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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.Model order reduction of quasi-static problems based on POD and PGD approaches
http://hdl.handle.net/10985/7234
Model order reduction of quasi-static problems based on POD and PGD approaches
HENNERON, Thomas; CLENET, Stephane
In order to reduce the computation time of a quasi-static problem solved by the nite element method, methods of model order reduction can be applied. In this context, two approaches, the Proper Orthogonal Decomposition and the Proper Generalized Decomposition, are applied to the vector potential formulation used to solve the quasi static problem. The developped methods are compared on an academic example.
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/72342013-01-01T00:00:00ZHENNERON, ThomasCLENET, StephaneIn order to reduce the computation time of a quasi-static problem solved by the nite element method, methods of model order reduction can be applied. In this context, two approaches, the Proper Orthogonal Decomposition and the Proper Generalized Decomposition, are applied to the vector potential formulation used to solve the quasi static problem. The developped methods are compared on an academic example.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.Solution of Large Stochastic Finite Element Problems – Application to ECT-NDT
http://hdl.handle.net/10985/7317
Solution of Large Stochastic Finite Element Problems – Application to ECT-NDT
BEDDEK, Karim; MOREAU, Olivier; LE MENACH, Yvonnick; CLENET, Stephane
This paper describes an efficient bloc iterative solver for the Spectral Stochastic Finite Element Method (SSFEM). The SSFEM was widely used to quantify the effect of input data uncertainties on the outputs of finite element models. The bloc iterative solver allows reducing computational cost of the SSFEM. The method is applied on an industrial Non Destructive Testing (NDT) problem. The numerical performances of the method are compared with those of the Non-Intrusive Spectral Projection (NISP).
Version éditeur disponible à cette adresse : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514633
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/73172013-01-01T00:00:00ZBEDDEK, KarimMOREAU, OlivierLE MENACH, YvonnickCLENET, StephaneThis paper describes an efficient bloc iterative solver for the Spectral Stochastic Finite Element Method (SSFEM). The SSFEM was widely used to quantify the effect of input data uncertainties on the outputs of finite element models. The bloc iterative solver allows reducing computational cost of the SSFEM. The method is applied on an industrial Non Destructive Testing (NDT) problem. The numerical performances of the method are compared with those of the Non-Intrusive Spectral Projection (NISP).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 formulationsComparizon of Conventional and Unconventional 5-phase PM Motor Structures for Naval Applications
http://hdl.handle.net/10985/7378
Comparizon of Conventional and Unconventional 5-phase PM Motor Structures for Naval Applications
SEMAIL, Eric; CHARPENTIER, Jean-Frederic; SCUILLER, Franck; CLENET, Stephane
Multi-phase motors are widely used in marine propulsion. In this paper, a Multi-machine modeling of Surface Mounted PM motors is presented and applied to a 5-phase one. The latter is proved to be equivalent to a set of two-phase fictitious machines each ones being characterized by a set of specific harmonic rank. A simple control consists in supplying each fictitious machine by a current which contains only one harmonic. A five phase machine is then supplied by currents with only both first and third harmonics. Considering this kind of control, it is proved that for given stator resistance and average torque the Joule losses and the torque ripple are minimized if a simple criterion on the harmonics of electromotive force at constant speed is fullfilled. Different structures of rotor are then compared to examine numerically which improvements can be practically obtained
Thu, 01 Jan 2004 00:00:00 GMThttp://hdl.handle.net/10985/73782004-01-01T00:00:00ZSEMAIL, EricCHARPENTIER, Jean-FredericSCUILLER, FranckCLENET, StephaneMulti-phase motors are widely used in marine propulsion. In this paper, a Multi-machine modeling of Surface Mounted PM motors is presented and applied to a 5-phase one. The latter is proved to be equivalent to a set of two-phase fictitious machines each ones being characterized by a set of specific harmonic rank. A simple control consists in supplying each fictitious machine by a current which contains only one harmonic. A five phase machine is then supplied by currents with only both first and third harmonics. Considering this kind of control, it is proved that for given stator resistance and average torque the Joule losses and the torque ripple are minimized if a simple criterion on the harmonics of electromotive force at constant speed is fullfilled. Different structures of rotor are then compared to examine numerically which improvements can be practically obtainedStochastic Non Destructive Testing simulation: sensitivity analysis applied to material properties in clogging of nuclear power plant steam generators
http://hdl.handle.net/10985/7116
Stochastic Non Destructive Testing simulation: sensitivity analysis applied to material properties in clogging of nuclear power plant steam generators
MOREAU, Olivier; BEDDEK, Karim; LE MENACH, Yvonnick; CLENET, Stephane
A Non destructive Testing (NDT) procedure is currently used to estimate the clogging of tube support plates in French nuclear power plant steam generators. A stochastic approach has been applied to Finite Element electromagnetic field simulation to evaluate the impact of material properties uncertainties on the monitoring signal. The Polynomial Chaos Expansion method makes it possible to easily derive the Sobol decomposition which measures how much the variability of each input parameter affects the model output
La version éditeur de cette publication est disponible à l'adresse suivante : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514684
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/71162013-01-01T00:00:00ZMOREAU, OlivierBEDDEK, KarimLE MENACH, YvonnickCLENET, StephaneA Non destructive Testing (NDT) procedure is currently used to estimate the clogging of tube support plates in French nuclear power plant steam generators. A stochastic approach has been applied to Finite Element electromagnetic field simulation to evaluate the impact of material properties uncertainties on the monitoring signal. The Polynomial Chaos Expansion method makes it possible to easily derive the Sobol decomposition which measures how much the variability of each input parameter affects the model output