International Journal of Applied Electromagnetics and Mechanics - Volume 11, issue 2

Authors: Yeh, Chau-Shioung | Lin, Chun-Bo

Article Type: Research Article

Abstract: In this paper, on the basis of electromagnetic fields in statistical formulation and the material description for solid medium, the governing equations are decomposed into different states with the necessary approximations. The relevant equations with boundary equations are applied to investigate the phase change of electromagnetic wave and the mode transition of guided electromagnetic wave in a slab waveguide, which is caused by the mechanical disturbance such as strain or elastic wave. The conditions of the …mode transition for TE mode are determined and the physical meaning of the results is interpreted. Show more

DOI: 10.3233/JAE-2000-166

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 2, pp. 55-76, 2000

Authors: Baginski, Michael E. | Shaffer, Edward C. | Thomas, Keith A. | McGuirk, Jeffrey S.

Article Type: Research Article

Abstract: A numerical investigation of the behavior of electrically thin exploding foils is presented. This work examines the effect that non-linear material properties have on the electrodynamic behavior of three metallic bridgefoils (Al, Cu, Au) having identical geometries but different material compositions. Previous experimental work and simulations focused on copper bridgefoils electrically excited using the first quarter cycle of a 1200 A, 1.7 Mhz current source. This high power current pulse induced solid to vapor phase …transitions over the entire foil surface in exploding foil experiments. Use of a finite element code (FEM) to determine the transient thermal and electrical effects in the pre-melt regime has been previously demonstrated for copper. The FEM code solves two non-linear partial differential equations which account for the thermal conductivity, latent heat of fusion, and specific heat (C_{\rm v} ) of the foil. The focus of this research is to contrast the simulated behavior of three metal foils (Al, Cu, Au) by examining corresponding plots of electrical and thermal signatures as the foils progress temporally to melt. The model predicts that the pattern of pre-melt behavior for all three foils is similar. The time to melt was found to be shortest for gold, followed by copper, and finally, aluminum (T_m {\rm Au} < T_m {\rm Cu} < T_m{\rm Al} ). Show more

DOI: 10.3233/JAE-2000-169

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 2, pp. 77-91, 2000

Authors: Oh, J. | Ruzzene, M. | Baz, A.

Article Type: Research Article

Abstract: The fundamentals of controlling the structural vibration of beams treated with a new class of Passive Magnetic Composites (PMC) are studied. The PMC is a constrained damping treatment, where a viscoelastic core is sandwiched between two layers of permanent magnets. The interaction forces between the magnets aim at enhancing the damping characteristics of the viscoelastic. The effectiveness of such treatments is demonstrated both numerically and experimentally. In particular, a finite element code is developed to model …the interaction between the dynamic behavior of the beam, the viscoelastic layer and magnetic layers. The model is validated experimentally at various operating conditions and the performance of the treatment is evaluated for different configurations of the magnetic layers. The obtained results suggest the potential of the new class of PMC as an effective and simple mean for controlling structural vibrations. Show more

DOI: 10.3233/JAE-2000-175

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 2, pp. 93-114, 2000

Authors: Sheikh, Sharif Iqbal

Article Type: Research Article

Abstract: The gyromagnetic properties of magnetized ferrites are widely used in many novel rf and microwave devices. According to the Drude model, similar principles should also be applicable to magnetized semiconductors due to its gyroelectric properties. In this study, an axially magnetized semiconductor resonator is characterized in terms of bias field and signal frequency. The resonance and loss regions are identified at 77 K. The affect of changing material and geometrical properties of the resonator on the …splitting and tuning behavior of normal modes are illustrated. Green's Function approach is used to derive the S-parameters of a two port semiconductor network. The network response and the material properties can be used to calibrate the semiconductor material before measuring the millimeter-wave properties of the resonator. This theoretical analysis may prove to be vital in realizing miniaturized and broadband semiconductor junction circulators and filters for high-T_c superconductive circuits. Show more

DOI: 10.3233/JAE-2000-176

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 2, pp. 115-124, 2000

Authors: Inan, Aziz S. | Osterberg, Peter M.

Article Type: Research Article

Abstract: In this article, the authors apply a new technique based on expressing the Coulomb force in terms of a special singularity integral to calculate the electrostatic force exerted on a conductor coated with a lossless dielectric. Specifically, the example of the calculation of the electrostatic Coulomb force on a lossless dielectric slab attached to the lower plate of a parallel-plate capacitor is considered.

DOI: 10.3233/JAE-2000-168

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 11, no. 2, pp. 125-128, 2000