碩士 / 國立海洋大學 / 造船工程學系 / 86 / Four important measures has been discussed for effectively
reducing the transmission of structure-borne noise onboard ships
in this thesis. They are the utilization of resilient mounts,
viscoelastic damping material, branch structure and fluid
radiation damping. The effectiveness of resilient mount
for the isolation of vibration and noise can be evaluated by the
four-pole parameters theory combining with the measurement of
mobility spectra. The effects of different kinds of
antivibration rubber in a sleeve type of resilient mount were
studied analytically and experimentally in this paper.
Noise attenuation effects of branch structure is analyzed by
elastic wave approach and compared the result with that by the
finite element method. In the elastic wave approach, the element
mobility matrices of finite beam and rectangular plate have been
derived. This approach has the advantage to reduce the number of
degrees of freedom in the analysis, especially in the higher
frequency range of structure-borne noise transmission.From the
results by analysis and measurement of a model structure, it has
been shown that the vibration reduction is 20~40 dB via the
mounts. Around more 5 dB reduction can be got by using the CFRP
damping strips. For branch structure of the case of two plates
joined in right angle, it can be able to make a 3~5 dB radiated
noise reduction. The radiation damping effect due to water which
contacting the structure can reduce 5~30 dB noise transmission
in structure. Contrarily, the contacted water has an adverse
effect to reduce the isolation effectiveness of the resilient
mounts. By experiment validation, the four-pole
parameters method can be used to predict the structure-borne
noise transmission of power flow.
| Identifer | oai:union.ndltd.org:TW/086NTOU1345002 |
| Date | January 1998 |
| Creators | Chen, Ping-Hsu, 陳炳旭 |
| Contributors | Wei-Hui Wang, 王偉輝 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 125 |
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