埋入式光纖感測器的動態響應研究

Abstract

光纖除了在通訊方面應用外，利用光纖干涉原理製作之感測器也逐漸被應用於材料或結構的長期健康監測。本文推導埋入式光纖感測器在複合材料層板中的動態應響，複材層板內對稱與反對稱板波之位移與應力擾動會影響埋入式光纖感測器的主應變，改變光纖感測器的折射率及長度，使得光傳遞相位與參考光發生干涉。本文假設光纖直徑極為微小，簡化了光纖感測器與板波間的動態互制關係，有助於未來有關光纖感測器相位變化的數值計算。

Beaides application in communication, fiber optic sensors based on the principle of interferometer, are being increasingly used in structures to monitor health and integrity. Dynamic response of the embedded fiber optic sensor insonified by an incident plate wave in compostie plates is formulated in this study. The principal straing of the embedded fiber are influenced by the disturbances of the extensional waves and flexural waves. The refracted waves into optic fibers alter the refractive indices and gauge length of the fiber optic sensor in one arm of the interferometer. The phase changes of interferometer are resulted from the variation of environment around the sensor. This study approximates the dynamic interaction between fiber optic sensors and the composite plates by ignoring some terms that have small contribution ot results since the radii of optic fibers are generally very small. It is of benefit for future simulation of dynamic phase variations from the fiber optic sensors.