Optimization And Analysis Of Interior Noise And Vibration For A SRV

The environmental problem of vehicle’s noise and vibration has been raised more attention than before, also more and more auto companies and institutions are trying their best to do research to vehicle’s NVH with the development of the World’s economics and technology. Vehicle’s NVH means the level of vibration and noise under different conditions and this performance would be related to consumers’ satisfaction and auto companies’ sales directly.In the paper, with a SRV as an example, the structural finite element model was established in the first step and its accuracy was verified by correlation analysis of the mathematical and experimental model. On this basis a coupled acoustic boundary element model was built and the model’s torsional and bending’s stiffness was analyzed. The acceleration signals at cab mounting and the respond signals of interior noise were measured under 60km/h driving condition with road test. According to the analysis results of sound pressure response, applying the excitation signals to the coupled boundary element model to make the low frequency(between 20Hz and 200Hz) response analysis. Finally, the panel contribution and the modal participation factor analysis were implemented, by which the panels and modes that have the largest contribution to the peak noise were identified.After getting the panels that have large impact to the noise peak, the vehicle’s some places whose stiffness are weak were modified by applying sensitivity analysis and Topology optimization. In the process of the sensitivity analysis, with the nodes’ vibration velocities as the objective and the range of the panels’ thickness and the whole vehicle’s quality as the constraint conditions, the changes of panels’ thickness were got, and on this basis the thickness of panels were optimized concerned the actual technological conditions. In the process of Topology optimization, with improving the flexibility of the shell units as the objective and the relative density of each unit in the optimized area as the design variable, the changes of panels’ stiffness were got,and on this basis the stiffness of panels were improved concerned the actual engineering experience. Finally, the optimized and the original acoustic pressure response curves were compared, and the optimized results were evaluated. This paper provides a reference for vehicles’ low noise design and has practical engineering value.