线路支承状态变化对轨道动态特性的影响

Dynamic Response of CWR Track to the Supporting Conditions

把温度力作用下的无缝线路简化为纵向力作用的弹性等间距支承的无限长均匀梁结构,通过连续梁理论,建立了纵向力作用下无缝线路钢轨的振动模型。分析了轨道结构钢轨自振频率与其纵向力间的内在关系,分别讨论了钢轨在承受纵向拉力和纵向压力时自振频率的变化特征,比较了钢轨类型改变、钢轨支承间距变化后对上述变化的影响。结果表明:纵向拉力作用下钢轨的竖向自振频率会随着拉力的增加而增大,钢轨支承间距加大会降低其自振频率;纵向压力作用下,钢轨的竖向自振频率随着压力的增加而减小;第一振型变化趋势基本分为两个阶段,当轴向压力较小时,呈线性变化,随着轴向压力的不断增加,逐渐地产生了非线性的变化;二阶及以上振型变化与受拉状态相似。

As the use of continuous welded rail （CWR） increases in track structure, the derailing disasters associated with track also increase in great numbers due to the high compressive thermal stress. The CWR track on the temperature stress can be simplified when the length infinity uniform beam with discrete supports at regular intervals and the harmonic transverse concentrated force at the center of the beam is assumed. According to the beam bending theory of structural dynamics with a consideration of the influence of axially load, this paper presents the dynamic characteristic of the CWR track on the variety of supporting conditions subjected to the longitudinal force in the rail due to fluctuation of temperature. It is shown that the main vibration characteristics of CWR track can be demonstrated by an analytical model. This model would help us to evaluate the real rail temperature force by analyzing the dynamic response of CWR track.