3. Eddy Currents
The eddy current NDE inversion problem is to determine flaw parameters from eddy current sensor impedance changes. Two approaches to solving this problem are discussed for geometries with two components of eddy current. The first is to use the Finite Element Method of numerical analysis to compute the sensor impedance change for each flaw parameter value. The second approach is to combine the Finite Element Method with an analytical scattering technique. These two approaches are applied to the problem of an infinitely long coil surrounding an infinitely long conducting bar with an infinitely long surface crack. The calculated impedance changes show good agreement with known analytical and experimental results.
Kincaid, T. G.; Chari, M. V. K.; Csendes, Z. J.; Fong, K.; and McCary, R. O., "Two Approaches to Solving the Inversion Problem for Eddy Current NDE" (1980). Proceedings of the DARPA/AFML Review of Progress in Quantitative NDE, July 1978–September 1979. 10.