| Research Abstract |
The use of computer software for the design of electromagnetic devices is now almost universal. The phenomena in electromagnetic fields, which are central to many aspects of electro magnetic machines, intrinsically spread over the infinite space. We sometimes have to consider the infinite region rigorously, e.g. for estimating the mangetic field made by superconduting magnets. The purpose of this research is to provide a useful method for the numerical calculation of electromagnetic field with open boundary, and particular attention is given to the 3-D eddy current problems. The finite element method (FEM) and the boundary element method (BEM), which have entirely different features from each other, are very useful for numerical analysis. Both methods seem to be complementary partners and not opponents. The FEM suits for the analysis of such a coplicated region which includes no-linear materials. However, it has some disadvantages in dealing with the infinitely extending fields. On the other hand, the BEM is useful for analyzing very large linear fields. Therefore taking account of the advantages in these methods, this research is concerned with the hybrid finite element and boundary element (FE-BE) method for the 3-D eddy current analysis. Both the FEM and the BEM can adopt various kinds of physical quantities as unknowns, so ther are many ways to combine both methods. Inthis research we have proposed several hybrid formulations in which some kinds of physical quantities are adopted as unknowns. The advantages and disadvantages of respective hybrid methods are examined. The appropriate boundary element discretization using edge elements is also developed, which is suitable for combining the FE region with the BE region. The approaches proposed in this research are always verified by concrete munerical examples.
|
