Absorbent acoustic metamaterial
AssigneesUniversite De Franche-Comte, Centre National De La Recherche Scientifique
InventorsAbdelkrim Khelif, Mahmoud Addouche, Aliyasin El Ayouch
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Abstract
Some embodiments are directed to an elementary acoustic metamaterial cell, including a body made of solid material and at least one resonator defining a groove of width l and depth p, the groove being open on the surface of the body, wherein the depth p is set by a resonant frequency (f) of the cell according to a relationship x, c being the speed of sound in air and the width l is set by an energy density confined in the cell according to a logarithmic relationship Emax αlog (l) determined experimentally, the groove having an acoustic absorption controlled by a ratio between the depth p and the width l of the groove. Some embodiments are also directed to an acoustic screen including such an elementary cell.
Claims19
An elementary cell of acoustic metamaterial, comprising:
- a body made of solid material;
- and
- at least one resonator defining a groove of width l and of depth p, the groove opening only onto one surface of the body,
- wherein:
- the groove is cylindrical, polygonal or rectilinear;
- wherein the one or more grooves are folded, in a section orthogonal to said surface, so as to have only one aperture and a plurality of folds in the interior of the cell;
- the depth p is determined by a resonant frequency (f) of the cell using a relationship
- f
- =
- c
- 4
-
-
- p
- ,
- c being the speed of sound in air;
- and
- the width l is determined by an energy density confined in the cell using an experimentally determined logarithmic relationship Emax∝log (l),
- the groove having a sound absorption controlled by a ratio between the depth p and the width l of the groove.
Dependencies are inferred from the claim text.