Research On Long-period Fiber Gratting Used In Structural Health Monitoring

Long-period fiber gratting (LPG) becomes a most important part of fiber sensors because of it's good prospects in application. Meanwhile, most research on it are in the laboratory while a little in application. This thesis is about the research of the application of LPG in structural health monitoring. The contents of the article are as following:In chapter one, the circs of the fiber sensor and grating is introduced simply. And it emphasizes on long-period fiber gratting.In chapter two,model coupling theory is studied. It is introduced that the formation mechanism of LPG's writing. On the bases of the model coupling, it shows the formula of transmission and resonance peak.In chapter three, the basical characters of long-period fiber gratting are studied.It includes the character on strain, temperature, bending and refractive index. It gives the simple theories and farther experiments.Chapter four is about LPG's application in the board structure. In this chapter, LPG is used as a sensor to measure the dynamic signal. With LabVIEW, It makes up of a instrument to monitor the structural health.In chapter five, long-period fiber gratting is used in civil engineering. A sensor based on LPG is designed and produced to monitor the corrosion of steel in concrete.In chapter six, a simple and effective method of temperature compensation about LPG is discussed. It is very useful in measuring refractive index with LPG.