Spectrum of natural vibrations of a layered medium consisting of a Kelvin–Voigt material and a viscous incompressible fluid

The spectrum of one-dimensional natural vibrations is described for a two-phase medium consisting of periodically alternating layers. It is supposed that the first phase is an isotropic Kelvin–Voigt material and the second one is a viscous incompressible fluid. The set of initial approximations to the points of the above spectrum is found. Numerical results illustrating the accuracy of the proposed approximations are presented.