Starovoit I. Flexural waves of the Raleigh-Lamb in a semi-infinite elastic layer

The dissertation investigates the wave field at the antisymmetric vibration of elastic layer with free lateral surfaces and dynamic and kinematic boundary conditions on its end. Influence of physical parameters (Poisson coefficient), the method of excitation wave field (forced vibrations or reflection of normal waves), the type of boundary conditions at the edge (free or incarcerated bound) on the performance of wave fields at the level of excitation of various types of normal waves is investigated. In this paper the existence of resonance for evanescent waves at antisymmetric vibration of the layer with the free edge are considered. As shown by this work the resonance is observed not for all Poisson coefficients. Resonant frequency matches the frequency at which the first complex root of the dispersion equation degenerates into the purely imaginary. For all considered types of load can be identified frequency bands in which the different waves that spread is dominant. For the kinematic boundary conditions at the excitation field the first wave, propagating this wave remains dominant in all the considered frequency range. Comparison of reflection process of the first and second normal bending waves from the free or pinched end face are considered possible to establish the rule of reciprocity for the frequency range in which there are only two modes that apply.