Omnidirectional acoustic absorber with a porous core and a metamaterial matching layer
Elliott, A S, Venegas Castillo, RG, Groby, JP and Umnova, O 2014, 'Omnidirectional acoustic absorber with a porous core and a metamaterial matching layer' , Journal of Applied Physics, 115 (20) .
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An omnidirectional sound absorber based on the acoustic analogy of the electromagnetic metamaterial “black hole” has been developed and tested. The resulting structure is composed of a hollow cylindrical porous absorbing core and a graded index matching layer which employs multiple rods of varying size and spacing to gradually adjust the impedance of the air to that of the porous absorbing core. A semi-analytical model is developed, and the practical challenges and their implications with respect to performance are considered. A full size device is built and tested in an anechoic chamber and the semi-analytical model used in the design process is validated. Finally, the theory is extended to allow for losses in the metamaterial matching layer, and it is shown that improved performance may be achieved with a dual purpose layer which acts as an absorber whilst also providing the required impedance matching condition.
|Schools:||Schools > School of Computing, Science and Engineering > Salford Innovation Research Centre (SIRC)|
|Journal or Publication Title:||Journal of Applied Physics|
|Publisher:||American Institute of Physics|
|Funders:||Defence Science and Technology Laboratory|
|Depositing User:||O Umnova|
|Date Deposited:||29 May 2015 17:12|
|Last Modified:||24 Feb 2016 16:36|
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