【作者】 何建平；

【导师】 欧进萍； 周智；

【作者基本信息】 哈尔滨工业大学 ， 工程力学， 2010， 博士

【摘要】 重大土木工程结构具有体积大、覆盖面广、造价高、服役环境恶劣、设计寿命长等特点,其结构损伤往往表现为机理复杂、耦合影响因素多、时变演化效应显著、损伤位置隐蔽等特性,满足工程需要的高性能全尺度监测手段一直是结构健康监测的客观需求。本文围绕分布式光纤布里渊(Brillouin Optical Time Domain Analysis/Reflectometry,简称BOTDA/R)的感知特性和温度补偿方法、高性能光纤封装传感探头、融合全尺度光纤布里渊和局部高精度光纤光栅(Fiber Bragg Grating)的共线传感网络、基于光纤与FRP(Fiber Reinforce Polymer)复合的全分布式智能结构部品以及基于全尺度分布式监测手段的结构损伤探测等问题展开了较系统研究。主要研究内容包括:首先,在介绍光纤布里渊传感工作原理的基础上,理论分析和试验探讨了光纤布里渊温度和应变感知的耦合作用,提出了布里渊应变感知绝对温度补偿方法,并进行了试验验证。其次,通过大量对比试验,归纳和总结了目前可能用于布里渊传感的系列封装传感光纤的剪切力学性能、轴向拉伸极限应变、环境适应性及其相应的感知特性,为工程应用传感光纤的选择提供了依据。这些封装光纤包括通信用普通裸光纤、碳涂覆光纤、聚酯封装光纤、FRP封装光纤等。第三,提出融合全尺度光纤布里渊测试技术和局部高精度光纤布拉格光栅传感技术的共线集成传感网络系统,分析了光纤光栅对光纤布里渊传感信号的影响;为了提高光纤布里渊测试结果的精度,发展了实测布里渊信号二次信号处理的小波分析和洛伦兹数据拟合方法。此外,探讨了长周期光纤光栅监测腐蚀的可行性及其与光纤布里渊测试技术复合的有效性。第四,针对不同布设工艺要求,研制开发出系列可大规模分布的工程化光纤布里渊传感探头和共线传感探头部品。在此基础上,将共线传感探头部品分别与平行钢拉索和钢绞线复合,发展了一套索式结构的全尺度长期监测技术。进而,提出了一种钢绞线的长期预应力损失监测技术,并通过长期试验验证了该技术的有效性。最后,利用全尺度分布式监测手段对结构损伤探测问题展开了较系统研究,包括:监测了6根分别布设BOTDA/R探头和共线探头的钢筋混凝土梁在静力加载过程中的裂缝、钢筋滑移和应变分布等信息;试验验证了光纤布里渊传感技术监测输油管在冻胀融沉下变形特性的有效性;将研制开发的全分布式探头在施工过程中分别布设到广州体育西路某人防工程和大庆抽油井套管,监测了工程结构应力热点位置施工过程的应变增量、分布和在役期间的变化情况。更多还原

【Abstract】 Critical civil infrastrucuture can be characterized by large size and surface area, high cost, harsh environment, long service period, etc. Their damages have complicate mechanism, multi-affecting factors, noticeable time-dependent evolution and they are hard to be localized. To date, qualified full-scale monitoring technique is in urgent need for structural health monitoring of critical civil infrastructure. This dissertation focuses on the topics of full-scale monitoring technique including highly-performanced optical Brillouin sensor, collinear system by combining Fiber Bragg Grating (FBG) and Brillouin Optical Time Domain Analysis/Reflectometry (BOTDA/R) sensing technology, and fully-distributed smart sensor by combining Fiber Reinforce Polymer (FRP) and optical fiber sensor. The content of this work mainly contains:Firstly, the principle of optical Brillouin sensing technoloy has been introduced. Its strain-temperature coupling effect has been discussed in details and a novel absolute temperature compensation for strain measurement is put forward and experimentally validated.Secondly, the sensing characteristics of BOTDA/R based optical sensors such as their shear strength, axial tensile ultimate strain of series of coating Brillouin sensing optical fiber are investigated by large numbers of comparison tests. The compared optical fiber sensors include common Corning optical fiber, carbon coating optcial fiber, polymide coating high-temperature optical fiber and FRP coating optical fiber. The results provide basic guide for the selection among various kinds of sensing optical fibers in field application.Thirdly, a novel intelligent collinear optical sensor system (named BOTDA/R-FBG system) is developed by combining the full-scale distributed Brillouin sensing system and local high-precise Fiber Bragg Gratting (FBG) sensing system. The impact of FBG to Brillouin sensing signal has been studied. To improve the accuracy of the novel sensor, two data processing techniques such as wavelet denoising method and Lorentz fitting algorithm are applied. Besides, the feasibility of long period fiber grating(LPFG) based corrosion sensor and the probability of collinear system by combining LPFG and Brillouin sensing technique has been studied as well. Forthly, in regard to various requirments of installation, series of full-scale distributed Brillouin sensors and collinear BOTDR/FBG sensors are developed. Besides, a long-term monitoring method for cable-based structure is developed by combining collinear sensor and the stay cable/steel strand together. Thus, a corresponding long-term prestress monitoring technique has been put forward and validated experimentally.Finally, based on the full-scale measuring technique, structural damage detection has been investigated systematically. This work includes: damge mornitoring such as large deforamtion, cracks and steel sliding detection of six RC beams under static loads based on BOTDA/R sensors and collinear sensors; the feasibility study for the mornitoring of in-service oil pipes based on Brillouin sensing technique; the BOTDA/R sensor application in civil defense project in Guanzhou City and casing pipe project in Daqin Oilfield for the monitoring of the strain increment at the hot position and casing damage at construction and in-service stages.更多还原