Research On Vehicle Acoustic Vibration Coupling Characteristics And Design Of Dynamic Vibration Absorber

The low frequency vibration and noise produced by car body seriously affect the riding comfort of drivers and passengers.It not only reduces the service life of the car body,but also easily causes the driver’s restlessness and fatigue symptoms.If it is not handled properly,it is likely to cause serious traffic hazards.In view of the late stage of automobile development,it is not easy to directly modify the relevant parts of the automobile,so the flexible dynamic vibration absorber is adopted,which can reduce the vibration and noise of the body,frame,suspension,transmission shaft,etc.In this paper,a small car as the research object,using Simulation software,the structural characteristics of the car body and the internal noise are analyzed,and through the method of installing dynamic vibration absorber in the car body to achieve the purpose of vibration and noise reduction of the body.The finite element model of the car body structure is established by ANSYS software,and the modal analysis of the car body structure is carried out.The modal shape and natural frequency of the car body structure are analyzed and studied.It’s that the simplified model of the car body is established and the harmonic response analysis is carried out.The peak frequency of the car body under the harmonic response condition is found,and the displacement result file obtained after the analysis and calculation is used as the boundary condition of the subsequent acoustic solid coupling analysis.The car body acoustic finite element model and structure acoustic coupling model are established.The acoustic structure coupling mode is analyzed by Simulation software,It’s that the sound pressure near the driver’s ear as the sound pressure field point is calculated,and the distribution rule of the cab sound field is preliminarily understood.The finite element finite element model of sound structure coupling of car body is established,the acoustic structure coupling model is analyzed by Simulation software,and the sound pressure at the driver’s left ear as the target field point is calculated.And the sound field distribution of the car body is preliminarily known.Based on the acoustic structure coupling model of the car body,the contribution of the car body parts is analyzed,and the car body bottom plate at the driver’s left ear is determined to be the body part with the largest acoustic contribution.The orthogonal polynomial method is used as the equivalent mass identification method of the main system to obtain and the equivalent mass of the main control system is obtained.Then the key parameters of the dynamic vibration absorber(equivalent mass,equivalent stiffness,equivalent damping,etc.)are obtained.Finally,the method of installing the dynamic vibration absorber at the car body floor is used to reduce the vibration and noise of the car body.