基于分布式光纤声振传感的索结构监测  

Cable structure monitoring based on distributed optical fiber acoustic sensing

作　　者：况卓林 李素贞[1] Kuang Zhuolin;Li Suzhen(College of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院,上海200092

出　　处：《仪器仪表学报》2023年第9期195-203,共9页Chinese Journal of Scientific Instrument

基　　金：国家自然科学基金(52378525)项目资助。

摘　　要：索结构凭借自身良好的抗拉性能被广泛应用于工程领域。因而拉索索力是影响其安全性的重要因素,对其进行测试十分必要。现工程中索力测试多采用自振频率法,其大多是通过加速度计或计算机视觉测量拉索自振频率,从而计算拉索索力值。而近年发展出的相位敏感光时域反射计(φ-OTDR)仅凭1根成本较低的通信光纤即可实现结构内全部拉索的自振频率测量,具有较好的测试前景。然而在实际中,用于确定分布式光纤系统灵敏度的有效光弹系数并不唯一。为确保φ-OTDR应用于索力测试的数据来源可靠,本研究通过将传感光纤粘贴于拉索搭建了用于索结构监测的分布式光纤传感系统性能标定平台,基于数字图像相关法对不同设计工况下的拉索跨中位移信号进行测量,并通过分析拉索模型将跨中位移信号转换为轴向信号,最后通过对比拉索轴向信号以及φ-OTDR采集信号从而实现了分布式光纤传感系统的标定实验。Cable is widely used in engineering due to the good tensile performance.The cable tension is an important factor affecting the safety,which is necessary to be tested.Currently,the testing of cable tension mostly is calculated by the frequency method,which is to measure the cable frequency based on accelerometer or computer vision.Recently,theφ-OTDR has been developed,which can measure the frequency of several cables with just one low-cost communication fiber.It has a great prospect in the testing of cable tension.However,the coefficient of effective optical elasticity used to determine the sensitivity of the distributed fiber optical system is not unique in practice.To ensure the reliability of the data collected byφ-OTDR in the testing of cable tension,this study establishes a performance calibration platform for the distributed fiber optical system for cable monitoring by attaching the sensing fiber to the cable,and the midspan displacement of cable under different testing conditions are measured by using the digital image correlation method.The mid-span displacement is converted into the axial displacement of cable by analyzing the dynamic model of cable.Finally,based on the converted axial signal of cable and the phase collected byφ-OTDR,the performance calibration of distributed fiber optical sensing system is realized.

关 键 词：标定 相位敏感光时域反射计 传感光纤 应变 索结构 

分 类 号：TH82[机械工程—仪器科学与技术] TU990.3[机械工程—精密仪器及机械]