基于CLPG的FBG监测系统及其应用

为了实现可变体机翼的结构健康监测,提出了一种基于级联长周期光栅(cascaded long-period fiber grating,CLPG)的光纤Bragg光栅(fiber Bragg grating,FBG)监测系统.该监测系统以FBG为传感元件,以CLPG为边沿滤波器件,经CLPG调制后FBG反射光功率会发生变化,通过对FBG谐振波长处光功率的探测,从而实现FBG传感信号的监测.监测系统具有结构简单、成本低、解调速度快等优点.利用该监测系统对某型可变体机翼进行结构健康监测,结果表明该监测系统的应变分辨率为2με,实验结果与有限元分析结果相符,最小误差仅为3.27％,表明该监测系统能够用于可变体机翼的结构健康监测.

FBG interrogation system based on CLPG and its application

To realize structural health monitoring(SHM) of morphing wing,a fiber Bragg grating(FBG) interrogation system based on a cascaded long-period fiber grating(CLPG) is proposed in this article.The FBG is used as a sensor and the CLPG is used as an edge filter in this interrogation system.The power of the reflected light of the FBG after being modulated by the CLPG would change;so the sensing signal monitoring of the FBG is realized through detecting the transmission power at the resonant wavelength of the FBG.This system has the advantages such as simple structure,low cost,fast speed demodulation and etc.This system was utilized for the SHM of a certain kind of morphing wing.The result shows that the strain resolution of this system is 2 με.The experiment result was compared with that of finite element analysis,both of the results agree with each other;and the minimum error is only 3.27%.The research results indicate that this FBG interrogation system based on CLPG can be used to achieve the SHM of morphing wing.