| Ship shafting system is an important part of the ship power plant and the good quality of shafting alignment is a basic condition of the ship long-term smooth sailing. At this stage, the rational ship shafting alignment is already mature. The calculation of the rational alignment is usually carried out with the finite element method. There have been many large-scale general-purpose finite element softwares in engineering field in recent years, and it is convenient for solving those problems especially with complex geometrical shape, forces and boundary conditions. However, when alignment calculation of ship shafting is worked out in theory, dynamic factors influence on the performance of the shafting are not considered, therefore it is very necessary to monitor the alignment state of ship shafting system.Firstly, we used ANSYS software to establish the ship shafting rational alignment model which considered the actual crankshaft based on a large number of papers at home and abroad and the conditions of the laboratory. We improved the traditional finite element model of the ship shafting system, created the crankshaft mathematical model according to the actual shape, and calculated the improved model. Using the model, we obtained the bearing loads and shafting deflection, rotation angle, shear and bending moment under the condition of rational alignment of shafting system.Secondly, in order to monitor the alignment state of ship shafting, we collected shafting displacement signals where the shaft was supported by bearing in horizontal and vertical direction with eddy current displacement sensor. Axis orbit was synthesized and purified with wavelet packet and the result was satisfied. It is showed that the axis orbit can reveal the change of the shafting state to some extent when compared axis orbits in different positions on shafting system.Finally, we extracted the vertical component of the axis orbit and calculated the dynamic loads of the intermediate bearings and tail bearing considered the shafting loads influence coefficient of the ship shafting bench, and then obtained the bearing loads law varying with time, furthermore the value of bearing loads is within the limit of standard. |
