Analysis And Research On The Interior Structural Noise Of Tractor

The indoor noise of the vehicle is one of the important indexes for evaluating the comfort and performance of the vehicle,so the analysis and research of it has already infiltrated the whole development process.Based on the theory of the finite element and boundary element analysis,this paper took LX-754 large horsepower tractor as the research object,tested under different conditions of indoor noise,gave a series of research and analysis by using acoustic simulation software as Virtual.lab simulation analysis of and Optimization.Firstly,a 3D entity model of tractor structure can be built by CATIA software,and created the finite element model of the structure,the acoustic finite element,boundary element and boundary element sound-solid coupling model,which can be lead more structure modal analysis and acoustic modal analysis.Secondly,in three kinds of conditions: idle,hanging gear speed 2000rad/min,rated 2600rad/min,using NI(national instrument)acquisition equipment collected the sound pressure level of the noise beside the driver's ears,spectrum analysis on tractor cab noise signal can be made based on LabVIEW signalexpress signal analysis and processing platform.Donghua DH5922 signal acquisition test system can be applicated to test the cab four suspension set point of acceleration signal and take the measured signal into a frequency domain signal by a signal processor.The acceleration signal in the frequency domain can be took as acoustic boundary conditions,and the driver ear pressure can be calculated by Virtual.lab acoustic software and analyzed the tractor cab noise and vibration plate mainly from tractor ceiling,floor,seat,fenders and other plates.Again,based on the analysis results of the amount of cab sector contribution,the acoustic analysis of the optimizated model can be took by using coupled acoustic boundary element method;and then on the basis of the results of the spectrum analyses,tractor driving chamber of the entity structure can be optimized.The result is that optimizing frequency 63 Hz noise reached a peak 106.3dB and frequency 125 Hz noise reached a peak 103.5dB.When adding stiffener in the indoor floor or adding acoustic vibration isolation material in roof,fender,floor,low frequency noise peak down to the 94.78 dB.So it can decrease the indoor noise of the cab cab and improve the comfort for the driver.