“…The concept of impedance boundary condition is widely used in numerous studies, mainly in electro-magnetics and mechanics; see, for instance, earlier studies [4,5] for the Helmholtz equation in acoustics, prior studies [6,7] for Maxwell equations, and earlier research [8,9] in structure mechanics; see also previous research [10,11]. In the framework of linear elasticity with voids, impedance is a measure of how a material or structure resists deformation or responds to the application of external forces and moments of forces.…”