Based On Analysis Of Car Panels Damping Noise Reduction And Control Research Of Interior Middle And High Frequency Noise

At present,the vehicle’s interior noise is seriously affects the comfort of drivers and passengers.If drivers and passengers are exposed to middle and high frequency noise environment for a long time,it will lead to dizziness,nausea and other symptoms to cause traffic accidents.Therefore,the effective reduction of middle and high frequency noise in the car is a guarantee for the safety of the car.The source of middle and high frequency noise in an automobile is generally the vibration and noise between the body panels and parts of the vehicle when the vehicle is running at high speed,and the noise source outside the vehicle is transmitted to the vehicle through the air through the body surface.Is to reduce the interior noise,just by adding the acoustic materials within the body surface,(sound insulation,sound-absorbing cotton pad),noise barrier,but the actual engineering experience,found that only use acoustic material can’t effectively reduce the interior noise,Therefore,according to this situation,for the structural vibration noise of the body plate in the range of intermediate frequency,and the middle and high frequency noise transmitted from the outside noise to the inside of the car,using damping materials and acoustic absorption material under effective control,combining the concrete research content is as follows.For vibration radiation noise test of without damping steel plates.Two kinds of models FE-SEA and SEA model were established,and the accuracy of the model was verified by acoustic radiation simulation and comparative test.Moreover,the vibration velocity distribution on the surface of the steel plate is simulated,and the response region of the vibration velocity is obtained,and the radiation noise when the damping coverage is complete and the damping distribution coverage is compared,which verifies that the radiation noise of the vibration of the plate is better than the fully damped vibration in the middle frequency band when the damping coverage is reduced.Establish FE-SEA hybrid model of car floor and front wall,on the floor and front wall structure vibration radiation noise of intermediate frequency scope,and by simulating the surface velocity distribution.Moreover,the effectiveness of the steel plate with damping distribution was applied to the floor and front wall verify that the structural noise value in the middle frequency band decreased by 6 to10 d B after the damping distribution in the floor and front wall.Finally,sound absorption and insulation materials are added on the basis of damping to verify that damping can not only reduce the vibration radiated noise in the intermediate frequency,but also increase the sound insulation by about 3 d B in the high frequency band.Establish vehicle’s SEA model.SEA method was used to analyze and predict the middle and high frequency noise in the car,and the subsystems of body parts were divided,and the material properties of body parts were defined and added,as well as the sound absorption and insulation materials of the whole car were added.Energy parameters such as mode density,internal loss factor and coupling loss factor of each subsystem are obtained by means of formula derivation and software simulation calculation.The noise outside the vehicle was tested and the acoustic material parameters were optimized.External noise is obtained and loaded onto the vehicle model through the test,and the in-car noise is predicted and compared with the test results to verify the accuracy of the model.Secondly,the noise transmission path is analyzed to determine which parts of the vehicle body will cause the noise inside the vehicle to rise.According to the determined parts of the vehicle body,the parameters of sound absorption material and damping material are optimized to reduce the noise inside the vehicle.Finally,the optimal material parameters were obtained after optimization,and the in-car noise was predicted.It was verified that the in-car noise decreased by an average of 3 to4 d B in the range of middle and high frequency after the acoustic material optimization,which fully proved the effectiveness of the optimization scheme.