複合材料內埋光纖光柵感測器之研究

The stress and measurement analyses of Fiber Bragg Grating sensor embedded in composite material

陳智宏(Zhi-Hong Chen)

指導教授 ： 何旭川

元智大學/工程學院/機械工程學系/碩士(2001年)

摘要

隨著智慧型材料結構及量測技術的快速發展，將光纖光柵感測器埋入複合材料使其成為智慧型材料結構是近幾年發展的重點。本文結合力學分析、光彈理論推導光纖光柵感測器埋入複合材料結構之力學行為及量測靈敏度。力學分析係以光纖、被覆、樹脂及主結構組成的四個同心圓為分析幾何模型，推導主結構遠場應變傳遞至光纖的應變，再應用光彈理論求得光纖應變及溫度變化所產生的光纖光柵布拉格波長偏移量，做為量測結構應變與溫度的理論基礎。本文依主結構遠場負載型式，定義五種量測靈敏度包括單位軸向應變量測靈敏度、單位橫向應變量測靈敏度、單位軸向應力量測靈敏度、單位橫向應力量測靈敏度及單位溫度量測靈敏度等，可用以評估光纖光柵之量測特性，並就被覆材料性質及厚度對量測的影響進行參數分析。為能同時量測結構軸向、橫向應變及溫度，本文將光纖內之光柵分成三段，每段外圍塗以不同之被覆材料，使每段光柵反射回來的布拉格波長均不同，再由此三種不同反射波長求得結構軸向應變、橫向應變及溫度。

關鍵字

光纖光柵感測器 ； 靈敏度 ； 被覆

並列摘要

Fiber Bragg grating are receiving considerable attentions in recent years, especially in the area of smart structures. In this presentation, theories of elasticity and optic are incorporated to study the mechanical behavior and measurement performance of fiber Bragg grating sensor embedded composite structure . A four-layer concentric cylinder model which includes optic fiber, fiber coating , matrix and host material, is adopted to derive the relation of the strains in the host material far from the optic fiber to the strain inside the optic sensor. The shift of the Gragg wavelength due to the strains and temperature in the optic fiber is also derived. In this presentation , various sensitivities of measurement are defined according to the types of loading, such as longitudinal strain, transverse strain, longitudinal stress, transverse stress and temperature. The sensitivity can be used to evaluate the measurement performance of the fiber Bragg grating sensor. The effects of coating on the measurement sensitivity are included through the parametric study. In order to measure the longitudinal strain, transverse strain, and temperature simultaneously, the Bragg grating in the fiber is divided into three sections, each section coated with different material. Thus, the Bragg wavelength shifts different in each section. Using these three different Bragg wavelength shifts, one is able to measure the longitudinal strain, transverse strain and temperature inside the host material.

並列關鍵字

optic fiber bragg grating sensor ； sensitivity ； coating

參考文獻

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