Figure 1
From: Graphite-oxide hybrid multi-degree of freedom resonator metamaterial for broadband sound absorption
(a) Schematic of honeycomb (HC) structure which is either composed of a micro-perforated panel (MPP) as a top facesheet or a graphite oxide (GO) layer, (b) unit cell of MPP-HC and GO-HC. Sound absorption of the metamaterial is investigated from a plane acoustic wave normally incident to the top facesheet.
