FINITE-ELEMENT POYNTING VECTOR CALCULATIONS FOR REMOTE FIELD EDDY-CURRENT INSPECTION OF TUBES WITH CIRCUMFERENTIAL SLOTS

Finite element calculations were made for a remote field low frequency through-wall eddy current inspection probe in a steel pipe. Results showing magnetic vector potential and Poynting vector distributions in the vicinity of near and far side circumferential slots of various penetrations and widths are presented. It is found that energy tends to be funneled into the outside of the slot, that the peak power density in the slot is a little way in from the outside and increases rapidly with decreasing slot width and that very high current densities occur at the tips of the slots.