A General Boundary Integral Equation Approach to Eddy Current Crack Modeling

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Chao, J.
Nakagawa, Norio
Raulerson, D.
Moulder, J.
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Review of Progress in Quantitative Nondestructive Evaluation
Center for Nondestructive Evaluation

Begun in 1973, the Review of Progress in Quantitative Nondestructive Evaluation (QNDE) is the premier international NDE meeting designed to provide an interface between research and early engineering through the presentation of current ideas and results focused on facilitating a rapid transfer to engineering development.

This site provides free, public access to papers presented at the annual QNDE conference between 1983 and 1999, and abstracts for papers presented at the conference since 2001.


Eddy current techniques have been widely used in the NDE inspection of aircraft engine components. Depending on the flaw characteristics and specimen composition, various EC probe designs have been employed to achieve the maximum probability of detection (POD). Traditionally, the effectiveness of a probe design for a given inspection is determined experimentally. In particular, parameters such as probe types, operating frequency, scan spacing, etc. are evaluated experimentally in terms of POD. It is obvious that this is a costly way of defining inspection parameters. A more cost-effective alternative is to evaluate the test parameters through the use of numerical simulation. This can be done by casting the entire EC inspection process in terms of a numerical model governed by a set of integral equations. By computing the solutions to the integral equations, outputs in the form of impedance changes due to flaws can be used to generate the POD. Previously, we have introduced a modified version of the Hertzian magnetic potential approach for eddy current probe design [1]–[3]. In those papers, it was shown that the formulation can be used to solve problems with arbitrary geometries including geometrical singularities such as edges and corners. In the present paper, we have modified the boundary integral equations (BIEs) formulation for computing the impedance change in the presence of ideal tight cracks. Some unique features of this model include the allowance for arbitrarily shaped air core probes and test components that include singular geometries.

Wed Jan 01 00:00:00 UTC 1997