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

Article Type: Editorial

Abstract: Preface to the special volume: Proceedings of the eleventh International Symposium on Applied Electromagnetics and Mechanics ISEM-Versailles ISEM 03

DOI: 10.3233/JAE-2004-652

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

Authors: Takahashi, S. | Sato, H. | Kamada, Y. | Ara, K. | Kikuchi, H.

Article Type: Research Article

Abstract: Cr concentration and the volume fraction in Inconel 600 alloy were accurately analyzed by the new magnetic method according to the magnetic properties of the ternary alloys. The depletion has a maximum at aging for 10~h at 973 K and diminishes with longer aging. Cr depletion below 10 wt. % was observed in the aging. After aging for 100 h the depletionremarkably recovers, but it definitely remains compared with the initial state. The depleted zone extends …to 300 nm from the grain boundary. These results agree well with those of a previous analysis by scanning transmission electron microscope analysis. The new magnetic method, herein reported, for evaluation of chromium depletion has nondestructive evaluation characteristics. Show more

DOI: 10.3233/JAE-2004-526

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 3-8, 2004

Authors: Boubendir, Yassine

Article Type: Research Article

Abstract: A non-overlapping domain decomposition method based on the coupling of a finite-element and boundary-element method is proposed. Several improvements concerning the convergence of the iterative algorithms are given by modifying the transmission conditions at the artificial interfaces between the connected domains.

Keywords: domain decomposition, boundary and finite element, differential transmission conditions

DOI: 10.3233/JAE-2004-527

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 9-13, 2004

Authors: Toscano, Alessandro | Vegni, Lucio

Article Type: Research Article

Abstract: An efficient procedure is developed for characterizing the frequency-domain behavior of superconducting microstrip planar structures with non conventional (bianisotropic) layers. Most of the frequency domain techniques in computational electromagnetics result in a matrix equation, which is solved at a single frequency. In the proposed technique, a rational function expansion around that frequency is applied to the matrix equation. This paper addresses three aspects in employing such an expansion: a) a generalization of …the spectral domain analysis of superconducting patch antennas over bianisotropic layers, b) a robust and reliable estimation of confidence in the interpolated values, c) a criterion for selecting new sample frequencies. As a first numerical example, the radiation efficiency as a function of thickness for a copper and superconducting square patch antenna is presented. Show more

Keywords: green functions, superconducting materials, rational approximation

DOI: 10.3233/JAE-2004-528

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 15-18, 2004

Authors: Yuan, Jing | Clemens, Markus | Weiland, Thomas

Article Type: Research Article

Abstract: The paper presents a numerical method for transient magneto-quasistatic field analysis including hysteretic ferromagnetic materials. The procedure is based on a Finite Integration Implicit Time Domain (FI^2 TD) formulation using the classical Preisach model. An hybrid scheme using the magnetic polarization update scheme for hysteretic materials and the successive approximation scheme for non-hysteretic nonlinear materials is given. Relaxation parameters are introduced to avoid convergence problems of the iterative scheme around the …critical zones of the hysteresis curve. In numerical experiments with a test configuration the simulated hysteresis loops are compared with those achieved by measurements and the corresponding hysteretic losses are presented. Show more

Keywords: hysteresis, transient magnetic field simulation, convergence, hysteretic losses, finite integration technique

DOI: 10.3233/JAE-2004-529

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 19-24, 2004

Authors: Enge, Olaf

Article Type: Research Article

Abstract: The usage of the linear complementarity problem (LCP) for modelling electrical systems with variable structure is shown. Starting point is a method for modelling electromechanical systems (EMS) using a unified mathematical theory based on the Lagrange formalism. The variable structure is represented by unilateral constraints depending on the characteristics of the switching components. This makes it possible to include such components into the unified theory and, this way, to extend the class of EMS which can …be covered. Show more

Keywords: electromechanical system, variable structure, linear complementarity problem

DOI: 10.3233/JAE-2004-530

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 25-28, 2004

Authors: Allweins, Kai | Gierelt, Gertrud | von Kreutzbruck, Marc

Article Type: Research Article

Abstract: The choice of the NDT industry for an appropriate NDT method focuses on an optimum balance between quality control and cost effectiveness. For this reason SQUID technology, because of its higher costs and handling inconvenience, might be used only where standard NDE techniques fail to ensure sufficiently high reliability. A promising SQUID NDE application is testing of very thick aircraft lap-joint structures, where currently no standard testing method achieves satisfactory results. We present SQUID measurements of …a three-layer aluminum sample of the Airbus A-380 with a total thickness of 62 mm, which resembles the planned outer wing splice of the megaliner. The combination of field sensitivities of a few pT/√Hz and a large dynamic range of about 140 dB/√Hz enables us to detect defects at a depth ranging between 30–45 mm. Show more

Keywords: eddy current testing, HTS SQUID, FEM simulations

DOI: 10.3233/JAE-2004-531

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 29-33, 2004

Authors: Gierelt, Gertrud | Allweins, Kai | von Kreutzbruck, Marc

Article Type: Research Article

Abstract: Due to the skin effect, the induced eddy current (EC) density at the sample's surface is higher than at deeper levels. Thus currents flowing close to the surface generate most of the background signals caused by the sample's own components. One way of minimizing those EC interference is to reduce the surface currents and enhance the current density at the depth in which defects can occur. Unfortunately, magnetic fields cannot be focused to one point in the …way rays of light can be concentrated in optics. Magnetic fields are always divergent – as quantified by Maxwell's Equations. To tackle this problem we superimposed two different excitation fields generated by a dual gradiometric coil excitation scheme (DGC). It consists of two double-D coils. Both double-D coils are applied with the same frequency but driven with two different excitation currents (J_1 , J_2 ) and phase shifts (φ_1 , φ_2 ). In addition we implemented a sensitive magnetometer in our eddy current testing system to measure very thick structures of the Airbus A-380. We report on FEM simulations and EC-measurements using the dual gradiometric coil excitation scheme to detect deep lying defects. Show more

Keywords: Eddy Current Testing, Sensitive Magnetometer, Dual-Gradiometric Coil System

DOI: 10.3233/JAE-2004-532

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 35-39, 2004

Authors: Yusa, Noritaka | Demachi, Kazuyuki | Chen, Zhenmao

Article Type: Research Article

Abstract: This paper proposes the application of a superconductor to a remote field eddy current testing probe in order to shorten the probe length and then overcome many of the disadvantages of the remote field eddy current testing, such as the small signal amplitude and the difficulty in handling the probes. Numerical simulations were carried out to confirm that a superconductor located between the exciter and the detector of a remote field eddy current testing probe inhibits …the magnetic flux from coming directly from the exciters. Then, a remote field eddy current testing probe equipped with a superconducting shield was designed and fabricated. Experimental results confirmed that a superconducting shield can shorten the probe length and provide clearer signals due to artificial wall thinnings machined on the outside surface of a ferromagnetic tube. Show more

Keywords: remote field eddy current testing, superconductor, magnetic shield, non-destructive testing

DOI: 10.3233/JAE-2004-533

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 41-46, 2004

Authors: Pinchuk, Anatoliy

Article Type: Research Article

Abstract: Nonlinear composite structures show great promise for use in optical switching, signal processing, etc. I derive an effective nonlinear dielectric permittivity of a composite structure where coated ellipsoidal nonlinear particles are imbedded in a linear host medium. The derived expression for the effective dielectric permittivity tensor follows the Clasius-Mossotti approximation. The conditions for the existence of the optical bistability effect in a coated ellipsoidal particle with a nonlinear core and a metallic …shell were obtained. Show more

Keywords: effective medium theory, nonlinear composites, bistability effect

DOI: 10.3233/JAE-2004-534

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 19, no. 1-4, pp. 47-50, 2004