References of "Dular, Patrick"      in Complete repository Arts & humanities   Archaeology   Art & art history   Classical & oriental studies   History   Languages & linguistics   Literature   Performing arts   Philosophy & ethics   Religion & theology   Multidisciplinary, general & others Business & economic sciences   Accounting & auditing   Production, distribution & supply chain management   Finance   General management & organizational theory   Human resources management   Management information systems   Marketing   Strategy & innovation   Quantitative methods in economics & management   General economics & history of economic thought   International economics   Macroeconomics & monetary economics   Microeconomics   Economic systems & public economics   Social economics   Special economic topics (health, labor, transportation…)   Multidisciplinary, general & others Engineering, computing & technology   Aerospace & aeronautics engineering   Architecture   Chemical engineering   Civil engineering   Computer science   Electrical & electronics engineering   Energy   Geological, petroleum & mining engineering   Materials science & engineering   Mechanical engineering   Multidisciplinary, general & others Human health sciences   Alternative medicine   Anesthesia & intensive care   Cardiovascular & respiratory systems   Dentistry & oral medicine   Dermatology   Endocrinology, metabolism & nutrition   Forensic medicine   Gastroenterology & hepatology   General & internal medicine   Geriatrics   Hematology   Immunology & infectious disease   Laboratory medicine & medical technology   Neurology   Oncology   Ophthalmology   Orthopedics, rehabilitation & sports medicine   Otolaryngology   Pediatrics   Pharmacy, pharmacology & toxicology   Psychiatry   Public health, health care sciences & services   Radiology, nuclear medicine & imaging   Reproductive medicine (gynecology, andrology, obstetrics)   Rheumatology   Surgery   Urology & nephrology   Multidisciplinary, general & others Law, criminology & political science   Civil law   Criminal law & procedure   Criminology   Economic & commercial law   European & international law   Judicial law   Metalaw, Roman law, history of law & comparative law   Political science, public administration & international relations   Public law   Social law   Tax law   Multidisciplinary, general & others Life sciences   Agriculture & agronomy   Anatomy (cytology, histology, embryology...) & physiology   Animal production & animal husbandry   Aquatic sciences & oceanology   Biochemistry, biophysics & molecular biology   Biotechnology   Entomology & pest control   Environmental sciences & ecology   Food science   Genetics & genetic processes   Microbiology   Phytobiology (plant sciences, forestry, mycology...)   Veterinary medicine & animal health   Zoology   Multidisciplinary, general & others Physical, chemical, mathematical & earth Sciences   Chemistry   Earth sciences & physical geography   Mathematics   Physics   Space science, astronomy & astrophysics   Multidisciplinary, general & others Social & behavioral sciences, psychology   Animal psychology, ethology & psychobiology   Anthropology   Communication & mass media   Education & instruction   Human geography & demography   Library & information sciences   Neurosciences & behavior   Regional & inter-regional studies   Social work & social policy   Sociology & social sciences   Social, industrial & organizational psychology   Theoretical & cognitive psychology   Treatment & clinical psychology   Multidisciplinary, general & others     Showing results 1 to 20 of 195 1 2 3 4 5 6     Corner asymptotics of the magnetic potential in the eddy-current modelDauge, Monique; Dular, Patrick ; Krähenbühl, Laurent et alin Mathematical Methods in the Applied Sciences (2014), 37(13), 19241955In 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: 35 (6 ULg) Comparison of implementation techniques for Galerkin projection between different meshesWang, Zifu; Henneron, Thomas; Dular, Patrick et alin International Journal of Numerical Modeling: Electronic Networks, Devices and Fields (2014), 27(3), 517-526To solve multiphysics problems, weak coupling of finite element calculations can be carried out: the subproblems of which the physical nature differs are solved separately on their own meshes. In this ... [more ▼]To solve multiphysics problems, weak coupling of finite element calculations can be carried out: the subproblems of which the physical nature differs are solved separately on their own meshes. In this case, Galerkin projection provides useful tool to ensure the transfer of physical fields between different meshes. In terms of implementation, the Galerkin projection system can be either accurately assembled over the intersection of two meshes or approximately integrated over the target mesh. This paper describes and compares these two implementation techniques for the Galerkin projection. [less ▲]Detailed reference viewed: 22 (5 ULg) Optimized Waveform Relaxation Methods for Modeling Electromagnetic Field-Circuit ProblemsNshimiyimana, Jean de Dieu ; Plumier, Frédéric ; Dular, Patrick et alin Proceedings of Sixteenth Biennal IEEE Conference on Electromagnetic Field Computation (2014, April)The convergence of classical and optimized waveform relaxation methods is compared for the simulation of field-circuit problems, where a finite element solver is used for the solution of the field problem ... [more ▼]The convergence of classical and optimized waveform relaxation methods is compared for the simulation of field-circuit problems, where a finite element solver is used for the solution of the field problem and a circuit simulator is used for the electronic circuit. [less ▲]Detailed reference viewed: 45 (14 ULg) Modeling of Transformer Core Joints via a Subproblem FEM and a Homogenization TechniqueFerreira da Luz, Mauricio Valencia; Dular, Patrick ; Vianei Leite, Jean et alin IEEE Transactions on Magnetics (2014), 50(2), A subproblem finite element method is developed for modeling the transformer core joints. It applies magnetostatic and magnetodynamic models on progressive geometries and different components of the ... [more ▼]A subproblem finite element method is developed for modeling the transformer core joints. It applies magnetostatic and magnetodynamic models on progressive geometries and different components of the solution, supported by different meshes. It allows an efficient and robust analysis of magnetic circuits in any frequency range, with an accurate calculation of flux density, losses, reluctance, and impedance in transformer core joint zone. The models of the study properly account for the effects of core design parameters such as length of air gaps and overlap length in stacked-lamination cores. The proposed models, which include saturation, are applied to grain-oriented silicon steel and two types of step-lap joints are considered: single-step-lap (SSL) joints and multistep-lap (MSL) joints. The values of magnetic reluctance, impedance, and Joule losses obtained with SSL joint are bigger than with MSL joint. [less ▲]Detailed reference viewed: 30 (1 ULg) Comparison of Residual and Hierarchical Finite Element Error Estimators in Eddy Current ProblemsDular, Patrick ; Tang, Zuqi; Le Ménach, Yvonnick et alin IEEE Transactions on Magnetics (2014), 50(2), The finite element computation of eddy current problems introduces numerical error. This error can only be estimated. Among all error estimators (EEs) already developed, two estimators, called residual ... [more ▼]The finite element computation of eddy current problems introduces numerical error. This error can only be estimated. Among all error estimators (EEs) already developed, two estimators, called residual and hierarchical EEs, proven to be reliable and efficient, are theoretically and numerically compared. Both estimators show similar behaviors and locations of the error. [less ▲]Detailed reference viewed: 17 (1 ULg) Perfect Conductor and Impedance Boundary Condition Corrections via a Finite Element Subproblem MethodDular, Patrick ; Péron, Victor; Perrussel, Ronan et alin IEEE Transactions on Magnetics (2014), 50(2), A finite element subproblem method is developed to correct the inaccuracies proper to perfect conductor and impedance boundary condition models, particularly near edges and corners of the conductors, for ... [more ▼]A finite element subproblem method is developed to correct the inaccuracies proper to perfect conductor and impedance boundary condition models, particularly near edges and corners of the conductors, for a large range of conductivities and frequencies. Successive local corrections, supported by fine local meshes, can be obtained from each model to a more accurate one, allowing efficient extensions of their domains of validity. [less ▲]Detailed reference viewed: 23 (2 ULg) Nonlinear Computational Homogenization Method for the Evaluation of Eddy Currents in Soft Magnetic CompositesNiyonzima, Innocent ; Sabariego, Ruth Vazquez; Dular, Patrick et alin IEEE Transactions on Magnetics (2014), 50(02), In this paper, a heterogeneous multiscale method technique is applied to model the behavior of electromagnetic fields in soft magnetic composites (SMC). Two problems are derived from the two-scale ... [more ▼]In this paper, a heterogeneous multiscale method technique is applied to model the behavior of electromagnetic fields in soft magnetic composites (SMC). Two problems are derived from the two-scale homogenization theory: a macroscale problem that captures the slow variations of the overall solution, and many mesoscale problems that allow determining the constitutive laws at the macroscale. As application, an SMC core is considered. [less ▲]Detailed reference viewed: 48 (9 ULg) Shape Optimization of Interior Permanent Magnet Motor for Torque Ripple ReductionKuci, Erin ; Geuzaine, Christophe ; Dular, Patrick et alin Proceedings of The 4th International Conference on Engineering Optimization: Lisbon (Portugal), 8-11 September 2014 (2014)The objective of the paper is to present an open source environment to perform the design, simulation (Gmsh, GetDP) and optimization (OpenOpt) of electrical machines. The design of the permanent magnets ... [more ▼]The objective of the paper is to present an open source environment to perform the design, simulation (Gmsh, GetDP) and optimization (OpenOpt) of electrical machines. The design of the permanent magnets of a v-shaped interior permanent magnet machine is then considered. The later is modeled using the finite element method with a formulation based on the magnetic vector potential. Optimization is based on mathematical programming approach. A semi-analytical sensitivity analysis is compared with the finite difference. Thanks to this approach, the design time is much shorter than that required by an approach of trial and error used by industry. The reduction of the torque ripple is about 70 \% with respect to the original design. [less ▲]Detailed reference viewed: 113 (24 ULg) Subproblem Approach for Modeling Multiply Connected Thin Regions with an h-Conformal Magnetodynamic Finite Element FormulationDang, Quoc Vuong ; Dular, Patrick ; Vazquez Sabariego, Ruth et alin European Physical Journal : Applied physics (2013), in pressA subproblem h-conformal eddy current nite element method is proposed for correcting the inaccuracies inherent to thin shell models. Such models replace volume thin regions by surfaces but neglect border ... [more ▼]A subproblem h-conformal eddy current nite element method is proposed for correcting the inaccuracies inherent to thin shell models. Such models replace volume thin regions by surfaces but neglect border e ects in the vicinity of their edges and corners. The developed surface-to-volume correction problem is de ned as a step of the multiple subproblems that can split a complete problem, consisting of inductors and magnetic or conducting regions, some of these being thin regions. The general case of multiply connected thin regions is considered [less ▲]Detailed reference viewed: 105 (20 ULg) Nonlinear Computational Homogenization Method for the Evaluation of Eddy Currents in Soft Magnetic CompositesNiyonzima, Innocent ; Sabariego, Ruth Vazquez; Dular, Patrick et alin Proceedings of the 19th Conference on the Computation of Electromagnetic Fields (COMPUMAG2013) (2013, July)In this paper, a heterogeneous multiscale method (HMM) technique is applied to model the behaviour of electromagnetic fields in soft magnetic composites (SMC). Two problems are derived from the two-scale ... [more ▼]In this paper, a heterogeneous multiscale method (HMM) technique is applied to model the behaviour of electromagnetic fields in soft magnetic composites (SMC). Two problems are derived from the two-scale homogenization theory: a macroscale problem that captures the slow variations of the overall solution, and many mesoscale problems that allow determining the constitutive laws at the macroscale. As application, an SMC core is considered. [less ▲]Detailed reference viewed: 15 (7 ULg) Computational Homogenization for Laminated Ferromagnetic Cores in MagnetodynamicsNiyonzima, Innocent ; V Sabariego, Ruth; Dular, Patrick et alin IEEE Transactions on Magnetics (2013), 49(5), 2049-2052In this paper, we investigate the modeling of ferromagnetic multiscale materials. We propose a computational homogenization technique based on the heterogeneous multiscale method (HMM) that includes both ... [more ▼]In this paper, we investigate the modeling of ferromagnetic multiscale materials. We propose a computational homogenization technique based on the heterogeneous multiscale method (HMM) that includes both eddy-current and hysteretic losses at the mesoscale. The HMM comprises: 1) a macroscale problem that captures the slow variations of the overall solution; 2) many mesoscale problems that allow to determine the constitutive law at the macroscale. As application example, a laminated iron core is considered. [less ▲]Detailed reference viewed: 130 (37 ULg) Subproblem h-Conform Formulation for Accurate Thin Shell Models Between Conducting and Nonconducting RegionsDang, Quoc Vuong ; Dular, Patrick ; Vazquez Sabariego, Ruth et alin Proceeding of the 9th International Symposium on Electric and Magnetic Fields, EMF 2013 (2013, April 23)A subproblem method (SPM) with h-formulation is developed for correcting the inaccuracies near edges and corners that arise from using thin shell (TS) models to replace thin volume regions by surfaces ... [more ▼]A subproblem method (SPM) with h-formulation is developed for correcting the inaccuracies near edges and corners that arise from using thin shell (TS) models to replace thin volume regions by surfaces. The developed surface-to-volume correction problem is defined as a step of multiple SPs, with inductors and magnetic or conducting regions, some of them being thin. The TS model assumes that the fields in the thin regions are approximated by a priori 1-D analytical distributions along the shell thickness (C. Geuzaine et al., “Dual formulations for the modeling of thin electromagnetic shells using edge elements,” IEEE Trans. Magn., vol. 36, no. 4, pp. 799–802, 2000). Their interior is not meshed and ratherextracted from the studied domain, which is reduced to a zero-thickness double layer with interface conditions (ICs) linked to 1-D analytical distributions that however neglect end and curvature effects. This leads to inaccuracies near edges and corners that increase with the thickness. To cope with these difficulties, the authors have recently proposed a SPM based on the h-formulation for a thin region located between non-conducting regions (Vuong Q. Dang et al., “Subproblem Approach for Thin Shell Dual Finite Element Formulations”, IEEE Trans. Magn., vol. 48, no. 2, pp. 407–410, 2012). The magnetic field h is herein defined in nonconducting regions by means of a magnetic scalar potential , i.e. h = -grad{\phi} , with discontinuities of through the TS. In this paper, the SPM is extended to account for thin regions located between conducting regions or between conducting and nonconducting regions, in the general case of multiply connected regions. In these regions, the potential is not defined anymore on both sides of the TS and the problem has to be expressed in terms of the discontinuities of h, possibly involving on one side only, to be strongly defined via an IC through the TS. In the proposed SP strategy, a reduced problem with only inductors is first solved on a simplified mesh without thin and volume regions. Its solution gives surface sources (SSs) as ICs for added TS regions, and volume sources (VSs) for possible added volume regions. The TS solution is further improved by a volume correction via SSs and VSs that overcome the TS assumptions, respectively suppressing the TS model and adding the volume model. Each SP has its own separate mesh, which increases the computational efficiency. Details on the proposed method will be given in the extended paper, with practical applications. [less ▲]Detailed reference viewed: 105 (11 ULg) A Computational Homogenization Method for the Evaluation of Eddy Current in Nonlinear Soft Magnetic CompositesNiyonzima, Innocent ; Vazquez Sabariego, Ruth ; Dular, Patrick et alin Proceeding of the 9th International Symposium on Electric and Magnetic Fields, EMF 2013 (2013, April 23)The use of the soft magnetic composite (SMC) in electric devices has increased in recent years. These materials made from a metallic powder compacted with a dielectric binder are a good alternative to ... [more ▼]The use of the soft magnetic composite (SMC) in electric devices has increased in recent years. These materials made from a metallic powder compacted with a dielectric binder are a good alternative to laminated ferromagnetic structures as their granular mesoscale structure allows to significantly reduce the eddy current losses. Furthermore unlike the laminated ferromagnetic structures, SMC exhibit isotropic magnetic properties what makes them good candidates for manufacturing machines with 3D flux paths. The isotropy of the thermal conductivity also allows for a more efficient heat dissipation. The use of classical numerical methods such as the finite element method to study the behavior of SMC is computational very expensive. Indeed a very fine mesh would be required in order to capture fine scale variations i.e. variations at level of metallic grains whence the use of multiscale methods for modelling SMC. The application of multiscale method to study the behaviour of SMC is relatively recent. In (A. Bordianu et al “A Multiscale Approach to Predict Classical Losses in Soft Magnetic Composites”, IEEE Trans. Mag., vol. 48, no. 4, 2012.), the authors used a homogenization technique to compute electrical and magnetic constitutive laws on a representative volume element (RVE). These laws were then used in finite element computations. Herein, the RVE has been chosen to account for the grain- grain contact that can occur in a actual SMC structure due to the compaction process and that can lead to the appearance of macroscale eddy currents. In this paper, we will extend the computational homogenization method success- fully used for modelling the behaviour of laminated ferromagnetic cores in mag- netodynamics (I. Niyonzima et al “Computational Homogenization for Laminated Ferromagnetic Cores in Magnetodynamics”, in Proc. of the 15th Biennal Confer- ence on Electromagnetic Field Computation, 2012) to the case of SMC. The method is based on the heterogeneous multiscale method (HMM) and couples two types of problems: a macroscale problem that captures the slow variations of the overall so- lution and many microscale problems that allow to determine the constitutive laws at the macroscale. The choice of RVE will also be discussed. [less ▲]Detailed reference viewed: 98 (14 ULg) Dual Formulations for Accurate Thin Shell Models in a Finite Element Subproblem MethodDang, Quoc Vuong ; Dular, Patrick ; Vazquez Sabariego, Ruth et alin Proceeding of the 19th COMPUMAG Conference on the Computation of Electromagnetic Fields, 2013 (2013, April 01)A subproblem finite with dual finite element magnetostatic and magnetodynamic formulations is developed for correcting the inaccuracies near edges and corners coming from thin shell models, that replace ... [more ▼]A subproblem finite with dual finite element magnetostatic and magnetodynamic formulations is developed for correcting the inaccuracies near edges and corners coming from thin shell models, that replace thin volume regions by surfaces. The surface-to-volume correction problem is defined as one of the multiple subproblems applied to a complete problem, considering successive additions of inductors and magnetic or conducting regions, some of these being thin regions. Each SP requires a proper adapted mesh of its regions, which facilitates meshing and increases computational e ciency. [less ▲]Detailed reference viewed: 43 (3 ULg) Progressive Eddy Current modeling via a finite element subproblem methodDular, Patrick ; Péron, Victor; Krähenbühl, Laurent et alin International Journal of Applied Electromagnetics and Mechanics (2013)Detailed reference viewed: 13 (1 ULg) Influence of the frequency for the numerical modeling of the parasitic capacitances of wound magnetic componentsDe Greve, Zacharie; Lehti, Leena; Deblecker, Olivier et alin 9th International Symposium on Electric and Magnetic Fields (EMF2013) (2013)Detailed reference viewed: 9 (1 ULg) Accurate h-Conform Finite Element Model of Multiply Connected Thin Regions via a Subproblem MethodDang, Quoc Vuong ; Dular, Patrick ; Vazquez Sabariego, Ruth et alin Proceedings of the 15th Biennial IEEE Conference on Electromagnetic Field Computation (CEFC2012) (2012, November)A subproblem method for solving eddy current finite element is developed to correct the inaccuracies near edges and corners arising from thin shell models. Such models replace thin volume regions by ... [more ▼]A subproblem method for solving eddy current finite element is developed to correct the inaccuracies near edges and corners arising from thin shell models. Such models replace thin volume regions by surfaces but neglect border effects in the vicinity of their edges and corners. A thin shell solution, performed by a simplified mesh near the thin structures, serves as a source of a correction problem consisting of the actual volume thin regions alone and concentrating the meshing effort on the thin regions. The general case of multiply connected thin regions is considered. [less ▲]Detailed reference viewed: 51 (12 ULg) Subproblem h-Conform Magnetodynamic Finite Element Formulation for Accurate Model of Multiply Connected Thin RegionsDang, Quoc Vuong ; Dular, Patrick ; Vazquez Sabariego, Ruth et alin Proceedings of the 7th European Conference on Numerical Methods in Electromagnetism (NUMELEC 2012) (2012, July 03)A subproblem $\vh$-conform eddy current finite element method is proposed for correcting the inaccuracies inherent to thin shell models. Such models replace volume thin regions by surfaces but neglect ... [more ▼]A subproblem $\vh$-conform eddy current finite element method is proposed for correcting the inaccuracies inherent to thin shell models. Such models replace volume thin regions by surfaces but neglect border effects in the vicinity of their edges and corners. The developed surface-to-volume correction problem is defined as a step of the multiple subproblems applied to a complete problem, consisting of inductors and magnetic or conducting regions, some of these being thin regions. The general case of multiply connected thin regions is considered. [less ▲]Detailed reference viewed: 60 (20 ULg) Multiscale Quasistatic Homogenization for Laminated Ferromagnetic CoresNiyonzima, Innocent ; Vazquez Sabariego, Ruth ; Dular, Patrick et alin Proceedings of the 7th European Conference on Numerical Methods in Electromagnetism (NUMELEC 2012) (2012, July 03)In this paper, we investigate the modeling of ferromagnetic multiscale materials. We propose a computational homogenization method based on the heterogeneous multiscale method (HMM) with inclusion of a ... [more ▼]In this paper, we investigate the modeling of ferromagnetic multiscale materials. We propose a computational homogenization method based on the heterogeneous multiscale method (HMM) with inclusion of a hysteresis model. The HMM involves: 1) a macroscale problem that captures the slow variations of the overall solution; 2) many microscale problems that allow to determine the constitutive law at the macroscale. At the microscale, a novel energy consistent hystere- sis model is incorporated. As application example, a laminated iron core is considered. [less ▲]Detailed reference viewed: 105 (25 ULg) ONELAB: Open Numerical Engineering LABoratoryGeuzaine, Christophe ; Henrotte, F.; Marchandise, E. et alin Proceedings of the 7th European Conference on Numerical Methods in Electromagnetism (NUMELEC2012) (2012, July)Detailed reference viewed: 120 (14 ULg)