Interior Noise Analysis And Structure Optimization Of A SUV

In order to improve the market competitiveness,the main automobile,s enterprises pay more and more attention to the research and development of vehicle NVH performance.As the vehicle body is the carrier of other main accessories,the modal performance and acoustic performance of the vehicle body directly affect the NVH performance of the vehicle.Based on the NVH performance research and development project of an SUV,this paper studies the body noise transfer function,taking the attachment point of mount and body as an example.In view of the problem that the z-direction noise transfer function of the rear mount has high peak sound pressure at 146 Hz,169Hz and 191 Hz,the body structure is optimized to achieve the effect of controlling the interior noise.The main contents are as follows:(1)The finite element model of BIP is established,and the simulation mode is compared with the test mode to verify the accuracy of the finite element model.In order to solve the problem that the torsional modal frequency of the rear end of the white car is not up to the standard,first,the strain energy analysis method is used,then the sensitivity analysis method is used to optimize the dimension of BIW panel thickness,improve the frequency of rear torsional mode,and improve the modal performance of BIW.(2)The finite element model of the cavity and the coupling finite element model of sound and structure are established.The mode shape and pressure distribution of the cavity mode are analyzed,and the influence of each mode on the interior noise of the vehicle is predicted.The noise transfer function of 9 paths of left,right and rear mount attachment points is analyzed.The results show that the peak sound pressure of Z-direction noise transfer function curve of rear mount is too high.(3)In view of the problem that the peak sound pressure of the rear mount Z-direction noise transfer function curve is too high at 146 Hz,169Hz and 191 Hz,the dynamicstiffness and the contribution of the plate at the attachment point of the rear mount are analyzed.The ceiling,left and right front floor with large contribution of the plate are determined as the optimized plate.The mode of TB body structure is analyzed.There is a local mode of roof at the peak frequency of sound pressure,which causes strong vibration of roof.Using the method of ERP node contribution analysis,the area of acoustic radiation energy concentration of ceiling,left and right front floor is determined as the specific location of panel optimization.(4)The topology optimization of damping is carried out in the area where the acoustic radiation energy is concentrated on the left and right front floors;In order to optimize the shape of the roof,the optimization scheme was designed to maximize the local modal natural frequency of the roof,then,reinforced structure is added to the ceiling;In order to strengthen the rigidity of the connection between the front windshield and the body and reduce the vibration of the front windshield,a reinforcing plate is added on both sides of the front window frame of the body.After the optimization of the vehicle body,the peak sound pressure of the z-direction noise transfer function curve of the rear mount is significantly reduced,which verifies the accuracy of the analysis method and optimization scheme of the vehicle interior noise in this paper.