Study On Shafting Alignment Of 57300DWT Bulk Carrier

Over recent years, the shafting alignment has become more complicated due to increases of ships' size, shafting stiffness and hull flexibility, as consequence the conventional methods is not satisfied for requirement of shafting alignment. Therefore, it is necessary to study the calculating and measuring methods which are applicable to the shafting alignment of new ships.Based on references of a large number of papers ,several dynamic factors which affect the shafting alignment have been studied. a set of new alignment method was established by using existing calculating software. Considering several dynamic factors of shafting alignment to further study,conventional methods are improved and perfected,looking forward to satifying for requirement of shafing alignment.In this thesis, the shafting alignment techniques of shafting for domestic design,building and survey 57300DWT HANDYMAX bulk carrier has been studied as follows:Firstly, optimization calculation of bearing displacement has been carried out by using the linear programming method, and aligning calculation of ships propulsion shafting has been completed by using finite element and transfer matrix method. The feasibility of the calculation method was proved by practical measuring.Rational aligning calculation of propulsion shafting in cold and warm conditions,and confirm several fitting technics parameters include of temporary supports,sags and gaps between flanges.Secondly, based on the original shafting calculation model, ships' shafting alignment was calculated in considerations of hull girder deflection, propeller water dynamics and bearing stiffness factors. In fact that hull girder deflection could greatly affect the bearing load, so the calculation must take it into consideration. The vertical shear force produced by the propeller and lateral moment also have to been considered, and the effect on the parameters of ships shafting were calculated. Furthermore, the influence coefficient of bearing stiffness and parameters of ships shafting in warm conditions have been analyzed. Finally, comparing practical measuring results on working site with calculations, have close results, in accordance with criterion.Measuring crank deflections for per cylinder, in accordance with diesel works requirements and criterions.In the thesis studying measure methods of bearing load, include of strain gauge and jack-up method. In shafting alignment making use of strain gauge method, to check shafting bending stress and bearing reaction forces to meet the requirements of shafting alignment check. The numerical analysis of jack-up method in the whole process confirmed that the nearest bearing to jack could not be regarded as the measured bearing. Therefore, a new measured bearing positioning method was proposed, which provided reliable reference in the measuring of bearing load in future.