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Proceedings Paper

Nondestructive inspection of tagged composites using real-time magneto-optic imaging
Author(s): Gerald L. Fitzpatrick; David K. Thome; Richard L. Skaugset; William C.L. Shih
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Paper Abstract

While magneto-optic/eddy current imagers (MOIs) are widely used for the nondestructive inspection (NDI) of aging aluminum airframes, they are not currently used to inspect aerospace composites for two reasons. First, most composites are essentially electrical insulators, which makes it difficult for the MOI to induce sufficient eddy currents in these materials for imaging. Second, unlike steel, which can be easily magnetized and inspected using the MOI, most composites are not appreciably magnetic. Exceptions to these two stated limitations are composites containing electrically conducting 'screens' of aluminum or copper for lighting-protection, 'stealthy' military composites containing iron particles for radar absorption, and some commercial composites containing nickel-coated carbon fibers for lighting protection and/or electromagnetic shielding. These existing composites can be inspected, to one degree or another,with the MOI. Moreover, by 'tagging' the matrix component of newly-manufactured composites with magnetic oxides, excellent MOI images of cracks, voids, potential disbonds and defects in fiber-weave are possible. Experimental results presented here demonstrate these facts. It is anticipated that when this new technology is perfected, and when magnetic 'tagging' at the time of manufacture becomes an accepted practice, the MOI will be widely used for the NDI of composites during their manufacture, in-service inspection or repair.

Paper Details

Date Published: 15 November 1996
PDF: 14 pages
Proc. SPIE 2944, Nondestructive Evaluation of Materials and Composites, (15 November 1996); doi: 10.1117/12.259061
Show Author Affiliations
Gerald L. Fitzpatrick, Physical Research, Inc. (United States)
David K. Thome, Physical Research, Inc. (United States)
Richard L. Skaugset, Physical Research, Inc. (United States)
William C.L. Shih, Physical Research, Inc. (United States)


Published in SPIE Proceedings Vol. 2944:
Nondestructive Evaluation of Materials and Composites
Steven R. Doctor; Carol A. Nove; George Y. Baaklini, Editor(s)

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