International Journal of Applied Electromagnetics and Mechanics - Volume 20, issue 1

Authors: Shah, Rajesh C. | Bhat, M.V.

Article Type: Research Article

Abstract: Ferrofluid lubrication of a bearing with slider having a convex pad surface and stator having a porous facing of uniform thickness was examined using Jenkins flow behaviour and considering slip velocity at the interface of porous matrix and film region. Expressions were obtained for film pressure, load capacity, friction on the slider, coefficient of friction and the position of the centre of pressure. The load capacity, friction and the position of the centre of pressure decreased …when the slip parameter increased. On the other hand, the load capacity decreased and friction as well as the coefficient of friction increased when the material parameter of the Jenkins model increased. No significant change in the co-efficient of friction was found when the slip parameter increased. The position of the centre of pressure shifted towards the inlet when the material parameter increased. Show more

Keywords: ferrofluid lubrication, porous, slider, convex pad, Jenkins model, slip

DOI: 10.3233/JAE-2004-292

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 20, no. 1, pp. 1-9, 2004

Authors: Li, Xian Fang | Tang, Guo Jin

Article Type: Research Article

Abstract: The electroelastic analysis of a cracked transversely isotropic piezoelectric layer sandwiched between two elastic layers is made under electromechanical loading. The crack is assumed to be situated at the mid-plane of the piezoelectric layer and penetrate through the piezoelectric layer along the poling direction. By using an integral transform technique, the problem is reduced to dual integral equations. Further a singular integral equation with Cauchy kernel of the first kind is derived and solved numerically by …the Lobatto-Chebyshev collocation technique. The field intensity factors and the energy release rate are obtained and the results indicate that they are independent of electric loading for the case of prescribed stress, and depend on electric loading for the case of prescribed displacement on the top and bottom surfaces. The electric field has no any singularity near the crack tips, while the electric displacement exhibits the same singularity as the stress near the crack tips. Some numerical results are presented graphically to show the influence of layer thickness-to-crack length ratio and the material properties on the normalized energy release rate. Show more

Keywords: crack, electroelastic field, piezoelectric layer, field intensity factors, energy release rate

DOI: 10.3233/JAE-2004-294

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 20, no. 1, pp. 11-28, 2004

Authors: Im, Chang Hwan | Jung, Hyun Kyo | Lee, Yong Ho | Kwon, Hyuk Chan

Article Type: Research Article

Abstract: Magnetoencephalography (MEG) source reconstruction problems suffer from their own ill-posed characteristics, especially when a cortically distributed source model is used. This is because many variables have to be determined using small amounts of measured data, and this leads to a large computational cost. In this paper, a very efficient method is proposed to localize the source space effectively. A Fourier based 3-dimensional spatial function approximates the spatial distribution of the current dipole moments. …The coefficients of the function are determined using the sensitivity analysis employing the steepest decent updating scheme. By repeatedly applying the method to smaller and smaller domains, a reduced source space, which includes the small number of variables, can be obtained. By applying this method to a real brain model, its usefulness was verified. Show more

Keywords: function approximation, inverse problem, magnetoencephalography (MEG), sensitivity analysis

DOI: 10.3233/JAE-2004-295

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 20, no. 1, pp. 29-36, 2004

Authors: Vasil'ev, A. | Takagi, T.

Article Type: Research Article

Abstract: Magnetically driven shape memory alloys, among them Ni_{2 ± x ± y} Mn_{1 ± x} Ga_{1 ± y} , represent a novel type of material which allow magnetic fields to influence their shape and dimensions in a martensitic state. The basic approach to employ the intelligent properties of these compounds is associated with the rearrangement of martensitic variants by the magnetic field. To realize this possibility, the magnetic anisotropy of the …martensitic phase should be large enough to overcome the potential barriers for the motion of the martensite domain boundaries. Huge strains at room temperatures were reported under the competing stress of about 1~MPa and a magnetic field of about 1 T. Show more

DOI: 10.3233/JAE-2004-297

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 20, no. 1, pp. 37-56, 2004