Constriction resistance of conducting spots by the boundary element method

The finite-element method (FEM) has been applied as a powerful numerical method to the study of electric contacts. In this work, the boundary element method (BEM), is introduced into the study of contacts, and the constriction resistance of conducting spots is computed by the method. The constriction resistance of circular spot is computed, and by comparing the computed value with the exact solution presented by Holm (1979), the high accuracy of the calculated value by the BEM is assured. The constriction resistance of square spot was computed by the FEM, but the value computed by the FEM is a very rough estimation. A far more accurate value is calculated by the BEM. The conductances of ring-shaped spots against the thickness of ring are computed, and it is verified that the conductances do not decrease because of the strong current constriction at conducting spots until the thickness becomes close to zero