The Prediction of Structure-Borne Sound Transmission and the Radiated Underwater Sound Power at Medium Frequency

• Main Authors: Liou, Shang-Wei, 劉翔瑋
• Other Authors: Shyu Rong-Juin
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/97548067917747883588

碩士 === 國立海洋大學 === 造船工程學系 === 84 === The predictions of low frequency ship structure vibration are usually done by finite element method . For higher frequency range of vibration ,in the audible range of human ears , is termed as structural borne sound . And its predictions are usually done by energy method. In this frequency range , modal density is higher . For ship structure, the frequency range can be predicted by is abover 2 KHz. Whereas the upper frequency limit can be predicted by finite element method is around 100 to 200 Hz for ship structures. Therefore , in the frequency range from 200 to 2KHz , a prediction model is needed . In this study , the combination of energy method and finite element method will be used to predict vibration in these frequency range. The finite element method will be used first to determine the input power and coupling loss factor for the energy mode . Then , the prediction will be made by energy method. The prediction will be compared with the actual measurement from a model ship structure to improve the accuracy of the prediction.