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See detailFinite Element Mesh Adaptation Strategy From Residual and Hierarchical Error Estimators in Eddy Current Problems
Dular, Patrick ULg; Le Menach, Yvonnick; Tang, Zuqi et al

in IEEE Transactions on Magnetics (2015), 51(3),

A strategy of mesh adaptation in eddy current finite element modeling is developed from both residual and hierarchical error estimators. Wished distributions of element sizes of adapted meshes are ... [more ▼]

A strategy of mesh adaptation in eddy current finite element modeling is developed from both residual and hierarchical error estimators. Wished distributions of element sizes of adapted meshes are determined from the element-wise local contributions to the estimators and define constraints for the mesh generator. Uniform distributions of the local error are searched. [less ▲]

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See detailAnisotropic and feature sensitive triangular remeshing using normal lifting
Nivoliers, Vincent; Lévy, Bruno; Geuzaine, Christophe ULg

in Journal of Computational and Applied Mathematics (2015), 289

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See detailA quasi-optimal domain decomposition algorithm for the time-harmonic Maxwell's equations
El Bouajaji, Mohamed; Thierry, Bertrand; Antoine, Xavier et al

in Journal of Computational Physics (2015), 294

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See detailComputational advances in quasi-optimal domain decomposition methods for time-harmonic electromagnetic wave problems
Marsic, Nicolas ULg; Vion, Alexandre ULg; Geuzaine, Christophe ULg

Conference (2015)

In this talk we will present recent advances in the construction of quasi-optimal domain decomposition methods for time-harmonic electromagnetic wave problems. In particular, we will discuss the parallel ... [more ▼]

In this talk we will present recent advances in the construction of quasi-optimal domain decomposition methods for time-harmonic electromagnetic wave problems. In particular, we will discuss the parallel implementation and computational efficiency of sweeping-type preconditioners, as well as the use of high order finite element discretizations, potentially mixing orders for the volume and interface formulations. Results on several large scale test cases will be analysed. [less ▲]

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See detailPragmatic two-step homogenisation technique for ferromagnetic laminated cores
Henrotte, François; Steentjes, Simon; Hameyer, Kay et al

in IET Science, Measurement Technology (2015), 9(2), 152-159

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See detailThe generation of valid curvilinear meshes
Geuzaine, Christophe ULg; Johnen, Amaury ULg; Lambrechts, Jonathan et al

in IDIHOM: Industrialization of High-Order Methods - A Top-Down Approach (2015)

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See detailA finite-element reciprocity solution for EEG forward modeling with realistic individual head models
Ziegler, Erik ULg; Chellappa, Sarah Laxhmi ULg; Gaggioni, Giulia ULg et al

in NeuroImage (2014), 103

Highlights • Creates EEG forward models suitable for high-resolution source localization. • Automatic T1-based whole-head finite element meshing and leadfield computation. • Pipelines can incorporate ... [more ▼]

Highlights • Creates EEG forward models suitable for high-resolution source localization. • Automatic T1-based whole-head finite element meshing and leadfield computation. • Pipelines can incorporate conductivity tensors from diffusion-weighted images. • Open-source toolbox shared under a permissive software license. • Accuracy comparable to SimBio FEM and superior to OpenMEEG BEM solutions. [less ▲]

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See detailCorrection of Homogenized Lamination Stacks via a Subproblem Finite Element Method
Dular, Patrick ULg; Ferreira da Luz, Mauricio; Kuo-Peng, Patrick et al

in Proceedings of IGTE 2014 (2014, September)

A subproblem finite element method is developed for efficient modeling of lamination stacks in magnetic cores. Their homogenization is first performed followed by local corrections in certain thin regions ... [more ▼]

A subproblem finite element method is developed for efficient modeling of lamination stacks in magnetic cores. Their homogenization is first performed followed by local corrections in certain thin regions separately, surrounded by their insulating layers and the remaining thin regions kept homogenized. Accurate determinations of Joule losses are obtained. [less ▲]

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See detailProgressive Models of Current Sources for the Magnetic Vector Potential Finite Element Formulation
Dular, Patrick ULg; Ferreira da Luz, Mauricio; Kuo-Peng, Patrick et al

in Proceedings of IGTE 2014 (2014, September)

Progressive refinements of the current sources for the magnetic vector potential finite element formulation are done with a subproblem method. The sources are first considered via perfect magnetomotive ... [more ▼]

Progressive refinements of the current sources for the magnetic vector potential finite element formulation are done with a subproblem method. The sources are first considered via perfect magnetomotive force or Biot-Savart models up to their volume finite element models, from statics to dynamics. Conversions of the common volume sources to surface sources are first done to lighten the computational resources. Accuracy improvements are then efficiently obtained for local currents and fields, and global quantities, i.e. inductances, resistances, Joule losses and forces. [less ▲]

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See detailOptimizing Perfectly Matched Layers in Discrete Contexts
Modave, Axel ULg; Delhez, Eric ULg; Geuzaine, Christophe ULg

in International Journal for Numerical Methods in Engineering (2014), 99(6), 410437

Perfectly Matched Layers (PMLs) are widely used for the numerical simulation of wave-like problems defined on large or infinite spatial domains. However, for both the time-dependent and the time-harmonic ... [more ▼]

Perfectly Matched Layers (PMLs) are widely used for the numerical simulation of wave-like problems defined on large or infinite spatial domains. However, for both the time-dependent and the time-harmonic cases, their performance critically depends on the so-called absorption function. This paper deals with the choice of this function when classical numerical methods are used (based on finite differences, finite volumes, continuous finite elements and discontinuous finite elements). After reviewing the properties of the PMLs at the continuous level, we analyse how they are altered by the different spatial discretizations. In the light of these results, different shapes of absorption function are optimized and compared by means of both one- and two-dimensional representative time-dependent cases. This study highlights the advantages of the so-called shifted hyperbolic function, which is efficient in all cases and does not require the tuning of a free parameter, by contrast with the widely used polynomial functions. [less ▲]

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See detailProgressive Source and Reaction Fields for Magnetodynamic Model Refinement via a Finite Element Subproblem Method
Dular, Patrick ULg; Ferreira da Luz, Mauricio; Kuo-Peng, Patrick et al

in MOMAG 2014: 16o SBMO - Simpósio Brasi- leiro de Micro-ondas e Optoeletrônica e 11o CBMag - Congresso Brasileiro de Eletro- magnetismo (2014, August)

Magnetodynamic models are split into a sequence of progressive finite element subproblems. The source fields generated by the active conductors alone are calculated at first via either finite elements or ... [more ▼]

Magnetodynamic models are split into a sequence of progressive finite element subproblems. The source fields generated by the active conductors alone are calculated at first via either finite elements or the Biot-Savart law. The associated reaction fields for each added magnetic and/or conducting region, and in return for the source regions themselves when massive, are then calculated with finite element models, possibly with initial perfect magnetic, conductor and/or impedance boundary conditions to be further corrected. The resulting subproblem method allows efficient solving of parameterized analyses thanks to a proper mesh for each subproblem and the reuse of previous solutions to be locally corrected. Accuracy improvements are obtained for local fields and global quantities, i.e. inductances, resistances, Joule losses and forces. [less ▲]

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See detailA relaxation scheme to combine Phasor-Mode and Electromagnetic Transients Simulations
Plumier, Frédéric ULg; Aristidou, Petros ULg; Geuzaine, Christophe ULg et al

in Proceedings of the 18th Power System Computation Conference (2014, August)

This paper deals with a new scheme for coupling phasor-mode and electromagnetic transients simulations. In each simulation, an iteratively updated linear equivalent is used to represent the effect of the ... [more ▼]

This paper deals with a new scheme for coupling phasor-mode and electromagnetic transients simulations. In each simulation, an iteratively updated linear equivalent is used to represent the effect of the subsystem treated by the other simulation. Time interpolation and phasor extraction methods adapted to this scheme are presented and compared to existing methods. Finally, simulation results obtained with a 74-bus test system are reported. [less ▲]

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See detailJamming Signal Immunity Tests on GSM-R Communications Compared to EMC Basic Standards
Beauvois, Véronique ULg; Fontana, Michele; Canavero, Flavio et al

Conference (2014, July 29)

This paper presents the work being done in SECRET project (European Program FP7/2007-2013 under grant agreement number “285136”) to strengthen the European rail network against the potential jamming of ... [more ▼]

This paper presents the work being done in SECRET project (European Program FP7/2007-2013 under grant agreement number “285136”) to strengthen the European rail network against the potential jamming of the railway communications. Standardized immunity tests, currently conducted on communication equipment in the presence of electromagnetic (EM) interferences are presented. It then presents the tests carried out in SECRET to assess the resistance of railway communication systems face the signals generated by telecommunication jammers. [less ▲]

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See detailGeometrical validity of high-order pyramidal finite elements
Johnen, Amaury ULg; Geuzaine, Christophe ULg

Conference (2014, July 24)

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See detailProgressive inductor modeling via a finite element subproblem method
Dular, Patrick ULg; Krähenbühl, Laurent; Geuzaine, Christophe ULg

in Proceedings of EPNC 2014 - Electromagnetic phenomena in nonlinear circuits (2014, July)

The modeling of inductors is split into a sequence of progressive finite element subproblems. The source fields generated by the coil conductors alone, with a wire representation, are calculated at first ... [more ▼]

The modeling of inductors is split into a sequence of progressive finite element subproblems. The source fields generated by the coil conductors alone, with a wire representation, are calculated at first via either the Biot-Savart law or finite elements. The associated reaction fields for each added or modified region, mainly the magnetic cores, and in return for the source conductor regions themselves when massive, are then calculated with finite element models. Changes of magnetic regions go from perfect magnetic properties up to volume linear and nonlinear properties. The resulting subproblem method allows efficient solving of parameterized analyses thanks to a proper mesh for each subproblem and the reuse of previous solutions to be locally corrected. [less ▲]

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See detailProgressive inductor modeling via a finite element subproblem method
Dular, Patrick ULg; Krähenbühl, Laurent; Geuzaine, Christophe ULg

in Proceedings of EPNC 2014 - Electromagnetic phenomena in nonlinear circuits (2014, July)

The modeling of inductors is split into a sequence of progressive finite element subproblems. The source fields generated by the coil conductors alone, with a wire representation, are calculated at first ... [more ▼]

The modeling of inductors is split into a sequence of progressive finite element subproblems. The source fields generated by the coil conductors alone, with a wire representation, are calculated at first via either the Biot-Savart law or finite elements. The associated reaction fields for each added or modified region, mainly the magnetic cores, and in return for the source conductor regions themselves when massive, are then calculated with finite element models. Changes of magnetic regions go from perfect magnetic properties up to volume linear and nonlinear properties. The resulting subproblem method allows efficient solving of parameterized analyses thanks to a proper mesh for each subproblem and the reuse of previous solutions to be locally corrected. [less ▲]

Detailed reference viewed: 19 (0 ULg)
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See detailOn the convergence of relaxation schemes to couple phasor-mode and electromagnetic transients simulations
Plumier, Frédéric ULg; Geuzaine, Christophe ULg; Van Cutsem, Thierry ULg

in Proceedings of the IEEE PES General Meeting (2014, July)

Hybrid simulations combining phasor-mode and electromagnetic transients models aim at taking advantage of computational speed of the former and accuracy of the latter. For simulation accuracy, a ... [more ▼]

Hybrid simulations combining phasor-mode and electromagnetic transients models aim at taking advantage of computational speed of the former and accuracy of the latter. For simulation accuracy, a relaxation process is used, which consists of iterating between both models. The convergence properties of this relaxation process are investigated. The speed of convergence is assessed when the variables exchanged at the interface between both models are respectively pure voltage/current sources, Norton/Thévenin equivalents, or a combination of them. Iteratively updated Norton/Thévenin equivalents are shown to drastically reduce the number of relaxation iterations. [less ▲]

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See detailCorner asymptotics of the magnetic potential in the eddy-current model
Dauge, Monique; Dular, Patrick ULg; Krähenbühl, Laurent et al

in Mathematical Methods in the Applied Sciences (2014), 37(13), 19241955

In this paper, we describe the scalar magnetic potential in the vicinity of a corner of a conducting body embedded in a dielectric medium in a bidimensional setting. We make explicit the corner asymptotic ... [more ▼]

In this paper, we describe the scalar magnetic potential in the vicinity of a corner of a conducting body embedded in a dielectric medium in a bidimensional setting. We make explicit the corner asymptotic expansion for this potential as the distance to the corner goes to zero. This expansion involves singular functions and singular coefficients. We introduce a method for the calculation of the singular functions near the corner and we provide two methods to compute the singular coefficients: the method of moments and the method of quasi-dual singular functions. Estimates for the convergence of both approximate methods are proven. We eventually illustrate the theoretical results with finite element computations. The specific non-standard feature of this problem lies in the structure of its singular functions: They have the form of series whose first terms are harmonic polynomials and further terms are genuine non-smooth functions generated by the piecewise constant zeroth order term of the operator. [less ▲]

Detailed reference viewed: 54 (7 ULg)
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See detailOptimizing the geometrical accuracy of 2D curvilinear finite element meshes
Remacle, Jean-François; Lambrechts, Jonathan; Toulorge, Thomas et al

Conference (2014, June 27)

Detailed reference viewed: 28 (6 ULg)