Distributed Optic-fiber Sensing Monitoring of Cracks and its Application to Lineal Structural Engineering
In this paper presented is a distributed optic-fiber crack sensing technology based the Rayleigh Optical Time Reflectometry (OTDR). It possesses the peculiarly functions of continuous and quantitative monitoring, including not only locating the cracks but also determining each crack width, and thereby it is especially adequate for the health monitoring of the lineal engineering, e.g concrete structures.The creative idea which underlies this technology is the non-orthogonal fiber configuration as a direct transducing mechanism between mechanical and optical effects. A series of experiments have been performed to verify the new microbend sensing method and the simi-empirical equation of the relation of localized loss to crack width as well as the dynamic range obtained. An analysis theory of micromechanics of fiber-concrete complex and a nonlinear finite element method have been formulated. The numerical computation is consistent roughly with the experiment results.This optic-fiber crack monitoring system has been applied successfully for first time to the Wu Gorge Yantze Bridge, China. A number of long interface cracks have been detected by the system in 2004, and the results coincide with that of the ultrasonics detect qualitatively, and in particular are confirmed by the drill hole inspection. It is concluded that to date the OTDR crack sensing technology is a feasible distributed monitoring method with the most practical value for engineering application.
health monitoring crack of concrete distributed fiber-optic sensing technology OTDR micromechanical theoretical model non-orthogonal fiber configuration mechanical-optic constitutive relation mechanical analysis of fiber-concrete complex engineering
LIU Haowu
School of Water Resource and H vdropower, Sichuan university, Chengdu 610065, China
国际会议
南京
英文
20-26
2007-10-18（万方平台首次上网日期，不代表论文的发表时间）