Propagation of surface waves in deformed, anisotropic thin layered solids

This paper provides a method to determine the velocities of surface waves propagating in finitely predeformed, anisotropic thin layered solids based on acoustoelasticity of surface waves. First, the constitutive equations and the equations of motion required for examining the propagation of surface waves in deformed layered solids are derived, by reexamining the theory of small (infinitesimal) wave motions superimposed on a largely deformed body. It follows to solve the surface wave velocities from the derived equations of motion by using the extended Farnell's analytical formalism. Next, for the forward problem of acoustoelasticity it is necessary to have a priori knowledge of the initial deformations in thin films and, thus, this paper introduces planar stress system and some typical stress-strain filed models in thin films. Finally, based on the developed theory, a series of numerical experiments has been carried out in this work to examine the change of the surface wave velocities caused by stress or strain in thin films. This paper gives the representative calculated results from which some of the important conclusions are extracted.