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Proceedings Paper

Quantitative evaluation of defect depth in concrete structures using Fourier analysis for sequential thermal data
Author(s): Shiro Nakamura; Takahide Sakagami; Shuusuke Harada; Shiro Kubo
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Paper Abstract

In this paper, active thermography NDT method with active heating is developed for concrete structures. Active heating is effectively employed when temperature fluctuation on structure is small. As an estimation method of defect depth, the Fourier analysis of temperature descent curve after heating is employed. As the results, by using the phase delay distribution obtained from the Fourier analysis, the influence of the irregularity heating was reduced in comparison with the original temperature distribution. The phase delay image was also useful for determination of defect depth. Values of phase difference between delamination area and sound area show peaks at certain values of data processing period. These peaks can be directly related to defect depth. It is shown that three-dimensional shape of delamination defect can be accurately evaluated by the proposed technique.

Paper Details

Date Published: 17 March 2008
PDF: 10 pages
Proc. SPIE 6939, Thermosense XXX, 693910 (17 March 2008); doi: 10.1117/12.779906
Show Author Affiliations
Shiro Nakamura, Sumitomo-Osaka Cement Co., Ltd. (Japan)
Takahide Sakagami, Osaka Univ. (Japan)
Shuusuke Harada, Sumitomo-Osaka Cement Co., Ltd. (Japan)
Shiro Kubo, Osaka Univ. (Japan)


Published in SPIE Proceedings Vol. 6939:
Thermosense XXX
Vladimir P. Vavilov; Douglas D. Burleigh, Editor(s)

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