A Research On The Effect Of Hull Static Stiffness On Vibration Performance Of Marine Shafting System

Ship propulsion shafting is an important component of the marine power plant, which vibration and performance is directly related to the viability of the ship power system. If Shaft design quality is poor, it will result in adverse shafting alignment and severe vibration, thus cause the body vibration, transmission system parts damaged, excessive bearing wear and even axis broken accidents, finally mechanical systems will abort normal operation. Hull stiffness is the hull ability of resisting the longitudinal bending deformation. In practical engineering applications, the value of hull stiffness related to the axial vibration model is only according to experience estimate, the results do not meet the actual requirements. Therefore, exploring and resolving the impact of the hull stiffness of shaft whirling vibration is particularly essential now.Looking up a large number of data in both at home and abroad, this paper which based on the hull stiffness on shaft vibration give a further research on the shaft vibration. At the same time, this paper consider the double bottom structure stiffness of the shaft in whirly vibration computing using of ANSYS software, and can reflect value of hull stiffness more accurately for shaft vibration.The main content of the paper summarized is as follows:(1) In the double bottom structure stiffness analysis, from hull structure of three-dimensional, with local double bottom structure as an example, create the double bottom structure model, the effects of the analysis of the selection include steel thickness, reinforcing rid space and side girder space of double bottom structure, the effects of the analysis of the selection. The analysis include the selection of calculation method of the double bottom, ANSYS finite element modeling and the specific calculation.(2) Physical modeling based on finite element software of whirling vibration of the ship shaft. Due to the structural stiffness values of the double bottom of the modeling process will be imported model, so the modeling methods for similar problems in this article on have certain reference significance.(3) On the base of fully consider the hull stiffness, this paper select a real ship shaft whirling vibration calculation, and compared with without regard to hull stiffness, analysis the shaft natural frequencies and mode shapes changes with the two cases, the analysis is reasonable and credible.(4) Finally, the research results and relevant problems are summarized and the work is looked far ahead into the future.