Electromagnetic characterization of the CFRPs anisotropic conductivity: modeling and measurements

This work deals with the characterization of the conductivity tensor of a carbon fiber reinforced polymer composite (CFRP) thin plate. We propose a contactless method based on the eddy current non destructive testing technique. The used eddy current sensor consists of a ferrite torus on which a winding is wound. The torus is of a rectangular section and contains a thin air-gap in which the thin CFRP plate is inserted. We developed analytical relations giving the longitudinal and transversal conductivities of the CFRP plate as functions of the impedances variations of the eddy current sensor, corresponding to the orientations of the carbon fibers parallel and transverse to the direction of the torus width which is much greater than its thickness. The analytical relations are developed by inverting interpolation functions of curves giving the variations of the sensor impedances as functions of the longitudinal and transversal conductivities of the CFRP plate. These curves are obtained by a numerical model based on a simplified integro-differential formulation in terms of the electric vector potential in the CFRP plate, coupled to the magnetic circuit equations in the ferrite torus. The modeling results are supported by measurements

Modeling the response of a rotating eddy current sensor for the characterization of carbon fiber reinforced composites

This work deals with the eddy current nondestructive testing of carbon fiber reinforced polymer composites (CFRPs), and the development of rapid numerical models for the simulation of the interaction between the electromagnetic field and complex structures. We show qualitatively the possibility of characterizing the CFRPs by using a rotating eddy current sensor. We make use of a numerical model which we have developed in a previous work for eddy current computation in CFRPs. This model is completed in this work to account for the impedance variation of the rotating eddy current sensor, used to determine the anisotropy factor and the fiber orientation in each ply of a layered CFRP plate

Magneto-thermo-elastic-plastic simulation of inductive heating of metals

The magneto-thermo-mechanical behavior of metals in inductive heating devices is investigated by means of numerical calculations. The goal of this paper is to attract attention to necessity of mechanical problems solution for inductive heating technology and to develop three-dimensional and two-dimensional (axisymmetrical) mathematical models, coupling algorithm and software for such computations. The paper presents a finite element formulation, based on an indirect coupling model of electromagnetic, thermal and static elastic-plastic mechanical processes in treated workpieces in inductive heating devices. The effect of electromagnetic, thermal and mechanical material properties depending on temperature is taken into account. The presented numerical technique is applied for technological problems of practical interest

A Saturated Synchronous Machine Study for the Converter-Machine-Command Set Simulation

The electromagnetic study presented models a saturated synchronous machine for the Converter-Machine-Command (CMC) set simulation. The proposed method is based on a modified Park model (Garrido and De Jaeger Model: GDJ model [1,2]) when calculating the GDJ model laws and the GDJ model parameters using a field computation based on the Finite Element Method (FEM). The first model (GDJ model) is modified in accordance to the field results and a 4.8% improvement has been estimated. The model validity is obtained when comparing the computed and measured reactances. The improved model is elaborated in order to be introduced into the saturated machine algorithm to simulate the CMC set. In comparison with the model based on experiments, the proposed one avoids complex tests on high power range synchronous machines. On the other hand, this study reveals Potier parameter variations with the saturation state whereas the conventional methods consider it as a constant value. Finally we develop the saturated synchronous machine model associated with the converter.

Outil de modélisation de systèmes d'enregistrement magnétique

We have developed a Computer Aided Design tool for magnetic recording devices ; that permits us to study the digital write/read processes when using an integrated head and an anisotropic storage medium. Our tool is based on finite element analysis.Nous avons développé un outil de CAO de systèmes d'enregistrement magnétique, permettant l'étude des processus d'écriture/lecture de bits par une tête intégrée, sur un milieu caractérisé par des phénomènes d'hystérésis et d'anisotropie. Notre outil est basé sur un calcul de champ par éléments finis

Outil de modélisation de systèmes d'enregistrement magnétique

Nous avons développé un outil de CAO de systèmes d'enregistrement magnétique, permettant l'étude des processus d'écriture/lecture de bits par une tête intégrée, sur un milieu caractérisé par des phénomènes d'hystérésis et d'anisotropie. Notre outil est basé sur un calcul de champ par éléments finis

Modélisation par éléments finis des phénomènes couples électromagnéto-thermiques caractérisant le frittage par induction

An electromagnetic and thermal phenomena coupling model is presented and discussed. Called Direct Coupling Model: MCD, the proposed method is based on a finite element solution of the set of the magnetic vector potential and temperature equations. The MCD is applied to the case of the induction sintering technique, used for the design of the tantalum condenser. The model validity is obtained when comparing the computed and measured data.Un modèle de représentation du couplage réel des phénomènes électromagnétique et thermique est proposé et discuté. Appelé Modèle de Couplage Direct de phénomènes Electro-Mangéto-Thermiques (MCDEMT), ce modèle est basé sur une résolution par éléments finis du système des équations du potentiel vecteur magnétique et de la température. Le MCDEMT est appliqué à la modélisation d'un dispositif axisymétrique utilisé dans le frittage par induction pour l'élaboration de condensateurs au tantale. La validation de la méthode proposée est réalisée par comparaison des profils de température calculé et mesuré sur la surface de l'anode

A novel model for magnetic hysteresis of silicon-iron sheets

A new approach to calculate the magnetic hysteresis, based on the Brillouin theory associated with the Jiles-Atherton approach, is presented. This study represents a general model compared with the classical Jiles-Atherton one. A Brillouin function, using the kinetic atomic moment \mathaccent"017E{J}, allows to determine accurately the value of the anhysteretic magnetization. The obtained results are compared with experimental ones of the silicon-iron sheets

Analysis of Trapped Magnetic Field During Magnetization Process by SPA Method of Bulk Superconductor

International audienc

3D Numerical Evaluation of Trapped Magnetic Field and Temperature of a Rectangular GdBaCuO Bulk Magnetized by MMPSC Method

International audienc