A hybrid method is presented for the calculation of the
interaction of a complicated shape ferrite-core eddy current testing probe
with extremely small size cracks in a plate. The method is obtained by
blending the boundary integral (BIM) and finite element (FEM) methods
preserving their attractive properties, that is, the fast and accurate
evaluation of the defect field and the versatility in specimen and probe
geometry, respectively. FEM is applied for the computation of the electric
field induced in the specimen without cracks. Using the obtained, so-called,
incident field the BIM is used for the calculation of the field perturbation
due to the presence of the cracks in the tested specimen. With the
application of the presented hybrid calculations, a very fast and accurate
method is developed for the solution of a problem that would pose
considerable difficulties for either the FEM or the BIM if they were applied
purely alone in the conventional way. The results of the calculations are
compared with a large number of experimental data. The very good correlation
between the measured and simulated probe responses proves the applicability
of the presented method.