A previous attempt by Dunbar to model eddy current NDE data using the volume integral equation method produced qualitative agreement with experimental data, but true verification was not possible due to the fact that the results were not independent of the discretization of the flaw and there were numerical problems encountered in calculating the unperturbed electric field. We have overcome these problems by calculating the integrals of the Green's tensor more accurately, especially in the vicinity of any singularities, and by using a fast Hankel transform to calculate the incident electric field. Further improvements were made by considering a linear variation of the electric field, instead of taking it to be constant over each cell used in the discretization. Results obtained from rectangular flaws in a half-space and in a thin plate are presented.
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McKirdy, D.M. Recent improvements to the application of the volume integral method of eddy current modeling. J Nondestruct Eval 8, 45–52 (1989). https://doi.org/10.1007/BF00566587
- Eddy current NDE
- volume integral equation
- Green's tensor