Corrugated pipe-based optical fiber stress sensing device

Abstract

The invention discloses a corrugated pipe-based optical fiber stress sensing device. An A-side deformation tooth and a B-side deformation tooth which correspond to each other in a staggering manner are respectively arranged on two opposite surfaces at the sunk place of a corrugated pipe wall, and a signal optical fiber is clamped between two deformation teeth. When a corrugated pipe expands and deforms under stress, a distance between the A-side deformation tooth and the B-side deformation tooth on the corrugated pipe wall changes, so that a bending curvature of the signal optical fiber clamped between the two deformation teeth changes, and bending loss of the signal optical fiber changes, the change degree of the bending loss of the signal optical fiber can be obtained through a test unit, and the stress size of the corrugated pipe can be calculated. The corrugated pipe and an optical fiber micro-bending structure are organically combined to form an intelligent device with many advantages of high precision, soundness and durability, strong adaptability and convenience and flexibility for use. The corrugated pipe-based optical fiber stress sensing device has broad application prospect.

Description

technical field [0001] The invention belongs to an optical fiber stress sensing device, in particular to a device based on a corrugated tube and achieves the purpose of stress sensing by detecting the change of optical fiber microbending loss. Background technique [0002] The bellows has a wide range of uses. The bellows is an elastic element that can be deformed longitudinally and is basically not deformed laterally. In terms of sensing, it can be used for various measurement, adjustment, control, and sensing instruments. And seals, etc.; as the flexible section of the expansion joint, it can be used to compensate for the axial, lateral and angular displacement of the pipeline due to temperature difference, and can also be used in the pipeline to compensate for positional deviation, absorb the vibration of the pipeline, etc. It can be seen that the bellows, as a key element in the sensing device, can be adapted to a variety of practical application environments. [0003] ...

AI Technical Summary

Problems solved by technology

However, the fiber grating type sensor also has disadvantages: 1) the dynamic range is small, the fiber grating is generally made of bare optical fiber exposed to ultraviolet rays, its intensity value is low, and the deformation ability is small, resulting in a small dynamic range; in addition, a good Encapsulation can only be used, and encapsulation is a process with high cost; 2) The cost of test equipment is high, and it needs to be used with high-priced optical wavelength demodulation equipment

[0008] The solution provided by Chinese patent 87107210 is based on the microbending loss of the optical fiber to realize the microbending optical fiber strain gauge, but because it is realized by two flat plates, the size of the flat plates cannot be too large, so that the length of the optical fiber that can be bent Limited, which hinders the improvement of the dynamic range and accuracy of this type of fiber optic sensor

In addition, the adjustable distance of the relative movement of the two boards is only a few hundred microns at most, and the two boards must be kept basically parallel during the movement, so this type of sensor has high requirements for the mechanical structure of the adjustment, which not only increases the implementation cost, but also It also limits the improvement of the dynamic range and accuracy of this type of fiber optic sensor

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