Dynamic Performance Analysis And Research On Marine Propulsion Shafting

Marine propulsion shafting is an important part of the marine power plant, and its reliability is the basic condition to pledge these systems to work safely, so people always pay great attention to the operating state. The propulsion shafting is subjected to the various dynamic factors when it is running, including hydro-oscillation force, ship hull' distortion, lubricative oil force and so on. For the naval ship, shock forces such as contactile explosion, underwater uncontactile explosion and the bounce-back force caused by weapon's emission may probably befallen to the propulsion shafting. If the design quality of the shafting is not good enough, it will bring about undesirable shafting alignment results and exquisite shafting vibration, sequentially bring about engine block vibration, transmission system components damage, bearings excessive wearing, shaft break and so on, which not only pauses the normal running of the mechanical system, but also endangers the life safety of the working personnel. So the shafting must be had a deep research so as to get an accurate design, manufacture, installation and checking.Firstly, this article has an analysis on influencing factor to shafting dynamic alignment calculation, and synoptically studying the influence 0:1 shafting alignment by bearing rigidity, stern bearing position, hull distorsion and shafting vibration.Secondly, in allusion to the coupled axial and torsion vibration and coupled bending and torsion vibration appearing frequently in the marine propulsion shafting, studying the mechanism of the coupled axial and torsion vibration, establishing the coupled axial and torsion vibration model, and solving the free vibration equation and forced vibration equation of coupled axial and torsion vibration, and deducing the vibration equation of the coupled bending and torsion vibration, and discussing the influence on torsion vibration by bending vibration and the influence on bending vibration by torsion vibration as well as the coupled bending and torsion vibration.Thirdly, expounding the basic flow to solve marine propulsion shafting vibration problems with FEM method in detail, and having an analysis on coupled axial and torsion vibration of a river-sea through bulk carrier propulsion shafting.Fourth, having model analysis and response prediction on a large practical marine propulsion shafting, and discussing the influence on shafting inherent characteristic by rotation softening effect and stress stiffening effect, and combining with rotor dynamics theory and finite element software, making a study of the natural frequency calculation of whirling vibration with gyroscopic effect taken unto account.Finally, making a summary of the research findings and the pertinent problems, and having a prospect on future work.