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. 

Mechanism of Suppression of Polygonal Wear of Wheel on High-Speed Trains by Abrasive Block

The wheel polygonal wear has been one of the most serious problems in China’s high-speed trains since they were put into operation in 2008, which directly affects the operation safety of high-speed trains. The abilities of improving the adhesive coefficient and repairing local defects by an abrasive block were experimentally studied on a high-speed wheel-rail rolling test rig. The frictional self-excited vibration model of a wheelset-track system consisting of a wheelset, two rails and monolithic track beds was established. The occurrence tendencies of friction self-excited vibration of the wheelset-track system under the wheel-rail adhesion and sliding conditions were studied. The main mechanism of suppression of the wheel polygonal wear by abrasive block was concluded as follows: (1) the ability of the abrasive block increasing the adhesive coefficient, which made it difficult for the wheel to slip on the rail upon braking or powering the train. Therefore, the conditions to initiate wheel polygonal wear no longer exisited; (2) the hard particles of the abrasive block can effectively remove the microscopic defects of the wheel tread in time, thereby can effectively suppress the polygonalization, abnormal wear and contact fatigue crack of wheels.