Research On Vibro-acoustic Behavior Of A Cabin Model With Floating-raft System

Study on the vibro-acoustic performance of a cabin model with floating-raft system is of significance in naval engineering. Therefore, the vibration isolation performance of a self-designed cabin model with floating-raft system is studied in full spectrum in this paper. Besides, the low frequency acoustic radiation of the model is also considered, in view of the characteristics of slow attenuation and far radiation for low frequency noise. Firstly, the background and development of the floating-raft system is summarized based on the review of a great number of references and data. Meanwhile, the isolation system modeling methods and the key issues in research are presented.Secondly, the vibration isolation performance in full spectrum of the floating-raft system is studied, with the vibration acceleration level at the base taken as the evaluation criteria. Different numerical methods are adopted for different frequencies. The finite element method (FEM) and the statistical energy analysis (SEA) are used respectively for low-frequency and high- frequency. Particularly, the intermediate frequency, which is most difficult to solve in the past, is resolved by the hybrid method (FE-SEA) based on software VA One. Further more, the influences of system parameters (such as stiffness and damping of vibration isolator as well as stiffness of raft and base etc.) on the entire system performance are discussed.Finally, the interaction between the shell and fluid is taken into consideration with the virtual fluid mass analysis based on MSC.Nastran. And the underwater acoustic radiation of a cabin with floating-raft at some specified depth is studied by the combination of FEM and BEM. Moreover, the influence of the isolation system parameters on the acoustic characteristics of the entire system is discussed.