NVH Characteristic Analysis Of Mini Bus Subjected To Different Road Excitations

In modern automobile productions, NVH (Noise, Vibration and Harshness) characteristic has become an important indicator of evaluating automobile comfort, therefore it has very important practical significance to analyze and improve NVH performance.Based on a mini bus as the object, combining with finite element and multi body dynamics simulation method, the NVH characteristic was analyzed and optimized subjected to different road excitations. Firstly, four wheel spatial B, C grade road spectra were generated by MATLAB. Secondly, whole vehicle flexible model was built by MSC.ADAMS, dynamic analysis was done and the excitation force loads were obtained in connecting point position of body and suspension, which served as the boundary condition of acoustic prediction. Then, the vehicle NVH characteristic was analyzed subjected to different road excitations by LMS Virtual.Lab and MSC.PATRAN/NASTRAN, and the acoustic characteristics of interior coupled acoustic field were predicted and evaluated. Finally, the interior noise factors were found through the body panel acoustic contribution analysis (PACA), and body structure was optimized in order to reduce interior noise and improve NVH performance.The research shows that road excitation energy is concentrated in the low frequency region within the scope of0～45Hz, and the sound pressure level (SPL) of the mini bus is a slightly higher subjected to C grade road excitation than B grade road excitation, besides, the focal regions which need acoustic treatment were found through PACA, on the basis, interior noise level was reduced by optimizing body panel thickness, which achieved better optimization effect.