STUDY ON SHIP HULL VIBRATION AND RADIATED NOISE CONTROL CAUSED BY SHIP LATERAL

Main engine is an important excitation source to ship hull vibration and radiated noise. Vibration of main engine transfers to ship hull via coupling, propulsion shafting and its supporting bearings, causing radiated noise. Vibration isolation is applied to the main engine in some ships to alleviate this problem, resulting in reduction of supporting stiffness of main engine. However, ship can present variable forms of movement at sea owing to complex waves. Under ship lateral rolling, main engine and propulsion shafting will perform loss of movement synchronization due to different supporting stiffness, which adds additional excitation at coupling causing coupled vibration of shafting and ship hull. Based on the issues above, a coupled model of main engine, propulsion shafting, propeller and ship hull is established through FEM. Natural characteristics are analyzed by computation. Then ship lateral rolling is simulated to achieve the effect additional excitation makes to ship hull vibration and radiated noise. Finally, a control strategy is raised to realize depression of ship hull vibration and radiated noise.