International Journal of Applied Electromagnetics and Mechanics - Volume 9, issue 4

Authors: Ghaleb, A.F. | Ayad, M.M.

Article Type: Research Article

Abstract: A complete set of field equations, constitutive relations and boundary conditions is derived in material form, within the framework of rigorous thermodynamics, to study the nonlinear thermo‐magnetoelastic interactions in anisotropic continuous media for which the specific heat capacity depends on strain and magnetic field. The proposed model includes several other couplings as well and may be considered as a refinement of other existing models. When the medium has finite electric conductivity, it is appropriate to represent the electromagnetic field in terms of the electromagnetic potentials. This has the advantage of reducing the number of field equations. The special case of …the perfect electric conductor is briefly mentioned and the linear theory for the isotropic medium of finite electric conductivity is investigated. Comparison is carried out with previous results. The bilinear theory and the propagation of surface regimes and surface magnetoacoustic waves will be dealt with separately. Show more

DOI: 10.3233/JAEM-1998-093

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 9, no. 4, pp. 339-357, 1998

Authors: Ghaleb, A.F. | Ayad, M.M.

Article Type: Research Article

Abstract: Relying on a nonlinear continuum model of thermo‐magnetoelasticity previously introduced by the authors, in which the heat capacity of the medium depends on strain and magnetic field, we investigate the effect of this dependence on the one‐dimensional propagation of nonlinear, thermo‐magnetoacoustic waves in an anisotropic (but centrosymmetric) half‐space of a perfect electric conductor permeated by a constant magnetic field. The obtained formula for the relative variation of the phase velocity of the wave due to this dependence may be used, in combination with the proper experimental data, to predict the value of a material constant.

DOI: 10.3233/JAEM-1998-092

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 9, no. 4, pp. 359-379, 1998

Authors: Chiampi, M. | Fuerntratt, G. | Magele, Ch. | Ragusa, C. | Repetto, M.

Article Type: Research Article

Abstract: The use of a decision making scheme based on fuzzy logic applied to the design of electromagnetic devices is presented. In the Multi-Objective Optimisation, the different scalar objectives are merged together firstly by means of a fuzzyfication process and then by the application of a fuzzy logical operator. This scheme can be easily coupled to any search optimisation (zeroth order algorithm) since it does not require differentiation of the scalar functions. Two different implementations of the procedure, coupled to Simulated Annealing and to Genetic Algorithm stochastic search are presented. The two procedures are tested versus a two solenoids SMES (Superconducting …Magnetic Energy Storage) Multi-Objective Optimisation problem. Show more

DOI: 10.3233/JAEM-1998-097

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 9, no. 4, pp. 381-389, 1998

Authors: Sikora, R. | Chady, T. | Sikora, J.

Article Type: Research Article

Abstract: The eddy current non-destructive testing of conductive materials is a well-known problem. There are a lot of different kinds of transducers. For one of them the mathematical model was built and the Inverse Problem formulated. In order to solve this problem the Artificial Neural Network approach, relatively new, was adopted. The public domain software, developed at Warsaw University of Technology, was used to teach the network. It was proved that a standard feedforward multilayered neural network is sufficient to identify the parameters of the defect with a satisfying accuracy.

DOI: 10.3233/JAE-1998-119

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 9, no. 4, pp. 391-398, 1998

Authors: Yang, J.S.

Article Type: Research Article

Abstract: Equations for the buckling of a thin piezoelectric plate are obtained from an existing set of equations for the extension and flexure of piezoelectric plates. The equations for buckling are specialized for piezoelectric ceramic plates poled in the thickness direction. Solutions for the buckling of a ceramic plate into cylindrical shape and the buckling of a rectangular ceramic plate are obtained. The effect of piezoelectricity on the critical load for buckling of a ceramic plate is examined. Results show that the effect of piezoelectricity is not negligible.

DOI: 10.3233/JAEM-1998-120

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 9, no. 4, pp. 399-408, 1998

Authors: Yang, J.S.

Article Type: Research Article

Abstract: One-dimensional equations for the extension and flexure with shear deformations of a piezoelectric beam with rectangular cross section are derived from the three‐dimensional equations for linear piezoelectricity by double power series expansion in the thickness and width directions. The equations are reduced to the case of elementary flexure without shear deformations. As an application of these equations, the buckling of a ceramic piezoelectric beam is discussed.

DOI: 10.3233/JAEM-1998-121

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 9, no. 4, pp. 409-420, 1998

Authors: Moldovanu, A. | Chiriac, H. | Ioan, C. | Moldovanu, E. | Lozovan, M. | Apetrei, V.

Article Type: Research Article

Abstract: A multilayer shielding system with five concentric cylinders of P-80 high-permeability material has been design and constructed in the Magnetometry Laboratory of our institute. The paper presents the results of the functional study of the shielding system. The P‐80 annealed alloy was especially elaborated for this application. The d.c. shielding effectiveness of the system is 3\times 10^{3} along the longitudinal axis and 5\times 10^{4} for the transversal direction. The a.c. shielding factor is studied for different frequencies. The remanent magnetic field inside the inner cylinder is in the order of units of nT, as a function …of the deperming procedures. A mechanical device situated inside the shields allows the determination of the offset and magnetic noise of the fluxgate sensors, even in urban magnetically polluted conditions. Show more

Keywords: magnetic shield, shielding factor, offset evaluation

DOI: 10.3233/JAEM-1998-124

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 9, no. 4, pp. 421-425, 1998

Article Type: Other

Abstract: Author Index to Volume 9 (1998)

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 9, no. 4, pp. 427-430, 1998