Accession Number : ADD015853

Title :   Method and Device for Measuring Underwater Vehicle Hull Vibration.

Descriptive Note : Patent, filed 25 Jul 91, patented 4 May 93,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Striffler, Foster L

Report Date : 04 May 1993

Pagination or Media Count : 5

Abstract : A method and device for measuring higher mode vibrational energy is provided. The device includes a plurality of sensors placed with uniform spacing around the circumference of a structure and a processing unit. The sensor placement may be either on the inside or the outside of a structure depending on the structure and on the experiment. In operation, signals from individual sensors, preamplified if required, are fed to processing equipment. The processing equipment performs a double Fast Fourier Transform. The first transform is done on temporal data thereby providing an output representing a frequency spectrum. The second transform is performed on simultaneous data readings from all sensor locations thereby providing an output representing a spectrum of mode numbers. The combining of these outputs provides a three-dimensional plot of amplitude versus frequency and mode number.

Descriptors :   *UNDERWATER EQUIPMENT, *HULLS(STRUCTURES), *VIBRATION, *MEASUREMENT, *PATENTS, AMPLITUDE, ENERGY, FAST FOURIER TRANSFORMS, FREQUENCY, NUMBERS, OPERATION, OUTPUT, PROCESSING EQUIPMENT, SIGNALS, STRUCTURES, THREE DIMENSIONAL, UNIFORMS

Subject Categories : Marine Engineering
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE