A finite element model for elastic porous materials is presented that allows for interfaces with adjacent acoustical media that are arbitrarily oriented with respect to the global coordinate system. The foam finite element is based on a complete elastic porous material theory that can account for all the three wave types known to be significant in foams. Example problems are used to illustrate the application of foam finite elements to the optimal design of a foam wedge terminating a waveguide. The wedge angle is used as a design parameter (while the wedge volume is held constant) and the performance measure is the frequency-averaged absorption coefficient.

1.
Astley
R. J.
, and
Cummings
A.
,
1987
, “
A Finite Element Scheme for Attenuation in Ducts Lined with Porous Material: Comparison with Experiment
,”
J. Sound Vib.
, Vol.
116
, pp.
239
263
.
2.
Beranek
L. L.
, and
Sleeper
H. P.
,
1946
, “
The Design and Construction of Anechoic Chambers
,”
J. Acoust. Soc. Am.
, Vol.
18
, pp.
140
150
.
3.
Biot
M. A.
,
1956
, “
Theory of Propagation of Elastic Waves in Fluid-Saturated Porous Solid. I. Low Frequency Range. II High Frequency Range
,”
J. Acoust. Soc. Am.
, Vol.
28
, pp.
168
191
.
4.
Bolton
J. S.
,
Shiau
N.-M.
, and
Kang
Y. J.
,
1996
, “
Sound Transmission through Multi-Panel Structures Lined with Elastic Porous Materials
,”
J. Sound Vib.
, Vol.
191
, pp.
317
347
.
5.
Craggs
A.
,
1978
, “
A Finite Element Model for Rigid Porous Absorbing Materials
,”
J. Sound Vib.
, Vol.
61
, pp.
101
111
.
6.
Craggs
A.
,
1979
, “
Coupling of Finite Element Acoustic Absorption Models
,”
J. Sound Vib.
, Vol.
66
, pp.
605
613
.
7.
Craggs
A.
,
1986
, “
A Finite Element Model for Acoustically Lined Small Rooms
,”
J. Sound Vib.
, Vol.
108
, pp.
327
337
.
8.
Easwaran
V.
, and
Munjal
M. L.
,
1993
, “
Finite Element Analysis of Wedge Used in Anechoic Chambers
,”
J. Sound Vib.
, Vol.
160
, pp.
333
350
.
9.
Kang, Y. J., Tsoi, W., and Bolton, J. S., 1993, “The Effect of Mounting on the Acoustical Properties of Finite-Depth Polyimide Foam Layers,” Proceedings of NOISE-CON 93, pp. 285–290.
10.
Kang, Y. J., 1994, “Studies of Sound Absorption by and Transmission through Layers of Elastic Noise Control Foams: Finite Element Modeling and Effects of Anisotropy,” Ph.D. Thesis, School of Mechanical Engineering, Purdue University, W. Lafayette, IN.
11.
Kang
Y. J.
, and
Bolton
J. S.
,
1996
, “
Finite Element Modeling of Isotropic Porous Materials Coupled with Acoustic Finite Elements
,”
J. Acoust. Soc. Am.
, Vol.
98
, pp.
635
643
.
12.
Koidan
W.
,
Hruska
G. R.
, and
Pickett
M.
,
1972
, “
Wedge Design for National Bureau of Standard Anechoic Chamber
,”
J. Acoust. Soc. Am.
, Vol.
52
, pp.
1071
1076
.
13.
Zwikker, C., and Kosten, C. W., 1949, Sound Absorbing Materials, Elsevier, New York.
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