Sensitivity calibration method of fiber Bragg grating strain sensor

Abstract

The invention, which belongs to the measuring technology, relates to a sensitivity calibration method of a fiber Bragg grating strain sensor. In the invention, a four-point-bending equal-strength beam is used to calibrate a fiber Bragg grating strain sensor sensitivity. The method is characterized by: determining a position where the fiber Bragg grating is pasted on a standard beam; installing the standard beam on a fixed platform and using a standard beam fulcrum to support the standard beam on the platform; adjusting loading points of a loading beam so as to achieve uniform force on the standard beam; connecting the fiber Bragg grating sensor with a fiber Bragg grating demodulation device; applying a transverse force which is perpendicular to an axis on a midpoint of the loading beam, wherein an effect direction of the transverse force is superposed with a longitudinal symmetrical plane of the standard beam; applying load on the standard beam; using the fiber Bragg grating demodulation device to record wavelength change of the fiber Bragg grating; then calculating the strain of a beam surface and a sensitivity coefficient of the fiber Bragg grating so as to realize calibration. By using the method of the invention, uniform loading can be achieved; the uniform and stable force of the fiber Bragg grating can be guaranteed; a reliable parameter can be provided for technology research and measurement of the fiber Bragg grating sensor.

Description

technical field [0001] The invention belongs to measurement technology and relates to a method for calibrating the sensitivity of an optical fiber grating strain sensor. Background technique [0002] At present, modern structural health monitoring and diagnosis are getting more and more attention from the society, and the use of fiber grating sensors for structural health monitoring has also expanded from bridges, tunnels, buildings, earthquakes, etc. to aerospace fields. The rapid development of fiber grating sensors also requires higher and higher measurement accuracy. At present, the sensitivity of the fiber grating used is based on the coefficient provided by the supplier, which is a general coefficient, and the accuracy is low. When the measurement accuracy is high or the environmental conditions change, the change of the coefficient has affected the measurement result. [0003] So far, there is no reliable and accurate calibration method for the calibration of optical...

AI Technical Summary

Problems solved by technology

Now the sensitivity of the fiber grating used is based on the coefficient provided by the supplier, which belongs to the general coefficient, and the accuracy is low. When the measurement accuracy is high or the environmental conditions change, the change of the coefficient has affected the measurement result.

[0003] So far, there is no reliable and accurate calibration method for the calibration of optical grating strain sensor sensitivity, and precise sensitivity is an important parameter to ensure the accuracy and repeatability of measurement results

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