Dispersion of quasi-Lamb waves in a multilayer composite plate in
contact with a compressible, inviscid fluid layer.
Abstract
The paper investigates the dispersion of quasi-Lamb waves in a
hydro-elastic system consisting of a plate of multilayer composite
material and a compressible, inviscid fluid layer whose flow is confined
by a rigid wall. The multilayer composite material is modeled as a
transversely isotropic material whose axis of symmetry is aligned along
the thickness of the plate. The motion of the plate is described by the
exact equations and relations of elastodynamics for anisotropic bodies,
but the fluid flow is described by the linearized Euler equations. The
analytical solutions of these equations are found and according to these
solutions the dispersion equations are obtained from the corresponding
boundary, compatibility and impermeability conditions. The dispersion
equation is solved numerically and the numerical results are obtained
for the case where the plate material consists of two alternating
layers. Based on these results, a parametric study of the influence of
the density ratio of the plate and fluid materials and the ratio of the
shear wave propagation velocity in the stiffer material layer of the
plate to the sound velocity of the fluid on the dispersion curves with
respect to the first four subsequent modes (denoted as A
0, S 0, A
1 and S 1 modes) of the
quasi-Lamb waves is performed. The influence of the ratio of the shear
moduli of the components of the multilayer material and the influence of
the contact of the plate with the fluid are investigated.