Lamb and Love acoustic waves in porous-elastic plates and coatings

Based on the Biot theory, a model is proposed and the features of the propagation of Lamb and Love waves in flat thin plates and coatings made of porous-elastic two-phase materials such as isolon and foamed polyurethane with free boundaries are analyzed. The developed model of a two-phase medium for porous gas-filled materials allows to analyze any types of volumetric, longitudinal and transverse waves at arbitrary values of porosity. The method of potentials was used for solving boundary value problems describing the propagation of waves in a two-phase porous medium with closed and permeable pores. The velocities of transverse Lamb waves in a plate and Love waves in a coating were calculated for different parameters of a porous body. A qualitative analysis of the behavior of the dependences of the velocities S0 of zero-order modes of Lamb waves and first-order Love waves on changes in the medium parameters and the porous medium geometry in the low-frequency region was carried out.