Vehicle NVH Optimization Based On Interactive Verification Of Test And Simulation

The advancement of science and technology and the improvement of people’s quality of life have brought car comfort into the eyes of consumers.Automotive comfort is currently evaluated using the "NVH" feature.Its pros and cons are a very important consideration for car consumers to purchase the car.According to statistics,NVH is related to about one-third of customers’ dissatisfaction and about one-fifth of after-sales service.On the other hand,external noise generated by automobiles has become an important part of urban noise.Today,as people’s awareness of environmental protection continues to increase,the government and the community are paying more and more attention to noise.Therefore,research on the performance of automotive NVH is very important.Various OEMs and research institutes are also increasingly researching the performance of automotive NVH.With the continuous development of finite element technology and the automotive market demand for short-cycle,low-cost vehicle development,it is of great significance to use simulation technology to improve the performance of automotive NVH.Based on finite element technology and acoustic-solid coupling technology,this paper takes the MPV model of a company as an example to carry out the following research:Firstly,the finite element method is used to establish the TrimBody model of the target model.The free mode analysis is carried out,and the main modal pattern and typical modal frequency are obtained,and the dynamic characteristics are analyzed.The acoustic cavity finite element model is built,and then the analysis is carried out to obtain the first six-order modal natural frequency and vibration mode,and the distribution of sound pressure in the vehicle is analyzed to lay the foundation for subsequent analysis.Secondly,the target model BIW modal analysis and considering the influence in TrimBody,vibration analysis and noise transmission analysis,acoustic-solid coupling analysis,road noise analysis,pointing the target value to indicate the optimization direction.Then optimize the body mode,and then consider the influence in the TrimBody,using topology optimization to propose the direction of the board optimization.Through the analysis of the plate contribution amount,the upper end of the left suspension mounting area is connected with the ECU mounting plate,the lower end of the left suspension mounting area and the left longitudinal beam are added by the plate,and the struts are added behind the left suspension mounting area.The left longitudinal beam is connected with three optimization schemes for the transfer function scheme.Two optimization schemes for adding the roof longitudinal beam and optimizing the front diaphragm structure are proposed for the interior noise function by the node contribution analysis.The optimization scheme has been verified by simulation,and the performance of the vehicle NVH has been improved,which provides an important reference for real vehicle NVH optimization.Finally,the real vehicle is tested and verified,modified and compared with the original noise.Using a test sample vehicle as the research object,a series of tests and analysis of vibration noise were carried out on the prototype.The main test items included the chassis attachment point to the NTF test in the vehicle,and the vehicle interior noise test was carried out in the rough road test environment.And the comparison between the test of the interior noise and the original car after the modification of the top cover.The test results show that the simulation results are consistent with the actual results,and the reforming scheme can effectively improve the roaring sound of the car at 50-60 Hz.