This paper introduces a method to identify the bending modes of vibration of railway tracks by using a laser Doppler vibrometer (LDV) mounted on a moving platform. Two sets of experiments were conducted at Transportation Technology Center Inc. (TTCI) in Pueblo Colorado, in order to validate the proposed method. First, the bending vibration modes were identified using the signals collected from a rail span (rail section between two consecutive sleepers) by accelerometers under moving car excitation. Then, vibration measurements from rail spans were obtained by using an LDV mounted on the moving railcar. All tests were carried out at four different rail car speeds: 8 km/h (5 mph), 16 km/h (10 mph), 35 km/h (22 mph), and 45 km/h (28 mph). To find LDV signal segments corresponding to rail spans, a novel approach based on the sleeper passing frequency is introduced. Comparison of the results from both sets of tests demonstrated good agreement for all speeds.

中文翻译：

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移动平台上激光多普勒测振仪识别钢轨弯曲模态

本文介绍了一种利用安装在移动平台上的激光多普勒测振仪（LDV）识别铁路轨道振动弯曲模式的方法。在科罗拉多州普韦布洛的运输技术中心公司 (TTCI) 进行了两组实验，以验证所提出的方法。首先，使用加速度计在移动汽车激励下从轨道跨度（两个连续轨枕之间的轨道部分）收集的信号来识别弯曲振动模式。然后，使用安装在移动轨道车上的 LDV 获得轨道跨度的振动测量值。所有测试均以四种不同的轨道车速度进行：8 公里/小时（5 英里/小时）、16 公里/小时（10 英里/小时）、35 公里/小时（22 英里/小时）和 45 公里/小时（28 英里/小时）。要找到对应于轨道跨度的 LDV 信号段，介绍了一种基于轨枕通过频率的新方法。两组测试结果的比较表明所有速度都具有良好的一致性。