Measurements of Acoustic Properties of Porous and Granular Materials and Application to Vibration Control

Experimental methods to measure the vibration characteristics of the frame for porous and granular materials were proposed in this paper. The damping of structural vibration using porous and granular materials was also considered. The measured dynamic properties followed the characteristics of typical viscoelastic materials: the dynamic moduli increased with frequency and its frequency dependence was determined by its loss factor. The bending stiffness of the cylindrical beams that contained different damping materials was derived using the transfer function method from data acquired through the slip table tests. By using the measured frame properties of the damping materials, the loss factor of the beam was predicted. Comparison to measured values suggested that the acoustic-structure interaction between the frame of the damping material and the structure increased the vibration damping significantly. The maximum of the loss factor occurred at the first resonance frequency of the frame vibration in the cross section of the hollow beam. In future vibro-acoustic control applications, the measured properties of the vibration characteristics of granular and porous materials should be useful in understanding sound transmission characteristics.

Language

  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: pp 641-650
  • Monograph Title: Noise-Con 04. The 2004 National Conference on Noise Control Engineering

Subject/Index Terms

Filing Info

  • Accession Number: 01054313
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Jul 25 2007 2:54PM