Research On Propulsion Shafting Alignment Technology Based On Stern Hull Deformation Coupling Effect

The shafting alignment is a very important part of the shafting design and installation. The quality of shafting alignment has an important impact to the running of shafting and main engine, as well as to reduce hull vibration. The hull deformation can cause each of the bearings change in the vertical direction and then affect the quality of the shaft alignment. In order to save costs and reduce the shipbuilding time, some shipyards want to install the shafting in the dock, and also need to know the relative deformation between the ships floating in the dock and into the water after the state. So studying about the affect between hull deformation and shaft alignment is very meaningful.In this paper, a large bulk carrier is taken as the research object, the method of combining theoretical research and practical application is using to research the effect of shaft alignment which comes from hull deformation, bearing clearance and propeller hydrodynamic. According to the research objectives, the main contents of this paper are as follows:1. Overview the reason of hull deformation and point out that hull longitudinal bending deformation is the greatest impact on shaft alignment.2. Summary the finite element method of hull structural deformation calculation and take92500DWT bulk carriers for instance, to establish including a finite element model of the cargo hold before the end of the engine room, the superstructure and the engine room, then calculate and analysis the hull deformation of its sitting pier, floating, ballast and full load condition.3. Use the hull deformation data of92500DWT bulk carriers in various conditions to study the the impact which caused by hull deformation of shafting alignment, and point out that full load condition is the greatest impact on shaft alignment.4. Bearing clearance and propeller hydrodynamic also affect shaft alignment; take the shaft of92500DWT bulk carriers for instance, calculate the shaft alignment considering the bearing clearance and propeller hydrodynamic.5. Introduce regular alignment technology and point out that the difficulty of alignment technology in dock is to obtain the relative deformation, and according to the regular alignment technology and the hull deformation data, discuss the alignment technology in dock of92500DWT bulk carriers.