Studying the effect of strain induced birefringence on the sensitivity of FBG sensors for Guided wave measurements

Conference paper (2022)

Authors

Rohan Soman Polish Academy of Sciences
L. Fazzi Structural Integrity & Composites - Aerospace Engineering
A. Nokhbatolfoghahai Structural Integrity & Composites - Aerospace Engineering
R.M. Groves Structural Integrity & Composites - Aerospace Engineering
Wieslaw Ostachowicz Polish Academy of Sciences
Research Group
Structural Integrity & Composites (Aerospace Engineering) (TU Delft)
Copyright: © 2022 Rohan Soman, L. Fazzi, A. Nokhbatolfoghahai, R.M. Groves, Wieslaw Ostachowicz
DOI
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https://doi.org/10.1117/12.2612487
Plate Sensitivity Guided waves Fiber optic sensors Fiber Bragg grating birefringence
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Published Date

2022

Language

English

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Faculty

Aerospace Engineering

Department

Aerospace Structures & Materials

Research Group

Structural Integrity & Composites

Abstract

To perform active structural health monitoring (SHM), guided waves (GW) have received great interest as they can inspect large areas with a few sensors and are sensitive to barely-visible structural damages. Fiber Bragg grating (FBG) sensors offer several advantages such as small size, low weight and ability to be embedded but their use has been limited for GW sensing due to their limited sensitivity while using spectrometers. FBG sensors in the edge-filtering configuration have overcome this issue with reasonable sensitivity and there is a renewed interest in their use. It is well known that when subjected to a transverse strain, the circular cross-section of the fiber deforms into an elliptical shape generating the birefringence phenomenon. This deformation, influences the coupling mode of the light inside the FBG and hence, modifies the resulting reflectivity spectrum. This paper investigates how controlled changes in the reflectivity spectrum can be introduced using different transverse loads. The effect of the modified spectrum on the sensitivity of the FBG for GW measurements is then studied. The study also investigates the effect of the transverse strain on the coupling of the GW from the structure into the fiber.