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首页> 外文会议>Annual Symposium on Quantitative Nondestructive Evaluation >REAL-TIME PROCESSING OF CONTINUOUS DOPPLER SIGNALS FOR HIGH-SPEED MONITORING OF RAIL TRACKS
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REAL-TIME PROCESSING OF CONTINUOUS DOPPLER SIGNALS FOR HIGH-SPEED MONITORING OF RAIL TRACKS

机译：用于高速监测的连续多普勒信号实时处理轨道轨道

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A novel concept based on the Doppler effect was introduced for continuous monitoring of rail defects at high speed. This approach exploits the relative motion between the propagating ultrasound and the rail defect. It was shown from the feasibility tests that low frequency air-coupled transducers can be effectively used for detecting rail surface defects, thereby eliminating contact between the transducers and rail surface. The feasibility of this technique was experimentally studied and verified in a laboratory setting. In a test conducted using a rotating disk with a notch on the periphery, the Doppler effect was clearly observed. The continuous wave ultrasonic signals are reflected from the surface notch, resulting in Doppler shift in the as-obtained waveform. Due to the narrow bandwidth of the signal, the magnitude of the shifted frequency was clearly pronounced in the frequency spectrum. The shift was experimentally detected in the frequency domain using the Short-Time Fourier Tranform and peak-detecting the transformed signals. It is believed from this feasibility test that CW Doppler can be used as an effective means of high-speed rail monitoring, particularly for detecting surface defects and broken rails. For the future work, a criterion to set a threshold magnitude of the peak-dected STFT should be established. Once the threshold is determined, the system can be designed to issue an alarm when the peak magnitude exceeds the threshold value. This condition may indicate any surface anomalies and thus can be used as a criterion for the alarm. More importantly, further investigation is necessary for monitoring internal defects which may also seriously affect the rail integrity.
机译：引入了一种基于多普勒效应的新颖概念，以连续监测高速轨道缺陷。该方法利用传播超声和轨道缺陷之间的相对运动。从可行性测试中示出了低频空气耦合换能器可以有效地用于检测轨道表面缺陷，从而消除换能器和轨道表面之间的接触。在实验研究和验证该技术的可行性在实验室环境中进行了验证。在使用旋转盘进行的测试中，在周边上的凹槽，清楚地观察到多普勒效应。连续波超声信号从表面凹口反射，导致AS获得的波形中的多普勒频移。由于信号的窄带宽，在频谱中清楚地发出偏移频率的大小。使用短时傅里叶变换和峰值检测转换信号在频域中实验检测转变。据信，CW多普勒可以用作高速轨道监测的有效手段，特别是用于检测表面缺陷和断路器。对于未来的工作，应该建立要设置峰值峰值的峰值幅度的标准。一旦确定阈值，系统可以设计为当峰值幅度超过阈值时发出警报。该条件可以指示任何表面异常，因此可以用作警报的标准。更重要的是，对监测内部缺陷的进一步调查是必要的，这也可能严重影响铁路完整性。

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