應用光纖光柵感測器量測結構應變、溫度及振動

THE MEASUREMENTS OF STRAIN、TEMPERATURE AND VIBRATION BY FIBER BRAGG GRATING SENSOR

周志成(Chih-Chen Chou)

指導教授 ： 何旭川

元智大學/工程學院/機械工程學系/碩士(2006年)

https://doi.org/10.6838/YZU.2006.00289

摘要

光纖對於現代通訊系統有巨大的貢獻，其高頻寬及低耗損之特性讓大筆的資料及資訊可快速並可靠的傳遞。光纖本身具有直徑小、重量輕、韌性強、抗腐蝕等優點，小巧的外形作為感測器使用更能真實地量測到結構體實際的變化。本文以光纖光柵為感測器應用光柵反射波長偏移量測結構應變、溫度與振動，研究實驗內容分為靜態和動態兩部分。在靜態部分是將光纖光柵全長之一半黏貼於試片表面另一半長度則未黏貼，當試片分別施加機械負載或溫度負載，光纖光柵黏貼與未黏貼部分承受不同應變，產生兩個不同反射波長，藉由此部分黏貼光纖光柵所反射之兩個波長可同時量測結構承受之機械應變和溫度。動態部分則是以短週期光纖光柵結合長週期光纖光柵，將短週期光纖光柵因動態應變變化導致之反射波長變化，轉換為光強度變化，再藉由偵測光強度變化量測結構動態響應。並以懸臂樑為試片分別施予自由振動、基座激振及強制振動三種不同振動模式，應用光纖光柵感測器量測振動響應，再與應變規量測所得比較，驗證光纖光柵感測器量測結構動態響應之準確度與可行性。

關鍵字

光纖光柵 ； 懸臂樑 ； 自由振動 ； 基座激振 ； 強制振動

並列摘要

In this investigation, the application of fiber Bragg grating senor on the measurements of strain, temperature and vibration are studied. The measurements are classified into two categories: statics and dynamics. In the case of statics, half of fiber Bragg grating senor is bonded on the surface of the test specimen. As the specimen subjected to thermal or mechanical load, two optic waves reflected from the fiber Bragg grating senor can be observed. Basing on the two reflected wavelengths, one is able to measure the mechanical strain and temperature simultaneously. In the case of dynamics, the fiber Bragg grating senor surface bonded on the test specimen is connected to a long period fiber grating. As the light transmits through the long period fiber grating, the intensity of the light is decayed and is dependent on the wavelength. By measuring the intensity of the light, one is able to measure the shift of the wavelength reflected from the fiber Bragg grating senor, leads to the determination of the strain in the test specimen. To explore the technique, the fiber Bragg grating senor is used to measure the strain of a vibrating cantilever beam. The vibration test includes free vibration, forcing vibration, and base excitation. In the cases of forcing vibration and base excitation, the cantilever beam is subjected to single or double frequency at resonance or non-resonance. The strains measured by the fiber Bragg grating sensor are compared with the results obtained by the strain gauge to examine the accuracy of the fiber Bragg grating sensor.

並列關鍵字

fiber Bragg grating sensor ； long period fiber grating ； cantilever beam ； free vibration ； force vibration ； base excitation

參考文獻

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