Spoke type fiber bragg grating fatigue sensor with temperature self-compensation function

Abstract

The invention discloses a spoke type fiber bragg grating fatigue sensor with a temperature self-compensation function. The sensor comprises an elastomer and a fiber bragg grating, wherein the elastomer consists of a rim, a hub and spokes, wherein the rim is concentrically sheathed to the outer side of the hub; the rim and the hub are fixedly connected through four spokes which are evenly distributed; peripheral screw through holes are evenly distributed on the rim; the center of a circle of the hub is provided with a central thread through hole; the fiber bragg grating comprises a No. 1 grating, a No. 2 grating and a No. 3 grating, wherein the three gratings are connected in series in one fiber; four spokes are arranged in sequence according to mark numbers; a phase angle of 180 degrees isformed between the No. 1 and No. 3 spokes; a phase angle of 180 degrees is formed between the No. 2 and No. 4 spokes; the No. 1 grating is pasted to the front side surface of the No.1 spoke; the No.2 grating is pasted to the rear side surface of the No.3 spoke; the No. 3 grating is pasted to the middle of the upper surface of the No.2 or No.4 spoke; the pasting direction of the No. 1 grating andthe pasting direction of the No.2 grating are the same, are both in a tensile strain direction and form an angle of 45 degrees with a neutral surface; and the pasting direction of the No. 3 grating is vertical to the length direction of the No. 2 or No. 4 spoke, and the pasting thickness is greater than 1mm.

Description

technical field [0001] The invention belongs to the technical field of sensors, in particular to a wheel-spoke fiber grating fatigue sensor with temperature self-compensation function. Background technique [0002] In the fatigue testing machine, the commonly used fatigue sensors are mainly electrical measuring sensors. Most electrical measuring sensors adopt the transformation principle of resistance strain type. By applying load, the elastic body of the sensor is deformed, and then surface strain is generated, and then the resistance strain is applied. The strain gauge is induced to measure the strain, and finally the variation of the resistance strain gauge is converted into an electrical signal for output. [0003] Although the electrical measuring sensor has the characteristics of good dynamic response and high sensitivity, due to the complicated bridge circuit of the strain gauge, it is easily affected by electromagnetic interference. Fatigue failure occurs, resulting...

AI Technical Summary

Problems solved by technology

Although the FBG sensor can measure strain, temperature and other physical parameters, in the actual application of the FBG sensor, the strain and temperature will cause the central wavelength of the FBG to drift at the same time, making it impossible to distinguish the measurement results, resulting in Temperature-strain cross-sensitivity problem, which has been affecting the application of fiber Bragg gratings in the field of sensors

[0005] Taking the existing wheel-spoke fiber optic force sensor as an example, two gratings are generally used in the sensor. The pasting positions of the two gratings are both on the side of the spoke of the elastic body and are relatively distributed. The first grating is used for sensing tensile strain, and the second grating Branched gratings are used to induce compressive strain. However, in the traditional elastic body structure design, only the strain in the tension direction can be guaranteed, but the strain uniformity in the compression direction cannot be guaranteed, and the inhomogeneity of the strain will cause the grating The reflection spectrum produces fission, so it will seriously affect the measurement accuracy of the sensor

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