The Optimization Of Vehicle Panel With Porous Damping And Control Of Vehicle Interior Noise

As the rising of people’s requirement for ride comfort, especially the vehicleinterior acoustic environment, auto companies pay more and more attention to controlthe interior noise, therefore, the interior noise prediction and control are especiallyimportant. In this paper, interior noise caused by the car body structure vibration hasbeen studied by using the finite element method and boundary element method, and theoptimization of the constrained layer damping structure with porous damping layer hasbeen conducted too. What’s more, the constrained layer damping and the porousdamping structure are used for controlling the car interior noise. The contents of thispaper are expressed as follows:①The finite element model of a car body and the interior acoustic cavity havebeen established. The modal analysis of the car body structure, the interior acousticcavity and the coupling system of the car body structural-passenger compartmentacoustic have been taken, then a research on the dynamic characteristics and acousticcharacteristics of these system is carried out, laying a foundation for finding out thevibration source which caused the car body structure resonance and interior acousticcavity resonance easily.②The interior acoustic frequency response under the excitation on the left andright engine mount have been calculated separately, position of the excitation andexcitation frequency which caused peak value of sound pressure have been found, andthe panel acoustic contribution analysis of peak value at driver’s ear has been conductedto find out the panel which makes the greatest contribution.③The damping layer of constrained layer damping plate is designed in the porousdamping layer with periodic square cells, the finite element model of the porus dampingcomposite plate considering the homogenization of the porous damping layer isdeveloped, the size of square cell is optimized to minimize the vibration amplitude ofthe porous damping composite plate through searching the optimal equivalent shearmodulus of the porous damping layer, effectively restrain the structural vibration. AndModal analysis experiment verified the correctness of the theoretical results.④Control the car interior noise by using the constrained layer damping structure and porous damping composite structure. Porous damping structure is laid on thepivotal panel, the size of square cell is optimized to minimize the sound pressure atdriver’s ear through searching the optimal equivalent shear modulus of the porousdamping layer.The results show that the constrained layer damping laid on the pivotalpanel caused a maximum decline of3.09dB on measuring point’s SPL, while thestructure of porous damping caused a decline of3.19dB on measuring point’sSPL,obtains a better car noise suppression effect in the case of reducing the amount ofdamping materials.