| Summary: | 碩士 === 國立成功大學 === 土木工程學系 === 103 === SUMMARY
In this paper, finite element method is used to analyze the acoustic properties of porous materials. Two-dimensional acoustic models were built in ABAQUS. In the models, the porous materials contain two medium, which are solid skeleton and fluid (air) in the pores. By arranging the pore structures in the models, we explore its influence on the acoustic performance of porous material. In the open-cell model, the solid and fluid are arranged in parallel to the direction of sound propagation. In the closed-cell model, the solid were arranged in series with the fluid in along the direction of sound propagation. The results show that open-cell structure dissipates sound energy by the volumetric drag of pore fluid. In order to improve sound absorption ability, we shall expect the use of open-cell material in the surface layer. Meanwhile, open-cell structure also provides good sound insulation in a wide frequency range due to volumetric drag. Closed-cell structure often show strong resonance in the analyses, which indicates the effects of pore structure. Our analyses can be extended further to explore more on the effects of pore structures and the connectivity of pores.
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