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Proceedings Paper

Quantifying flaw characteristics from IR NDE data
Author(s): Wayne O. Miller; Noah Philips; Michael W. Burke; Christopher L. Robbins
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Paper Abstract

Work is presented which allows flaw characteristics to be quantified from the transient IR NDE signature. The goal of this effort was to accurately determine the type, size and depth of flaws revealed with IR NDE, using sonic IR as the example IR NDE technique. Typically an IR NDE experiment will result in a positive qualitative indication of a flaw such as a cold or hot spot in the image, but will not provide quantitative data thereby leaving the practitioner to make educated guesses as to the source of the signal. The technique presented here relies on comparing the transient IR signature to exact heat transfer analytical results for prototypical flaws, using the flaw characteristics as unknown fitting parameters. A nonlinear least squares algorithm is used to evaluate the fitting parameters, which then provide a direct measure of the flaw characteristics that can be mapped to the imaged surface for visual reference. The method uses temperature data for the heat transfer analysis, so radiometric calibration of the IR signal is required. The method provides quantitative data with a single thermal event (e.g. acoustic pulse or flash), as compared to phase-lock techniques that require many events. The work has been tested with numerical data but remains to be validated by experimental data, and that effort is underway. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.

Paper Details

Date Published: 1 April 2003
PDF: 9 pages
Proc. SPIE 5073, Thermosense XXV, (1 April 2003); doi: 10.1117/12.485968
Show Author Affiliations
Wayne O. Miller, Lawrence Livermore National Lab. (United States)
Noah Philips, Harvey Mudd College (United States)
Michael W. Burke, Lawrence Livermore National Lab. (United States)
Christopher L. Robbins, Lawrence Livermore National Lab. (United States)

Published in SPIE Proceedings Vol. 5073:
Thermosense XXV
K. Elliott Cramer; Xavier P. Maldague, Editor(s)

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