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http://hdl.handle.net/10985/7276
Comparison of two approaches to compute magnetic field in problems with random domains
MAC, Duy Hung; MIPO, Jean-Claude; CLENET, Stephane
Methods are now available to solve numerically electromagnetic problems with uncertain input data (behaviour law or geometry). The stochastic approach consists in modelling uncertain data using random variables. Discontinuities on the magnetic field distribution in the stochastic dimension can arise in a problem with uncertainties on the geometry. The basis functions (polynomial chaos) usually used to approximate the unknown fields in the random dimensions are no longer suited. One possibility proposed in the literature is to introduce additional functions (enrichment function) to tackle the problem of discontinuity. In this study, the authors focus on the method of random mappings and they show that in this case the discontinuity are naturally taken into account and that no enrichment function needs to be added.
This paper is a postprint of a paper submitted to and accepted for publication in Science, Measurement & Technology, IET and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library
Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/10985/72762012-01-01T00:00:00ZMAC, Duy HungMIPO, Jean-ClaudeCLENET, StephaneMethods are now available to solve numerically electromagnetic problems with uncertain input data (behaviour law or geometry). The stochastic approach consists in modelling uncertain data using random variables. Discontinuities on the magnetic field distribution in the stochastic dimension can arise in a problem with uncertainties on the geometry. The basis functions (polynomial chaos) usually used to approximate the unknown fields in the random dimensions are no longer suited. One possibility proposed in the literature is to introduce additional functions (enrichment function) to tackle the problem of discontinuity. In this study, the authors focus on the method of random mappings and they show that in this case the discontinuity are naturally taken into account and that no enrichment function needs to be added.Transformation Methods for Static Field Problems With Random Domains
http://hdl.handle.net/10985/7274
Transformation Methods for Static Field Problems With Random Domains
MAC, Duy Hung; MIPO, Jean-Claude; CLENET, Stephane
The numerical solution of partial differential equations onto random domains can be done by using a mapping transforming this random domain into a deterministic domain. The issue is then to determine this one to one random mapping. In this paper, we present two methods-one based on the resolution of the Laplace equations, one based on a geometric transformation-to determine the random mapping. A stochastic magnetostatic example is treated to compare these methods.
Sat, 01 Jan 2011 00:00:00 GMThttp://hdl.handle.net/10985/72742011-01-01T00:00:00ZMAC, Duy HungMIPO, Jean-ClaudeCLENET, StephaneThe numerical solution of partial differential equations onto random domains can be done by using a mapping transforming this random domain into a deterministic domain. The issue is then to determine this one to one random mapping. In this paper, we present two methods-one based on the resolution of the Laplace equations, one based on a geometric transformation-to determine the random mapping. A stochastic magnetostatic example is treated to compare these methods.Influence of the Manufacturing Process of a Claw-Pole Alternator on Its Stator Shape and Acoustic Noise
http://hdl.handle.net/10985/12995
Influence of the Manufacturing Process of a Claw-Pole Alternator on Its Stator Shape and Acoustic Noise
TAN-KIM, Antoine; HAGEN, Nicolas; LANFRANCHI, Vincent; MIPO, Jean-Claude; LEGRANGER, Jerome; PALLESCHI, Frédéric; COOREVITS, Thierry; CLENET, Stephane
This paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are investigated. Results show that the deformations caused by the manufacturing process significantly increase the sound power level of particular orders.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/129952017-01-01T00:00:00ZTAN-KIM, AntoineHAGEN, NicolasLANFRANCHI, VincentMIPO, Jean-ClaudeLEGRANGER, JeromePALLESCHI, FrédéricCOOREVITS, ThierryCLENET, StephaneThis paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are investigated. Results show that the deformations caused by the manufacturing process significantly increase the sound power level of particular orders.Experimental characterization of the iron losses variability in stators of electrical machines
http://hdl.handle.net/10985/7115
Experimental characterization of the iron losses variability in stators of electrical machines
RAMAROTAFIKA, Rindra; BENABOU, Abdelkader; MIPO, Jean-Claude; CLENET, Stephane
Manufacturing processes may introduce a significant variability on the magnetic properties of claw pole generator stators. The present work deals with the analysis of two groups of stator samples. The first group is composed of 28 slinky stators (SS) and the second group is composed of 5 stators, manufactured using laser cut stacked laminations (SL). Both groups are made from the same lamination grade and with the same geometrical dimensions. Characterization was carried out for several levels of excitation field at 50Hz. A noticeable variability has been observed on the iron losses for SS samples, whereas it appears to be not significant for SL samples. The loss separation technique has then been investigated for the SS samples. Results show that the variability of static losses is more important than the one of dynamic losses.
Version éditeur disponible à l'adresse suivante : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6172417
Sun, 01 Jan 2012 00:00:00 GMThttp://hdl.handle.net/10985/71152012-01-01T00:00:00ZRAMAROTAFIKA, RindraBENABOU, AbdelkaderMIPO, Jean-ClaudeCLENET, StephaneManufacturing processes may introduce a significant variability on the magnetic properties of claw pole generator stators. The present work deals with the analysis of two groups of stator samples. The first group is composed of 28 slinky stators (SS) and the second group is composed of 5 stators, manufactured using laser cut stacked laminations (SL). Both groups are made from the same lamination grade and with the same geometrical dimensions. Characterization was carried out for several levels of excitation field at 50Hz. A noticeable variability has been observed on the iron losses for SS samples, whereas it appears to be not significant for SL samples. The loss separation technique has then been investigated for the SS samples. Results show that the variability of static losses is more important than the one of dynamic losses.Solution of Static Field Problems With Random Domains
http://hdl.handle.net/10985/7275
Solution of Static Field Problems With Random Domains
MAC, Duy Hung; MIPO, Jean-Claude; MOREAU, Olivier; CLENET, Stephane
A method to solve stochastic partial differential equations on random domains consists in using a one-to-one random mapping function which transforms the random domain into a deterministic domain. With this method, the randomness is then borne by the constitutive relationship of the material. In this paper, this method is applied in electrokinetics in the case of scalar potential and vector potential formulations. An example is treated and the proposed method is compared to a nonintrusive method (NIM) based on the remeshing of the random domains.
Fri, 01 Jan 2010 00:00:00 GMThttp://hdl.handle.net/10985/72752010-01-01T00:00:00ZMAC, Duy HungMIPO, Jean-ClaudeMOREAU, OlivierCLENET, StephaneA method to solve stochastic partial differential equations on random domains consists in using a one-to-one random mapping function which transforms the random domain into a deterministic domain. With this method, the randomness is then borne by the constitutive relationship of the material. In this paper, this method is applied in electrokinetics in the case of scalar potential and vector potential formulations. An example is treated and the proposed method is compared to a nonintrusive method (NIM) based on the remeshing of the random domains.A priori error indicator in the transformation method for problems with geometric uncertainties
http://hdl.handle.net/10985/7114
A priori error indicator in the transformation method for problems with geometric uncertainties
MAC, Duy Hung; MIPO, Jean-Claude; TSUKERMAN, Igor; CLENET, Stephane
To solve stochastic problems with geometric uncertainties, one can transform the original problem in a domain with stochastic boundaries and interfaces to a problem defined in a deterministic domain with uncertainties in the material behavior. The latter problem is then discretized. There exist infinitely many random mappings that lead to identical results in the continuous domain but not in the discretized domain. In this paper, an a priori error indicator is proposed for electromagnetic problems with scalar and vector potential formulations. This leads to criteria for selecting random mappings that reduce the numerical error. In an illustrative numerical example, the proposed a priori error indicator is compared with an a posteriori estimator for both potential formulations
Version éditeur de cette publication à l'adresse suivante : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514655
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/71142013-01-01T00:00:00ZMAC, Duy HungMIPO, Jean-ClaudeTSUKERMAN, IgorCLENET, StephaneTo solve stochastic problems with geometric uncertainties, one can transform the original problem in a domain with stochastic boundaries and interfaces to a problem defined in a deterministic domain with uncertainties in the material behavior. The latter problem is then discretized. There exist infinitely many random mappings that lead to identical results in the continuous domain but not in the discretized domain. In this paper, an a priori error indicator is proposed for electromagnetic problems with scalar and vector potential formulations. This leads to criteria for selecting random mappings that reduce the numerical error. In an illustrative numerical example, the proposed a priori error indicator is compared with an a posteriori estimator for both potential formulationsInfluence of the Manufacturing Process of a Claw-Pole Alternator on its Stator Shape and Acoustic Noise
http://hdl.handle.net/10985/11835
Influence of the Manufacturing Process of a Claw-Pole Alternator on its Stator Shape and Acoustic Noise
TAN-KIM, Antoine; HAGEN, Nicolas; LANFRANCHI, Vincent; MIPO, Jean-Claude; LEGRANGER, Jerome; PALLESCHI, Frédéric; COOREVITS, Thierry; CLENET, Stephane
This paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are investigated. Results show that the deformations caused by the manufacturing process significantly increase the sound power level of particular orders.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/118352017-01-01T00:00:00ZTAN-KIM, AntoineHAGEN, NicolasLANFRANCHI, VincentMIPO, Jean-ClaudeLEGRANGER, JeromePALLESCHI, FrédéricCOOREVITS, ThierryCLENET, StephaneThis paper shows the influence of the manufacturing process of a claw-pole alternator on its acoustic noise. First, the stator welds and the assembly of the stator in the brackets are linked to deformations of the inner diameter of the stator. Then, the influences of these deformations on the magnetic forces and the subsequent acoustic noise are investigated. Results show that the deformations caused by the manufacturing process significantly increase the sound power level of particular orders.Characterization of the local incremental permeability of a ferromagnetic plate based on a four needles technique
http://hdl.handle.net/10985/11754
Characterization of the local incremental permeability of a ferromagnetic plate based on a four needles technique
ARBENZ, Laure; BENABOU, Abdelkader; CLENET, Stephane; FAVEROLLE, Pierre; MIPO, Jean-Claude
The performances of electrical machines depend highly on the behavior of ferromagnetic materials. In some applications, these materials operate under DC polarization, i.e. when the magnetic field oscillates around a DC bias. In that condition, it is required to know the incremental permeability which characterizes the magnetic behavior of the material around the operating point. In this paper, a non-destructive approach, involving a combination of experiment and Finite Element (FE) technique, is presented in order to determine the incremental permeability. The proposed sensor is based on the four-needles method. With this sensor, Bowler et al. have proposed a method to determine the initial permeability of homogeneous metal plates based on an analytical model. Here we propose to use the same kind of sensor to determine the incremental permeability. The measurement process is analyzed using a FE model. It is shown that the analytical approach reaches its limits if the permeability of the plate and its thickness become too high. A combination between the measurements and a FE model is introduced to overcome this
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/117542016-01-01T00:00:00ZARBENZ, LaureBENABOU, AbdelkaderCLENET, StephaneFAVEROLLE, PierreMIPO, Jean-ClaudeThe performances of electrical machines depend highly on the behavior of ferromagnetic materials. In some applications, these materials operate under DC polarization, i.e. when the magnetic field oscillates around a DC bias. In that condition, it is required to know the incremental permeability which characterizes the magnetic behavior of the material around the operating point. In this paper, a non-destructive approach, involving a combination of experiment and Finite Element (FE) technique, is presented in order to determine the incremental permeability. The proposed sensor is based on the four-needles method. With this sensor, Bowler et al. have proposed a method to determine the initial permeability of homogeneous metal plates based on an analytical model. Here we propose to use the same kind of sensor to determine the incremental permeability. The measurement process is analyzed using a FE model. It is shown that the analytical approach reaches its limits if the permeability of the plate and its thickness become too high. A combination between the measurements and a FE model is introduced to overcome thisEnhanced Meta-model Based Optimization under Constraints using Parallel Computations
http://hdl.handle.net/10985/13417
Enhanced Meta-model Based Optimization under Constraints using Parallel Computations
EL BECHARI, Reda; BRISSET, Stéphane; MIPO, Jean-Claude; CLENET, Stephane
Meta-models proved to be a very efficient strategy for optimization of expensive black-box models, e.g. Finite Element simulation for electromagnetic devices. It enables to reduce the computational burden for optimization purposes. Kriging is a popular method to build meta-model. Its statistical properties were firstly used in efficient global optimization for unconstrained problems. Afterwards many extensions were introduced in the literature to deal with constrained optimization. This paper presents a comparative study of some infill criteria for constraints handling and a new strategy for parallelization of the expensive computations of models. TEAM workshop problem 22 is taken as an electromagnetic test problem.
Sun, 01 Jan 2017 00:00:00 GMThttp://hdl.handle.net/10985/134172017-01-01T00:00:00ZEL BECHARI, RedaBRISSET, StéphaneMIPO, Jean-ClaudeCLENET, StephaneMeta-models proved to be a very efficient strategy for optimization of expensive black-box models, e.g. Finite Element simulation for electromagnetic devices. It enables to reduce the computational burden for optimization purposes. Kriging is a popular method to build meta-model. Its statistical properties were firstly used in efficient global optimization for unconstrained problems. Afterwards many extensions were introduced in the literature to deal with constrained optimization. This paper presents a comparative study of some infill criteria for constraints handling and a new strategy for parallelization of the expensive computations of models. TEAM workshop problem 22 is taken as an electromagnetic test problem.Characterization of the local Electrical Properties of Electrical Machine Parts with non-Trivial Geometry
http://hdl.handle.net/10985/9861
Characterization of the local Electrical Properties of Electrical Machine Parts with non-Trivial Geometry
ARBENZ, Laure; BENABOU, Abdelkader; MIPO, Jean-Claude; FAVEROLLE, Pierre; CLENET, Stephane
In electrical machines, knowing the electrical conductivity is of importance for the eddy current calculation, especially when massive iron parts are involved. Generally the conductivity is measured on samples of raw materials with simple geometries. Indeed, a simple geometry is suitable for applying an analytical approach to deduce the electrical conductivity from the measured electrical quantities. Nevertheless, when a non destructive measurement is required, the measurement of the electrical conductivity can become rather difficult on parts with complex geometry. To that end, with the help of the Finite Element Modeling approach (FEM), a strategy is developed to characterize the local electrical properties of parts with a non-trivial geometry.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/98612015-01-01T00:00:00ZARBENZ, LaureBENABOU, AbdelkaderMIPO, Jean-ClaudeFAVEROLLE, PierreCLENET, StephaneIn electrical machines, knowing the electrical conductivity is of importance for the eddy current calculation, especially when massive iron parts are involved. Generally the conductivity is measured on samples of raw materials with simple geometries. Indeed, a simple geometry is suitable for applying an analytical approach to deduce the electrical conductivity from the measured electrical quantities. Nevertheless, when a non destructive measurement is required, the measurement of the electrical conductivity can become rather difficult on parts with complex geometry. To that end, with the help of the Finite Element Modeling approach (FEM), a strategy is developed to characterize the local electrical properties of parts with a non-trivial geometry.