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The electromagnetic field around a subsurface flaw in a metal

journal contribution
posted on 26.02.2013, 14:10 by Maureen McIver
This work is a theoretical investigation into the detection and measurement in metals of flaws that do not break the surface, with the use of AC electric fields. The flaw is modelled by a semi-infinite slot, which is perpendicular to the surface and whose top edge is at a finite distance below the surface. The electromagnetic field is governed by Maxwell's equations and the skin depth of the field is assumed to be large compared to the ligament remaining between the top edge of the crack and the metal surface. Matched asymptotic expansions are used to describe the field mathematically and numerical results are presented, illustrating the variation of the potential difference on the surface of a number of metals with different-size ligaments in them. Good agreement is obtained from comparisons with some results using a Fourier-series technique. It is found that the maximum centreline voltage signal is obtained if measurements of the potential difference are made at a phase of approximately — 1/4π compared to the upstream signal.

History

School

  • Science

Department

  • Mathematical Sciences

Citation

MCIVER, M., 1986. The electromagnetic field around a subsurface flaw in a metal. IMA Journal of Applied Mathematics, 37 (2), pp. 93-111.

Publisher

© Oxford University Press

Version

VoR (Version of Record)

Publication date

1986

Notes

This article is closed access.

Language

en

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