A composite and deformable honeycomb acoustic metamaterial

This paper reports the design of a deformable honeycomb acoustic metamaterial, which consists of honeycomb structures and ethylene-vinyl acetate (EVA) copolymer films stacked on each other. The FEA results agree well with the experiment analysis, and it is proved that the proposed structure can break the acoustic mass law below 1000 Hz. This paper reveals that dislocation, compression, and tensile deformation can regulate the sound transmission loss (STL) in a wider frequency range. It is concluded that the STL of a bilayer structure is, on average, 10 dB higher than that of a monolayer structure at low-frequencies. When the dislocation distance b = 1.5 mm, the corresponding STLs reach their maximum values. The FEA and experiment results prove that compression and tensile deformation can considerably improve the sound insulation effect. Such a deformable honeycomb acoustic metamaterial with high STL provides a new concept for engineering noise control.