A Boundary Integral Formulation on Unstructured Dual Grids for Eddy-Current Analysis in Thin Shields

Dipt. di Ingegneria Elettrica, Padova Univ.
IEEE Transactions on Magnetics (Impact Factor: 1.21). 05/2007; 43(4):1173 - 1176. DOI: 10.1109/TMAG.2006.890948
Source: IEEE Xplore

ABSTRACT A 3-D boundary integral method (3-D BIM) capable of analyzing eddy currents in thin shields is presented. This novel approach is formulated in terms of loop currents in order to implicitly fulfill the div-free condition for quasi-magnetostatic problems. Using nonorthogonal dual grids unknowns are defined on nodes, resulting in a very efficient formulation with limited memory requirements. The proposed method is tested on an axisymmetric model showing a good agreement with the analytical solution. 3-D BIM is then applied to analyze a real case of low-frequency magnetic shielding

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    ABSTRACT: We present an effective technique to solve eddy current problems in thin conductors of arbitrary topology by a boundary element method based on a stream function. By considering a mesh of the thin conductor, which we assume to be a surface (i.e., an orientable combinatorial two-manifold embedded in R 3), the aim of this paper is to introduce a novel technique to render the stream function single valued when the thin conductor is not topologically trivial. In particular, a novel combinatorial algorithm to compute the appropriate cohomology generators in linear time worst case complexity is introduced, providing an effective and rigorous solution for the required topological preprocessing. Index Terms— Boundary element method (BEM), cohomology, eddy currents, stream function, thin shields with holes.
    IEEE Transactions on Magnetics 03/2015; 51(3). DOI:10.1109/TMAG.2014.2347894 · 1.21 Impact Factor
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    ABSTRACT: Export Date: 19 July 2012, Source: Scopus, CODEN: CODUD, doi: 10.1108/03321640810847742, Language of Original Document: English, Correspondence Address: Moro, F.; Dipartimento di Ingegneria Elettrica, Università di Padova, Padova, Italy; email:, References: Alotto, P., Guarnieri, M., Moro, F., A boundary integral formulation on unstructured dual grids for eddy current analysis in thin shields (2007) IEEE Trans. on Magnetics, 43 (4), pp. 1173-6;
    COMPEL International Journal of Computations and Mathematics in Electrical 03/2008; 27(2):460-466. DOI:10.1108/03321640810847742 · 0.44 Impact Factor
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    ABSTRACT: Purpose - The purpose of this paper is to present a simplified rigorous mathematical formulation of the problem of electric agents induced in thin shields with holes yielding more efficient numerical computations with respect to available methods. Design/methodology/approach - A surface integral equation satisfied by the current density was constructed, which is, subsequently, represented at any point by linear combinations of novel vector basis functions only associated with the interior nodes of the discretization mesh, such that the current continuity is everywhere insured. The existence of the holes in the shield is taken into account by associating only one surface vector function with each hole. A method of moments is then applied to compute the scalar coefficients of the vector functions employed. Findings - It was found that the induced current distribution for shields with holes having the complexity of real world structures can be determined with a satisfactory accuracy utilizing a moderate size processor notebook in a time of the order of minutes. Originality/value - The originality of the proposed method consists in using specialized surface vector functions only associated with individual interior nodes of the shield, its multiply connected structure being efficiently accounted for by introducing one unknown for each hole, instead of unknowns for every node along the hole contours. The method presented is straightforward and highly efficient for mathematical analysis of thin shields with holes, and of other physical fields in the presence of multiply connected surface structures.
    COMPEL International Journal of Computations and Mathematics in Electrical 07/2009; 28(4):964-973. DOI:10.1108/03321640910959035 · 0.44 Impact Factor

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