Steady state and transient responses of flexible ship structures travelling in irregular seaways
Steady state and transient responses of flexible ship structures travelling in irregular seaways
The steady state and transient responses of flexible ship structures in irrgular seaways are investigated employing two-dimensional and three-dimensional hydroelasticity analyses.
For beam-like hulls, using two-dimensional liner hydroelasticity analysis dry hull natural frequencies and mode shapes are obtained from the Timoshenko beam theory while fluid actions are described by strip theory. The slam pressures are determined from the concepts of `impact' and `momentum' slamming and the impulsive transient (slamming) responses in irregular head seaways are predicted using convolution integral techniques.
Through time simulations of bending moments, shearing forces and motion characteristics, the effects of different load conditions, forward speed, seaway characteristics and slamming intensity are examined for various types of ship such as clean product carried, a bulk carrier and a patrol boat. The predicted results are compared, where possible, with the measured results obtained from full scale trials and model experiments.
The proportionality between the bending moment and the shearing force towards the ends of the ship is highlighted and the implications of this phenomenon on principal stresses are investigated. The analysis predicts positions along the hull where structural weakness or failure is likely to occur.
A three-dimensional slamming theory is developed and is incorporated into the general three-dimensional hydroelasticity analysis. The dry hull natural frequencies and mode shapes are evaluated from a suitable finite element model and hydrodynamic actions are obtained using three-dimensional potential flow analysis.
The results predicted from two-dimensional and three-dimensional analyses are compared for uniform barge structures. For a slender barge structure, good agreement is achieved. It is demonstrated that for non-slender barge structures while two-dimensional analysis fails to predict any rational results, the steady state and transient symmetric and antisymmetric responses at any point in the structure in irregular oblique seaways are predicted by three-dimensional analysis.
University of Southampton
1993
Aksu, Ṣeref
(1993)
Steady state and transient responses of flexible ship structures travelling in irregular seaways.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The steady state and transient responses of flexible ship structures in irrgular seaways are investigated employing two-dimensional and three-dimensional hydroelasticity analyses.
For beam-like hulls, using two-dimensional liner hydroelasticity analysis dry hull natural frequencies and mode shapes are obtained from the Timoshenko beam theory while fluid actions are described by strip theory. The slam pressures are determined from the concepts of `impact' and `momentum' slamming and the impulsive transient (slamming) responses in irregular head seaways are predicted using convolution integral techniques.
Through time simulations of bending moments, shearing forces and motion characteristics, the effects of different load conditions, forward speed, seaway characteristics and slamming intensity are examined for various types of ship such as clean product carried, a bulk carrier and a patrol boat. The predicted results are compared, where possible, with the measured results obtained from full scale trials and model experiments.
The proportionality between the bending moment and the shearing force towards the ends of the ship is highlighted and the implications of this phenomenon on principal stresses are investigated. The analysis predicts positions along the hull where structural weakness or failure is likely to occur.
A three-dimensional slamming theory is developed and is incorporated into the general three-dimensional hydroelasticity analysis. The dry hull natural frequencies and mode shapes are evaluated from a suitable finite element model and hydrodynamic actions are obtained using three-dimensional potential flow analysis.
The results predicted from two-dimensional and three-dimensional analyses are compared for uniform barge structures. For a slender barge structure, good agreement is achieved. It is demonstrated that for non-slender barge structures while two-dimensional analysis fails to predict any rational results, the steady state and transient symmetric and antisymmetric responses at any point in the structure in irregular oblique seaways are predicted by three-dimensional analysis.
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Published date: 1993
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Local EPrints ID: 462098
URI: http://eprints.soton.ac.uk/id/eprint/462098
PURE UUID: 6ed0c7b3-2bb9-4805-bd2d-34d9f2c7f7dc
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Date deposited: 04 Jul 2022 19:01
Last modified: 04 Jul 2022 19:01
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Author:
Ṣeref Aksu
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