The propagation of Love-type waves in a nonlocal elastic layer with voids resting over a nonlocal elastic solid half-space with voids has been studied. Dispersion relations are derived using appropriate boundary conditions of the model. It is found that there exist two fronts of Love-type surface waves that may travel with distinct speeds. The appearance of the second front is purely due to the presence of voids in layered media. Both fronts are found to be dispersive in nature and affected by the presence of the nonlocality parameter. The first front is found to be nonattenuating, independent of void parameters and analogous to the Love wave of classical elasticity, while the second front is attenuating and depends on the presence of void parameters. Each of the fronts is found to face a critical frequency above which it ceases to propagate. For a specific model, the variation of the phase speeds of both the fronts with frequency, nonlocality, voids and thickness parameters is shown graphically. Attenuation coefficient versus frequency for the second front has also been depicted separately. Some particular cases are deduced from the present formulation.

Propagation of time harmonic plane waves in an infinite thermoelastic solid medium with double porosity is studied in this paper. It is found that there may exist five basic waves consisting of four sets of coupled longitudinal waves and an independent transverse wave traveling at different speeds. Each set of coupled longitudinal waves is found to be dispersive, attenuating and depends upon the presence of both types of voids and thermal properties in the medium. The lone transverse wave is found to be non-dispersive and non-attenuating, and does not depend on the presence of voids and thermal properties, and travels with the speed of the shear wave of classical elasticity. Two sets of the coupled longitudinal waves face critical frequencies, below which these waves do not propagate in the medium. These critical frequencies depend upon the presence of voids and thermal parameters of the medium. The reflection phenomenon of a set of incident coupled longitudinal wave from the stress-free and thermally insulated boundary surface of a half-space has been studied. For a particular model, the phase speeds, attenuation coefficients, amplitude ratios and energy ratios have been computed numerically, presented graphically and discussed.