Design of vibration reducer for thrust bearing of marine shaft

of marine propulsion shafting system may bring serious problems and many efforts have been performed to mitigate theses vibrations. Propeller oscillations due to the small variations of thrust, when the propeller blades rotate through the non-uniform wake, result in the longitudinal vibrations in the propulsion shafting system. These oscillations can be transmitted to the hull through the thrust bearing of the vessel. In this study, the propulsion shafting system is modeled with the decomposition of FRF method. The comparison between the numerical solution of system in MATLAB Simulink software, and the decomposition of FRF method; shows that the numerical solution has less 4 percent error. In order to decrease the transmitted vibrations to the hull, Goodwin Resonance Changer (RC) is utilized. An optimization method is used to optimize the RC’s stiffness, damping and mass coefficients . The results show that if the appropriate coefficients are selected, the transmitted vibrations can be reduced up to 99 percent in the hull.