應用布拉格光纖光柵感測器於複合材料結構應變量測之研究

本研究主要探討埋入式布拉格光纖光柵感測器應用於複合材料之結構應變量測，利用光譜分析儀解析波長飄移與半峰全幅值（FWHM）之變化，並利用應變規作為參考之比較值，同時亦以數值模擬方法及數學模型之解析結果進行驗證。本研究首先設計一預拉伸系統並配合板狀試片規劃，執行挫曲與非均佈負荷試驗，以獲得光纖感測器於不同應變狀態下之訊號變化，並利用其所得之結果，將感測器進一步應用於管狀結構，分別執行壓力試驗與集中負荷之試驗。結果顯示，光纖感測器於應變梯度下仍能量得所對應之應變，因此可以利用應變梯度與半峰全幅值之線性關係取得結構中之應變分佈，並針對其波型變化找出所對應之結構變化。而由管狀試片之壓力試驗，發現波長飄移量與壓力之線性關係，因此可將其視為一壓力感測元件，並由波形之FWHM變化判別管狀結構承受一集中負荷下之結構變形狀態。

關鍵字

光纖光柵感測器；應變；複合材料；非破壞檢測

並列摘要

This thesis aims to measure the uneven strain in composites using embedded FBG sensor. An optical spectrum analyzer (OSA) is employed to monitor the shift in Bragg wavelength of the FBG, and the variations of full width at half maximum (FWHM) in reflected spectra. The strain gauge readings are compared with those of FBG sensor. In addition, finite element (FE) models are developed to verify the response of an embedded FBG to the applied loading. This study first design several plate specimens with different shapes for the buckling test and uneven strain tensile test. The fundamental results with the methodology of strain assessment are then utilized for the pipe composite structures. In this event, the pipe is subjected to the internal pleasure and a concentrated point load separately. It is found that the FBG sensor can measure the strain accurately even though the strain gradient exists. The strain distribution in composite material structures, consequently, can be obtained by the linear relationship of the strain gradient and FWHM. With regard to the pipe structure, it reveals that the internal pressure is related to the shift in Bragg wavelength. Moreover, the fluctuations of the FWHM can be used to determine the strain state while an external load is applied.

並列關鍵字

Fiber Bragg Grating Sensor ； Strain ； Composite Material ； NDT

參考文獻

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應用布拉格光纖光柵感測器於複合材料結構應變量測之研究

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