Influence Of Shafting Installation Error On The Performance Of Shafting

In recent years,the safety and reliability of ship navigation and the problem of the quality of shafting installation has been widely concerned.The installation process of shaft system involving a wide range of consideration is complex,and the installation error is very easy to appear.The installation quality for the shafts is often the main cause of accidents such as shaft breakage,drop oars and bearing heating and so on.So the quality controls for the whole process of the shaft installation are necessary to ensure the installation accuracy for the proper operation of the shaft system.In order to investigate the influence of installation error on the shafting performance,this paper summarized the causes of the errors in the actual installation process of shafting,and analyzed the influence of some typical installation errors on the performance of shafting system taking 8530 TEU container ship as the research object.The main research contents of this paper are as follows:(1)The installation error of the main engine was analyzed.The finite element analysis model of the ship shaft was established,and the shafting static calibration was calculated by changing the displacement of the main engine.It is concluded that the load on the middle bearing increases linearly with the increase of the mounting error of the main engine base,and the farther away from the host side,the slower the load on the bearing increases.(2)The positioning error of middle bearing in the course of installation was investigated.Based on the calculation in the marine shafting alignment calculation software,it suggests that the load on each bearing varies linearly with the increase of radial displacement of the middle bearing when the radial positioning error exists in the middle bearing,and the load on the bearing differs when the shift of the middle bearing is changed.(3)The stern shaft of the ship shaft was set as the research object,and the influence of the bore error of stern tube on the shaft performance was analyzed.The boring error of shaft was simulated with the finite element software,through which the static calibration of shaft was calculated.It is found that the boring error has the greatest influence on the load on the stern tube bearing and the nearest middle bearing from tail shaft,and the load on the rear tube bearing and the nearest middle bearing form tail shaft increases with the increases of the boring error,while the load on the stern tube bearing decreases gradually.(4)The influence of ambient temperature on the installation quality of shaft was studied,and the relationship between temperature and the thermal expansion of the middle bearing was established,through which the static calculation was carried out.It is concluded that the displacement of the middle bearing increases gradually with the increase of the temperature difference between the ambient temperature and the working temperature,and accordingly the load on each bearing is changing linearly.