Accession Number : AD0466936

Title :   ACOUSTIC RADIATION FROM RIBBED PLATES INCLUDING FLUID-LOADING EFFECTS,

Corporate Author : BOLT BERANEK AND NEWMAN INC CAMBRIDGE MA

Personal Author(s) : Maidanik, Gideon ; Kerwin, Edward M., Jr.

Report Date : OCT 1963

Pagination or Media Count : 71

Abstract : The acoustic radiation from flat ribbed plates is considered in two ways: first as radiation from an infinite orthotropic plate and second, as radiation from the reverberant vibratory motion of the panels making up the ribbed plate. The orthotropic plate response to a localized force includes a forced-wave near field and a freewave propagating field. Fluid loading effects on these responses are included exactly, and are seen to reduce the radiation from that which would be found if the fluid did not alter the plate response. Structural damping can reduce the acoustic radiation from the free-wave field if such structural damping exceeds the radiation damping. Structural damping has practically no influence on the forced-field response and radiation. Radiation from the reverberant motions of the panels is estimated for the limiting cases of discrete and diffuse modal distributions. The influence of radiation load on shifting modal frequencies is estimated. The report includes discussion of the effects of cylindrical geometry and of some of the desirable features of future experiments. (Author)

Descriptors :   (*STRUCTURES, ACOUSTIC PROPERTIES), (*PANELS, ACOUSTIC PROPERTIES), MECHANICAL WAVES, VIBRATION, DAMPING, RESONANCE, FREQUENCY, FLUID FLOW, SHELLS(STRUCTURAL FORMS), STIFFENED CYLINDERS, SHEETS.

Distribution Statement : APPROVED FOR PUBLIC RELEASE