Analytical and Numerical Acoustic Behavior of an Automotive Passenger Compartment in order to Reduce Interior Noise Level with Viscoelastic Material

Abstract

The noise and vibration signature of automotive passenger cabin substantially has become the overall impression of vehicle quality from the point of view of customers. In this paper, vibro-acoustic behavior of interior compartment of a vehicle is investigated. Interior noise level near the driver's ear due to engine exciting has calculated with finite element method. In this study, the panel vibration is considered as noise source in the frequency range of 0 to 200 Hz. Numerical simulation in acoustic analysis helps to reduce the new design period and to create the facility of improvement especially in passive noise control. The results obtained from finite element method has verified with closed formulation for a simple cubic box. Then, the model has been completed to be considered the boot cavity and seats of the car. The proposed model allows prediction of structural borne sound field due engine and wheels excited at low frequencies (0-200 Hz). Also the effect of viscoelastic material in acoustic behavior has been investigated and determined that the unconstrained and constrained viscoelastic material reduces 10% and 30% respectively in average noise level. Positioning of viscoelastic material has a marked effect in noise level reduction. In addition, the results illustrate the viscoelastic installation on roof panel is more efficient than the floor panel.

Keywords

• Vibro-acoustic; Viscoelastic; Noise reduction; FEM.