Widening the sound absorption bandwidths of flexible micro-perforated curved absorbers using structural and acoustic resonances

In this paper, the sound absorptions of flexible curved micro-perforated panels that are backed by an air cavity are studied in detail. A theoretical model that is based on the classical plate equation coupled with an acoustic wave equation is developed for the prediction of sound absorption. This model considers both symmetrical and antisymmetrical structural acoustic responses. Using the electro-acoustic analogy approach, another model is developed that only considers single structural and acoustic modes. It is proposed to make use of panel and cavity resonances to widen the absorption bandwidth of a single/double perforated absorber. The absorption of a flexible micro-perforated panel can be further enhanced by adjusting its curvature to bring the resonant frequencies closer together. The effects of various parameters such as boundary condition, incidence angle, and curvature on the absorption are studied. Predicted results for the single and double layer absorbers show good agreement with measurements.

[1]  T. Lu,et al.  Sound absorption in metallic foams , 1999 .

[2]  A. Leissa,et al.  Vibration of shells , 1973 .

[3]  Dah-You Maa,et al.  Microperforated-panel wideband absorbers , 1987 .

[4]  George W. Swenson,et al.  Compact Sound Absorbers for Low Frequencies , 1992 .

[5]  Louis A. Roussos.  Noise transmission loss of a rectangular plate in an infinite baffle , 1984 .

[6]  L. Cremer,et al.  Structure-Borne Sound: Structural Vibrations and Sound Radiation at Audio Frequencies , 1973 .

[7]  Arthur W. Leissa,et al.  Vibration of Plates , 2021, Solid Acoustic Waves and Vibration.

[8]  Masayuki Morimoto,et al.  ACOUSTIC PROPERTIES OF AN INFINITE ELASTIC PLATE WITH A BACK CAVITY , 1993 .

[9]  Masayuki Morimoto,et al.  Sound absorption of a cavity-backed membrane: A step towards design method for membrane-type absorbers , 1996 .

[10]  W. C. Tang,et al.  Low Frequency Acoustic Performance of Close-Fitting Sandwich Panels , 1998 .

[11]  A. J. Pretlove.  Free vibrations of a rectangular panel backed by a closed rectangular cavity by a closed rectangular cavity , 1965 .

[12]  R. D. Ford,et al.  Panel sound absorbers , 1969 .

[13]  Masayuki Morimoto,et al.  Effect of an air-back cavity on the sound field reflected by a vibrating plate , 1999 .

[14]  Colin H. Hansen,et al.  ENGINEERING NOISE CONTROL: Theory and Practice , 1988 .

[15]  D. Takahashi,et al.  Flexural vibration of perforated plates and porous elastic materials under acoustic loading. , 2002, The Journal of the Acoustical Society of America.

[16]  W. C. Tang,et al.  Effect of Sandwich Panel for Duct Noise Reduction at Low Frequency , 1997 .

[17]  H. Kraus,et al.  Literature Review : VIBRATION OF PLATES Arthur W. Leissa NASA SP-160, Scientific and Technical Information Division, National Aeronautics and Space Administration, Washington, D. C. (1969) , 1972 .

[18]  E. Dowell,et al.  Acoustoelasticity - General theory, acoustic natural modes and forced response to sinusoidal excitation, including comparisons with experiment , 1977 .

[19]  W. Frommhold,et al.  Acoustic Performance of Membrane Absorbers , 1994 .

[20]  Masahito Yasuoka,et al.  Sound insulation of a rectangular thin membrane with additional weights , 1991 .

[21]  R. W. Guy,et al.  The transmission of sound through a cavity-backed finite plate , 1973 .