The Analysis of FBG Central Wavelength Variation with Crack Propagation Based on a Self-Adaptive Multi-Peak Detection Algorithm.

Weifang Zhang,Meng Zhang,Yan Zhao,Wei Dai,Bo Jin,Xiangyu Wang

doi:10.3390/s19051056

Abstract

We propose a peak seeking algorithm to extract the damage characteristic-variation of central wavelength to monitor the crack damage status in aluminum alloy plates using surface bonded fiber Bragg grating (FBG) sensors. The FBG sensors are sensitive to the uniform and non-uniform strain distribution along their longitudinal direction, and the effect appears in the power spectrum of the reflected light from the gauge section. In this paper, we propose a fast-self-adaptive multi-peak seeking algorithm to detect the central wavelength shifting of the FBG reflection spectrum with the crack propagation. The proposed peak searching algorithm results point to a significant improvement compared to other conventional methods. Then the central wavelength shifting is applied to explain the crack propagation behavior of the aluminum plates under quasi-static tensile test conditions. The different damages feature changing intervals which are associated with the crack position and the FBGs location, demonstrating that central wavelength shifting performs as an indicator to detect structural crack damage.

Highlights

Introductionfiber Bragg grating (FBG) sensors have shown broad application prospects in structure health monitoring due to their advantages, such as small size, light weight, high resolution, multiplexing capability and immunity to electromagnetic fields [2]
Structure health monitoring (SHM) is a critical process for enhancing structural integrity or validity.Sensing technologies using various sensors for intelligent structure have been investigated [1].fiber Bragg grating (FBG) sensors have shown broad application prospects in structure health monitoring due to their advantages, such as small size, light weight, high resolution, multiplexing capability and immunity to electromagnetic fields [2]
The damage monitoring experimental procedure was carried out as described in Section 3, and the healthy and damage signals received are used to evaluate the effectivity of the central wavelength algorithm and monitor the damage crack propagation

Summary

Introduction

FBG sensors have shown broad application prospects in structure health monitoring due to their advantages, such as small size, light weight, high resolution, multiplexing capability and immunity to electromagnetic fields [2]. FBG sensors have shown great potential for monitoring strain [3], vibration [4] and temperature [5], various studies based on the FBG sensitivity characteristics have been performed to detect different environmental states as strain sensors, temperature sensors, etc. The stress concentrated sections caused by crack damages in structures must be monitored. Grating gauges can sense inhomogeneous stress/strain and the reflection spectrum of the bonded FBG sensor, which includes information on strain distribution, which is useful for monitoring the damage status

Methods

Results

Conclusion