High-sensitivity fiber Bragg grating strain sensor based on flexible hinges

Abstract

The invention discloses a high-sensitivity fiber Bragg grating strain sensor based on flexible hinges. The high-sensitivity fiber Bragg grating strain sensor comprises an elastic strain substrate and a fiber Bragg grating cluster, wherein the elastic strain substrate comprises a transverse beam, an elastic strain unit, a fixed end and displacement amplification mechanisms; two ends of the transverse beam are connected with the fixed end through the elastic strain unit respectively, so that a temperature compensation mechanism is formed; the displacement amplification mechanisms are symmetrically distributed at upper and lower sides of the transverse beam along the transverse axis; the fiber Bragg grating cluster comprises a strain measurement grating and a temperature compensation grating; the strain measurement grating is located at a longitudinal axis position of the elastic strain substrate and is mounted on two longitudinal displacement arms; two ends of the temperature compensation grating are located at a transverse axis position of the elastic strain substrate and the temperature compensation grating is mounted on the transverse beam. The high-sensitivity fiber Bragg grating strain sensor based on the flexible hinges has the advantages of great strain sensitivity, simple and small structure, high reliability, easiness of being mounted and capability of effectively eliminating temperature drift, and is suitable for high-precision strain measurement of a small measurement range in all mechanical structures.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensors, in particular to a flexible hinge-based high-sensitivity optical fiber grating strain sensor, especially suitable for high-precision measurement of strain in various mechanical structures. Background technique [0002] Fiber grating has the characteristics of small size, light weight, explosion-proof, electrical insulation, anti-electromagnetic interference, high reliability, good environmental adaptability, and multiple measuring gratings for different parameters can be arranged on a single optical fiber to form a distributed sensor. , so it has become one of the research hotspots in the field of optical fiber sensing. The fiber grating strain sensor uses the relationship between the grating strain and the Bragg wavelength for strain measurement. It is currently widely used in the fields of health monitoring and safety early warning of large-scale projects such as bridges, dams, mi...

AI Technical Summary

Problems solved by technology

Embedded packaging is installed on the surface to be tested by directly embedding bare gratings into other organic polymer adhesive substrates, but due to the loss of transfer efficiency caused by the strain of the polymer matrix, its strain sensitivity is smaller than that of bare fiber gratings

In the substrate packaging scheme provided by the Chinese invention patent publication number CN101571380, the fiber grating is fixed on the metal substrate with a flat spring structure, so that the two ends of the sensor can bear a large strain (±2500με), and this scheme can realize a large range range of strain sensing, but there is no corresponding improvement in the strain sensitivity of fiber gratings, so it is difficult to apply to small strain measurements in mechanical structures

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