Long wave dispersion in an incompressible elastic layer subject to an initial static
simple shear deformation is investigated. Long wave approximations of the dispersion
relation associated with zero incremental traction on the faces are derived for both
low and high-frequency motion. Comparison of approximate and numerical solutions
is shown to provide excellent agreement over a surprisingly large wave number range.
Within both the low and high-frequency regimes, the approximations are employed to
establish the relative asymptotic orders of the displacement components and
hydrostatic pressure. In the high-frequency case, the in-plane component of
displacement is shown to be asymptotically larger than the normal component;
motion is, therefore, essentially that of thickness shear resonance. The influence of
this specific form of initial deformation is, therefore, seemingly minor in respect of
long-wave high-frequency motion. However, in the long-wave low-frequency case,
considerable differences are noted in comparison with both the classical
and previously published prestressed cases. Specifically, both the normal
and in-plane displacement components are of the same asymptotic order,
indicating the absence of any natural analogue of either classical bending or
extension.