Abstract
This paper deals with analysis for acoustic properties of automotive exhaust system having sound absorbing materials. Elements of the sound absorber having complex density are modeled 3D finite element. It was applied to the automotive exhaust system to verify the accuracy of acoustic analysis. The results show good agreement with results from acoustic experiments. Further, using asymptotic method to the equations of motion, explicit expressions of modal loss factor are derived. And the contribution for modal loss factor can be calculated. Applying the proposed method to the automotive muffler, it enables a more efficient layout of the sound absorbing materials.
