Accession Number : ADA321158

Title :   Surface Excitation: A Theoretical and Experimental Study of Strip Mobility on a Line-Stiffened Plate.

Descriptive Note : Partial rept.,

Corporate Author : TECHNISCH PHYSISCHE DIENST TNO-TH DELFT (NETHERLANDS)

Personal Author(s) : Jong, C. A. de ; Kooyman, P. P. ; Knaap, F. G. van der

PDF Url : ADA321158

Report Date : 23 SEP 1996

Pagination or Media Count : 34

Abstract : Theoretical and experimental methods are described, that can be used to quantify the effects of surface excitation on line-stiffened plate structures. These methods are of relevance for the study of structure-borne noise transmission from shipboard machinery to underwater. It is shown that the distribution of the excitation force from a machine on the ship structure over a large contact area is beneficial for the reduction of noise transmission at higher frequencies. The criterium for the ocurrence of this effect is that the contact area should have at least one dimension larger than the governing wavelength in the ship structure. The results of laboratory experiments support this conclusion. Two different experimental techniques, direct mobility measurements and structural intensity measurements on the receiving plate, lead to the same results.

Descriptors :   *VIBRATION, *UNDERWATER ACOUSTICS, *MECHANICAL IMPEDANCE, LOAD DISTRIBUTION, NETHERLANDS, STRUCTURAL PROPERTIES, SHIP NOISE, SHIP MOTION, ELASTIC PROPERTIES, SOUND TRANSMISSION, SHIPBOARD, ACOUSTIC MEASUREMENT, NOISE REDUCTION, UNDERWATER SOUND, MACHINERY NOISE, SHIP STRUCTURAL COMPONENTS.

Subject Categories : Marine Engineering
      Acoustics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE