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Proceedings Paper

Online detection method for transient waves applied to continuous health monitoring of carbon-fiber-reinforced polymer composites with embedded optical fibers
Author(s): Jean-Michel Papy; Sabine Van Huffel; Laurent Rippert; Martine Wevers
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Paper Abstract

It has been proven that the embedment of optical fibers into a composite material could offer an alternative to robust piezoelectric transducers used for Acoustic Emission (AE) monitoring. In this configuration optical fibers are used as intensity-modulated sensors. A set of propagating elastic waves is generated whenever damage occurs in the composite material. These waves locally modify the optical and geometrical properties of the optical fiber and hence can be detected by them as a transient signal that modulates the light intensity. In this paper a method for detecting the transients by on-line signal processing is presented. It is then applied to optical signals resulting from tensile tests performed on CFRP composites material with embedded optical fibers. By means of the Short-Time Fourier Transform (STFT), the level of the noise added to the signal is estimated by filtering the time trajectories. This filter is continuously adapted according to the principle of minimization of the mean squared error. Finally the detection is achieved by a constant false alarm rate power-law detector. This technique is fast and doesn't take into account neither the statistical distribution of the noise nor the frequency content of the transients as long as the frequency component distribution can be approximated by an exponential law. The detected transient features can be correlated with the AE results but an off-line analysis and classification is still needed.

Paper Details

Date Published: 1 August 2003
PDF: 14 pages
Proc. SPIE 5049, Smart Structures and Materials 2003: Modeling, Signal Processing, and Control, (1 August 2003);
Show Author Affiliations
Jean-Michel Papy, Katholieke Univ. Leuven (Belgium)
Sabine Van Huffel, Katholieke Univ. Leuven (Belgium)
Laurent Rippert, Katholieke Univ. Leuven (Belgium)
Martine Wevers, Katholieke Univ. Leuven (Belgium)

Published in SPIE Proceedings Vol. 5049:
Smart Structures and Materials 2003: Modeling, Signal Processing, and Control
Ralph C. Smith, Editor(s)

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