A Sandwich Coating Containing Micro-perforated Panel for Underwater Sound Absorption

Absorption of oblique incidence sound by a finite micro-perforated panel absorber.

In this paper, a theoretical model of a micro-perforated panel (MPP) backed by a finite cavity and flush-mounted in an infinite baffle is developed and its performance in terms of sound absorption is analyzed. The model allows an oblique incidence sound impinging upon the MPP absorber. The simplified Rayleigh integral method, thin plate theory and the acoustical impedance of the MPP are used to...

Sound attenuation using duct silencers with micro-perforated panel absorbers

Micro-perforated panel (MPP) can be used as non-fibrous acoustic absorber which can provide broadband sound absorption performance. In this study, a sub-structuring methodology based on the Patch Transfer Function (PTF) approach to deal with duct silencers with MPP absorbers and internal partitions is proposed, and the sound attenuation performance of such silencers is investigated. Reactive si...

Vibroacoustics of thin micro-perforated sound absorbers

Estimation of Sound Absorption Behavior of Combined Panels Comprising Kenaf Fibers and Micro-Perforated Plates below 2500 Hertz

Introduction: Natural materials are more efficient and attractive than synthetic materials. In this study, the sound absorption behavior by natural kenaf composite and Micro-Perforated Panel (MPP) at low and medium frequency region was investigated. Material and Methods: Initially, the results of kenaf fibers with a thickness of 10 mm were validated by the Finite Element Method (FEM) based on ...

Sound Absorption of Porous Material in Combination with Perforated Facings

The absorption characteristics of porous absorbers in combination with perforated facings was investigated. The effect of the hole size, hole pattern and open area ratio were examined. The absorption coefficients for an absorber of uniform cross-section were compared to those for an absorber with a tapered cross-section for various volumes of absorbent and different perforated facings.