| Summary: | 碩士 === 國立成功大學 === 工程科學系 === 103 === The main purpose of this thesis is to explore the multi-layered membrane-type acoustic metamaterials. In recent years, many researchers have shown that the single-celled metamaterial can give more effective sound insulation at low frequency. The periodic structure can block certain frequencies of sound waves. Hence, we combine these two different characteristics by stacking membrane-type acoustic metamaterials in series. It can give more bandwidth and more effective sound insulation.
In this thesis, we used Comsol Multiphysics, a finite element analysis software package to explore transmission loss (TL) and effective mass. We adjusted the mass weight, membrane density, the tension force on the edges of the membrane, and the arrangement of the membranes and metamaterials, and considered their effect on the characteristics of the TL curve. The TL valley and peak frequencies of the single-celled metamaterial are compared with the stacked metamaterials.
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