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Proceedings Paper

Stimulated dual-band infrared computed tomography: a tool to inspect the aging infrastructure
Author(s): Nancy DelGrande; Philip F. Durbin
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Paper Abstract

We have developed stimulated dual-band infrared (IR) computed tomography as a tool to inspect the aging infrastructure. Our system has the potential to locate and quantify structural damage within airframes and bridge decks. Typically, dual-band IR detection methods improve the signal-to-noise ratio by a factor of ten, compared to single-band IR detection methods. We conducted a demonstration at Boeing using a uniform pulsed-heat source to stimulate IR images of hidden defects in the 727 fuselage. Our dual-band IR camera and image processing system produced temperature, thermal inertia, and cooling-rate maps. In combination, these maps characterized the defect site, size, depth, thickness, and type. We quantified the percent metal loss from corrosion above a threshold of 5%, with overall uncertainties of 3%. Also, we conducted a feasibility study of dual-band IR thermal imaging for bridge deck inspections. We determined the sites and relative concrete displacement of 12- in. and 4-in. deep delaminations from thin styrofoam implants in asphalt-covered concrete slabs. We demonstrated the value of dual-band IR computed tomography to quantify structural damage within flash-heated airframes and naturally heated bridge decks.

Paper Details

Date Published: 8 September 1995
PDF: 10 pages
Proc. SPIE 2552, Infrared Technology XXI, (8 September 1995); doi: 10.1117/12.218230
Show Author Affiliations
Nancy DelGrande, Lawrence Livermore National Lab. (United States)
Philip F. Durbin, Lawrence Livermore National Lab. (United States)


Published in SPIE Proceedings Vol. 2552:
Infrared Technology XXI
Bjorn F. Andresen; Marija Strojnik, Editor(s)

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