Research On The Application Of Aircraft Structural Health Monitoring Using The Optical Fiber Sensing Technology

Single life monitoring can effectively ensure the service life of main battle aircraft, the focus of the single life monitoring is accurately record the key of each plane structure, degree of fatigue damage of dangerous parts. Structural strain measurement method based on optical fiber sensing technology is widely used in civilian areas, but in view of the main battle aircraft structure strain measurement is still in the theoretical validation phase. In this paper, the optical fiber sensing technology in the researches on the application aspects of aircraft structure strain measurement, through theoretical analysis and experimental verification, to establish a set of strain measurement system for main battle aircraft. This work is as follows:1.Using the coupled-mode theory of Bragg grating reflection spectrum function was deduced, center wavelength and the expressions of the effective refractive index, analyzes the structure of the Bragg grating sensor and sensing mechanism of Bragg grating temperature sensing model is established and the strain sensor model, and experimental verification.2.Bragg grating packaging technology is discussed, according to the characteristics of the aircraft structure strain, respectively adopt different packaging technology design and large strain sensor, the high sensitivity strain sensor for the design of two kinds of sensors, the finite element analysis method is used for modeling and analysis of the characteristics of the sensor is studied through experiment.3.Established is suitable for the plane strain measurement of demodulation system structure, the optical power demodulation mix reuse and adjustable cavity method through the linear demodulation method to realize the center of the Bragg grating wavelength demodulation signal, the method of using peak positioning the peak valley.4.On a certain type of aircraft, according to the actual aircraft structural strain monitoring requirements, we have two kinds of sensor and demodulation system for experimental verification, and compared with traditional strain gauge measurement data.