The propagation of generalized rayleigh waves in a coated material

Based on the linear elastodynamics theory, an analyticalmodel is established for the propagation of generalized Rayleigh waves in acoated structure. Moreover, the dispersion equation is derived from the wavemotion equations and the boundary conditions. The theoretical solutions ofthe phase velocity are obtained for the cases of different ratios of thecoating thickness to the wavelength, and different density ratios of thecoating to the substrate, by considering respectively the influence of lowlayers and fast layers on the phase velocity. In the numerical examples, thephase velocities, group velocities and the attenuating amplitudes ofdisplacement and stress component in a slow layer structure are comparedwith those in a fast layer structure. Besides, the model and the analysisare validated by comparing with those in the references. This paper providesa theoretical basis to determine the material parameters of various coatingmedia by means of surface wave method.