Accession Number:

ADA024985

Title:

Vibration and Sound Radiation of a Plate.

Descriptive Note:

Technical memo.,

Corporate Author:

PENNSYLVANIA STATE UNIV UNIVERSITY PARK APPLIED RESEARCH LAB

Personal Author(s):

Report Date:

1975-07-28

Pagination or Media Count:

121.0

Abstract:

Because of their many vibratory resonances, plates are mechanically soft and their suspending structures have a considerable effect on their vibration and sound radiation. Experimental evaluation of acoustic properties of plates is therefore difficult. Plates of different shapes and dimensions were supported in such a way as to eliminate effects of the support on the vibration, and the velocity amplitudes due to point forces were recorded by phonography cartridge and microphones in the near sound field. The results show that the many vibratory modes generate hotspots on the plates. The attachment of ribs and supports disturbs the vibration field and leads to localized areas of increased sound radiation. Long wavelength acoustic holography was used to locate on the vibrating plates the sources of far-field sound. These regions were also investigated by recording the vibratory and nodal line patterns of the plates by a near-field microphone method. This combination of techniques has a unique capability to locate acoustic sources on vibrating structures. Author

Subject Categories:

  • Acoustics
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE