### ASA 130th Meeting - St. Louis, MO - 1995 Nov 27 .. Dec 01

## 1aPA10. Interfacial waves in a finitely strained layered elastic
half-space.

**Dimitrios A. Sotiropoulos
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*Dept. of Eng. Sci., Tech. Univ. of Crete, Chania 73100, Greece
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**Christoforos G. Sifniotopoulos
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*Northwestern Univ., Evanston, IL 60208
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Propagating and standing interfacial waves between a surface layer and an
underlying half-space, both under finite strain, are examined. The media are
compressible nonlinear elastic and homogeneously pre-strained with their
principal axes of pre-strain aligned, one axis being normal to the planar
interface. For arbitrary strain energy functions and propagation along a
principal axis of pre-strain, the dispersion equation is obtained. A
low-frequency wave speed is subsequently obtained in explicit form yielding
nonpropagation parameter conditions which for a specific state of stress hold at
any frequency. The high-frequency limit of the dispersion equation yields the
secular equation for interfacial waves between two half-spaces. It is then found
that equal-density compressible materials may allow propagation and that
compressible materials with equal shear wave velocities parallel to the
interface may filter interfacial waves, even under isotropic in-plane
stretching. For an arbitrary layer thickness as compared to the wavelength,
material and pre-strain parameter conditions are also derived for the existence
of standing waves as solutions of the bifurcation equation, a limiting case of
the dispersion equation.