Abstract:  In order to explore the causes of corrugation on the steel spring floating slab track with the small radius curves of metro, the formation processes of rail corrugation were explained from the perspective of wheel-rail stick-slip vibrations. Firstly, according to the basic situation of the line, a three-dimensional finite element model of wheelset-floating slab track was established. Then, the wheel-rail contact stick-slip features and rail longitudinal wear characteristics were analyzed using the above model to quantify the occurrence trend of corrugation. Finally, the relationship between the natural vibration properties of wheel-rail system and the formation of corrugation was studied based on the complex modal theory. The results show that the stick-slip distribution of the inside wheel-rail interface changes periodically during the operation of the wheelset, indicating that the inside wheel-rail system has experienced periodic stick-slip vibrations, which may lead to periodic wavy wear on the inner rails, and finally form rail corrugation; the stick-slip distribution of the outside wheel-rail interface has not changed significantly in general, which indicates that there is no stick-slip vibrations in the outside wheel-rail systems, so it is not easy to form rail corrugation. In the longitudinal direction of the rail, the slip of the inner rail is significantly greater than that of the outer rail, illustrating that the longitudinal wear of the inner rail is greater; in the transverse direction of the rail, there is little difference between the slip of inner and outer rails, illustrating that the transverse wear of inner and outer rails is similar. The distribution of longitudinal and transverse slip nephograms of inner and outer rails shows a certain degree of periodicity, especially the longitudinal slip nephogram of the inner rail, with a wavelength of 28 mm close to the measured corrugation wavelength of 25 mm, which is consistent with the periodic characteristics of the contact stick-slip state of the inside wheel-rail interface, and further shows that the inner rail is more prone to serious periodic wear, namely rail corrugation. Combining the analysis results of wheel-rail contact stick-slip and wear features and wheel-rail system vibration characteristics, it may be concluded that the inner rail corrugation on the floating slab track with the small radius curves of metro is caused by the stick-slip vibrations induced by the unstable vibration modes of wheel-rail system corresponding to 664.1 Hz and 665.8 Hz, and the unstable modes are all presented as the bending vibrations of the inner wheel relative to the track. The sensitivity analysis of parameters indicates that properly increasing the vertical stiffnesses of the fastener and the steel spring may play a positive role in the control of corrugation.

Key words: metro, steel spring floating slab track, corrugation, stick-slip vibration, complex modal

摘要： 为探究地铁小半径曲线钢弹簧浮置板轨道上的波磨成因，从轮轨黏滑振动层面阐释了钢轨波磨的形成过程。首先，依据线路基本情况建立了轮对浮置板轨道三维有限元模型；然后，利用上述模型分析了轮轨接触黏滑特征和钢轨纵向磨耗特性以量化波磨的发生趋势；最后，基于复模态理论，研究了轮轨系统的固有振动属性与波磨形成的关系。结果显示，在轮对运行过程中，内侧轮轨黏滑分布呈现周期性变化，说明内侧轮轨系统发生了周期性的黏滑振动，进而可能导致内轨出现周期性的波状磨耗，最终形成钢轨波磨；外侧轮轨黏滑分布总体上未有明显变化，说明外侧轮轨系统未出现黏滑振动，从而不易形成钢轨波磨。在钢轨纵向上，内轨滑移量明显大于外轨滑移量，表明内轨纵向磨耗程度更大；在钢轨横向上，内外侧钢轨滑移量相差不大，表明内外侧钢轨横向磨耗程度相近。内外侧钢轨纵横向滑移云图分布均表现出了一定程度的周期性，尤其是内轨纵向滑移云图，其波长28 mm与实测波磨波长25 mm相近，这与内侧轮轨界面接触黏滑状态的周期特性相呼应，从而进一步说明了内轨更容易发生严重的周期性磨耗，即钢轨波磨。综合轮轨接触黏滑与磨耗特征及轮轨系统振动特性分析结果，可以得出实测地铁小半径曲线浮置板轨道上的内轨波磨是由664.1 Hz和665.8 Hz对应的轮轨系统不稳定振型诱发的黏滑振动所致，且该不稳定振型均表现为内轮相对于轨道的弯曲振动。参数敏感性分析表明适当地增大扣件和钢弹簧的垂向刚度能够对波磨控制起到积极作用。

关键词: 地铁, 钢弹簧浮置板轨道, 波磨, 黏滑振动, 复模态