Quasi-distributed composite structure strain and temperature detection system

Abstract

The invention relates to a quasi-distributed composite material structure strain and temperature detection system. The output light of a broadband light source enters the input end of a 2×2 optical fiber coupler through an optical fiber isolator; the output light of the 2×2 optical fiber coupler enters a 1×m optical fiber coupler. The input end of the switch; the output light of the 1×m optical switch enters the m×n network fiber grating sensor head; the reflected light of the m×n network fiber Bragg grating sensor head passes through the 1×m optical switch and the 2× 2. The fiber coupler enters the input end of the optical fiber tunable F-P filter; the output light of the optical fiber tunable F-P filter passes through the photoelectric conversion module, signal amplifier, data acquisition card and computer successively, and the data is processed by the computer processing and display. The invention utilizes an optical fiber adjustable F-P filter to realize the wavelength demodulation of all sensing fiber grating reflected signal light, and has the advantages of anti-electromagnetic interference, all-fiber type measurement, multiple measurement points, remote monitoring and non-destructive measurement, etc.

Description

technical field [0001] The invention relates to the technical field of fiber grating sensing, in particular to a quasi-distributed composite material structure strain and temperature detection system with multi-parameter and multi-point measurement functions. Background technique [0002] A fiber grating is an optical element that establishes a certain spatial refractive index periodic distribution in an optical fiber, so that the propagation characteristics of light can be changed in it. A fiber grating is an optical element that establishes a certain spatial refractive index periodic distribution in an optical fiber, so that the propagation characteristics of light can be changed in it. When the broadband light is incident on the fiber Bragg grating, the central wavelength of the reflected light (Bragg wavelength) λ B , given by the Bragg equation: λ B =2nΛ [0003] Among them, n is the effective refractive index of the fiber core, and Λ is the grating period. Since th...

AI Technical Summary

Problems solved by technology

In the prior art, if a fiber grating is used to measure multiple points, a spectrometer is often used to measure the wavelength signal, so that the cost of wavelength signal demodulation is relatively high; and the number of measurement points is limited by the bandwidth of the light source; and when the light source When the output power is constant, the larger the number of measurement points, the lower the signal-to-noise ratio, resulting in larger measurement errors

Therefore, the current fiber grating point multi-parameter system is usually low in cost performance, difficult to realize remote monitoring and poor in repeatability. At the same time, a large amount of useless data needs to be screened during measurement, and the signal-to-noise ratio of the measurement is not high, which affects the accuracy of the measurement.

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