The Research Of Nonlinear Vibration Analysis On Light Truck Cab Under Random Excitation

With the development of the automobile industry, more and more attention is paid to thecar ride comfort. The low frequency vibration and structure-borne noise of cab are main factorswhich affect the ride comfort of light truck. The cab of a light truck is chosen to be the researchobject in this paper. The vibration and acoustic coupling of cab which considers nonlinear ofcab suspension under random excitation are studied using the combining way of experimentand finite element simulation. Specific research work is as follows:(1)The structure, acoustic cavity and coupled finite element models of light truck’s cab areestablished. The modal analysis of those three FE model are conducted and the linkages ofthose three modal result is also analyzed which provides the judgment for following NVHsimulation analysis.(2)In Adams/Car, the vehicle dynamics model of a light truck is established and thedynamic simulation is done obtaining the acceleration, velocity, displacement informationunder the cab suspension which takes as down vibration excitation of rubber bearing forfollowing vibration analysis.(3)The mathematical models of rubber bearing under sinusoidal and random excitation areboth established through the dynamic performance experiment of a rubber bearing with typicalhysteresis nonlinearity. Using the mathematical model under random excitation, the conversionof cab suspensions’ up and down end signal is finished which provides the boundary conditionfor NVH simulation analysis.(4)The vibration analysis for structural model of cab is conducted. The acceleration anddisplacement response situation for concerned nodes is analyzed which find the frequency ofpeak vibration. The cloud images of displacement response are obtained in order to confirm thepanel which vibrates violently.(5)The acoustic analysis of acoustic-structure coupling model for cab is conducted. TheA-weighted sound pressure level curve of driver’s right ear and copilot’s left ear is extracted.The panels that contribute a lot to above two measure point’s sound pressure are found throughthe acoustic panel contribution analysis which provides a reference for improve the cab acousticenvironment in the future.