• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.4
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• pp.71-82
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• 1999

An axisymmetric shell element which includes the effects of the meridional and circumferential cable prestresses is developed. The fluid-structure interaction is expressed as added mass effect which is in proportion to the acceleration of the structure in interface surface. The added mass is obtained by using finite element method under the assumption that the fluid is invicid, incompressible and irrotational. It is coded for personal computer by the maximum use of axisymmetic properties and the dynamic analysis are performed under seismic exitations. A ring element makes the characteristics of the axisymmetric shell to be fully utilized. The elgenvalue solutons under the initial prestresses and the internal fluid are well agreed with the exact solutions and references by using under 20 elements. The eigenvalues are decreased along the increasing the height of internal fluid and these effects are dominant under the lower wave numbers. The results of the seismic analysis show that the radial deflection under the meridional prestress is a little larger than that under the circumferential prestress.

• Journal of Navigation and Port Research
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• v.29 no.8 s.104
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• pp.661-666
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• 2005

Recent warnings indicate that there is a potential risk of massive earthquake. These earthquakes could produce large-scale tsunamis. Consideration of the effect of Tsunami to the moored ship is very important bemuse it brings the loss of life and vast property damage in a viewpoint of ship operations within a harbor. If a tsunami occurs, a ship in a harbor may begin drifting in case of ship entering and departing harbor, and breakage of mooring rope and drifting of moored ship are happened. And extremely serious accident, such as stranding and collision to a quay, might occur. On the other hand, since the tsunami consists of approximately component waves of several minutes, there is a possibility of resonance with the long period motion of mooring vessel. As the speed of Tsunami is much faster than tidal current in a harbor, a strong resisting force might act on the moored ships. In this paper, the numerical simulation procedure in the matter of ship motions due to the attack of large-scale tsunamis are investigated and the effects on the ship motions and mooring loads are evaluated by numerical simulation.