ABSTRACT
The thesis focuses on aluminum porous board used in noise reduction. The experiment evaluates propagation of sound wave and examines acoustic characteristics of aluminum porous board when sound wave impinging on the aluminum porous board. Also, the material properties and acoustic properties of aluminum porous board are analyzed to help further understanding of aluminum porous board.
Biot`s poroelastic theory is essentially used to obtain the equation of motion of the elastic porous material, following the calculation of sound transmission loss via application of appropriate boundary condition. Supported by the theoretical analysis and measured data, the result in the thesis shows that aluminum porous board can provide well noise reduction throughout all frequency ranges. In addition, aluminum porous board lined with multi-panel structure, through analysis on sound transmission loss, proved better effect than single-paneled aluminum porous board in noise reducing. The difference is about 5dB in low frequency and more than 10dB in high frequency.
The studying of material mechanical properties of aluminum porous board is also included in the thesis, According to the database obtained in this thesis, acoustic properties and material properties of aluminum porous board can be worked out to estimate suitable aluminum porous board applied in noise reduction. The analysis suggests if higher noise reduction is required, one needs to thicken the aluminum porous board, or to increase density and Young`s modulus of the material, which results improvement in high frequency; but no effect in low frequency. Moreover, increasing material thickness and density will shift the resonance frequency to lower value; in addition, increasing Young`s modulus will move the resonance frequency to higher value.
| Identifer | oai:union.ndltd.org:NSYSU/oai:NSYSU:etd-0711100-101447 |
| Date | 11 July 2000 |
| Creators | Chung, Yao-Jen |
| Contributors | M-S Lee, Ruey-Chang Wei, S-K Yang, J-H Kuang |
| Publisher | NSYSU |
| Source Sets | NSYSU Electronic Thesis and Dissertation Archive |
| Language | Cholon |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lib.nsysu.edu.tw/ETD-db/ETD-search/view_etd?URN=etd-0711100-101447 |
| Rights | unrestricted, Copyright information available at source archive |
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