Study On The Effect Of Hull Deformation On Shafting Alignment Of Fishing Vessels

The propulsion shafting of fishing vessel is not only the main propulsion unit,but also the core component of the ship power system.Its shafting alignment quality can directly affect the safety and reliability of normal navigation.Good alignment can ensure the normal operation of the propulsion system of fishing vessel under different external environment.After formulating the preliminary shafting design,the fishing vessel has to check and calculate the shafting due to gravity and operation conditions to ensure that the shafting works in a reasonable range under various working conditions.In the calculation of shafting alignment,the inclination will not only affect the support force of bearing,but also directly affect the running state of shafting.Unreasonable inclination will lead to the failure of propulsion unit.In this paper,the shafting alignment technology of a purse seine fishing vessel is studied.The main research contents and achievements are as follows:1.Finite element method is used for numerical calculation of fishing vessel shafting.Before detailed calculation,commercial software and simulation results are used to compare the simplified model.It is concluded that the support force of straight line alignment is approximately equal,so that the simplified model can be verified.2.Considering the influence of hull deformation on fishing vessel alignment,the displacement calculation of the two support positions is carried out,and the stern shaft is most affected by the calculation data.Then the modal calculation and analysis before and after the change of the stern axis are carried out,and the trend of the frequency change of the shafting caused by the change of the modeling stern axis is obtained.3.The change of bearing lift may lead to the change of lubrication state of shafting,so the sliding friction analysis is carried out at the stern shaft.In the analysis process,the fatigue and wear of bearing are calculated and processed by simple numerical calculation,and the Miller method is used to predict simply.At the same time,the possible reasons are analyzed and coped with.