High spatial resolution sensing by using stepped pump light and its experimental validation  

作　　者：郭彤 虞宁生 

机构地区：[1]Structural Health Monitoring Institute,Southeast University [2]Nanjing COECOM Light and Electronic Equipment Co.,Ltd.

出　　处：《Chinese Optics Letters》2009年第6期465-468,共4页中国光学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China (Nos.50725828 and 50608017);the Sustentation Fund for Young Teachers of Southeast University

摘　　要：The spatial resolution of conventional distributed fiber optic sensors is 1 m at best, which is inadequate to locate the damage precisely. We adopt an improved sensing technique based on the Brillouin optical time-domain analysis （BOTDA）. The stepped pump light is input to stimulate the phonon so that the spatial resolution can be increased to centimeter order and the strain accuracy of 25 micro-strains is obtained. The feasibility of this sensing technique is demonstrated through strain measurement of three concrete box-girders in bending. Experimental results show that the improved BOTDA measurement can provide a comprehensive description on the strain distribution of steel rebar or concrete. Compared with the conventional strain gauges, the improved BOTDA measurement is more stable. By virtue of higher spatial resolution and better measurement accuracy, it has become possible to perform crack detection and localization for concrete structures.The spatial resolution of conventional distributed fiber optic sensors is 1 m at best, which is inadequate to locate the damage precisely. We adopt an improved sensing technique based on the Brillouin optical time-domain analysis （BOTDA）. The stepped pump light is input to stimulate the phonon so that the spatial resolution can be increased to centimeter order and the strain accuracy of 25 micro-strains is obtained. The feasibility of this sensing technique is demonstrated through strain measurement of three concrete box-girders in bending. Experimental results show that the improved BOTDA measurement can provide a comprehensive description on the strain distribution of steel rebar or concrete. Compared with the conventional strain gauges, the improved BOTDA measurement is more stable. By virtue of higher spatial resolution and better measurement accuracy, it has become possible to perform crack detection and localization for concrete structures.

关 键 词：Beams and girders Crack detection Fiber optic sensors Image resolution PUMPS Sensors STRAIN Strain gages Time domain analysis 

分 类 号：TP212.14[自动化与计算机技术—检测技术与自动化装置]