轨道预载对梯式轨道系统减振效果影响试验研究

插入损失是评价轨道减振效果的重要指标,与轨道所受荷载形式及测试环境密切相关。为分析轨道减振性能的室内试验中预载对动力响应及减振效果的影响,建立了简化的理论模型实现定性分析。同时,基于实验室定点锤击试验定量分析了预载值对条铺、点铺两种浮置梯式轨道减振效果的影响。研究结果表明:在整体刚度符合设计标准条件下,减振产品刚度越低其减振效果越好。施加预载会导致轨道减振元件刚度变化,显著改变系统的振动特性,降低减振轨道的工作频率。锤击荷载作用下,浮置梯式轨道系统的插入损失随着预载的增加而增大,当预载值达到一定程度后,Z振级插入损失趋于稳定。

Experimental Study of Preload Effect on Vibration Reduction of Floating Ladder Track

Insertion loss(IL)is an important index to evaluate vibration mitigation effect of railway tracks.The value of IL is dependent on the excitation load form and test environment of the track.In this paper,to analyze the preload effect on the dynamic response and vibration mitigation effect of the elastic element under sleepers,a theoretical qualitative model was built.In addition,the floating ladder tracks with two different under sleeper pads(USPs)were employed under drop-weight test in a laboratory environment to quantitatively analyze the effect of preload values on IL.The results indicate that,under the condition that the track stiffness meets the design standard,the lower the mitigation element stiffness,the better the vibration mitigation effect.The application of preload will cause the change of the mitigation element stiffness,significantly changing the vibration characteristics of the system and reducing the working frequency of the floating ladder tracks.Under the impact load,IL of the floating ladder tracks increases with the increase of the applied preload.As the preload increases to a certain extent,the insertion loss of the Z vibration level tends to be stable.