Negative refraction of elastic waves on a metamaterial with anisotropic local resonance

International audienceWave propagation through a locally resonant metamaterial characterized by anisotropic dynamic mass density is studied. The polarizations and velocities of waves are obtained from an extended Christoffel matrix. The set of waves induced by a body wave coming through the interface with an elastic material is described. Reflexion and refraction coefficients corresponding to the ratio of real Poynting vectors are obtained, showing that some of these coefficients are singular. In this case, the Poynting vector of the set of coupled waves must be used. This Poynting vector can display a negative refraction. The conditions leading to negative refraction are described and several examples of negative refraction are displayed