International Journal of Applied Electromagnetics and Mechanics - Volume 19, issue 1-4

Authors: Ni, Guangzheng | Ho, S.L. | Yang, Shiyou | Ni, Peihong

Article Type: Research Article

Abstract: A truly meshless local Petrov-Galerkin method to study electromagnetic field problems is introduced with the goal of eliminating the tedious mesh generations required by traditional numerical methods such as Finite Element Methods. The local weighted residual form, together with the penalty approach, is used to develop the discrete mathematical models.

DOI: 10.3233/JAE-2004-545

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 111-117, 2004

Authors: Brusquet, Laurent Le | Davoust, Marie-Eve | Fleury, Gilles

Article Type: Research Article

Abstract: The remote field eddy current technique is used to inspect conductive pipes and to estimate the dimensions of grooves liable to exist in the conductive material. The problem is to calculate an estimation of groove size from observed data. A two-step inversion is proposed. The first step consists of a reduction of the observed data. For that purpose, a parametric approach and a principal component analysis approach are presented. The second step is based on a …polynomial regression and a least square method is used for the two approaches described in the first step. Both approaches are finally compared in terms of precision and robustness. Show more

Keywords: parametric model, principal component analysis, non destructive evaluation

DOI: 10.3233/JAE-2004-546

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 119-124, 2004

Authors: Cheng, Weiying | Shiwa, Mitsuharu | Chen, Gangzhu | Yoneyama, Hiroshi | Horii, Yukihiko

Article Type: Research Article

Abstract: Post Weld Heat Treatment (PWHT) temperature can be evaluated by magneto inductive method. The mechanism of the bulk magnetic property change is explained in terms of Jiles-Atherton hysteresis model. A finite element simulation is implemented for the PWHT temperature evaluation. Comparison between simulation and experimental observation is made and factors influencing simulation are discussed in the present paper.

Keywords: PWHT, magneto inductive, finite element, higher harmonic components

DOI: 10.3233/JAE-2004-547

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 125-130, 2004

Authors: Wirgin, Armand

Article Type: Research Article

Abstract: The idea of the Modified Rayleigh Conjecture (MRC) [1], in the inverse scattering context, is to obtain the partial wave amplitudes directly from the scattered field, assumed to be known on a circle completely enclosing the body, and then to obtain the shape of the body by employing the Rayleigh hypothesis ansatz of the scattered field [2] in the boundary condition. This method does not require matrix inversions, contrary to the one exploited in [2]. It …is shown that in one of the forms of the MRC, the local radius of the body, for a given polar angle, can be obtained by solving a single non-linear equation, just as in the ICBA method [3]. The MRC method, like the ICBA method, leads to solutions of the inverse problem that are not unique. A technique is suggested for reducing this non-uniqueness. Show more

Keywords: inverse problem, Rayleigh hypothesis, uniqueness

DOI: 10.3233/JAE-2004-548

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 131-133, 2004

Authors: Belahcen, Anouar

Article Type: Research Article

Abstract: This work presents a magneto-elastic FE model for simulation and analysis of electrical machines. The model includes magnetic non-linearity and stress dependent magnetisation. Magnetostriction and effects of geometry changes on magnetic field are accounted for. The circuit equations of the windings are solved simultaneously with the magnetic and displacement fields. Calculations without magnetostriction, show that the radial displacement of the stator core of a synchronous machine is lower than the one calculated with a …non-coupled model. The difference in displacement field suggests that the magnetostriction changes due to a difference in stresses. Measured magnetostriction at different stresses is also presented for comparison. Show more

Keywords: magneto-elastic, coupling, magnetostriction, electrical machines

DOI: 10.3233/JAE-2004-549

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 135-138, 2004

Authors: Ohji, Takahisa | Ikeno, Shigeyuki | Amei, Kenji | Sakui, Masaaki | Yamada, Sotoshi

Article Type: Research Article

Abstract: This paper reports on the configuration and performance characteristics of a repulsive type magnetic bearing system, which contains a vertical shaft type inner rotor with polygon mirror facets. Generally, low cost, high-speed rotation, power saving and rotational accuracy are important factors for the polygon mirror system. The experimental model introduced in this paper has achieved the stable rotation without contact at 50,000 rpm and low power consumption for a motor drive under low vacuum condition.

Keywords: magnetic bearings, permanent magnet, stiffness, polygon mirror, high-speed rotation, power-saving

DOI: 10.3233/JAE-2004-550

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 139-144, 2004

Authors: Kusunoki, Atsushi | Tanaka, Mitsuru

Article Type: Research Article

Abstract: This paper presents a design procedure for a polarization-transformation transmission filter, which is composed of a chiral multilayer. The design procedure proposed is divided into two stages. An ordinary filter and a polarization-transformation filter for the transmitted wave are designed with a non-chiral multilayer and a chiral multilayer at the first and the second stages, respectively. According to the specifications of the filters, two objective functions are defined with the transmitted and …reflected powers. Applying a genetic algorithm to the maximization of the objective functions, one can obtain the optimal material parameters and thicknesses of the chiral multilayer. Numerical results are given to confirm the validity of the two-stage design procedure. It is seen from the numerical results that the proposed procedure is very effective in the optimal design of a polarization-transformation band-pass filter for the transmitted wave. Show more

Keywords: chiral multilayer, optimal design, polarization-transformation filter, genetic algorithm

DOI: 10.3233/JAE-2004-551

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 145-148, 2004

Authors: Todaka, Takashi | Szpryngacz, Mariusz | Enokizono, Masato

Article Type: Research Article

Abstract: A new ferromagnetic shape memory alloy consisting of Fe-Cr-Co-Ni-Si-Mn has been developed by means of the melt spinning technique. The alloy has both the shape memory effect and the comparatively high-magnetic permeability itself. The shape memory effect can be improved with annealing the alloy, however at the same time it loses good ferromagnetic properties. This paper presents the measured magnetic properties and shape memory characteristics measured by the vibration sample magnetometer (VSM), the …differential scanning calorimeter (DSC) and the thermo-mechanical analyser (TMA). Show more

Keywords: ferromagnetic shape memory alloy, shape memory effect, differential scanning calorimeter (DSC), thermo- mechanical analyser (TMA)

DOI: 10.3233/JAE-2004-552

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 149-152, 2004

Authors: Endo, Hisashi | Takasuka, Yoshihiro | Marinova, Iliana | Hayano, Seiji | Saito, Yoshifuru

Article Type: Research Article

Abstract: This paper proposes a method of data set representation by potential field equations. The principal idea of the representation is to regard a numerical data set as a kind of potential/source fields, leading to the governing equations. The modal analysis of the equations derives the orthonormal linear transform matrix. It is described that the matrix corresponds to that of discrete wavelets performing an efficient wavelet multi-resolution analysis.

DOI: 10.3233/JAE-2004-553

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 153-157, 2004

Authors: Letosa, J. | Usón, A. | Artal, J.S. | Samplón, M. | Arcega, F.J.

Article Type: Research Article

Abstract: The paper analyses the effect of crosstalk magnetic fields in current measurement devices with magnetic cores, as clamp-type current meters and current transformers. FEM modelization was used to calculate relative errors due to the crosstalk currents and how these errors are affected by variables as permeability, non-linearities and distance. Experimental results are also reported, in order to validate the numerical calculations. The measurements were obtained using the resources of the LME (Electric Metrology …Laboratory) of the Electrical Engineering Department of the University of Zaragoza, accredited by ENAC, a member of EA (European Co-operation for Accreditation). Show more

Keywords: high current, clamp-type current meters, crosstalk error, calibration, finite elements method

DOI: 10.3233/JAE-2004-554

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 159-164, 2004