Parametric study of reflection characteristics at ahiral-chiral interfaces

Materials described by the constitutive relations σji = μγji + μγij + λγkkδij + Cκji and χji = (ξ + ε)κji + (ξ - ε)κij + ηκkkδij + Cγji lack inversion symmetry due to chirality in their microstructures. Six wavenumbers are possible solutions for dispersion equations in acoustically active (chiral) medium. Two of these wavenumbers represent longitudinally polarized elastic waves, the remaining four wavenumbers stand for circularly polarized elastic waves. In this paper, reflection characteristics of elastic waves normally impinging upon achiral-chiral interfaces are thoroughly discussed. The effects of the constitutive parameters of chiral medium on reflection coefficients are elucidated. Simulation results illustrate that reflection coefficients may vanish by properly tailoring constitutive parameters of chiral medium. The methods for determining constitutive parameters of chiral medium for zero reflection at achiral-chiral interfaces are developed. Results obtained in this study can be applied for designing state-of-the-art acoustic materials, e.g. acoustic shielding and absorptive materials, using chiral composites.