Reflection of plane waves from the stress-free boundary of a nonlocal elastic solid half-space containing double porosity

Abstract

Reflection phenomena of a set of coupled longitudinal waves/shear wave striking obliquely against the mechanically stress-free boundary surface of a uniform nonlocal elastic solid half-space with double porosity structure have been investigated. Employing the appropriate nonlocal stress-free boundary conditions at the surface, the formulae for reflection coefficients and their corresponding energy ratios have been derived for the dissipative and non-dissipative models. Their variations have been computed against the angle of incidence for a specific model. It is found that all the reflection coefficients depend upon the presence of the nonlocality, porosities of both types, frequency and angle of incidence. Their impact on various coefficients is also studied numerically and depicted graphically.