Research On The Vibration And Noise Reduction Mechanism Of Ship Mesh Damped Water-lubricated Stern Bearing

The vibration and noise of the ship and other underwater vehicles will be caused by the operation of the shafting and the friction.In particular,the problem of vibration and noise of water lubricated stern bearing is especially serious.The porous structure is considered to be one of the ways to improve the vibration and noise reduction,some progress has been made in the high-speed railway carriage materials,concrete pavement,damper,foam metal materials,but the application in water lubricated stern tube bearing’s vibration and noise reduction is less.In order to study the influence of mesh structure on the water lubricated stern tube bearing vibration and noise,this paper defines the structural parameters and material parameters of the stern bearing.Static stiffness analysis,modal analysis and harmonic response analysis of the stern bearing and mesh damping stern bearing were carried out by ansys.And combined with the vibration and noise test of stern bearing,analyzed the influence of porous structure on stern bearing vibration and noise.The main research work and achievements are as follows:(1)The 3D model of stern bearing and mesh damping stern bearing were established.Simulation,analysis and comparison of static deformation and static stiffness of mesh damping stern bearing and stern bearing were carried out under the same boundary conditions and different external loads by ansys.Through the simulation we can see: after opening the axial mesh hole in the stern bearing plate,the static stiffness of the stern bearing will be slightly reduced but not much changed,compared with the stern bearing at the same order of magnitude.That is,the decrease of stern bearing stiffness of the stern bearing can be ignored when the mesh structure under the diameter of no more than 4 mm.(2)Modal analysis was carried out on the stern bearing and mesh damping stern bearing.Mesh damping stern bearings compared with stern bearing,natural frequency will be reduced,and with the increase of the mesh diameter,it’s natural frequency is smaller.When the mesh diameter is 4 mm,with the increase of the number of mesh,the natural frequency is smaller.(3)On the basis of modal analysis,the harmonic response analysis was carried out on the stern bearing and mesh damping stern bearing,it can be see that the amplitude of the vibration displacement of the stern bearing is greater than the mesh damping stern bearing.And the amplitude of the vibration displacement decreases with the increase of the diameter of the mesh diameter.When the diameter of the mesh is 4 mm,the amplitude of the vibration displacement of the stern bearing is particularly obvious,and only a weak amplitude of the vibration displacement appears.This shows that with the same confining boundary conditions and load conditions,the vibration displacement amplitude of the water lubricated rubber stern bearing is smaller with the increase of the diameter of the mesh.(4)The static load characteristic test of water lubricated rubber stern bearing was carried out.The error of the test result and the simulation analysis result is less than 15%.The stern bearing vibration and noise test was carried out,under the condition of the test shaft speed in 40~200 r/min,the loading pressure of 0.2 0.3 and 0.4 MPa,it shows that porous structure can effectively reduce the amplitude of vibration caused by shafting operation,so as to reduce the noise generated by the friction vibration of stern bearing.