International Journal of Applied Electromagnetics and Mechanics - Volume 22, issue 1-2

Article Type: Editorial

Abstract: Guest-editorial to SES 2004 special issue.

DOI: 10.3233/JAE-2005-686

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 22, no. 1-2, pp. 1-1, 2005

Authors: Huang, Lidu

Article Type: Research Article

Abstract: Three novel optic components utilizing linear electro-optic effect are described for applications in voice and data communication. These active components are a tunable micro lens, variable optical attenuator, and optical switches. They are essential building blocks of planar integrated lightwave circuits and can be fabricated using mature semiconductor processing technologies. Numerical results obtained by BPM (Beam Propagation Method) show that switching and tuneablity can be realized by using commercially available electro-optic materials …and semiconductor fabrication technologies. Show more

DOI: 10.3233/JAE-2005-687

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 22, no. 1-2, pp. 3-10, 2005

Authors: Sullivan, Matthew R. | Pirotta, Steven J. | Chernenko, V.A. | Wu, G.H. | Balasubramanium, G. | Hua, Susan Z. | Chopra, Harsh Deep

Article Type: Research Article

Abstract: This article presents our recent results on magnetic shape memory alloys (SMAs) and reviews some of our relevant past work. By treating the martensite structure as an assembly of microscopic crystalline tiles (twins), the observed micromagnetic structure or 'magnetic mosaic' in these alloys can be explained in terms of a spatially varying axis of the magnetocrystalline anisotropy and magnetostatic interactions across the tiles. A systematic investigation of ferroelastic structural domains of increasing structural …complexity leads to a novel concept of 'polymagnets'. Similar to the idea of hierarchical ferroelastic polydomains, polymagnets are hierarchical micromagnetic structures, and parallels the complexity of the underlying ferroelastic polydomains. Preliminary results on the dynamics of the transformation pathways reveal a strong correlation between the underlying microstructure and achievable strain. In addition, reversible shape memory effect has been observed in sputter-deposited Ni-Mn-Ga thin films, and Co-Ni films with controlled composition have been successfully made by electrodeposition. Show more

DOI: 10.3233/JAE-2005-688

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 22, no. 1-2, pp. 11-23, 2005

Authors: Maranville, C.W. | Ginder, J.M.

Article Type: Research Article

Abstract: An oscillatory double-lap-shear configuration was used to study the dynamic mechanical properties in shear of magnetorheological (MR) fluids entrained in open-cell polyurethane foams. The dynamic viscoelastic mechanical properties of the fluid were studied by varying strain amplitude, frequency, and magnetic field strength. We find that these samples exhibit linear viscoelastic behavior below a threshold level of strain and only in zero applied magnetic field. Above the critical strain, and in applied magnetic …fields, they behave as nonlinear viscoelastic materials with significant damping capacity that is strongly dependent on the field applied perpendicular to the direction of strain. For example, the energy dissipated by the material increases by over an order of magnitude when the flux density is increased from 0 to 0.6 Tesla. In addition, the magnitude of the complex modulus increases from 170 kPa in 0 Tesla to over 2 MPa with an applied flux density of 0.6 Tesla. We also found that the overall dynamic mechanical material properties changed very little with applied mechanical frequency in the range studied, 0.1 to 10 Hz. Show more

DOI: 10.3233/JAE-2005-689

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 22, no. 1-2, pp. 25-38, 2005

Authors: Vinogradov, Aleksandra M. | Schumacher, Shane C. | Rassi, Erik M.

Article Type: Research Article

Abstract: The paper concerns the dynamic response of polyvinylidene fluoride (PVDF), a commercially available piezoelectric polymer currently used in numerous applications. The paper consists of two parts. The first part presents a summary review of recent experimental results regarding the time-dependent behavior of PVDF tested under combined static and cyclic loading conditions. It has been observed that the polymer has demonstrated accelerated creep rates due to cyclic loading effects. Cyclic creep acceleration in PVDF has been …significant even in the range of stresses well below the viscoelastic linearity limit. This phenomenon, defined as "vibrocreep", appears to be essentially nonlinear, since the material response under combined static and cyclic loads did not represent a simple superposition of the responses to static and fully reversed cyclic loads applied separately. The second part of the paper provides a formulation of a nonlinear constitutive model, which describes the synergistic interaction between creep and cyclic damage evolution. The proposed constitutive model combines the concepts of linear hereditary viscoelasticity with damage characterization through a cyclic damage function. The latter is formulated using the basic principles of continuum damage mechanics. The potentials and limitations of the proposed constitutive model are discussed, and experimental results providing model validation are presented. Show more

DOI: 10.3233/JAE-2005-690

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 22, no. 1-2, pp. 39-51, 2005

Authors: Wang, Ji | Lin, Jingbo | Wan, Yongping | Zhong, Zheng

Article Type: Research Article

Abstract: The analysis of surface acoustic wave propagation in finite elastic solids is of essential importance in the study of the propagation nature and practical applications, and tremendous efforts have been made lately in employing both analytical and numerical methods for accurate solutions of the phase velocity and displacements. To overcome current difficulties in the physical model and computational intensity, a two-dimensional theory similar to Mindlin and Lee plate theories has been established for the surface acoustic …wave propagating in finite elastic solids. A systematic simplification of the three-dimensional equations resulted in a two-dimensional theory with accuracy and potential to solve surface acoustic wave problems in solids in a more efficient manner. For practical applications, the presence of a thin film over the substrate is studied with the two-dimensional theory with systematic modification, and straight-crested solutions with different film thickness are obtained. Show more

Keywords: Surface, wave, solid, propagation, velocity, finite, plate, vibration, electrode, platings

DOI: 10.3233/JAE-2005-691

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 22, no. 1-2, pp. 53-68, 2005

Authors: Yong, Yook-Kong | Patel, Mihir S.

Article Type: Research Article

Abstract: A quartz resonator subjected to acceleration will deform due to inertial effects. The deformation stresses and strains in the plate will in turn cause a shift in the resonator frequencies. A method is proposed to actively minimize the inertial stresses and strains by a DC-bias electric field. Finite element models are created to calculate the effects of acceleration on resonant frequency and to compare the results with experimental data. The non-linearity and non-homogeneity induced by the …inertial forces are modeled by using the concept of a superposed state. The model results for the acceleration effects are shown to compare well with the experimental results. The models are then used to calculate the effects of a DC electric field bias and to demonstrate the reduction of acceleration sensitivity. Show more

DOI: 10.3233/JAE-2005-692

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 22, no. 1-2, pp. 69-82, 2005

Authors: Wang, Ji | Yu, Jiun-Der | Yong, Yook-Kong

Article Type: Research Article

Abstract: The Mindlin plate theory was developed to provide accurate solutions of vibrations in the vicinity of the fundamental thickness-shear mode, which has a very high frequency compared to flexural vibrations. The most important application of the theory is the high frequency vibrations of crystal plates although it has been applied to many problems beyond the original purpose. Recent studies found that, to improve the frequency solutions for plates with larger aspect ratios, the third-order plate based …on Mindlin's power series expansion has to be used. It was shown through comparisons with three-dimensional elasticity solutions that the fundamental thickness-shear frequency is almost exact. The third-order theory was applied to frequency, mode shape, and other related analyses. In this study, we reconfirm that the third-order plate theory is very accurate because it has an almost exact cut-off frequency for the fundamental thickness-shear mode. By adopting a procedure developed by Mindlin, we find the inaccuracies in cut-off frequencies of the fundamental thickness modes and their overtones can be improved through the introduction of new correction factors. Corrections can be made with either the natural or symmetric procedure. Correction factors for natural and symmetric procedures based on stresses will be given. Show more

Keywords: Plate, Mindlin, crystal, vibration, resonator, frequency, thickness-shear, correction, factors

DOI: 10.3233/JAE-2005-693

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 22, no. 1-2, pp. 83-96, 2005

Authors: Yang, J.S. | Zhou, H.G.

Article Type: Research Article

Abstract: We study propagation of anti-plane (SH) waves in a piezoelectric ceramic plate carrying a thin layer of a semiconducting material on each of its major surfaces. Wave attenuation and dispersion caused by semiconduction as well as wave amplification by a biasing electric field are examined.

DOI: 10.3233/JAE-2005-694

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 22, no. 1-2, pp. 97-109, 2005

Authors: Simionescu-Panait, Olivian

Article Type: Research Article

Abstract: This paper deals with the study of the conditions of propagation of attenuated waves in cubic crystals subject to initial deformation and electric fields. The analysis is extended to all symmetry classes belonging to the cubic system, exhibiting, or not, the piezoelectric effect. We show the influence of the electrostrictive and piezoelectric effects on attenuated wave propagation in such media. We derive the velocities of propagation and the attenuation coefficients in closed-form, and we analyze the …influence of the initial fields on the wave polarization in the case of propagation on a cube face. For a particular choice of the initial electric field, we obtain and analyze the generalized anisotropy factor. Show more

DOI: 10.3233/JAE-2005-695

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 22, no. 1-2, pp. 111-120, 2005