It is effective to reduce vibration of a ship stern that vibration isolation on the dominant transmission path. The transmission paths model of a ship stern was built based on the ship stern structure. When excited longitudinally at the propeller, the transmission paths of stern is analyzed and sequenced by the transmission paths analysis method. The results show that the palace at bearing basement is a dominant path when excited longitudinally. Thus, when the dominant transmission path is identified, passive control or structural modifications on the path can attenuate vibration levels effectively. The numerical results explain that the acoustic radiations of the structure can reduced by modification of the bearings rigidities and of bearing basement configuration.
The Gaborexpansionbased time frequency filtering is employed to process measured signals before conducting parameter identification. With Gabor expansion, the local characteristics of a signal can be shown in the timefrequency domain, according to which the properties of responses are acquired and the response signals can be filtered by elimination or interception. This technique can be applied to both stationary and nonstationary signals. Attribute to this technique, more information about the signals and systems can be gained, such as the distribution of natural frequencies, energy assemble functions, quantity of properties contents in each channel.
