NUMERICAL AND EXPERIMENTAL STUDY ON THE VIBRO- ACOUSTIC CHARACTERISTICS OF COUPLED PROPEL- LER-SHAFT-HULL STRUCTURES

To investigate the vibration and sound radiation characteristics of the propeller-shaft-hull coupled structure, numerical models are established and a corresponding large-scale underwater experiment is designed and carried out. The hull vibration modes, excited by the force transmitting via the propeller-shaft system, and the radiated sound field due to the vibrating hull are measured by the acceleration sensor and the hydrophone, respectively. The results of the tests are compared with those obtained by the coupled finite element/boundary element model to verify the numerical simulation results. The longitudinal and transversal vibroacoustic coupling characteristics of the hull are analyzed by designing the nonhomogeneous mass and stiffness distribution on the hull, and different supporting structures of the shaft. Moreover, the relations between acoustic radiation of the hull and vibration modes of the propeller-shaft-hull structures are revealed by the transfer mechanism of the excitation from the propeller-shaft system to the hull.