| Summary: | 碩士 === 臺灣大學 === 機械工程學研究所 === 95 === Recently, fiber Bragg gratings (FBG) have been applied to sense strain and temperature variation due to their high sensitivity, electromagnetic immunity and good engineering properties. Many papers have been demonstrated their performance in many engineering fields, including strain measurements in civil engineering and composite structures. However, these applications were used for static or low frequency measurements, high frequency dynamic measurement needed further study.
We have used the intensity-modulated FBG sensing system with long period fiber grating (LPG) filter to measure micro-measurand in only one direction. In order to increase the sensitivity and signal-to-noise ratio of the FBG system and to make simultaneous dynamic measurements in multiple directions at a single point, we develop high-frequency in-plane and the out-of-plane FBG sensors with transmitted spectra of FBG filters to measure out-of-plane and in-plane dynamic responses. Furthermore, we integrate the FBG sensing system with Dynamic Signal Analyzer to develop a dynamic signal system. All dynamic responses are measured simultaneously by the LDV system and strain gage. Results agree with those obtained from LDV and strain gage.
Key words : FBG sensing system, high frequency dynamic measurement, FBG filter, simultaneous dynamic measurements, multiple directions.
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