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Dynamics of towers surrounded by water
Author(s) -
Liaw CY.,
Chopra Anil K.
Publication year - 1974
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.4290030104
Subject(s) - added mass , vibration , compressibility , tower , cantilever , modal , mechanics , harmonic , simple harmonic motion , fundamental frequency , modal analysis , normal mode , representation (politics) , fluid–structure interaction , dynamics (music) , structural engineering , classical mechanics , physics , acoustics , engineering , materials science , finite element method , politics , political science , polymer chemistry , law
The effects of interaction with surrounding water on the dynamic response behaviour of cantilever tower structures are studied. Expressions for response to harmonic ground motion in individual modes of vibration, including hydrodynamic interaction, are presented, the accuracy of responses obtained by ignoring surface waves and compressibility of water in the hydrodynamic solutions is evaluated, the effects of hydrodynamic interaction on the fundamental period of vibration are studied and the commonly used ‘added mass’ approach to account for effects of surrounding water is examined. The conclusions deduced from the results of this investigation include the following. Interaction with surrounding water increases the fundamental period of vibration of the tower and decreases the modal damping ratio. Compressibility of water has essentially no influence in the hydrodynamic effects on slender towers. The traditional definition of added mass is conceptually deficient, but is simple to employ; the errors in this simple added mass representation are negligible for the first mode of vibration of towers.