Abstract
More difficult fluctuation of rectangular flat element is the fluctuation when two of the opposite edges are hinge-supported, and two other edges have different types of fixing or they are free from tension. This class of tasks leads to the transcendental equations for determination of frequencies of own fluctuations which can be solved both numerically and analytically. The transcendental frequency equations can be reduced to algebraic ones and to investigate the influence of both boundary conditions at the edges of rectangular plate or rectangular flat element and parameters of geometrical and mechanical character on the frequencies of own fluctuations of rectangular flat elements. In the study of oscillations and wave processes in a deformable solid body core of a viscoelastic operators it is advisable to take regular, so as soon as such statements describe the instantaneous elasticity, and then viscous flow, which is typical for deformable bodies. Integra-differential equations with regular kernels, as you know, the equivalent differential equations.