Suspended type fiber grating vibration sensor

Abstract

The invention discloses a suspended type fiber grating vibration sensor, which comprises a shell, a signal transmission fiber, a protecting sleeve, a fiber grating and a vibrator, wherein the shell comprises a hollow bolt and a cylindrical protecting shell, the signal transmission fiber and the protecting sleeve coated out of the signal transmission fiber are stuck at the hollow top end of the hollow bolt through a colloid, the fiber grating is arranged on the lower end of the signal transmission fiber, a layer of an elastic polymer material is coated out of the fiber grating, and the lower part of the fiber grating is connected with the vibrator through a spring; the vibrator is suspended in the sensor through the spring and is coaxial to the fiber grating; and silicon oil is filled in an inner space of the sensor shell. According to the invention, by adopting a suspended structure, the measuring frequency of the sensor is greatly improved without a limit of inherent frequency of a mechanical structure attached on the fiber grating; the measuring stability can be improved by damping liquid in the suspended type fiber grating vibration sensor; the suspended type fiber grating vibration sensor is based on full optical signal design, and has the advantages of good stability, electromagnetic interference resistance, good waterproof property and convenience for realizing quasi-distributed multi-point real-time monitoring.

Description

technical field [0001] The invention relates to a suspended fiber grating vibration sensor, which is suitable for health monitoring of large structures such as bridges. Background technique [0002] Vibration is a ubiquitous phenomenon in nature, and vibration signals need to be detected in fields such as structural engineering, mechanical equipment, aviation and mining. At present, electrical vibration sensors are usually used, but they are easily affected by external factors, especially in harsh environments such as strong electromagnetic interference, high temperature and humidity, high voltage, high current, and loud noise. Traditional vibration sensors are difficult Effectively measure, not even work. [0003] Fiber Bragg fiber grating is an emerging basic optical fiber device in the world since the 1990s. It is used in the field of sensing with good durability, anti-electromagnetic interference, small size, quasi-distribution measurement, anti-humidity, and has nothin...

AI Technical Summary

Problems solved by technology

At present, fiber grating vibration sensors are mostly designed based on cantilever beam structure, fiber grating is prone to chirp phenomenon, and the sensor sensitivity is low

In order to further improve the performance of the fiber grating vibration sensor, someone has developed a fiber grating vibration sensor based on the L beam, but the free vibration attenuation is slow when the sensor is working, which affects the working performance of the sensor

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