An Acoustical Finite Element Model of Perforated Elements

P. Bonfiglio[1][2] and F. Pompoli[1][2]
[1]Materiacustica S.r.l., Ferrara, Italy
[2]Engineering Department, University of Ferrara, Ferrara, Italy

The present work deals with a numerical investigation of resonating systems used for noise control applications. In literature one can find analytical models based on fluiddynamics concepts for evaluating losses occurring across the holes of the perforates. In the paper an acoustical formulation based on the equivalent dissipative fluid approach will be analyzed. It will be firstly applied to simple acoustical resonators and normal incidence sound absorption coefficient will be calculated in a virtual plane wave tube. Successively the same formulation will be used in order to model perforated sheets utilized in mufflers and silencers for increasing sound transmission loss at low frequencies. Results for both analyses will be compared with experimental measurements and well extablished analytical models.

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