B. Meys

A Galerkin projection method for mixed finite elements

The aim of the proposed method is the projection of an electromagnetic field belonging to a given function space (continuous or not) onto a discrete one spanned by finite element basis functions. This technique is useful for imposing inhomogeneous boundary conditions or volumic source fields, for calculating a dual field given the primal one or for mesh to mesh interpolation.

Finite element modelling with transformation techniques

Transformation methods are a very powerful tool in finite element modelling. In many cases, an adequate mapping transforms the problem into an easier one or allows advantage to be taken of the symmetries. This paper demonstrates that any mapping can be handled automatically provided the classical vector analysis approach is given up for the benefit of a differential geometry approach. As a first example, it is shown that axisymmetrical problems need no more a particular treatment provided the mapping of the cylindrical coordinates on the cartesian ones is considered as it is. Furthermore, a novel axisymmetrical formulation is proposed which relies on one further transformation and improves considerably the quality of the interpolated field. Transformation methods are also of great help to model the infinite space by means of finite elements. Many authors have presented such transformations which are often instances of the same general shell transformation that is presented here.

An FETD approach for the modeling of antennas

In this paper an implicit Finite Element Time Domain (FETD) method is applied to the computation of the electromagnetic fields emitted by a commercial broadband log periodic antenna. The method is based on a Whitney edge finite element scheme for the space discretization together with a Newmark algorithm and a Krylov solver for the time integration. Global antenna performances are deduced thanks to a discrete Fourier transform and a boundary element extrapolation, and are compared with experimental data.

Arrangement of phases and heating constraints in a busbar

This paper presents the analysis of a busbar for a three-phase system. The best connection of the different phases is proposed to derive the optimal dissipation of the heat flux inside the busbar. The implementation of a magnetothermal coupled model which can take into account radiation exchange and the electric circuit parameters is necessary. A comparison of numerical results with experimental results is made on an industrial busbar.

Convergence of high order curl-conforming finite elements [for EM field calculations]

The aim of this paper is to present an experimental convergence study of several high order curl-conforming finite elements. Degrees of freedom are first mathematically defined in order to interpolate directly a set of analytical functions. The convergence is then analyzed on these functions before being compared with two- and three-dimensional finite element EM field computations.

An object-oriented decomposition of the FE procedure

The performance of a finite element (FE) programme is closely related to the richness of its FE library. An object-oriented organisation for FE programmes is proposed which intends to fit closely the mathematical structure of any kind of finite element. This philosophy leads to a concise and efficient FE programme. Moreover it allows the user to easily develop for himself his own formulations.

Dual harmonic and time approaches for the design of microwave devices

In this paper, different numerical techniques belonging to the harmonic and the time formalism have been confronted through the calculation of the performances of a three-dimensional microwave filter. Among those techniques, the Newmark and Lanczos algorithms appear to be particularly well adapted for the numerical design of such applications. Practical aspects of the implementation and the use of these techniques are pointed out by the authors.

An optimization method for the design of physical and Maxwellian absorbers

This paper presents a general deterministic optimization procedure to compute the spatial repartition of material property-dissipative and nondissipative part-which minimizes physical or numerical reflection in physical and Maxwellian absorbers. The reflection performances of particular absorbers are compared from many points of view and deeply analyzed. The obtained results can usefully guide the designer in the choice of a particular absorber for the treatment of practical or numerical applications.