Developments in efficiently modelling eddy current testing of narrow cracks

Further developments in a Boundary Element Method model for eddy current inspection of ideal or narrow cracks are presented. First, the required Green's function is rapidly computed in the spatial domain using the concept of discrete complex images. The approach is based on the analytical evaluation of the Sommerfeld type Integrals through the use of the Generalized Pencil of Function method. Computation times are recorded in order to show the remarkable reduction in the moment matrix fill time as well as in the total computational time. Second, the model is extended to arbitrary crack depth profiles. Theoretical results are compared to published benchmark measurements of the coil impedance change due to a semi-elliptic and an epicyclic crack and excellent agreement is achieved.