A Research On Sound Insulation Performance Of Body Sheet Metal With Rib Reinforcement

Nowadays,people are turning to the comprehensive requirements for driving performance and comfort while only improving the driving performance of automobiles cannot meet their needs.With the development of the market,customers are paying more and more attention to the quality of automobiles.The ribbed composite structures are widely used in the automotive field due to the advantages of light weight,high rigidity and good impact resistance.However,the ribbed composite structures are susceptible to bending deformation when they are subjected to external excitation and vibration,and noise problems are generated,which affect the NVH performance of the automobile,and then affect the comfort of people's ride.Firstly,this paper combines the relevant data at home and abroad to have much knowledge of the research objects and research methods of the ribbed composite structure.The research object of the ribbed composite structure basically follows from simple to complex,regular to irregular,and one-dimensional to multi-dimensional.The research methods mainly include deterministic methods and non-deterministic methods.Secondly,six different schemes of metal sheet with rib reinforcement(MSRR)are designed and manufactured in this paper,and the considering factors include the height of the rib reinforcement,the width of the rib reinforcement and holes in the rib reinforcement as well as the number of the rib reinforcement.Then,the sound insulation performance for these MSRRs were tested in the Reverberation-Anechoic chamber.The experimental results show that the width of the rib reinforcement increases,and the sound transmission loss increases;the holes of the rib reinforcement reduce the sound insulation;the number of the rib reinforcement increases,which result in the peak value and valley value of the sound insulation curve increase.Then,with the MSRR as the carrier,six different schemes of the MSRR with damping material were designed.The measurement results show that the proportion of the damping material area pasted at the MSRR increases and the sound transmission loss increases.The damping material is pasted at the MSRR,which can effectively reduce the peak or valley val-ue for the sound insulation curve of the MSRR and improve the valley value of the sound insulation curve.After that,based on the hybrid FE-SEA method theory,a calculation model for the sound insulation of the MSRR was established and validated by experiment.Moreover,the sound insulation of different structures for the MSRR was calculated and compared with the experimental data.It is verified that the method can be used as a general model to simulate the sound transmission loss for the structure of the MSRR.Finally,the sound insulation performance of a dash panel for a certain type of car was investigated in the thesis.The sound insulation performance of the dash panel was predicted and analyzed by two configurations:(a)the mainstream airborne simulation method and(b)another simulation method considering the structure of the rib reinforcement.The verification results show that the calculation results of the sound insulation for the dash panel is in good agreement with the experiments.The simulation method can be used to guide the prediction analysis of the sound insulation performance for the dash panel of the vehicle.The research conclusions have important guiding significance for the sound insulation performance of the MSRRs.At the same time,the experimental methods and simulation approaches in this paper can also be used for the analysis of sound insulation characteristics of other acoustic structures.