Study of Harmonic Oscillations in an Acoustic Medium with a Coating, Excited by an Internal Concentrated Source

In this paper, we consider the problems of vibration in an elastic coating on the surface of an extended acoustic medium (a layer on a non-deformable foundation and a half-space) under the influence of a harmonic concentrated source located in the acoustic medium. We model the coating as both a thin elastic layer and an elastic plate with parameters averaged over the thickness. The study of vibrations of acoustoelastic structures is carried out based on an integral approach. The representations of the Fourier displacement symbols we constructed in this work make it possible to calculate the real and imaginary parts of complex amplitudes depending on the frequency and distance from the origin. For frequencies below the frequency where the bending wavelength in the plate coincides with the acoustic wavelength, the results of the two coating models (plate and elastic layer) on the acoustic layer are almost identical. The picture changes for soft coatings modeled by a layer. The described approach makes it possible to study the features of the propagation for waves generated by oscillating loads in composite layered heterogeneous foundations with a coating.