车轮多边形对车辆动力学性能影响分析

为了研究车轮多边形对车辆动力学性能的影响,基于多体动力学理论和轮轨滚动接触简化理论,结合CRH2型动车组的动力学参数,建立考虑轮对柔性的刚柔耦合车辆动力学模型。分析车轮多边形阶数和幅值的变化对轮对振动特性、非线性临界速度和轮轨力等车辆动力学性能的影响。结果表明:当多边形激励频率与轮对某阶模态振型的固有频率相近或者相等时,将引发轮对共振,使车辆的动力学性能发生改变;非线性临界速度会随车轮多边形阶数和幅值的增大而降低;脱轨系数随车轮多边形阶数的增加略有增大,随幅值的增大呈线性增大趋势;轮重减载率和轮轨垂向力随阶数的增加波动增大,随幅值的增加显著增大;车轮多边形对运行平稳性的影响甚微,主要是因为一系减振器和二系减振器的减振作用。为保证列车运行安全,根据轮重减载率限值0.6制定出车轮多边形在160~240 km/h速度工况下2~20阶的幅值限值。

Analysis of Influence of Wheel Polygon on Vehicle Dynamic Performance

In order to study the influence of wheel polygon on vehicle dynamic performance, a rigid-flexible coupled vehicle dynamics model considering wheelset flexibility is established based on multi-body dynamics theory and wheel-rail rolling contact simplification theory and combined with the dynamic parameters of CRH2 EMU. The effects of wheel polygon order and amplitude on vehicle dynamics are analyzed, such as wheelset vibration characteristics, nonlinear critical speed and wheel-rail force. The results show that when the polygon excitation frequency is close or equal to the natural frequency of the wheel mode, it will induce the wheelset resonance and change the dynamic performance of the vehicle. The nonlinear critical speed decreases as the wheelset’s polygon order and amplitude increase. The derailment coefficient increases slightly with the increase of the wheel polygon order, and increases linearly with the increase of the amplitude. Wheel polygons have little effect on running stability, mainly due to the damping effect of the primary and secondary shock absorbers. In order to ensure the safe operation of the train, the amplitude limit of the 2 nd to 20 th order of the wheel polygon under the speed condition of 160~240 km/h is determined according to the limit of the wheel load shedding rate of 0.6.