The Research Of Humidity And Active Monitoring System Based On Optic Fiber Bragg Grating

In recent years, structural health monitoring (SHM) plays an important role in aerospace, civilengineering and other large projects. The optical fiber Bragg grating (FBG) is one of the mostimportant sensors used in SHM. It has the advantages of small quality, anti-electromagneticinterference and being applicable to quasi-distributed sensing networks. In this paper, the FBG used inhumidity monitoring and composite environment monitoring is studied. An active monitoring systemis researched and designed based on FBG. The works for this article are as follows:1. A humidity sensing probe based on FBG is designed. Selecting a appropriate humiditysensitive material by comparing and analyzing the advantages and disadvantages of various humiditysensitive material, according to the characteristics of FBG. The humidity sensor probe performanceoptimization is realized and the sensing probe is researched by the Optigrating simulation tool.2. The temperature compensation of Optical fiber Bragg grating is realized. A protectivepackaging is designed for the sensor. The parameters of sensor are researched, such as temperaturecharacteristics, humidity characteristics, repeatability, and response time. For concrete structure,internal humidity is difficult to measure. The sensor has realized monitoring the humidity in concrete.The distributed monitoring is realized by researching the distributed monitoring system of humiditybased FBG. According to the results of the compound material experiments in an extremeenvironment performance, the performance impactions of the optical fiber Bragg grating formonitoring in extreme environment is researched.3. A preliminary study of receiving the metal plate surface wave of incentive structure withoptical fiber Bragg grating is researched. Design stimulated interface of the wave based on theLabWindows/CVI which can realize controlling the LAI320-PCI arbitrary waveform card. The lightpath system including the edge filter is built. The photoelectric conversion and other follow-upregulate circuit are designed which realize the process of turning light signal to processed electricalsignal. Through the data collecting system designed by LabVIEW, the real-time data acquisition,processing and storage is realized. The experimental results validate the feasibility of the hardwareand software system, and build the foundation for the future research.