Efficient Calculation of Eddy Current Responses Due to Defects

Abstract The eddy current responses due to three dimensional defects embedded in a conducting half space are evaluated with an iterative numerical technique using a volume integral formulation in conjunction with a variational expression for the response. This approach is applied to defects of spherical and cylindrical geometry with dimensions up to several skin depths. Computations of the eddy current responses converge in one to four iterations and the comparison to moment-method results and experimental values is discussed. The iterative numerical approach has been found to be robust, to require modest computer time/storage, and to provide a model which can accomodate a wide range of defect parameters.