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Proceedings Paper

Square pulse thermography in frequency domain
Author(s): Ralf Arndt
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Paper Abstract

In this paper a new approach for quantitative non-destructive testing (NDT) of near-surface structures in civil engineering (CE) with active thermography is presented. It adopts the method known as pulsed phase thermography (PPT) for the special requirements of NDT-CE and was developed in a German research project of the Federal Institute for Materials Research and Testing (BAM) in cooperation with the Technical University of Berlin. The new quantitative concept that might be understood as a square pulse thermography in frequency domain or an amplitude-expanded PPT with square pulse heating is based on the thermal diffusivity of the material and the characteristic frequency of the negative maximum phase and amplitude contrast. It aims at complementing the established approaches for defects depth calculation for measurements with long heating and observation times quite usual at active thermography in CE but is easily extendable to other fields of application. After an introduction to the basics of active thermography in CE and the thermography concept of BAM, qualitative results of several case studies will be presented. The main focus of the last section of this contribution is on applications of the new quantitative approach at test specimens of BAM to determine the concrete cover of artificially manufactured defects.

Paper Details

Date Published: 17 March 2008
PDF: 12 pages
Proc. SPIE 6939, Thermosense XXX, 69390X (17 March 2008); doi: 10.1117/12.777697
Show Author Affiliations
Ralf Arndt, Federal Institute for Materials Research and Testing (BAM) (Germany)

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

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