Realizing polarization band gaps and fluid-like elasticity by thin-plate elastic metamaterials

Abstract

The flexible manipulation of elastic waves that exhibit abundant polarization characteristics in solid structures can be realized through ingenious microstructure design, thus accomplishing various unique physical properties. This paper proposes a lightweight, thin-plate elastic metamaterial with transverse, longitudinal, and torsional wave polarization band gaps. Due to the spatial asymmetry of the unit cell, the band gaps do not overlap and can achieve the selective suppression of elastic waves exhibiting different polarization forms. In addition, the stopband of the flexural vibrational overlaps the passband of the longitudinal vibration, allowing a fluid-like elasticity capable of transmitting longitudinal waves but not transverse waves to be realized via a multicellular elastic rod-like structure with integrated multiple unit cells. A corresponding rod-like structure was fabricated and verified, achieving a fluid-like elasticity through vibrational measurements. Furthermore, the unit cell behaves a negative moment of inertia characteristic in the torsional wave band gap, which can effectively attenuate the torsional vibrational propagation of the rod-like structure with integrated multiple unit cells in another form. This proposed elastic metamaterial structure can provide a practical implementation scheme for the separation and manipulation of elastic waves in different polarization forms in solid structures.