Vector-potential boundary-integral evaluation of eddy-current interaction with a crack

Journal Article · Mon Sep 01 00:00:00 EDT 1997 · IEEE Transactions on Magnetics

DOI:https://doi.org/10.1109/20.620437· OSTI ID:562001

Bowler, J R; Harfield, N ^[1]; Yoshida, Y ^[2]

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1. Univ. of Surrey, Guildford (United Kingdom). Dept. of Physics
2. Univ. of Tokyo, Ibaraki (Japan). Nuclear Engineering Research Lab.

In eddy-current nondestructive evaluation, an excitation coil, used to induce current in a conductor, changes impedance in the presence of a crack. The impedance change can be calculated from a knowledge of the coil parameters, the excitation frequency, and the crack geometry. Two boundary integral formulations of the problem are compared. The first formulation uses an electric field integral equation, and the second expresses the magnetic vector potential in integral form using an integral kernel with a weaker singularity. The vector potential formulation, presented here for the first time, leads to a more complicated equation but has a singular kernel that is easier to deal with. In addition, the new approach opens up a number of possibilities for further analytical developments. An example calculation is performed for a long, surface-breaking crack, and the results are compared to available analytical solutions. Very good agreement is found between the numerical solution of the integral equation and the analytical results.

• OSTI ID: 562001
• Journal Information: IEEE Transactions on Magnetics, Journal Name: IEEE Transactions on Magnetics Journal Issue: 5Pt3 Vol. 33; ISSN IEMGAQ; ISSN 0018-9464
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
42 ENGINEERING
BOUNDARY CONDITIONS
COMPARATIVE EVALUATIONS
CRACKS
EDDY CURRENT TESTING
INTEGRAL EQUATIONS
METALS