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Proceedings Paper

Health monitoring of bonded composite repairs using fibre optic sensors
Author(s): Henry C. H. Li; Olivier Dupouy; Israel Herszberg; Paul R. Stoddart; Claire E. Davis; Adrian P. Mouritz
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Paper Abstract

Structural health monitoring (SHM) technology may be applied to composite bonded repairs to enable the continuous through-life assessment of the repair efficacy. This paper describes an SHM technique for the detection of debonding in composite bonded patches using fibre optic Bragg grating strain sensors. A two sided doubler repair is examined in this paper. A finite element study was conducted which showed that the strain in the debonded region changed significantly compared to the undamaged state. A differential strain approach was used to facilitate the detection of debonds, where two sensors were strategically positioned so that their strain differential increased with the disbond length. With the use of matching gratings, this technique greatly reduces the interrogation equipment requirement by converting spectral information into an intensity-modulated signal, thus allowing a threshold value to be set to indicate imminent critical repair failure. An experimental investigation was conducted, using carbon/epoxy patches to carbon/epoxy substrates, to validate the theoretically predicted results. The experimental measurements agreed well with the numerical findings, indicating that the proposed scheme has great potential as a simple monitoring technique for composite bonded repairs.

Paper Details

Date Published: 11 April 2006
PDF: 10 pages
Proc. SPIE 6174, Smart Structures and Materials 2006: Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems, 617418 (11 April 2006); doi: 10.1117/12.658414
Show Author Affiliations
Henry C. H. Li, RMIT Univ. (Australia)
Olivier Dupouy, Ecole d'Ingenieurs Louis de Broglie (France)
Israel Herszberg, Cooperative Research Ctr. for Advanced Composite Structures Ltd. (Australia)
Paul R. Stoddart, Swinburne Univ. of Technology (Australia)
Claire E. Davis, Defence Science and Technology Organisation (Australia)
Adrian P. Mouritz, RMIT Univ. (Australia)

Published in SPIE Proceedings Vol. 6174:
Smart Structures and Materials 2006: Sensors and Smart Structures Technologies for Civil, Mechanical, and Aerospace Systems
Masayoshi Tomizuka; Chung-Bang Yun; Victor Giurgiutiu, Editor(s)

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