Now showing 1 - 2 of 2
No Thumbnail Available
Publication

Acoustic characteristic of Bio-Composite Micro-Perforated Panel (BC-MPP) backed with natural fiber

2023 , Faridah Wahab , Tan Wei Hong , Mohamad Haziman Mohamad Azhar , Nor Hafizul Hilni Abdul Rahman

We investigated the sound absorption properties of a bio-composite microperforated panel (BC-MPP) with a combination of backed-structure and several types of natural fibers such as loofah, kapok, and coconut coir. The sound absorption coefficient (SAC) of different combinations of natural fibers samples was obtained by using a two-microphone impedance tube. In addition, three models, including Delany-Bazley model, Maa theory, and electroacoustical analogy, were employed to estimate the SAC value of natural fiber, BC-MPP, and BC-MPP with a backed structure, respectively. The experimental results demonstrate that the SAC value was increased to almost 0.99 as compared to BC-MPP alone when natural fiber was introduced at the back of BC-MPP either by insertion in the hole of backed structure or attached directly at the back of BC-MPP. The SAC peak also shifted to a lower frequency bandwidth with the highest peak obtained at 930 Hz, 800 Hz and 640 Hz for MPP with coconut husk, BC-MPP with kapok and BC-MPP with loofah, respectively. The absorption frequency was also observed slightly wider than BC-MPP without natural fiber. In comparison of BC-MPP with loofah and BC-MPP with others natural fibers, the insertion of kapok and coconut coir in the hole of backed structure provides a wider effective sound absorption coefficient. The comparison of experimental result with the theoretical calculation shows that the SAC obtained from experiment provides higher SAC value over the theoretical model for both BC-MPP and BC-MPP backed structure.

No Thumbnail Available
Publication

Sound absorption coefficient measurement and analysis of bio-composite micro perforated panel (BC-MPP)

2023 , Tan Wei Hong , Lee Jia Jian , Faridah Wahab , Siti Hajar Ishak

The sound absorption performance of bio-composite micro-perforated panel (BC-MPP) made from composite polypropylene (PP) filled rice husk (PP/RH), and coconut coir (PP/CC) is presented. The sound absorption coefficient (SAC) of BC-MPP was obtained via the impedance tube two-microphone method, and the investigation was according to types of fillers, filler compositions, perforation ratio, and the air gap size. It was found that the SAC of BC-MPP PP/RH provides a higher SAC value than BC-MPP PP/CC. Furthermore, the SAC peak was observed to shift to the lower frequency spectrum when there was an increment in filler content, the distance between the perforation, and the air gap size. The SAC value from the simulation also shows a good agreement with the experimental result.