Fiber bragg grating high-frequency acceleration sensor based on flexible hinges

Abstract

The invention provides a fiber bragg grating high-frequency acceleration sensor based on flexible hinges. The fiber bragg grating high-frequency acceleration sensor based on the flexible hinges is composed of a composite base body, an optical fiber and a sensor shell. The composite base body is fixedly arranged in the sensor shell and composed of a base, the two flexible hinges and two inertia mass blocks. The two inertia mass blocks are connected with the base through the flexible hinges respectively, the two sides of the connecting portion are provided with horizontal notches respectively, and a vertical notch is vertically formed between the two inertia mass blocks. The optical fiber penetrates through the two sides of the sensor shell and is arranged in symmetrical optical fiber grooves formed in the two inertia mass blocks. The optical fiber between the two optical fiber grooves is provided with a bragg grating. The bragg grating is arranged at a groove in the center of the position between the two inertia mass blocks. The optical fiber located in the optical fiber grooves is bonded and fixed to the inertia mass blocks through adhesives. The fiber bragg grating high-frequency acceleration sensor based on the flexible hinges is integrated in core structure and convenient to install; the two inertia mass blocks are in lateral symmetry, so that tension strain of the fiber bragg grating bearing inertia force is multiplied, and the sensitivity of the sensor is greatly improved.

Description

technical field [0001] The invention belongs to the technical field of acceleration sensors, in particular to a fiber grating high-frequency acceleration sensor based on flexible hinges, and is especially suitable for medium-high frequency vibration testing and structural health monitoring of various mechanical equipment. Background technique [0002] An acceleration sensor is a sensor that senses acceleration signals based on inertial effects. Fiber optic acceleration sensors have received widespread attention in the remote monitoring of structural vibration parameters. Optical fiber acceleration sensors have superior performance in many aspects, such as electrical insulation, anti-electromagnetic interference, and good distributed measurement capabilities. These properties make the optical fiber acceleration sensor have unique advantages in many special fields that require remote operation in harsh environments, such as oil and natural gas mining, petrochemical electromech...

AI Technical Summary

Problems solved by technology

[0003] The Chinese patent No. ZL200510019733.0 "Fiber Bragg Grating Vibration Acceleration for Harmonic Matched Filter Demodulation" adopts a cantilever beam structure, on which a fiber grating is directly pasted, which can only measure vibration in the low frequency range, and cannot satisfy high frequency test requirements

The US patent "FIBER OPTIC ACCELEROMETER" with the patent number US7137299B2 uses four springs as elastic elements to expand its frequency measurement range, but the four springs in this structure are not easy to adjust and balance, which may easily cause the fiber grating to break

The U.S. patent "HIGHLY SENSITIVE CROSS AXIS ACCELEROMETER" with the patent No. US6891621B2 discloses a high-sensitivity acceleration sensor suitable for harsh environments. The acceleration sensor utilizes a hinge to connect a vibrating mass body with the base. When driving in the horizontal direction, the vibration mass of the sensor will swing around the hinge, and the optical fiber is connected between the base and the housing of the acceleration sensor in an alternate tension and compression manner. Although this structure can obtain high sensitivity, its resonance frequency is low.

Images