共查询到20条相似文献,搜索用时 41 毫秒
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《力学快报》2017,(3)
With the advent of left-handed magnetic materials, it is desirable to develop high-performance wave devices based on their novel properties of wave propagation. This letter reports the special properties of elastic wave propagation in magnetoelastic multilayered composites with negative permeability as comparecd to those in counterpart structures with positlve permeability. These novel properties of elastic waves are discerned from the diversified dispersion curves, which represent the propagation and attenuation characteristics of elastic waves. To compute these dispersion curves, the method of reverberation-ray matrix is extended for the analysis of elastic waves in magnctoelastic multilayered composites. Although only the results of a single piezomagnetic and a binary magnetoelastic layers with mechanically free and magnetically short surfaces as well as pelrfect interface are illustrated in the numerical examples, the analysis is applicable lo magnetoelastic multilayered structures with other kinds of boundaries/interfaces. 相似文献
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The shapes of magnetoelastic shear body waves in periodically inhomogeneous magnetostrictive dielectric media are studied
with emphasis on wave shapes in the neighborhood of the zones of interaction of elastic and magnetostatic waves
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Translated from Prikladnaya Mekhanika, Vol. 42, No. 10, pp. 13–20, October 2006. 相似文献
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J. J. Rushchitsky 《International Applied Mechanics》2009,45(1):73-93
A summary on transistors and some facts on nanocomposite materials and their classical models are provided. New models used
here for computer simulation are described. Results from a theoretical study of the interaction of cubic nonlinear harmonic
elastic plane waves in a Murnaghan material are presented. The interaction of two harmonic waves is analyzed using the method
of slowly varying amplitudes. The mechanism of energy pumping from a strong pump wave to a weak signal wave is examined. The
theoretical and numerical analyses conducted suggest that in theory, a nanocomposite material may be used to create a transistor
that would work with hypersonic waves and have a speed in the nanosecond range
Translated from Prikladnaya Mekhanika, Vol. 45, No. 1, pp. 90–117, January 2009. 相似文献
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The shapes of shear body waves in periodically inhomogeneous, magnetostrictive, dielectric media are studied with emphasis
on the partial (elastic and magnetostrictive) wave motions coupled to produce magnetoelastic waves
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Translated from Prikladnaya Mekhanika, Vol. 42, No. 7, pp. 57–63, July 2006. 相似文献
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Here we consider finite-amplitude wave motions in Mooney–Rivlin elastic materials which are first subjected to a static homogeneous deformation (prestrain). We assume that the time-dependent displacement superimposed on the prestrain is along a principal axis of the prestrain and depends on two spatial variables in the principal plane orthogonal to this axis. Thus all waves considered here are linearly polarized along this axis. After retrieving known results for a single homogeneous plane wave propagating in a principal plane, a superposition of an arbitrary number of sinusoidal homogeneous plane waves is shown to be a solution of the equations of motion. Also, inhomogeneous plane wave solutions with complex wave vector in a principal plane and complex frequency are obtained. Moreover, appropriate superpositions of such inhomogeneous waves are also shown to be solutions. In each case, expressions are obtained for the energy density and energy flux associated with the wave motion. 相似文献
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Jeremiah Rushchitsky 《Comptes Rendus Mecanique》2002,330(3):175-180
The problem of self-switching plane waves in elastic nonlinearly deformed materials is formulated. Reduced and evolution equations, which describe the interaction of two waves the power pumping wave and the faint signal wave are obtained. For the case of wave numbers matching the pumping and signal waves, a procedure of finding the exact solution of evolution equations is described. The solution is expressed by elliptic Jacobi functions. The existence of the power wave self-switching is shown and commented. To cite this article: J. Rushchitsky, C. R. Mecanique 330 (2002) 175–180. 相似文献
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Ya. Ya. Rushchitskii 《International Applied Mechanics》2001,37(1):107-113
The energy characteristics of waves propagating in composites are discussed. To describe the deformation of materials, two models are used — the classical model of an elastic body and the microstructural model of a two-phase elastic mixture. Both models take into account the quadratic nonlinearity of deformation based on the Murnaghan elastic potential. Analytical expressions for the velocity at which the energy of travelling plane longitudinal waves propagates are derived. It is shown that the nonlinearity of composite deformation decreases the velocities of energy propagation of both nondispersive and dispersive waves 相似文献
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In this paper the equations governing small amplitude motions in a rotating transversely isotropic initially stressed elastic solid are derived, both for compressible and incompressible linearly elastic materials. The equations are first applied to study the effects of initial stress and rotation on the speed of homogeneous plane waves propagating in a configuration with uniform initial stress. The general forms of the constitutive law, stresses and the elasticity tensor are derived within the finite deformation context and then summarized for the considered transversely isotropic material with initial stress in terms of invariants, following which they are specialized for linear elastic response and, for an incompressible material, to the case of plane strain, which involves considerable simplification. The equations for two-dimensional motions in the considered plane are then applied to the study of Rayleigh waves in a rotating half-space with the initial stress parallel to its boundary and the preferred direction of transverse isotropy either parallel to or normal to the boundary within the sagittal plane. The secular equation governing the wave speed is then derived for a general strain–energy function in the plane strain specialization, which involves only two material parameters. The results are illustrated graphically, first by showing how the wave speed depends on the material parameters and the rotation without specifying the constitutive law and, second, for a simple material model to highlight the effects of the rotation and initial stress on the surface wave speed. 相似文献
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The paper presents the effect of a rigid boundary on the propagation of torsional surface waves in a porous elastic layer
over a porous elastic half-space using the mechanics of the medium derived by Cowin and Nunziato (Cowin, S. C. and Nunziato,
J. W. Linear elastic materials with voids. Journal of Elasticity, 13(2), 125–147 (1983)). The velocity equation is derived, and the results are discussed. It is observed that there may be two
torsional surface wave fronts in the medium whereas three wave fronts of torsional surface waves in the absence of the rigid
boundary plane given by Dey et al. (Dey, S., Gupta, S., Gupta, A. K., Kar, S. K., and De, P. K. Propagation of torsional surface
waves in an elastic layer with void pores over an elastic half-space with void pores. Tamkang Journal of Science and Engineering, 6(4), 241–249 (2003)). The results also reveal that in the porous layer, the Love wave is also available along with the torsional
surface waves. It is remarkable that the phase speed of the Love wave in a porous layer with a rigid surface is different
from that in a porous layer with a free surface. The torsional waves are observed to be dispersive in nature, and the velocity
decreases as the oscillation frequency increases. 相似文献
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Plane waves in linear elastic materials with voids 总被引:2,自引:0,他引:2
The behavior of plane harmonic waves in a linear elastic material with voids is analyzed. There are two dilational waves in this theory, one is predominantly the dilational wave of classical linear elasticity and the other is predominantly a wave carrying a change in the void volume fraction. Both waves are found to attenuate in their direction of propagation, to be dispersive and dissipative. At large frequencies the predominantly elastic wave propagates with the classical elastic dilational wave speed, but at low frequencies it propagates at a speed less than the classical speed. It makes a smooth but relatively distinct transition between these wave speeds in a relatively narrow range of frequency, the same range of frequency in which the specific loss has a relatively sharp peak. Dispersion curves and graphs of specific loss are given for four particular, but hypothetical, materials, corresponding to four cases of the solution. 相似文献
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The paper is concerned with longitudinal and transverse waves propagating at a right angle to the layers of a nanocomposite
material with initial (process-induced residual) stresses. The composite consists of alternating layers of two dissimilar
materials. The materials are assumed nonlinearly elastic and described by the Murnaghan potential. For simulation of wave
propagation, a problem is formulated within the framework of the three-dimensional linearized theory of elasticity for finite
prestrains. It is established that the relative velocities of waves depend linearly on small prestresses. In some composite
materials, however, the thicknesses of the layers may be in a ratio such that the wave velocities are independent of the prestress
level
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Translated from Prikladnaya Mekhanika, Vol. 42, No. 7, pp. 3–22, July 2006. 相似文献
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J. J. Rushchitsky 《International Applied Mechanics》2005,41(11):1288-1298
General principles are formulated for modeling the elastic deformation of materials and analyzing plane waves in nonlinearly
elastic materials such as hyperelastic, hypoelastic, and those governed by the general law of elasticity. The results of studying
the propagation of plane waves in hypoelastic materials are further outlined. The influence of initial stresses and initial
velocities on the types and number of plane waves is studied. Wave effects characteristic of hypoelastic materials are predicted
theoretically. One of such effects is blocking of certain types of plane waves by initial stresses
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Translated from Prikladnaya Mekhanika, Vol. 41, No. 11, pp. 96–107, November 2005. 相似文献
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Features of the propagation of longitudinal and transverse plane waves along the layers of nanocomposites with process-induced
initial stresses are studied. The composite has a periodic structure: it is made by repeating two highly dissimilar layers.
The layers exhibit nonlinear elastic behavior in the range of loads under consideration. A Murnaghan-type elastic potential
dependent on the three invariants of the strain tensor is used to describe the mechanical behavior of the composite constituents.
To simulate the propagation of waves, finite-strain theory is used for developing a problem statement within the framework
of the three-dimensional linearized theory of elasticity assuming finite initial strains. The dependence of the relative velocities
of longitudinal and transverse waves on two components of small initial stresses in each layer and on the volume fraction
of the constituents is studied. It is established that there are thickness ratios of layers in some nanocomposites such that
the wave velocities are independent of the initial stresses and equal to the respective wave velocities in composites without
initial stresses
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Translated from Prikladnaya Mekhanika, Vol. 43, No. 4, pp. 3–26, April 2007. 相似文献
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A. Montanaro 《Journal of Elasticity》1999,57(1):25-53
By extending the procedure of linearization for constrained elastic materials in the papers by Marlow and Chadwick et al., we set up a linearized theory of constrained materials with initial stress (not necessarily based on a nonlinear theory).
The conditions of propagation are characterized for small-displacement waves that may be either of discontinuity type of any
given order or, in the homogeneous case, plane progressive. We see that, just as in the unconstrained case, the laws of propagation
of discontinuity waves are the same as those of progressive waves. Waves are classified as mixed, kinematic, or ghost. Then we prove that the analogues of Truesdell"s two equivalence theorems on wave propagation in finite elasticity hold for
each type of wave.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献