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ABSTRACT: A software environment for the treatment of discrete problems is
presented and used for teaching the finite element method in
electromagnetism. It makes use of a user-friendly data structure which
gives students a great freedom in testing, in an evolutive way, various
numerical techniques on practical problems, thanks to a total control on
all the components of the modeling process. In this way, the transition
from theory to practice is made quite directly and easily
IEEE Transactions on Magnetics 06/1999; · 1.36 Impact Factor
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ABSTRACT: Mixed formulations are characterized by the use, of not only one
kind of unknown, but of two distinct kinds of unknowns. Some well-known
mixed finite elements are well suited to the approximation of
electromagnetic fields. Several characteristics of magnetostatic and
magnetodynamic mixed formulations are presented and discussed. The use
of nodal, edge, facet and volume mixed elements enables their natural
and rigorous discretization. Their advantages compared with conventional
formulations are pointed out
IEEE Transactions on Magnetics 04/1997; · 1.36 Impact Factor
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ABSTRACT: A general method to compute source fields in magnetostatics or
magnetodynamics is presented for inductors of any shape. That source
field is not the physical one because the zero divergence condition is
not satisfied. However, the freedom so obtained is exploited to minimize
its support as well as to reduce the CPU time. The use of edge finite
elements enables its rigorous construction. A test problem illustrates
the method
IEEE Transactions on Magnetics 04/1997; · 1.36 Impact Factor
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ABSTRACT: Mixed formulations of Maxwell's equations are presented and the
nature of the matrices appearing in these formulations is discussed.
Their indefinite character is discussed. A method for solving these
unusual matrices is then developed and applied to a test problem
IEEE Transactions on Magnetics 04/1997; · 1.36 Impact Factor
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Proceedings of the Electromagnetic Field Problems and Applications conference (ICEF 1996). 01/1997;
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ABSTRACT: For linear systems excited with sinusoidal constraints, an exact
dynamical modelling can be performed with a phasor (complex number)
approach. For nonlinear systems (exhibiting saturation, hysteresis and
higher harmonics), a time stepping model is very time consuming. A
method to model such nonlinear systems with an approximated phasor
approach is presented. Determination of equivalent material
characteristics is discussed and applications are given
IEEE Transactions on Magnetics 10/1996; · 1.36 Impact Factor
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ABSTRACT: 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
IEEE Transactions on Magnetics 06/1996; · 1.36 Impact Factor
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ABSTRACT: The paper presents a method to control the quality of finite
element solutions error in the constitutive relation. An a posteriori
estimator is built up. Its construction is general and gives
quantitative results about the accuracy of the solution. Both problems
of control of quality and mesh optimisation are also discussed. Several
examples are presented. A method used to compute a magnetic field that
verifies Ampere's law using only local calculations is presented
IEEE Transactions on Magnetics 06/1996; · 1.36 Impact Factor
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Studies in Applied Electromagnetics and Mechanics. 01/1996; 10:926-929.
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ABSTRACT: This paper presents a new approach to solve nonlinear problems
using the complex formalism in the finite element method. The main idea
is to use a modified Newton Raphson procedure taking into account both
the derivative and the conjugate derivative of the unknowns in the
Jacobian matrix. To validate this method, the nonlinear complex analysis
is compared to a classical time stepping analysis for the computation of
the magnetic field outsides shielded three-phase cable
IEEE Transactions on Magnetics 12/1995; · 1.36 Impact Factor
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ABSTRACT: This paper presents a complete methodology to control the quality of electromagnetic field computation using the finite element method. An error estimate is built up using the error in the constitutive relation. Proof is made that this estimate relates to the exact error in some cases. Both problems of control of quality and mesh optimisation are then discussed
IEEE Transactions on Magnetics 12/1995; 31(6):3587-3589. · 1.36 Impact Factor
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ABSTRACT: A sequence of finite element spaces built on tetrahedra, hexahedra
and prisms, is presented, and gauge condition for vector potential is
shown to be well defined in these spaces. Results are presented for a
modified vector potentials formulation for 3D eddy current
problems
IEEE Transactions on Magnetics 06/1995; · 1.36 Impact Factor
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IEEE Transactions on Magnetics 01/1995; 31(6):3587-3589. · 1.36 Impact Factor
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ABSTRACT: A generalization of the Whitney complex is proposed, which is not
now associated with simplices, i.e. tetrahedra in three dimensions, but
with collections of three kinds of geometric elements: tetrahedra,
hexahedra and prisms. Nodal, edge, facet and volume finite elements,
i.e. mixed elements, associated with collections of those geometric
elements, are defined. Base functions for approximation relative to
these finite elements are defined and their properties are established.
A geometric interpretation of these functions is given
IEEE Transactions on Magnetics 10/1994; · 1.36 Impact Factor
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ABSTRACT: This paper presents a numerical modelling of an electromechanical
relay connected with an electric excitation circuit. This transient
modelling not only takes into account the classical electromagnetic
equations of the device but also the movement and circuit equations. The
use of the finite element-boundary element coupling method facilitates
the computation of the movement while the actual coupling with circuit
equations is necessary for an accurate and reliable representation of
transient phenomena
IEEE Transactions on Magnetics 10/1994; · 1.36 Impact Factor
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ABSTRACT: This paper describes the computation of waveforms of electrical
current and voltage in inductances, taking into account the hysteresis
phenomenon and electric circuit equations. The non-linear transient
magnetic field is computed with the finite element method. The classical
nonlinear case is compared to the hysteretic one: it is shown that
hysteresis has a crucial importance on the waveform by introducing
asymmetry and damping, and by modifying the natural frequency of the
oscillations
IEEE Transactions on Magnetics 10/1994; · 1.36 Impact Factor
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ABSTRACT: The representation of electromagnetic quantities by differential forms allows the use of nonorthogonal coordinate systems. A judicious choice of coordinate system facilitates the finite element modeling of infinite or very thin domains.
Journal of Applied Physics 06/1994; · 2.17 Impact Factor
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ABSTRACT: In studies, design or malfunction examination involving power cables accessories, it is important to locate the areas where the electric field can reach critical values and to know its components. The authors explain how an electric field computation software allows this kind of problem to be solved. This highly interactive software is based on a computation method well suited for problem solutions where the geometries are lengthy as is often the case for cable accessories. The computation of a time-harmonic analysis allows the resistivity of materials to be taken into account. Two practical examples show the application of this investigation method and high voltage accessories
Electricity Distribution, 1993. CIRED. 12th International Conference on; 06/1993
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ABSTRACT: The problem of unacceptable inaccuracies sometimes observed in the
fields computed with the classical axisymmetrical model (i.e.,
first-order finite elements with auxiliary potential V = A
/ r ) is solved. Two methods are proposed to improve the
accuracy of the results: isoparametrical second-order elements and
first-order elements with a suitable coordinate transformation. The
second method, using first-order elements, gives the exact solution for
piecewise linear materials; it has also been generalized for nonlinear
systems by defining a quadrilateral axis-dedicated element
IEEE Transactions on Magnetics 04/1993; · 1.36 Impact Factor
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ABSTRACT: A method which enables coupling between equations of electric
circuits consisting of a lumped element RLC configuration and a
magnetic field model is presented. The coupling between the
finite-element and the boundary-element methods is used to compute the
magnetic field produced by conductors excited by an electric circuit.
The conductors involved in this computation may be connected according
to any circuit topology and mixed with lumped elements. The method
presented is general and allows a transient simulation of eddy current
nonlinear problems with conductors excited by electric circuits
IEEE Transactions on Magnetics 04/1993; · 1.36 Impact Factor
