approach may be used to predict polygonal wear of railway wheels on tight curves and straight lines.The analysis result shows that when the appropriate sleeper support stiffness is applied or the wheel-rail friction coefficient is controlled to be not more than 0.27 polygonal wear of railway wheels may be suppressed or eliminated.
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