碩士 / 國立臺灣海洋大學 / 系統工程暨造船學系 / 106 / In this research, the level of noise and vibration of the engine room, steering gear room and Tally office of a 2800TEU container ship were investigated by on-site measurements which include the utilization of accelerometers, microphones and acoustic cameras. Additionally, the estimation procedure of cabin noise is established, and the results of the measurement and analysis show the same trend.
First, taking the acoustic camera is used to find the locations having maximum noise, and then the accelerometers and microphones measures the signal during the different conditions. In the signal processing, the author plots the spectrogram and one third octave band by using short-time Fourier transform and time-averaging approach in order to reduce the noise effect. There are two following results found by this research: One, during stable navigation the vertical vibration frequency is same as the noise frequency, and the frequency of propeller and the largest engine excitation force and its harmonic frequency often appear in the spectrogram’s peaks in cabin noise. Another, the spectral distribution of cabin noise is mainly below 250 Hz, and the maximum sound pressure level usually happens at the center of the plate.
Apart from on-site measurements, simulations of simple conditions are carried out numerically find the vertical vibration frequency of the plate is found to compare favorably with the peak frequency obtained by noise; however, there is a significant amount of deviation when comparing the amplitudes. Because of the values of noise contribution caused by the different vibration modes are different. For the whole container ship, numerically, the noise level under different excitation forces is carried out by simulating the acoustic field in the cabins; the excitation forces are available from the finite element results provided by the shipyard. The result of the analysis shows that rooms on the higher floor having the higher noise level, and also the rooms near the center of the superstructure.
| Identifer | oai:union.ndltd.org:TW/106NTOU5345003 |
| Date | January 2018 |
| Creators | Chen, Yan-Cheng, 陳彥棖 |
| Contributors | Chiu, Jinn-Tong, Hung, Chen-Far, 邱進東, 洪振發 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 114 |
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