Bragg optical grating axial heterogeneous strain reconstruction method based on genetic planning

Abstract

The invention discloses a genetic programming-based reconstruction method for axial nonuniform strain of the Bragg gratings and belongs to the field of nonuniform strain reconstruction. The method comprises the following steps: acquiring a structural response signal, randomly generating a Bragg grating axial nonuniform strain distribution expression, calculating a simulated reflection spectrum ofa Bragg grating, calculating a fitness function, optimizing the nonuniform strain distribution expression through the reproduction, intersection and variation operations of the genetic programming, and finally, repeating the last two steps till a preset maximum number of generations is reached. The method uses both a genetic programming algorithm and a modified T-array reflection spectrum formulation to reconstruct the grating axial nonuniform strain distribution expression, expresses a function expression in form of a binary tree without making any assumption concerning the grating axial strain distribution in any form in advance during the random generation of the strain distribution expression and optimizes any individual expression through the genetic manipulation of the binary tree. The method can accelerate convergence and improve calculation efficiency.

Description

technical field [0001] The invention relates to a non-uniform strain reconstruction method, in particular to a genetic programming-based Bragg grating axial non-uniform strain reconstruction method, which belongs to the field of non-uniform strain reconstruction. Background technique [0002] In recent years, Fiber Bragg Grating (FBG), as an important device for fiber optic communication and fiber optic sensing, has aroused great interest in its application in the field of health monitoring. When the stress, strain, temperature and other physical quantities of the FBG’s environment change, it will cause changes in the grating period or the effective refractive index of the fiber, resulting in changes in the shape of the reflection spectrum of the FBG. By measuring the change in the shape of the reflection spectrum, we can obtain Measure changes in physical quantities. [0003] It is a very difficult engineering inverse problem to reconstruct the axial strain and strain grad...

AI Technical Summary

Problems solved by technology

At present, genetic programming has been widely used in the fields of automatic design, pattern recognition, robot control, synthesis of neural network structures, symbol regression, music and image generation, but there is no related research in the field of health monitoring

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