采用剪切型减振器扣件的钢轨频率响应特性测试分析

Laboratory measurement on rail frequency response behavior for egg fastening system

轨道结构的频率响应特征反映了轨道结构在频域范围内的固有特性,是对轨道结构进行动力分析的一项重要内容。本文在一个25m长的足尺轨道试验平台上,采用锤击法对比测试了剪切型减振器扣件以及DTVI2扣件两种轨道结构型式下钢轨的垂向频率响应特性,并结合北京地铁发生的钢轨波磨现象,分析了钢轨的垂向频率响应特性与波磨特征频率的相关性。结果表明:(1)剪切型减振器扣件轨道结构型式下钢轨的垂向"pinned-pinned共振"不是导致钢轨波磨的主要原因;(2)试验得到的剪切型减振器扣件轨道结构型式下的钢轨垂向频率共振点与现场实测的典型波磨频率高度吻合。钢轨垂向频率响应特性是影响列车与轨道相互作用的必要非充分条件,只有车辆系统在特定频率的激扰下,才能诱发激烈的轮轨相互作用,导致钢轨波磨现象的发生。

Frequency response behavior is an important parameter to analyze the dynamic properties of the track system. The experimental study was performed on a 25 m laboratory test track to compare the rail frequency response behavior between Egg system track structure and the standard track form with DTVI2 fastening system. The rail frequency response behavior was measured using an accelerometer mounted on the railhead close to the point of excitation at the position both above the fastening system and at mid-span between fastening systems. The measurements indicated that:(1) the vertical ‘pinned-pinned resonance' was not the cause of rail corrugation occurs in the sections of the Egg system track on Beijing metro;(2) the dynamic behaviors of the Egg system track were contributed to the formation of corrugation by influencing the train/track interaction at some sensitive resonance frequencies. However, the dynamic property of the track structure was not the only reason for corrugation. The contribution of the vehicle should be taken into account in further research.