Research On The Influence Of Bearings Lubrication To Shafting Vibration

The research of ship shafting vibration characteristics is an important part of ship vibration and noise field,and the support shaft stiffness have a great impact on shafting vibration characteristics.As the shafting is working,there will be a layer of dynamic pressure film,which is connected to the bearing structure as an elastic element,and then it will change the support stiffness,ultimately it will affect the vibration characteristic of the shafting.Therefore,the liquid film stiffness should be taken into consideration when the shafting vibration problems are studied.As the state of shafting alignment is modified,the shape of the axis,the support load and the tilt angle will change too.It will also change the bearing film stiffness.And finally it will also have an effect on shafting vibration.So,we also need to study the influence of shafting alignment to shaft vibration.The Reynolds equation is derived based on the fluid dynamics theory in this paper.Then the 2-D Reynolds equation is calculated by the finite difference method.And the film thickness and pressure distribution in the radial sliding bearing and thrust bearing are calculated respectively.Meanwhlie the effects of the ratio of length to diameter,speed,viscosity of the liquid on the film pressure are studied.Then the film stiffness and damping are calculated,and the influence of the load,tilt angle and viscosity to film stiffness and damping is discussed.The shafting simulation model is built in the ANSYS software,and the influence of axis bending to shafting vibration.Then the impact of rotating speed,alignment and bearing stiffness to vibration is studied.The results show that the effect of alignment to shafting vibration is complex.At last,a series of experiments of mode and response are done on the shafting test bench.The natural vibration properties of the shafting and bench is gained,so as to the response of the bearings.The results of the simulation and experiments are compared,which identifies the rationality of the emulation results.