Decoupling method of strain and temperature aliasing signal of fiber grating sensor under dynamic loading

Abstract

The invention provides a method for decoupling the strain and temperature aliasing signals of an optical fiber grating sensor under dynamic loading, and belongs to the technical field of health monitoring of intelligent materials and structures. The method includes the following steps: Step 1, constructing a distributed fiber Bragg grating sensor strain and temperature monitoring system; Step 2, real-time monitoring and collection of strain and temperature aliasing response signals of the fiber Bragg grating sensor of the measured structure; Step 3, strain and temperature of the fiber Bragg grating sensor Feature extraction and analysis of the aliasing response signal: the signal S is decomposed by the analytical modal decomposition method; the fast-changing signal is used to represent the strain caused by the dynamic load, and the slow-changing signal is used to represent the temperature change information of the structure; step 4, the measured structural strain Reconstructed with temperature monitoring information. The invention only needs to use one fiber grating sensor, and can realize the decoupling of strain and temperature aliasing signals.

Description

technical field [0001] The invention belongs to the health monitoring of intelligent materials and structures, and specifically proposes a decoupling method for strain and temperature aliasing signals of a fiber grating sensor under dynamic loading. Background technique [0002] Due to its high sensitivity, immunity to electromagnetic interference, and reusability, fiber grating sensors have been rapidly developed and widely used in the past 30 years. Fiber Bragg Grating sensors use fiber Bragg gratings as sensitive units, which are embedded in target structures to monitor strain, vibration, etc. Fiber Bragg grating has excellent characteristics such as high isolation, low insertion loss, flexible adjustment of wavelength and bandwidth, and polarization independence. However, its central reflection wavelength drifts with temperature. These aspects are limited, so a variety of fiber grating sensor temperature compensation schemes have been proposed. [0003] Common fiber gr...

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Problems solved by technology

However, due to the use of single-point gluing in this packaging structure, and a certain prestress must be applied before bonding, it is easy to cause weak bonding and poor long-term stability.

In addition, Iwashima T and others proposed to use negative expansion materials for packaging, which solved the problem of weak adhesion. However, this packaging method cannot measure strain and can only be used in the field of communication.

At the same time, due to the high price of materials used in this method, it is only suitable for single-channel probe measurement mode

[0004] Ning Chenxiao and others adopted a simple and low-cost temperature compensation method, that is, using a reference fiber grating to compensate the sensing grating, which made the fiber grating strain sensor a step towards practicality, but this method needs to increase the temperature Compensating fiber gratings will lead to an increase in the monitoring system burden and monitoring costs, which makes its application have certain limitations

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