International Journal of Applied Electromagnetics and Mechanics - Volume 11, issue 4

Authors: Harcken, H. | Albrecht, M. | Ahlers, H.

Article Type: Research Article

Abstract: A method is presented which allows a system available for the measurement of the dynamic electromagnetic properties of magnetic stripes to be extended in such a way that the stripes' static properties can be determined from the remanent magnetization curve. The results of some check measurements show good correlation with the results of static measurement methods so far applied. The advantages and prerequisites, as well as the steps to be taken and the hardware required for …the set-up will be described and the measurement sequence explained. Show more

DOI: 10.3233/JAE-2000-183

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 4, pp. 203-209, 2000

Authors: Shen, Shengping | Kuang, Zhen-Bang | Nishioka, Toshihisa

Article Type: Research Article

Abstract: This work is concerned with the analytical characterization of the electromechanical nonlinear effects on the fields surrounding the tip of an interface crack of Yoffe type between ferroelectric-plastic bimaterials. A strip electric saturation and mechanical yielding model is developed for a mode III dynamic interfacial crack with electrical polarization reaching a saturation limit and shear stress reaching a yield stress along a line segment in front of the crack. The electrical saturation zone and mechanical yielding …zone may have different length scales depending on loading conditions. The results reveal insight into the structure of stress and electric displacement fields for different load conditions. The energy release rate and COD (crack-tip opening displacement) are also be obtained. It is also shown that the smaller nonlinear zone (mechanical yielding or electric saturation) size is related with the velocity v of the interfacial Yoffe crack. COD, COP (crack-tip opening potential) and the energy release rate J_a(v) all increase monotonically with increasingv . Show more

DOI: 10.3233/JAE-2000-184

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 4, pp. 211-222, 2000

Authors: Nowacki, J.P. | Alshits, V.I. | Lyubimov, V.N.

Article Type: Research Article

Abstract: SH acoustic fields in transversely isotropic media with magnetoelastic coupling due to a linearized magnetostriction are considered for a bicristalline structure with a gap. The surface and pseudosurface eigenmodes and the conditions of their existence are described. A study is carried out of the resonant excitation of the surface wave in one crystallite by means of a pumping bulk wave in the other crystallite. The potentialities of a control of wave parameters by means of the …bias magnetic field are considered. Show more

DOI: 10.3233/JAE-2000-185

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 4, pp. 223-232, 2000

Authors: Caorsi, Salvatore | Massa, Andrea | Pastorino, Matteo | Righini, Fabio

Article Type: Research Article

Abstract: The purpose of this paper is to present a microwave imaging approach for the determination of the position, the orientation and dimensions of a crack located inside a lossy dielectric host medium. The inversion procedure is based on a genetic algorithm which allows to iteratively generate a sequence of trial solutions minimizing a suitable cost function. The dependence of the performances of the proposed microwave imaging approach on the conductivity value of the host medium is …checked. Moreover, the robustness of the algorithm to operate with noisy data is evaluated. Finally, the reconstruction of an irregular crack is considered. Show more

DOI: 10.3233/JAE-2000-203

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 4, pp. 233-244, 2000

Authors: Mukhopadhyay, S.C. | Iwahara, M. | Yamada, S. | Dawson, F.P.

Article Type: Research Article

Abstract: Different topological configurations for a passive magnetic current limiter consisting of a permanent magnet and saturable core are discussed in this paper. The models for a series/parallel biasing mode, and a single/three phase supply system have been fabricated and the experiments have been carried out for the performance evaluation. Using tableau method, the transient performance of different models has been simulated. The feasibility of applying the current limiter for the protection of power semiconductor devices in …moderately low voltage applications is investigated. Show more

DOI: 10.3233/JAE-2000-204

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 4, pp. 245-254, 2000

Authors: Ohji, T. | Kano, M. | Mukhopadhyay, S.C. | Iwahara, M. | Yamada, S.

Article Type: Research Article

Abstract: A permanent magnet bearing (MB) system utilizing the repulsive forces operating between the stator and rotor permanent magnet for levitation and radial control has been fabricated in our laboratory. The consistency of the permanent magnet magnetization effects the continuous steady-state and dynamic performance of the system. Since both the magnets are repelling each other, there will be demagnetization of the magnetization of the permanent magnet. Due to demagnetization or ageing or manufacturing asymmetry, the field …distribution may not be uniform along the periphery of the magnet. In this paper the effect of this magnetization non-uniformity on the performances of the bearing system has been studied. Show more

DOI: 10.3233/JAE-2000-186

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 4, pp. 255-259, 2000

Authors: Lu, Junwei | Wong, Fu

Article Type: Research Article

Abstract: This paper presents the configuration of a high frequency (HF) coaxial winding transformer with Faraday shield and discusses the shielding effect of the transformer in the high frequency range. The experimental results show the voltage ratio, coupling coefficient and load characteristic of the HF coaxial transformer in the range up to 2 MHz. The numerical result illustrates the eddy current distribution in the windings and shielding coil, and the magnetic flux distribution in the shielded HF …coaxial transformer. Show more

Keywords: high frequency transformers, coaxial winding structures

DOI: 10.3233/JAE-2000-202

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 4, pp. 261-267, 2000

Article Type: Correction

Abstract: Corrigendum to Int. Journ. of Applied Electromagnetics and Mechanics 11(3) (2000), 141–162

DOI: 10.3233/JAE-2000-205

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 4, pp. 269-269, 2000