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Modes of Vibration of High Speed Ship Hull Sections

Citation

Davis, MR and Davidson, G and Roberts, T and Cato, CA, Modes of Vibration of High Speed Ship Hull Sections, Proc 11th International Conference on Fast Sea Transportation, 26-29 September 2011, Waikiki, Honolulu, pp. 524-531. (2011) [Refereed Conference Paper]

Copyright Statement

Copyright 2011 American Society of Naval Engineers

Official URL: https://www.navalengineers.org/publications/sympos...

Abstract

Impact testing of a typical high speed ship section has shown that the mode of vibration most likely to fall in the frequency range of excitation due to propeller or rotor blade passing is that where the ship frame rocks in a fore and aft direction about its base connection to the hull plate. This vibration has significant amplitude to either side of the keel and it is found that connection between the inboard and outboard sides is weak. As a consequence vibration can occur in two modes in which the opposite sides of the hull either move together or in anti phase. This leads to the structural strain energy in the two modes being slightly different, the mode with opposite motion to either side involving rather smaller strain energy. As a consequence the two modes have slightly different frequency, the mode with opposite motion to either side having rather less strain energy and thus a lower frequency. Because the frequencies of the two modes are thus close together the transient response exhibits beating in which vibration energy is exchanged between the two sides of the hull at the low beat frequency. Vibration of the ship frames in this manner appears to have been the cause of minor weld cracking where the top of stiffeners pass through cut outs in the web of the ship frames within the fuel tank areas of the hull.

Item Details

Item Type:Refereed Conference Paper
Keywords:Vibration modes, high speed ship hulls, lightweight hull
Research Division:Engineering
Research Group:Maritime Engineering
Research Field:Ship and Platform Hydrodynamics
Objective Division:Transport
Objective Group:Water Transport
Objective Field:Passenger Water Transport
Author:Davis, MR (Professor Michael Davis)
Author:Cato, CA (Mr Christopher Cato)
ID Code:75978
Year Published:2011
Deposited By:Engineering
Deposited On:2012-02-21
Last Modified:2014-08-06
Downloads:1 View Download Statistics

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