研磨子抑制高速列车车轮多边形磨耗的机理研究

高速列车车轮多边形磨耗是我国高速列车自2008年开行以来出现的最严重的问题之一，直接影响到高速列车的运行安全. 利用高速轮轨滚动试验机试验研究了研磨子的增黏作用和局部缺陷修复作用，探讨了其作用机制. 建立了由轮对、钢轨和整体道床组成的轮轨系统滑动摩擦自激振动模型，研究了轮轨黏着和滑动工况下的轮轨系统摩擦自激振动发生趋势，指出研磨子抑制高速列车车轮多边形磨耗的主要机理在于以下两个方面：(1)研磨子的增黏作用，使轮轨系统制动和牵引时不容易发生滑动，消除了车轮多边形发生的条件；(2)研磨子中硬质颗粒能够有效地将车轮踏面的微观缺陷及时打磨清除，从而有效抑制车轮多边形、异常磨耗及接触疲劳裂纹的产生.

Polygon wear of high-speed train wheels is one of the most severe problems encountered by China's high-speed trains since their commercial operation began in 2008, which directly threatens the operational safety of such trains. This study employs a high-speed wheel-rail rolling test rig to experimentally investigate the adhesion-enhancing effect and local defect repair performance of grinding pads, and explores their underlying action mechanisms. A sliding friction self-excited vibration model of the wheel-rail system, composed of wheel sets, rails and monolithic track beds, is established to analyze the occurrence trend of friction self-excited vibrations of the wheel-rail system under both wheel-rail adhesion and sliding conditions. The core mechanisms by which grinding pads suppress polygon wear of high-speed train wheels are clarified as follows: (1) The adhesion-enhancing effect of the grinding pads prevents sliding of the wheel-rail system during braking and traction, thus eliminating the prerequisite conditions for the formation of wheel polygon wear; (2) The hard particles contained in the grinding pads can timely and effectively polish and remove micro-defects on the wheel tread, thereby effectively inhibiting the generation of wheel polygon wear, abnormal wear and contact fatigue cracks.