Matching fiber grating acoustic emission sensing system with temperature compensation function

Abstract

The invention provides a matching fiber grating acoustic emission sensing system with a temperature compensation function. The system comprises a pump source, an optical wavelength division multiplexer, an erbium-doped fiber, a first optical isolator, a first fiber coupler, a first fiber Bragg grating, a second optical isolator, a second fiber coupler, a second fiber Bragg grating, a photoelectric detection circuit, a pre-amplification circuit, an analog-to-digital conversion circuit, a field programmable gate array (FPGA) and a computer. The system is mainly used for structural health monitoring and the damage detection of important structural parts; and compared with a power fiber Bragg grating emission sensing system, the system with the temperature compensation function has the advantages that the influence of temperature change on a fiber Bragg grating sensor can be effectively reduced, the detection accuracy of the fiber Bragg grating sensor is improved, equipment cost is reduced, and practical engineering application is facilitated.

Description

technical field [0001] The invention belongs to the technical field of acoustic emission detection, in particular to a matching optical fiber grating acoustic emission sensing system with temperature compensation. Background technique [0002] The phenomenon that metal materials or composite materials deform or break due to stress, and release strain energy in the form of elastic waves is called acoustic emission. Acoustic emission technology is to use high-sensitivity acoustic emission sensors to collect these acoustic emission signals from material defects in real time, and through the analysis and processing of these acoustic emission signals, to understand the development of material defects, so as to realize the monitoring of material health . Due to the advantages of dynamics, sensitivity, integrity, and universality of acoustic emission technology, it has been widely used in aviation, aerospace, seismic monitoring, and metal processing. [0003] The fiber Bragg grat...

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Problems solved by technology

[0004] Existing fiber grating sensing systems such as Chinese patents CN200920129512.2 "A Fiber Bragg Grating Sensor and Fiber Bragg Grating Sensing System" and CN200610130121.3 "Fiber Bragg Grating Sensing System" can simultaneously measure temperature and strain; the existing optical fiber Acoustic emission detection systems such as Chinese patent CN201110207340.8 "An acoustic emission signal sensing system based on fiber Bragg gratings" and other acoustic emission detection systems are suitable for detection in a constant temperature environment. If the ambient temperature changes greatly, it will affect the optical fiber Bragg grating. Grating detection accuracy

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