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Proceedings Paper

Chaotic and ambient vibration analysis of composite lap joint damage
Author(s): Lou Pecora; Jon Nichols; Mark Seaver; Steve Trickey; Sara Motley
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Paper Abstract

We examined strain time series from fiber Bragg gratings sensors located in various positions on a composite material beam attached to a steel plate by a lap joint. The beam was vibrated using both broad-band chaotic signals (Lorenz system), and a narrow band signal conforming to the Pierson-Moskowitz frequency distribution for wave height (ambient excitation). The system was damaged by decreasing the torque on instrumented bolts in the lap joint from very tight all the way through to a joint with a gap and slippage. We analyzed the strain data by reconstructing the attractor of the system in the case of chaotic forcing and a pseudo-attractor in the case of sea-wave forcing. Using the highest torque case as an "undamaged" baseline, we calculated the continuity statistic between the baseline attractor and the attractors of the various damage levels for both forcing cases. We show where one can and cannot say that the functional relationship between the attractors changes and how those changes are related to damage levels.

Paper Details

Date Published: 11 April 2007
PDF: 9 pages
Proc. SPIE 6532, Health Monitoring of Structural and Biological Systems 2007, 65320V (11 April 2007); doi: 10.1117/12.715143
Show Author Affiliations
Lou Pecora, Naval Research Lab. (United States)
Jon Nichols, Naval Research Lab. (United States)
Mark Seaver, Naval Research Lab. (United States)
Steve Trickey, Naval Research Lab. (United States)
Sara Motley, Naval Research Lab. (United States)

Published in SPIE Proceedings Vol. 6532:
Health Monitoring of Structural and Biological Systems 2007
Tribikram Kundu, Editor(s)

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