Structural-Acoustic Coupling Noise Characteristic Analysis And Optimization For Trimmed Body Of SUV

With improving requirements to the comfort of passenger vehicle,the NVH(Noise,Vibration,Harshness)issues received more attention of automobile manufacture rs,vehicle NVH performance has become one of the important symbol to measure the level of automobile.Based on a SUV vehicle as the research object,combining with the school enterprise cooperation project ‘a certain vehicle development project’,this paper studied on the sound and solid coupling noise characteristics of a SUV trimmed body.Based on the CAE simulation analysis technology and the validation of the test method,the vibration and noise level of the vehicle is predicted and analyzed.And then,we improved the body structure optimization.Firstly,the finite element model of BIW is established and the free mode is calculated.The analysis results show that the BIP structure has good dynamic characteristics,and it can avoid the engine idling wel.At the same time,the effectiveness of the model is verified by a white body modal test.Then,on this basis,the finite element model of the trimmed body is established.The model is used to extract the spatial cavity of the vehicle and calculate the free mode of the cavity to understand of the car acoustic characteristics preliminarily.Then,the sound and solid coupling model was established by the combining node around the boundary,which was formed by trimmed body structure model and cavity model.The sound pressure on the vehicle noise response point position will be obtained by the modal frequency response analysis method when a certain frequency range of unit excitation was exerted into the key installation point on the body.The sound pressure value is compared with the target value of the enterprise.It was found that the noise peak under the excitation of the left rear spring seat and the left rear shock absorber exceeded the target value.The accuracy of the simulation model is verified by real vehicle test,whose results show that the simulation and the experiment are nearly accordant,and the simulation model can be used to improve the body structure.Finally,according to the contribution analysis results,the paper puts forward the method to improve the thickness of the plate and the key position of the rear floor to reduce the noise of the vehicle.The vehicle body improvement scheme is applied to the simulation model to calculate the interior noise response,and the results show that the noise reduction scheme is effective.