Application Of Acoustic Metamaterials And Damping Materials In Vibration And Noise Reduction Of Marine Gearbox

Marine gearbox plays a very important role in warships,and its performance directly affects the normal operation of the warship system.With the development of science and technology,gearbox is developing in the direction of heavy load,light weight and high efficiency.Since the internal meshing of the gearbox generates vibration during the operation of the gearbox,if the natural frequency of the gearbox is close to or coincident with the frequency of the gear meshing,the two diffeerent forms of vibration will resonate with each other,seriously affecting the normal operation of the machine.Therefore,it is very necessary to carry out research on gearbox vibration and noise reductionIn this paper,the vibration characteristics of the gearbox are studied,the internal excitation of the gear pair is simulated,the meshing resonance frequency of the gearbox and the internal gear is obtained,and the natural frequency of the box is changed to keep it away from the resonance frequency.In this paper,two methods are selected to reduce the vibration of the gearbox,and the frequency before and after the vibration reduction is compared,and the structure-sound coupling method is studied.The main work of this paper includesFirstly,based on the principle of dynamic vibration absorber,the acoustic metamaterial vibration reduction method is proposed,and the structural parameters of acoustic metamaterials of two configurations are discussed and the rules are summarized.The metamaterial laying is placed at the maximum resonance displacement of the gearbox,and the optimal laying area is determined by using the dichotomy principle.The effectiveness of this method is verified by comparing the vibration frequencies before and after laying acoustic metamaterials.Secondly,based on the topological optimization SIM P principle,with the reduction of gear box mass as the optimization goal and the maximum displacement as the constraint condition,the redundant materials are eliminated and the damping layer established with rubber Mooney-Rivlin constitutive model as the reference is laid.By means of dynamic response simulation,the vibration frequency variation rules of gear boxes with different damping materials are compared,and the effectiveness of vibration suppression based on topology optimization theory and coupling damping materials is verified.Finally,based on the direct boundary element method,the external sound field of the gearbox is established in the acoustic software Virtual.lab.Five acoustic measuring points are randomly selected in the sound field outside the marine gearbox using acoustic metamaterials and damping material to simulate the radiation noise.Dynamic response results.The results show that both damping methods can reduce the radiation noise of the gearbox.