Analysis of wave motion in transversely isotropic elastic material with voids under a inviscid liquid layer

2009 ◽  
Vol 87 (4) ◽  
pp. 377-388 ◽  
Author(s):  
Rajneesh Kumar ◽  
Rajeev Kumar

The present investigation is to study the surface wave propagation in a semi-infinite transversely isotropic elastic material with voids under a homogeneous inviscid liquid layer. The frequency equation is derive after developing the mathematical model. The dispersion curves giving the phase velocity and attenuation coefficients versus wave numbers are plotted graphically to depict the effects of voids for (i) a transversely isotropic elastic half-space with voids under a homogeneous inviscid liquid layer and (ii) a transversely isotropic elastic half-space with voids. The particle path is also obtained for Rayleigh wave propagation in a transversely isotropic elastic half-space with voids, i.e., case (ii). The amplitudes of the displacements, the volume fraction field, and the normal stresses in both the media are obtained and are shown graphically for a particular model to depict the voids and anisotropy effects. Some special cases are also deduced from the present investigation.

1971 ◽  
Vol 38 (4) ◽  
pp. 899-905 ◽  
Author(s):  
L. B. Freund

Three-dimensional wave propagation in an elastic half space is considered. The half space is traction free on half its boundary, while the remaining part of the boundary is free of shear traction and is constrained against normal displacement by a smooth, rigid barrier. A time-harmonic surface wave, traveling on the traction free part of the surface, is obliquely incident on the edge of the barrier. The amplitude and the phase of the resulting reflected surface wave are determined by means of Laplace transform methods and the Wiener-Hopf technique. Wave propagation in an elastic half space in contact with two rigid, smooth barriers is then considered. The barriers are arranged so that a strip on the surface of uniform width is traction free, which forms a wave guide for surface waves. Results of the surface wave reflection problem are then used to geometrically construct dispersion relations for the propagation of unattenuated guided surface waves in the guiding structure. The rate of decay of body wave disturbances, localized near the edges of the guide, is discussed.


1992 ◽  
Vol 114 (2) ◽  
pp. 253-261 ◽  
Author(s):  
C. H. Kuo ◽  
L. M. Keer

The three-dimensional problem of contact between a spherical indenter and a multi-layered structure bonded to an elastic half-space is investigated. The layers and half-space are assumed to be composed of transversely isotropic materials. By the use of Hankel transforms, the mixed boundary value problem is reduced to an integral equation, which is solved numerically to determine the contact stresses and contact region. The interior displacement and stress fields in both the layer and half-space can be calculated from the inverse Hankel transform used with the solved contact stresses prescribed over the contact region. The stress components, which may be related to the contact failure of coatings, are discussed for various coating thicknesses.


1987 ◽  
Vol 54 (1) ◽  
pp. 121-126 ◽  
Author(s):  
R. Y. S. Pak

A method of potentials is presented for the derivation of the dynamic response of an elastic half-space to an arbitrary, time-harmonic, finite, buried source. The development includes a set of transformed stress-potential and displacement-potential relations which are apt to be useful in a variety of wave propagation problems. Specific results for an embedded source of uniform distributions are also included.


The effect of a liquid layer overlying a solid half-space excited by harmonically varying stresses on the surface of an embedded spherical cavity is examined. The Stoneley waves along the liquid/solid interface are studied in some detail. The results are then extended to the case of an exponential shock.


2018 ◽  
Vol 24 (5) ◽  
pp. 1425-1437 ◽  
Author(s):  
Jing Jin Shen

A transversely isotropic half space with surface effects subjected to axisymmetric loadings is investigated in terms of the Lekhnitskii formulism. Surface effects including residual surface stress and surface elasticity are introduced by using the Gurtin–Murdoch continuum model. With the aid of the Hankel transforms, solutions corresponding to several different axisymmetic loadings are derived and used to determine the influence of surface effects on contact stiffness in nanoindentations. Numerical results are provided to show the influence of surface effects and material anisotropy on the material behaviours. Meanwhile, the obtained analytical Green’s functions for two special cases can be used as building blocks for further mixed boundary value problems.


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