Research On Vibration And Noise Of Armored Vehicle's Gearbox

Tank and armored vehicles are the main weapons of the ground war,which bear the role of assault and fire support in combat.With the development of armored vehicle in the direction of high speed,high power,high power density and high reliability,more and more attention has been paid to the problem of vibration and noise.Gearbox is an important part of the power transmission system of armored vehicles,and it is one of the main noise sources.In this paper,a certain type of armored vehicle gearbox is used as the research object to study the vibration and noise of the gearbox using the method of multi-body dynamics,finite element,boundary element,etc.The followings are the main research work of this paper.1)The engine torsional vibration excitation model was established using the gas pressure data of a certain type of 8-cylinder engine in Matlab.Considering time-varying meshing stiffness,time-varying meshing damping,backlash and other factors,the transmission gear multi-body system dynamics model was established in LMS Virtual.Lab Motion.The engine torsional vibration moment was the excitation in the model.The gear meshing force,gear meshing stiffness and the reaction force at the bearings were calculated.The gear meshing forces and reaction forces were analyzed in the frequency domain and the spectrum results are compared with engine harmonic frequencies and gear mesh frequencies.2)The structure of the gearbox was simplified in Pro/E.The finite element model of the box was established,and modal analysis was carried out to get the modal natural frequency and modal vibration information;the results of the multi-body dynamic simulation were the driving forces to the box.Using the modal superposition method,dynamic response analysis of the box was carried out in LMS virtual.Lab Noise&Vibration to get the vibration velocity information of the box.The structure-fluid model of box and air,oil was established to carry out coupled modal analysis.Based on coupled modes,dynamic response analysis was carried out to analyze the effect of the oil and cavity on the vibration of the box.3)By setting the vibration velocity of the points on the housing as the real boundary conditions,the sound pressure on the surfaces of the box and the field points,and the acoustic power of radiated noise curve were obtained by using the direct acoustic boundary element method.The effect of the oil and cavity on the radiation noise of the box was analyzed.4)The panel acoustic contribution analysis was conducted to determine the main panels of noise radiation.Respectively,based on the noise source and the propagation path,proposed optimization methods were introduced to reduce the vibration and noise of the gearbox,and the effect of corresponding vibration and noise reduction were compared.