Rail crack monitoring system based on optical fiber ultrasonic guided wave technology

Abstract

The invention provides a rail crack monitoring system based on an optical fiber ultrasonic guided wave technology. The rail crack monitoring system comprises a high speed optical fiber grating signal demodulator, which is connected to one or a plurality of optical fiber grating sensors arranged on a rail through optical fibers, and comprises a broadband light source, an optical circulator, an interferometric wavelength division multiplexer, a light detector with signal amplification function, and a collection module. According to the present invention, the rail crack monitoring system uses the interferometric wavelength division multiplexing technology to achieve the high frequency and low noise collection of the sensing signals, such that the ultrasonic guided wave signals and the signal changes caused by the rail cracks or other anomalies can be collected; and the system does not require the electricity supply for each sensor, has the excellent long-distance rail monitoring practicality, and can synchronously collect the excitation signal and the response signal so as to conveniently achieve the active structure health monitoring based on the ultrasonic guided wave technology. 本发明提供一种基于光纤超声导波技术的铁轨裂纹监测系统，包括高速光纤光栅信号解调仪，该高速光纤光栅信号解调仪通过光纤与布置在铁轨上的一至多个光纤光栅传感器连接。高速光纤光栅信号解调仪包括宽带光源、光环形器、干涉式波分复用仪、具有信号放大功能的光探测器以及采集模块。该铁轨裂纹监测系统应用干涉式波分复用技术实现了对传感信号的高频和低噪声采集，使其能够采集超声导波信号和由铁轨裂纹或其他异常引起的信号变化；该系统不需要给每个传感器供电的特性使其具有优良的长距离轨道监测的实用性，同步采集激励信号和响应信号的功能使其便于实现基于超声导波技术的主动式结构健康监测。