Avoiding surface impedance modification in BE methods by singularity-free representations

Correct association of equivalent current and magnetic charge sheets in adjacent elements over the surface of nonmagnetic conducting media removes the logarithmic singularities which otherwise occur at the edges and corners. This not only improves the accuracy of computed fields near corners, but is also shown to allow magnetic flux to enter the medium naturally and to remove the need to modify the surface impedance near corners in eddy-current problems. For a particular 2-D test problem the method yields good agreement with both a finite-element solution of the same problem and an earlier solution using modified surface impedance. An earlier 3-D formulation using surface impedance modification has also yielded satisfactory solutions so that successful application of the present method to 3-D problems can be expected