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Research Of Fiber Bragg Grating Sensing Technology And Experiment

Posted on:2009-10-07Degree:MasterType:Thesis
Country:ChinaCandidate:X H JiFull Text:PDF
GTID:2132360242484793Subject:Disaster Prevention
Abstract/Summary:PDF Full Text Request
Optic fiber Bragg grating (FBG) sensor is a new type of high performance sensor, which is playing an important role in structural healthy monitoring. Based on the research of FBG's sensing properties, the packaged FBG sensors have been developed for the sake of long-term health monitoring of large civil infrastructure and present the performance of FBG sensors. Then apply the FBG sensors to strain and acceleration measurement of a steel frame structure and the model dynamic characteristics tests under simulated earthquake. The main contents of this article include:Firstly, based on the basic structure of light travel in FBG, the working principle and performance of sensing properties of the FBG strain sensors used in practice frequently are analyzed. In addition, a new packaging method of FBG strain sensor is put forward.Secondly, in view of the demand of long-term monitoring for engineering structures, a small dimension sensor with two gripper tubes in both sides of a fiber Bragg grating, which was protected and packaged by the stainless steel tube, was developed for strain measurement. The main content of this chapter are discussed as follows: (1) strain transferring characteristics of sensor when sticking the two-side-gripper packaged FBG sensors on different materials; (2) the effect of agglomerant on the strain transferring characteristics of sensor and the application scope; (3) the reliability of sensor when subjected to long-term cycle loads.Thirdly, homemade FBG strain sensors have been used in a series of experiments. The technique of FBG sensor installation in these experiments has been studied, and the strain and acceleration measurement of a steel frame has been realized. In earthquake destructive test of the whole concrete dam model, FBG strain sensor has been successfully monitored "remnant strain" of the modal in several tests. By analyzing of test data, the growing state of crack could be fund from elastic state to plastic state of structure. The experimental results show that FBG's superior ability of explosion proof, immunity to electromagnetic interference and high accuracy, and demonstrate promising potentials.
Keywords/Search Tags:Health Monitoring, Civil Engineering Structure, Fiber Bragg Grating Sensor, Strain sensing, Dam
PDF Full Text Request
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