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Experimental modal analysis on unit-linked large floating structure models

Conference ·
OSTI ID:256930
;  [1]; ;  [2];  [3]
  1. Polytechnic Univ., Kanagawa (Japan)
  2. Musasi Inst. of Technology, Tokyo (Japan)
  3. Nihon Univ., Chiba (Japan)

This paper is concerned with experimental modal analysis to estimate the dynamic properties of unit-linked large floating structure models. The fluid-coupled vibration test were carried out by using an impact hammer. The hammer impact test to be used in the authors` experiments must be performed by hitting force transducers arranged with each unit by an impact hammer made of very soft rubber. Six kinds of floating model were used in their study. The vertical acceleration responses are measured on upper surfaces of the models by arranging acceleration sensor on each unit, respectively. The transfer functions defined by normalized input and output data are analyzed by means of a multi-channel modal analysis software. The modal properties such as natural frequencies, damping ratios and mode shapes were estimated by using the curve fitting of the transfer functions which were obtained in the vibration test. These experimental results were compared with theoretical values obtained by using a lumped-mass model with the aid of BEM to take into account fluid-structure interaction.

OSTI ID:
256930
Report Number(s):
CONF-950604--; ISBN 1-880653-17-6
Country of Publication:
United States
Language:
English