Research On The Key Technology Of Optical Fiber High Temperature Strain Double Parameter Simultaneous Precise Measurement Sensor Sensorsensor

Real-time monitoring the temperature and strain of the key parts of the skin of the high-speed aircraft is an important technological device to master the thermal stress state during the flight of the aircraft,which can provide the technical guarantee for the safety,reliability and durability of the aircraft structure in service.Owing to optical fiber sensors' unique advantages such as high sensitivity,miniature size,immunity to electromagnetic interference,reliability,heat resistance,corrosion resistance,and multiplexing capability,etc,they have good sensing performance and huge potential application in the high temperature environment for thermal structural health detection.However,there are still some technical problems in the practical application of the optical fiber temperature-strain sensing technology.In this paper,the high temperature strain detection on the skin surface of high-speed aircraft is taken as the research background.The key issues of the paper are improving the thermal stability of optical fiber sensors,realizing the accurate measurement of temperature and strain in high temperature environment and realizing the high sensitivity detection.On the basis of improving thermal stability of the optical fiber sensing structure,the optical fiber high temperature-strain double parameters accurate measurement sensors are designed and manufactured.The accurate measurement the temperature and strain at the same time in the environment of high temperature of these sensors are realized by adopting the temperature compensation method to demodulater.Besides,adoupting the temperature compensation method improved to some extent the demodulation method of temperature and strain in high temperature environment,and improved the accuracy of the system.The main research contents are as follows:(1)An optical fiber high temperature strain sensor based on double thermal regenerated grating cascade structure is designed and manufactured.The thermal stability,temperature and strain response characteristics of the snesor are experimentally studied in high temperature environment,and the experimental results are discussed and analyzed.On the basis of the structure,combining the casing encapsulation technology,two new kinds of high temperature strain sensors are designed and manufactured.By adopting the temperature compensation method to demodulate,the two sensors realize the accurate measurement of temperature and strain in high temperature environment.(2)High temperature heat treatment is used to extend the temperature linear response range of the optical fiber Fabry-Pérot interference structure and improve its thermal stability.A high temperature strain sensor based on the optical fiber Fabry-Pérot interference structure cascading the thermal regenerated grating structure is designed and manufactured.The sensor is used to realize the accurate measurement of temperature and strain in high temperature environment.On this basis,a new optical fiber high temperature strain sensor is designed and manufactured,by using the vernier effect,to realize high strain sensitivity detection.(3)An encapsulation structure of the optical fiber high temperature strain sensor based on silicon carbide composite material is proposed and studied.Through the above research contents,it provides a new idea for the sensing technology needed in the field of skin health monitoring of high-speed aircraft.