Utilization of Coir Fiber in Multilayer Acoustic Absorption Panel

Mohammad, Hosseini Fouladi and mohd jailani, mohd nor and md, ayub and zulkarnain, zulkarnain (2010) Utilization of Coir Fiber in Multilayer Acoustic Absorption Panel. Applied Acoustics, 71 (3). pp. 241-249. ISSN 0003-682X

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    Abstract

    Coconut is one of the most important harvests in Malaysia. Industrial prepared coir fiber is obtained from coconut husk combined with latex and other additives to enhance its structural characteristics. Unfortunately, such inevitable process diminishes the acoustical features of material. Previous studies on industrial coir fiber and fiber–air gap layers showed that low frequency absorptions needed improvements. Therefore perforated plate (PP) was added to the multilayer structure to further enhance the sound absorption in this area. Analyses were accomplished through three PP modeling approaches (Allard, Beranek and Ver, Atalla and Sgard) and Allard Transfer Function (TF) method. Experiments were conducted in impedance tube to support the analytical results. Outcomes showed that Allard TF method was generally closer to measurement values and implemented for additional analyses. Two possible conditions of putting PP in front of fiber layer or between fiber–air gap layers were investigated. Both arrangements were suitable to enhance the sound absorption. Although, when PP was backed by coir fiber and air gap, porosity of the plate had great influence in adjusting the amount of low frequency absorption. Result derived that PP might improve the low frequency absorption of coir fiber but at the same time the medium frequency absorption was reduced. This effect was noticed previously in coir fiber–air gap structures while the air gap thickness increased. The advantage of using PP was that it assisted in greatly reducing the air gap thickness under the same acoustical performance. Hence it is an efficient tool to reduce the thickness of acoustic isolators in practical purposes.

    Item Type: Article
    Subjects: T Technology > TJ Mechanical engineering and machinery
    Divisions: Faculty of Engineering > Department of Mechanical Engineering
    Depositing User: Zulkarnain Ali Leman
    Date Deposited: 03 Mar 2015 09:43
    Last Modified: 03 Mar 2015 09:43
    URI: http://eprints.unsri.ac.id/id/eprint/5235

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