Coaxial Cable Bragg Grating Sensors for Large Strain Measurement with High Accuracy

Abstract

In this paper, a new coaxial cable Bragg grating (CCBG) is developed as a strain sensor and the sensor's capacity for large range strain measurement in structural health monitoring (SHM) is demonstrated for the first time. The sensor device is comprised of regularly spaced periodic discontinuities along a coaxial cable. The discontinuities are fabricated using a computer numerical controlled (CNC) machine to drill holes in the cable. Each discontinuity generates a weak reflection to the electromagnetic wave propagating inside the cable. Superposition of these weak reflections produces a strong reflection at discrete frequencies that can be explained by Bragg grating theory. By monitoring the resonant frequency shift of the sensor's reflection or transmission spectra, strain measurement sensitivity of 20µε and a dynamic range of 50000µε (5%) were demonstrated for axial strain measurements. The experimental results show that the CCBG sensors perform well for large strain measurement needed in structural health monitoring (SHM).

Meeting Name

SPIE Smart Structures + Nondestructive Evaluation and Health Monitoring (2012, Mar. 12-15, San Diego, CA)

Department(s)

Electrical and Computer Engineering

Keywords and Phrases

Bragg grating sensors; Computer numerical controlled; Discrete frequencies; Drill hole; Dynamic range; Grating theory; Large strains; Measurement sensitivity; Resonant frequency shift; Sensor device; Strain sensors; Transmission spectrums, Bragg gratings; Cables; Coaxial cables; Electromagnetic wave propagation; Natural frequencies; Strain measurement; Structural health monitoring, Sensors; Coaxial cable Bragg grating; Large strain

International Standard Book Number (ISBN)

978-0819490025

International Standard Serial Number (ISSN)

0277-786X

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2012 SPIE, All rights reserved.

Publication Date

01 Mar 2012

Link to Full Text

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