| The armor vehicle has strong vibration and noise, while it works in Special operatingenvironments and requires high power and rotational speed. As a key component of thepower drive unit, the noise of gearbox is one of the main sources of noise the armedvehicles. Therefore, how to control the radiation noise of gearbox is an important researchfield. This paper mainly analysis the vibration and noise of the gearbox. The integratedapplication of multi-body dynamics, finite element, and boundary element method are usedhere to solve this problem. Then this paper proposes a corresponding improvementprogram.Firstly, the generation and propagation mechanisms of the gearbox noise were beanalyzed. In many kinds of dynamic excitations that cause gearbox noise, this paper mainlydiscussed the gear mesh excitation.Considering the effects of time-varying stiffness andbacklash of the gear system,the multi-body dynamics model of the gearbox with theconstraints, drive, load and other conditions has been built in LMS Virtual.Lab software.Based on model above, the dynamic excitation of the gears on time domain and itsdistribution on frequency domain were obtained.This paper also obtain the results of themulti-body dynamic simulation of the gear shaft.Then, by establishing the finite element model of the box and modal analysis, thenatural frequency and mode shape were obtained. Compared to the results of the test data,the simulation results proved to be true and credible. The results of the multi-body dynamicsimulation of the gear shaft will be the driving forces on the housing as incentive loads ofmode superposition method to calculate the force response of the box.By setting the displacement of the points on the housing as the real boundaryconditions, we use the direct acoustic boundary element method to obtain the soundpressure, the field point radiated noise and so on. Then acoustic-vibration finite elementmode is also established by comparing the results between coupling and uncouplingconditions. The influence of the acoustic-vibration interaction role to the external noiseradiation of the gearbox was obtained too. Then the fluid-structure interaction finiteelement mode of the gearbox with certain highly lubricant oil was also established. Theexternal radiation noise of the model was computed with three different height of oil, whichindicates the influences to the vibration and noise of the gearbox with the variation of oil level.According to the simulation results, a proposed changing box structure as optimizationmeasures to reduce the gearbox of vibration and noise is introduced.After introduce of ridsand sound absorbing materials,the pattern of sound pressure of gearbox have been analyzedin the last part of this paper. |
