International Journal of Applied Electromagnetics and Mechanics - Volume 38, issue 1

Authors: Hamid, A.K. | Cooray, F.R.

Article Type: Research Article

Abstract: The problem of scattering of a plane wave from a perfect electromagnetic conducting semi-elliptic-cylindrical boss on an infinite perfectly conducting plane, is solved using the method of separation of variables. The formulation is realized by expressing the incident, reflected, and scattered electromagnetic fields as series expansions in terms of suitable angular and radial Mathieu functions. Imposing boundary conditions at the surface of the boss plus its image on the perfectly conducting plane, allows …the unknown scattered field expansion coefficients to be determined in closed form. Results are presented as normalized scattering widths for semi-elliptic-cylindrical bosses of different sizes, shapes, and perfect electromagnetic conducting admittances, to show the effects of these on scattering. Show more

Keywords: Perfect electromagnetic conducting, scattering, semi-elliptic-cylindrical boss

DOI: 10.3233/JAE-2011-1401

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 38, no. 1, pp. 1-8, 2012

Authors: Rybin, Oleg

Article Type: Research Article

Abstract: In the paper, the possibility of achieving negative permeability for two-component metamaterials is analytically proven. The metamaterial media are presented as an infinite host dielectric material (air) with periodically embedded ferric cylindrical and spherical inclusions saturated with a biasing external magnetic field. The appropriate frequency-dependent inequalities are obtained in the frequency range where permeability becomes negative. The cases when electromagnetic wave propagates parallel and transverse to the direction of biasing magnetic field …are studied. Show more

Keywords: Metamaterials, effective medium theory, inclusions, metaferrite, negative permeability

DOI: 10.3233/JAE-2011-1404

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 38, no. 1, pp. 9-15, 2012

Authors: Li, Hongmei | Chen, Zhenmao | Li, Yong | Takagi, Toshiyuki | Uchimoto, Tetsuya | Chigusa, Naoki | Yoshida, Yasuhiko

Article Type: Research Article

Abstract: In this paper, the correlation between plastic deformation and the deformation-induced magnetic field was experimentally investigated for the SUS304 austenitic stainless steel. Test-pieces with different shapes were fabricated to produce different strain distribution. Various plastic tensile loads were imposed into the specimens to introduce plastic deformations of different levels. The residual strain distributions at the surfaces of the specimens were measured by an optical 2D strain measurement system during loading process while …the distributions of the deformation-induced magnetic fields above the specimens were measured by using a fluxgate magnetometer after each loading cycle. The experimental results show that the amplitudes of the magnetic field have a clear and repeatable relationship with the maximum residual strains for all the specimens, and the relationship is independent of the strain distribution. Based on the experimental results, the mechanism of the deformation-induced magnetic field was discussed, and a NonDestructive Evaluation (NDE) method was proposed for the quantitative evaluation of plastic deformation in the SUS304 stainless steel. Show more

Keywords: Plastic deformation, deformation-induced magnetic field, nondestructive evaluation, SUS304 austenitic stainless steel

DOI: 10.3233/JAE-2011-1405

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 38, no. 1, pp. 17-26, 2012

Authors: Liu, Nan | Yang, Jiashi | Jin, Feng

Article Type: Research Article

Abstract: We analyze electrically forced, transient thickness-shear vibration of a piezoelectric plate of monoclinic crystals as an acoustic wave resonator. These crystals include the widely used, rotated Y-cut quartz and langasite crystal plate resonators as special cases. A trigonometric series solution is obtained with which a few transient effects in a piezoelectric resonator under a sudden change or fluctuation of the driving voltage amplitude or frequency are calculated and examined. It is found that under a sudden …change of the driving voltage amplitude the transition of the resonator vibration takes about 0.1 s for an AT-cut quartz resonator, and that a 10 Hz deviation of the driving frequency from the fundamental resonance causes a significant drop of the vibration amplitude. Show more

Keywords: Monoclinic crystals piezoelectric plate, transient thickness-shear vibration, AT-cut quartz resonator

DOI: 10.3233/JAE-2011-1406

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 38, no. 1, pp. 27-37, 2012

Authors: Qasim Mehmood, Muhammad | Junaid Mughal, Muhammad | Rahim, Tarim

Article Type: Research Article

Abstract: Analysis of high frequency field expressions for the Cassegrain system having perfect electromagnetic conducting (PEMC) boundaries are studied. Both the reflectors of Cassegrain system are PEMC and are embedded in chiral medium. Two different cases have been analyzed depending upon the values of chirality parameter (kβ). In the first case, chiral medium supports positive phase velocity (PPV) for both the left circularly polarized (LCP) and right circularly polarized (RCP) modes. In the second case, …chiral medium supporting PPV for one mode and negative phase velocity (NPV) for the other mode is taken into account. Mathematical recipe proposed by the Maslov is used to obtain the field expressions in the focal region because geometrical optics (GO) causes non-realistic singularity in this region. Field patterns of focal plane are given in the paper for different values of admittance (M) of the PEMC boundary and the chirality parameter (kβ). Show more

Keywords: Cassegrain system, chiral medium, perfect electromagnetic conductor, Maslov's method and geometrical optics

DOI: 10.3233/JAE-2011-1407

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 38, no. 1, pp. 39-45, 2012

Authors: Xu, Lizhong | Geng, Yanbo

Article Type: Research Article

Abstract: One of the important problems in developing the railgun is design of the rail and the related elements. The evaluation of the loads on rails is an important task. On operation, the armature runs at an acceleration. The acceleration load can cause more complicated dynamic responses of the railgun. Here, the dynamic equation of the rail for the railgun is given, and the equations for the forced responses of the rail under constant velocity load and …the acceleration load are developed. Using these equations, the dynamic displacement responses of the rail to the running electromagnetic force for various accelerations are investigated. The results show that the maximum dynamic displacement peak of the rail and its position depends on the boundary conditions and the acceleration of the running armature. The larger is the acceleration, the more obvious is the increase of the dynamic displacements under condition that the armature velocity is above the critical velocity. For a given acceleration, the effects of the damping on the dynamic displacements of the rail become more obvious when the armature velocity grows. The results are useful for design and application of the railgun system. Show more

Keywords: Railgun, dynamics, forced response, rail, armature

DOI: 10.3233/JAE-2011-1408

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 38, no. 1, pp. 47-64, 2012