The Interior Noise Prediction Analysis And Topology Optimization Of Damping Structural In Auto-Body

With the rapid development of automobiles’ lightweight and high speed, theinterior noise is becoming increasingly prominent, which can destroy the ride comfortdirectly. Therefore, it has been the hot research field of automobile to reduce vehicleinterior noise, to improve the acoustical environment in passenger compartment and toachieve high ride comfort.In this study, modal analysis and sound pressure frequency response analysis ofstructural-acoustic coupled system of an auto-body was performed firstly. As a result,the panel of auto-body with maximum sound contribution has been found. Then thevibration behavior of damping composite structure of the auto-body was studied. At last,the ESO method was adopted to optimize the layout of damping material so that thevehicle interior noise was effectively suppressed. This study mainly includes thefollowing items:①The FEM method was applied to stimulate the structural-acoustic coupledsystem of a certain auto-body. At the same time, the modal characteristics analysis ofauto-body and interior vocal cavity was performed. And the sound pressure response ofthe whole system excited by engine was also calculated. In terms of the maximumpressure of driver’s right ear, the panels’ acoustic contribution analysis has been workedout, and then the panel with maximum acoustic contribution was found out at thisfrequency. The work above provides a referenced position for subsequent structuraloptimization.②The modeling methods for damping behavior of composite panel was studied.And the modal strain energy method has been adopted to analyze the vibration behaviorof the damping composite panel, the result of which was compared with theexperimental result. This comparison indicates that the simulation result highly matchesthe experimental result, and it also shows that attaching the damping material to panelof auto-body can restrain its vibration response obviously.③The Modal Strain Energy（MSE） method was used to optimize the layout ofcomposite structure’s damping material. With damping material consumption as theconstraint condition and structural modal damping loss factor as an object function, thetopology optimization model was built. Then the sensitivity functions of modal lossfactor with damping material or not were deduced. And the best optimal layout of material was found out by computer programming. The experiments have validated thereliability and accuracy of the optimization method. Also this optimization result has agood vibration damping effect.④Attaching damping material to the front panel of auto-body, the ESO methodwas adopted to optimize the layout of damping material. The analysis of sound pressurelevel and frequency before and after optimization indicates that only50percentdamping material consumption has nearly the same peak value of sound pressure levelwith full covered material which demonstrates the effectiveness of damping material’slayout optimization.