應用光纖光柵感測器量測結構溫度與應變動態響應

Simultaneous measurements of thermal cycles and random vibration using fiber Bragg grating sensors

蔡至倫(Tsai Jr-Luen)

指導教授 ： 何旭川

元智大學/工程學院/機械工程學系/碩士(2012年)

https://doi.org/10.6838/YZU.2012.00358

摘要

光纖光柵承受機械應變與溫度變化所產生之反射波長偏移，可用於量測結構應力、應變、位移、溫度、振動與壓力等物理量。本文以光纖光柵結合光濾波器與光偵測器，將光纖光柵反射光波長偏移轉換為光強度電壓，用於量測結構動態變化。以自由振動實驗校正光強度電壓與應變關係，並於各個定溫下校正光強度電壓與溫度關係。利用校正結果量測懸臂樑結構承受隨機振動之應變變化與熱循環之溫度變化，將量測結果分別與應變規及熱電偶比較，驗證量測之準確性。最後將懸臂樑試片上下表面中央區域分別黏上相同反射光波長之光纖光柵，以相同實驗方法校正光強度電壓與溫度、應變關係。利用校正結果量測懸臂樑結構同時承受隨機振動與熱循環狀態下之應變變化與溫度變化。

關鍵字

光纖光柵 ； 光濾波器 ； 光強度 ； 隨機振動 ； 熱循環

並列摘要

Basing on the shift of Bragg wavelength, fiber Bragg grating sensors (FBG) have been developed to measure a variety of physical parameters such as stress, strain, displacement, temperature, vibration and pressure. In order to measure the dynamic responses, the FBG was incorporated with the optical filter and photo detector to convert the shift of Bragg wavelength to a change of light intensity. The relationship between the temperature change and light intensity was calibrated in a thermal chamber, while the relationship between the mechanical strain and light intensity was calibrated using free vibration test. In the experimental test, a cantilever beam was subjected to thermal cycling and random vibration at the same time. Two FBG sensors were attached on the top and bottom surface of the test specimen to measure the temperature change and mechanical strain simultaneously. The measuring results from the FBG sensors were compared with the strain gauge and thermal couple. Good agreement demonstrates that FBG sensors are capable of measuring the dynamic responses of temperature change and mechanical strain.

並列關鍵字

thermal cycling ； fiber Bragg grating ； random vibration ； optical filter ； light intensity

參考文獻

[18] 周志成，”應用光纖光柵感測器量測結構應變、溫度及振動”，元智大學機械工程研究所碩士論文 (2006)

[19] 謝文斌，”結合光纖光柵與Mach-Zehnder光干涉量測結構振動”，元智大學機械工程研究所碩士論文 (2007)

[22] 林威男，” 光纖光柵量測結構應變與溫度及水位監測研究

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