AN EFFICIENT SEMI‐ANALYTICAL INTEGRATION PROCEDURE IN THREE DIMENSIONAL BOUNDARY INTEGRAL METHOD

A semi‐analytical integration technique to evaluate the singular integration in 3‐D boundary element method for electromagnetic field computation is reported. The technique has been applied in a hybrid finite element—boundary integral model to evaluate the singular integral terms when constructing the “outside stiffness matrix” in the case of small air‐gaps, and it has also been used to calculate the exterior magnetic field in the proximity of the boundaries. The comparison with the conventional Gaussian quadrature has been carried out by modelling a 3‐D magnetostatic problem with a small air‐gap.