Method for calibrating surface-mounted fiber grating strain sensor

Abstract

The invention provides a method for calibrating a surface-mounted fiber grating strain sensor. A standard member of a same material with an object, of which the strain is measured, is selected, a certain surface treatment is carried on the central position of the upper surface of the standard member, and the fiber grating strain sensor is pasted along the horizontal direction. A fiber grating temperature sensor is arranged beside the fiber grating strain sensor, and suspended under an unstrained state. After standing for 48 hours, the standard member with the fiber grating sensor arranged is placed in a constant temperature tank. The fiber grating sensor is connected to a fiber grating demodulation instrument to record the wavelength change of a sensor. The temperature of the constant temperature tank is adjusted, and the standard member is deformed due to expending with heat and contracting with cold and changes the bearing state of fiber gratings. The surface strain of the standard member can be obtained based on finite element analysis, and calibrating strain sensitivity coefficient of the fiber grating strain sensor can be realized through certain calculation. The method minimizes the influence of strain transmissibility change due to pasting substrate material and adhesives, and the reliability of the strain sensitivity coefficient is improved.

Description

technical field [0001] The invention belongs to the technical field of optical fiber grating measurement, and in particular relates to a calibration method for a surface-mounted optical fiber grating strain sensor. Background technique [0002] With the development of fiber grating sensing technology, fiber grating sensor has many unique advantages, such as small size, light weight, anti-electromagnetic interference, and easy large-scale networking to realize real-time distributed measurement, etc., gradually replacing traditional electrical sensors. Sensors are widely used in structural health monitoring. At present, fiber gratings have been successfully applied in aerospace, ocean platforms, civil bridges, and long-span space structures. In the actual application process, the sensitivity of the surface-mounted fiber optic grating strain sensor to strain will vary due to the difference in strain transfer rate caused by the difference in the substrate material and adhesive,...

AI Technical Summary

Problems solved by technology

In the actual application process, the sensitivity of the surface-mounted optical fiber grating strain sensor to strain will vary due to the difference in the strain transfer rate caused by the different substrate materials and adhesives, which will cause the measured value of the optical fiber grating to deviate from the true strain value of the test piece.

[0003] At present, the calibration method of the surface-mounted FBG strain sensor does not consider the influence of the substrate material and adhesive on the strain sensitivity of the FBG strain sensor during the actual strain measurement process, resulting in deviations in the actual strain measurement results.

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