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Magnetoelectric effect in composite materials results from the combination of piezoelectric and magnetostrictive effects. This paper focuses on the development of a harmonic finite element formulation for such coupled problems, taking into account the nonlinearity of magnetostrictive behavior. An application to a magnetic sensor operating under dynamic excitation is presented in order to illustrate the formulation. The enhancement of the magnetoelectric coefficient when a low amplitude harmonic field is superimposed to the static field to be measured is shown to be related to the nonlinearity of magnetic and magnetostrictive behavior. [ABSTRACT FROM AUTHOR]

The main purpose of homogenization is the determination of the effective behavior (or macroscopic behavior) of heterogeneous materials. Mean fields per phase are generally used in homogenization and represent sufficient information in most cases. However, more information about the field distribution can be necessary, particularly in nonlinear cases. Then, intraphase fluctuations have to be determined. This paper presents a method, based on homogenization tools, for the determination of both estimates and bounds for the intraphase fluctuations. The presented applications deal with magnetic materials and the results obtained with homogenization are compared to those obtained using a finite element modeling. [ABSTRACT FROM AUTHOR]

This paper deals with the modeling of the magnetoelectric effect in composite materials. This work focuses on the modeling of a magnetoelectric multilayer using a full 2D finite element model. It is shown that the magnetic induction in the direction normal to the plane can be neglected in 2D formulations under low frequency. An application is made on a bilayer and on an asymmetric multilayer magnetic sensor based on extrinsic magnetoelectric effect. Both structures give approximately the same first resonance frequency but a higher electric voltage is obtained in the asymmetric multilayer. [ABSTRACT FROM PUBLISHER]

The aim of the method detailed in this paper is to get an equivalent thermal model of a stator slot, in order to simplify the calculation of desired temperatures in an electrical machine winding. This study is divided in two steps: First, the equivalent thermal conductivity is deduced from a homogenization of the winding, and next, a discretization is achieved using the finite integration technique considering transient analysis. In order to evaluate the method, results from the equivalent model are compared with finite element simulations considering two slot geometries. [ABSTRACT FROM AUTHOR]

The design of electromagnetic devices submitted to high mechanical stress is a growing issue and requires consequently appropriate modeling tools. We propose in this paper to implement a multiscale model for magneto-elastic behavior into a finite-element code. The 2-D magneto-elastic constitutive law is derived from a multiscale model based on a local energetic approach. The method is applied to study the effect of stress on the magnetic behavior of a switched reluctance motor. This work provides a finite-element tool for the modeling of the effect of multiaxial stress on electrotechnical devices. [ABSTRACT FROM PUBLISHER]

The magnetoelectric (ME) effect in composite materials results from the combination of the magnetostrictive effect and the piezoelectric effect via elastic interaction. This work focuses on the modeling of multilayer structures under dynamic excitation. The calculated ME coefficient versus frequency shows the enhancement of the ME effect at mechanical resonance in accordance with experimental measurements. The impact of electric conductivity is investigated. Applications on the ME sensor and tunable inductor are proposed. [ABSTRACT FROM PUBLISHER]

This paper deals with two-dimensional modeling of a multifilamentary wire composed of two superconducting filaments in a conducting matrix. In order to avoid three-dimensional problem solving, a novel technique is proposed to solve the coupled problem in two dimensions. For that, it is enough to divide the filaments in several sections in the direction of the length of the wire and to impose a relation between the currents crossing the matrix and the electric fields in the different sections of the filaments. The numerical simulation results show the distributions of the current density in the modeled domain. The influence of the wire length on the total magnetization is also considered. [ABSTRACT FROM AUTHOR]

In this paper, the computation of magnetization of a strand constituted of two superconducting square bars immersed in a uniform magnetic field is studied. The numerical results are obtained from the program developed with the FEM. Bean's critical state model is carried out to characterize the electrical behavior law of superconducting materials. The magnetization cycle, the magnetic field and the current density distributions are presented. The influence of strand length on the electromagnetic coupling phenomena in the superconducting square bars is also considered. The obtained results are in good agreement with the theoretical results. [ABSTRACT FROM AUTHOR]

This paper examines a model of magnetomechanical and piezoelectric coupling. This model, based on the association of the magnetoelastic and piezoelectric constitutive laws, is implemented in a transient finite element formulation. The application is the reduction of the noise emitted by switched reluctance machines by means of an active damping. The active elements are piezoelectric actuators placed on the stator, for the purpose of reducing its vibrations. The control is based on a positive position feedback regulation. Thus, an infinite impulse response filter is added to the model in order to control the piezoelectric elements depending on information of the stator vibration. [ABSTRACT FROM AUTHOR]

Vibrations in thin structures are often not desired, especially because of their harmful effects on lifespan. The addition of piezoelectric materials with appropriate connections can really be useful to reduce this drawback. To study such a damping effect, numerical modeling is necessary and leads to a coupled problem (between mechanics and electricity). This paper presents a 2-D model of a plate with piezoelectric patches. From the coupled behavior laws and with the use of a variational formulation, a finite element model is developed. After a validation process, the influence of the width of piezoelectric patches on damping is studied. [ABSTRACT FROM AUTHOR]

The aim of this work is to present a three-dimensional generalized finite element modelling of magnetostrictive materials including direct and inverse effects through strongly coupled magnetic and elastic behaviours. Emphasis is put on adapted constitutive laws that incorporate explicitly the physical coupling between magnetic and mechanical magnitudes. We used a variational formulation in terms of magnetic vector potential circulation and displacement. The studied example is composed of a solenoid with a magnetostrictive core where a three dimensional analysis is performed. [ABSTRACT FROM AUTHOR]

In the large hadron collider main magnets, persistent currents in the superconducting filaments determine the quality of the magnetic field at an injection field. It is thus necessary to examine the magnetization of the superconducting filaments during production of the cable strands. The prediction of the magnetization can be based on numerical solutions obtained by using the finite-element method. We have computed the magnetization curves of coupled and noncoupled superconducting filaments in two dimensions. In addition, we have taken into account the dependence of the current density according to the magnetic field. [ABSTRACT FROM AUTHOR]

Highlights • Maximum temperature is reduced by using oil-based ferrofluid instead of pure oil. • Thermomagnetic convection enhances heat transfers by modifying the flow. • Ferrofluid thermophysical properties lead to better cooling. • Thermomagnetic convection is increased in the presence of a ferromagnetic core. Abstract The thermal convection in a cylindrical container heated by a solenoid and cooled with an oil-based ferrofluid is numerically studied. The temperature and the velocity fields are compared to those obtained with pure oil to assess the benefits of using ferrofluids for cooling systems like electrical transformers. The influence of the magnetic body force on the flow and the temperature in the system is investigated in various configurations. One original result established in this paper is that the changes in the fluid properties due to the presence of nanoparticles, such as viscosity and thermal conductivity, have a significant impact on the heat transfers. A second result is that the use of a ferromagnetic core enhances the cooling. [ABSTRACT FROM AUTHOR]