Theoretical and Experimental Investigations into Crack Detection with BOTDR-Distributed Fiber Optic Sensors
Theoretical and Experimental Investigations into Crack Detection with BOTDR-Distributed Fiber Optic Sensors
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DOI：
10.1061/(asce)em.1943-7889.0000622
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发表时间：
2013-12-01
影响因子：
3.3
通讯作者：
Ansari, Farhad
中科院分区：
文献类型：
--
作者：
Feng, Xin;Zhou, Jing;Ansari, Farhad
本研究提出一个分析应变奇异性之布里渊感测器应变传递机制的模型。研究的主要目标是开发一种方法，用于精确检测基于布里渊的光纤分布式传感器的裂纹及其位置。这项工作涉及制定的剪切滞后为基础的模型，考虑弹性以及弹塑性阶段的光纤涂层应变。所提出的方法的可行性进行了评估，通过一个实验程序。实验方案涉及使用的布里渊光时域反射计（BOTDR）的分布式测量的应变和检测模拟裂纹在15米长的梁。结果表明，基于理论分析的应变分布的不连续性提供了精确定位模拟裂纹位置的手段。另一方面，由于在系统的空间分辨率上对应变进行平均，BOTDR系统的畸变效应掩盖了应变不连续性的影响。与通过BOTDR中的平均过程获得的应变相反，理论计算与应变沿梁长度沿着的实际分布有关。光学力学关系也被用来模拟空间分辨率的理论结果的影响。将以这种方式获得的表观应变与BOTDR测量值进行比较。由于测量噪声，基于理论计算的表观应变提供了关于裂纹位置的更好信息。(C)2013年美国土木工程师协会。
Development of a model for the analysis of strain transfer mechanism in Brillouin-based sensors with strain singularities is provided in this study. The main objective of the research pertained to the development of a method for accurate detection of cracks and their locations in sensing with Brillouin-based fiber optic distributed sensors. The work involved formulation of a shear lag-based model considering the elastic as well as elastoplastic stages of the fiber optic coating strains. Feasibility of the proposed approach is evaluated through an experimental program. The experimental program involved use of a Brillouin optical time domain reflectometer (BOTDR) for distributed measurement of strain and detection of simulated cracks in a 15-m-long beam. The results indicate that the discontinuities in the strain distribution based on the theoretical analysis provide the means to accurately pinpoint the location of simulated cracks. On the other hand, the distortion effect of the BOTDR system due to averaging of the strains over the spatial resolution of the system masked the influence of strain discontinuities. In contrast to the strains acquired through the averaging process in BOTDR, the theoretical computations pertain to the actual distribution of strain along the length of the beam. Optomechanical relationships were also used to simulate the effect of spatial resolution on the theoretical results. The apparent strains obtained in this way were compared with the BOTDR measured values. Because of the measurement noise, the apparent strains based on the theoretical computations provided better information about the location of the cracks. (C) 2013 American Society of Civil Engineers.