Vibration Characteristics Analysis on Ship Propulsion System Taking Hull Deformations into Account

Original scientific paper Since an evident tendency of the shipbuilding is that the sizes of ships are larger and larger, the dynamic interactions between the propulsion system and ship hull in large scale ships are much severer than those of the small sized ships. Ship hull deformations caused by the action of heavy excited wave forces could affect the vibration characteristics of the propulsion system through bearings mounted on the ships. The reliability and safety of the propulsion system would be in a dangerous condition. In this paper, a novel simplified hull-propulsion system mathematical model is presented to investigate the dynamic interactions between the ship propulsion and hull deformations. Ship hull deformations were obtained as the excited forces under different sea conditions by numerical analysis. Then, based on the gained hull deformations, variable parameters involving stiffness of support bearings are considered on the vibration characteristics of propulsion. The findings of this work may provide a new insight to keep economy and security in both shipbuilding and ship operation fields.