Direct determination of dynamic properties of railway tracks for flexural vibrations
Direct determination of dynamic properties of railway tracks for flexural vibrations
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DOI：
10.1016/j.euromechsol.2016.08.010
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发表时间：
2017
影响因子：
4.1
通讯作者：
Jeongwon Park;Sangkeun Ahn;Jaehyung Kim;H. Koh;Junhong Park
中科院分区：
文献类型：
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作者：
Jeongwon Park;Sangkeun Ahn;Jaehyung Kim;H. Koh;Junhong Park
列车车轮转动引起的移动动载作用，使受扣件约束和支承的钢轨发生竖向振动。轨道在粘弹性介质中的动态刚度和阻尼力是评价其减振性能和环境噪声的重要指标。本研究提出了一种利用波传播法测量轨道弯曲振动粘弹性特性的实验方法。用该方法分析了在滚动噪声产生频率下钢轨垂直振动的产生和传递，并对实际轨道模型进行了检验。试验中采用了板式轨道模型和埋设轨道。钢轨由振动器或冲击锤激励，产生的加速度响应在两个位置进行了测量。弯曲波的传播只发生在高于钢轨质量-弹簧共振频率的频率处。通过测量响应之间的传递函数得到波数，计算出轨道结构的频变刚度和损耗因子。在实验室装置上对不同长度钢轨的粘弹性特性进行了精确测量。然后，为了验证所提出的方法的有效性，使用用于有轨电车的无限长埋设轨道进行了现场测试。室内有限长埋设轨道的动刚度测量结果与现场试验结果非常接近。该方法可以直接确定不同轨道的动力特性和比较不同轨道的弯曲波传播特性。
The vertical vibration of rails constrained and supported by fastening systems occurs due to moving dynamic loads induced from rotating train wheels. The dynamic stiffness and damping capability of the railway track on the viscoelastic medium are essential to evaluate their performance on minimizing rail vibration and environmental noise generation. In this study, a new experimental method to measure the viscoelastic properties of the railway track for flexural vibration was proposed using the wave propagation approach. The proposed method was used to analyze the generation and transfer of vertical rail vibration at frequencies of rolling noise generation and to test actual track models. A slab track model and embedded railway tracks were used in the experiments. The rail was excited by a shaker or an impact hammer, and the resulting acceleration responses were measured at two locations. The flexural wave propagation was found to occur only at frequencies higher than the mass-spring resonance frequency of the rails. After obtaining the wavenumber from the transfer function between the measured responses, the frequency-dependent stiffness and loss factor of the track structures were calculated. The viscoelastic properties of different railway tracks of finite length were measured accurately in the laboratory setups. Then, for validation of the proposed method, the field test was performed using the infinitely long embedded tracks used for a tramway. The measured dynamic stiffness from the finite embedded tracks in the laboratory was very similar to the field test results. The proposed method enables direct determination of the dynamic properties and comparison of flexural wave propagation characteristics of different railway tracks.