嵌入式轨道超弹性力学属性对轮轨动态作用的影响研究

Study on the influence of embedded track hyperelasticity on the dynamic action of wheel and rail

嵌入式轨道结构内的聚氨酯填充材料具有非常明显的超弹性力学特性,对轨道系统的力学行为及振动噪声有较大影响。为研究填充材料超弹性特性对嵌入式轨道轮轨系统动力特性的影响,以焊接接头不平顺为例,建立了考虑填充材料超弹性本构的嵌入式轨道三维轮轨瞬态滚动接触有限元模型,分析了焊接接头不平顺对嵌入式轨道轮轨瞬态滚动接触力学行为的影响。结果表明:考虑填充材料超弹性本构的嵌入式轨道模型可以很好的模拟高分子材料受到外力冲击时的能量转换及减振过程。焊接接头不平顺中的短波不平顺波长和波深对轮轨冲击响应的影响十分显著。轮轨冲击载荷随车速的增加而增大,所对应的轮轨动态响应主频频段也会明显上移。钢轨表面接触应力极值出现的位置与焊缝几何形状关系很大,接触斑面积和接触应力的峰值基本出现在焊缝的低塌处。聚氨酯填充材料在对于较低频率(400 Hz以下)的振动的抑制作用不明显,对500~2000 Hz的高频振动具有良好的抑制作用,嵌入式轨道的减振特性表现出一定的频率相关性。

Wheel/rail The polyurethane filling material in the embedded track structure has very obvious superelasticity,which has a great influence on the mechanical behavior and vibration noise of the track system.In order to study the influence of superelastic characteristics of filling material on the dynamic characteristics of embedded rail wheel/rail system,taking the irregularity of welded joint as an example,a three-dimensional finite element model of embedded rail wheel/rail transient rolling contact considering the superelastic constitutive of filling material was established.The influence of welded joint irregularity on the mechanical behavior of embedded rail wheel/rail transient rolling contact was analyzed.The results show that the embedded track model considering the superelastic constitutive model of filled materials can well simulate the energy conversion and damping process of polymer materials under external force impact.The short-wave irregularity wavelength and wave depth in the welding joint irregularity have a significant influence on the wheel/rail impact response.The wheel/rail impact load increases with the increase of vehicle speed,and the corresponding main frequency band of wheel/rail dynamic response also moves up obviously.The position of the extreme contact stress on the rail surface is closely related to the geometric shape of the weld,and the peak value of contact spot area and contact stress basically appear in the low collapse of the weld.The polyurethane filling material has no obvious inhibitory effect on the vibration of lower frequency(below 400 Hz),but has a good inhibitory effect on the high-frequency vibration of 500-2000 Hz,and the damping characteristics of the embedded track show certain frequency correlation.