A low frequency underwater metastructure composed by helix metal and viscoelastic damping rubber

We report an underwater metastructure with excellent acoustic absorption that is constructed by perforating a helix structure into viscoelastic damping rubber. Finite element method results show that this metastructure can achieve the low frequency and broadband acoustic absorption below 1000 Hz. Waveform transformation, multiple scattering, and reflection energy dissipation mechanisms are the critical factors affecting the absorption performance. Different geometries and materials of the helix structure can adjust the acoustic absorption to a great extent. The proposed metastructure provides more possibilities for underwater acoustic manipulation applications.