Experimental research on the characteristics of ship propulsion system under dynamic excitations

With the development of the size of the ships, the power and size parameters of propulsion increase apparently, which leads the problems caused by dynamic excitations, such as hull deformation and stern excitations, are increasingly prominent. Based on the characteristics of dynamic excitations for the ship propulsion system in navigation, a reasonable experiment plan is designed, considering the present experimental conditions. In this experiment, the hull deformation excitations are seen as the vertical and transversal loads on the intermediate bearings, while vertical, transversal, longitudinal excitations on the stern bearings at the end of the shaft are used to simulate vertical and transversal excitation caused by propeller rotating and the axial trust excitation from the propeller, respectively. The dynamic responses of propulsion shaft in transversal and vertical direction are gained by the experimental system. The effects of amplitudes, directions, frequencies of these dynamic excitations and shaft rotation speed on the characteristics of shaft vibration are studied. The vibration performances and coupling effects of ship propulsion system under hull deformation and stern dynamic excitations are discussed.