Tunability for anomalous refraction of flexural wave in a magneto-elastic metasurface by magnetic field and pre-stress

This letter reports the design of a magneto-elastic metasurface composed of arrayed Terfenol-D pillars deposited on a homogeneous aluminum plate, aiming to realize the tunability of flexural wave anomalous propagation without altering the structure. Considering the magneto-mechanical coupling of magnetostrictive materials, the phase shift and transmission of the functional unit can be calculated. The anomalous refraction of incident flexural wave (i.e. negative refraction) can be accomplished by adjusting the magnetic field and pre-stress properly, the refraction angle is remarkably affected by magnetic distribution. The proposed metasurface provides a method for flexible tunability of elastic waves in the fields of vibration/noise control.