Title: Dissipative expansion chambers with two concentric layers of fibrous material

Authors: A. Selamet, M.B. Xu, I.J. Lee, N.T. Huff

Addresses: Department of Mechanical Engineering, The Ohio State University, 206 West 18th Ave, Columbus, OH 43210-1107, USA. ' Department of Mechanical Engineering, The Ohio State University, 206 West 18th Ave, Columbus, OH 43210-1107, USA. ' Department of Mechanical Engineering, The Ohio State University, 206 West 18th Ave, Columbus, OH 43210-1107, USA. ' Owens Corning, 4600 Humboldt Drive, Novi, MI 48377, USA

Abstract: The acoustic performance of a dissipative expansion chamber lined with two concentric, annular layers of fibrous material with different resistances is investigated. A two-dimensional analytical approach is used to determine the transmission loss of this dissipative silencer. From the boundary conditions at the rigid wall, and the interfaces between the fibre layers and the central airway, the characteristic function and thus eigenvalues and eigenfunctions for sound propagation in the dissipative chamber are obtained, leading to transmission loss through application of pressure and velocity matching. The effects of geometry and fibre properties on the acoustic attenuation are also discussed.

Keywords: acoustic performance; dissipative expansion chambers; muffler; sound absorbing material; fibrous material; transmission loss; sound propagation; noise control; dissipative silencers; vehicle noise.

DOI: 10.1504/IJVNV.2005.007531

International Journal of Vehicle Noise and Vibration, 2005 Vol.1 No.3/4, pp.341 - 357

Available online: 02 Aug 2005 *

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