Macro- and micro-structure designs for porous sound absorbers

Macro-structures that improve the sound absorption of hard-backed layers of rigid-porous material include graduated arrangements for obtaining impedance matching and vertical and horizontal partitioning which can result in meta-material behaviour. Instead of using bulk-manufactured porous materials...

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Bibliographic Details
Published inApplied acoustics Vol. 145; pp. 349 - 357
Main Author Attenborough, Keith
Format Journal Article
LanguageEnglish
Published Elsevier Ltd 01.02.2019
Subjects
Impedance matching
Partitions
Porous absorber
Slit microstructures
Porous absorber
Slit microstructures
Partitions
Impedance matching
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Summary:Macro-structures that improve the sound absorption of hard-backed layers of rigid-porous material include graduated arrangements for obtaining impedance matching and vertical and horizontal partitioning which can result in meta-material behaviour. Instead of using bulk-manufactured porous materials as the host media, normal incidence absorption coefficient spectra are predicted for combinations of these macro-structures with simple micro-structures consisting of uniform or non-uniform slits either normal or inclined to the layer surface. The results suggest that, subject to manufacturing constraints, the production of composite structures like these instead of traditional porous sound absorbing configurations would result in comparable or superior acoustical performances.
ISSN:0003-682X
1872-910X
DOI:10.1016/j.apacoust.2018.10.018