Research Of The Design Method Of The Vibration Isolation System Based On Elastic Base

When the submarine is crewing in the low speed, the main noise is from the running machine in the submarine. It occupys about 70% of the total radiation noise. The raft isolation system now is wildly used in the modern submarines to control the vibration from the running machine. It uses the mid mass and the stiffness of the isolation to get the high isolation efficiency. But even so, as the base is elastic and the natural frequecies of the hull are quite low, the resonance of the hull structure still can be excited and will influence the efficiency.To solve this problem, adding a structrue between the base and the low-layer isolation is presented, and the structure can control the transmission character from the running machine to the hull, so that the frequecy of the running machine can be different from the hull natural frequency.The Four Pole Parameter Method is used to build the model of the double-deck isolation system and also the numerical simulation of the system is done. The influence of the m-c-k impedance changer, the plate-nod impedance changer,the periodical structure impedance changer and the value of the m-c-k impedance changer on the transmission properties of the system is investigate. Furthermore, the GA optimization method based on the sensitive analysis is used to optimize the values of m-c-k impedance changer.Moreover the Frequecy Response Function coupling method is used to bulid the model of the complicated raft isolation system and the power transmission of the system and the influence of the m-c-k impedance changer on this system is researched. The application program of the Frequency Response Function Coupling Method(FRFCM) and the result of the experiment which is used to validate that the FRFCM is suitable to build the model of the raft isolation system.