• Journal of the Society of Naval Architects of Korea
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• v.39 no.4
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• pp.32-41
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• 2002

Present study aims to investigate draft effects on hydro-elastic response of pontoon type VLFS(Very Large Floating Structure). A three dimensional higher-order boundary element method(HOBEM: Hong et al;1999, Choi, Hong and Choi; 2001) is extended to analyze elastic response of structures. Intensive numerical calculations were carried out for box type structure to investigate the draft effect on hydrodynamic forces on pontoon type VLFS. Main attention was paid to wave run-up along the waterline for various cases of draft scantling. It is found that the draft effects on the hydro-elastic response of pontoon type VLFS are important especially in short wave range and shallow water region.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.138-140
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• 2007

폰툰형 레저보트는 쌍동식 또는 삼동선식의 안전성이 확보된 선체와, 다양한 기능을 만족할 수 있는 상부구조로 구성, 건조비 뿐만 아니라 레저 접근성이 용이한 보트로서, 해양레저 선진국에서는 내수면뿐만 아니라 해수면에서도 함께 즐길 수 있는 가족형 레저보트로 인식되어 최근 보급이 확대되고 있는 추세이다. 그러나 폰툰형 레저보트는 최적의 공간활용을 위해 사각모양의 갑판형태로 인해 유체의 저항에 취약한 단점이 있다. 이로 인해 선저형상, 추진시스템 및 조향운전장치 뿐만아니라 선수선저부의 슬래밍 충격에 대비한 구조강도 등 체계적인 연구를 통한 개발이 필요하다. 이에 본 연구에서는 2가구 4인 가족단위로 함께 즐길 수 있는 안전성이 높고, 낚시, 스쿠버 둥을 위한 편의시설이 확보한 선형 최적형상 연구 및 구조강조 해석을 통한 9인승 규모의 폰툰형 레저보트를 개발하고자 한다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.13 no.3
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• pp.213-217
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• 2007

Pontoon type very large floating structure has been considered and actively studied as one of the most important ocean space utilization. The hydroelastic displacement of the pontoon type floating structure in waves is the largest at its weather side. The purpose of this study is to investigate the characteristics and effects of the submerged horizontal plate which is developed to reduce the wave exciting forces acting on the pontoon type floating structure using numerical analysis. The numerical method based on the finite difference method has been adopted and compared with the experimental data to confirm the reliability of it. We have performed the numerical computation of wave exciting forces acting on the pontoon type floating structure with/without submerged plate and discuss the results of simulation.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.36 no.4
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• pp.149-157
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• 2024

In this study, hydraulic model tests were conducted to investigate the effect of a horizontal damping plate on the motion of the pontoon-type floating structure. The floating structures with and without the horizontal damping plates were fabricated with the scale of 1/20 and their motion responses to the regular and irregular wave conditions were investigated. From the comparison for the responses of each model with 16 wave conditions, it could be known that the damping plate made the response of the the pontoon to be smaller by about 5 to 10 % compared with the normal rectangular pontoon.

• Journal of Navigation and Port Research
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• v.31 no.8
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• pp.683-687
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• 2007

Hydroelastic deformation of pontoon type floating structure in waves is critical in structural design. Therefore, it is necessary to develop additional technology that make to dissipate the wave energy as the submerged horizontal plate. In this study, we investigate the characteristics of hydrodynamic interaction effect by the submerged plate affecting to the radiation forces on a pontoon type floating structure using numerical analysis. We have developed the numerical method based on the composite grid system that consists of moving and fixed grid to compute the radiation forces due to the heaving motion of pontoon type floating structure and submerged plate. The numerical simulations based on the finite difference method are carried out to solve the fully nonlinear free surface involving the breaking waves and compared with the experimental data to confirm the reliability of the numerical method. Then, we discuss the interaction effects on the hydrodynamic forces that could influence on the hydroelastic response of floating structure.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.2 s.42
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• pp.47-58
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• 2005

Dynamic response analysis in time dimain is conducted for floating bridges with discrete pontoons subject to spatial variation of ground motions. The Spatial variation of ground motions is considered with the coherency function model which represents wave passage, incoherence and local site effects. The superstructure of the bridge is represented by space frame and elastic catenary cable elements, the abutment us modelde with the spring element of FHWA guideline for considering soil structure interaction and the concept of retardation function is utilized to consider the frequency dependency of the hydrodynamic coefficients which are obtainde by boundary element method. multiple support excitations considering the spatial variation. The noticeable amplification of the response can be shown when the spatial variation of ground motions is incorporated in the anallysis of floating bridges.

• Journal of Ocean Engineering and Technology
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• v.22 no.1
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• pp.22-29
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• 2008

A numerical investigation is made on the effects of the location and shape of the front wall of an OWC(Oscillating Water Column) chamber on the hydroelastic response of a VLFS. Most of the studies on the effects of an OWC chamber on the response of a VLFS have assumed the location of the OWC chamber to be at the front of the VLFS. In the present study, an OWC-chamber is introduced at an arbitrary position in relation to a VLFS to determine the influence of the location and shape of the OWC chamber on the hydroelastic response of the VLFS. A finite element method is adopted as a numerical scheme for the fluid domain. or the finite element method, combined with a mode superposition method, is applied in order to consider the change of mass and stiffness The OWC chamber in a piecewise constant manner. or the facilitated anefficient analysis of The hydroelastic response of the VLFS, as well as the easy modeling of different shape and material properties for the structure. Reduction of hydroelastic response of the VLFS is investigated for various locations and front wall shapes of the owe chamber.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.1
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• pp.82-89
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• 2016

In this study, we proposed a pier of pontoon-type, "Very Large Floating Structure" (VLFS), with the length of 500m, breadth of 200 m and height of 2 m in Yeosu domestic port. Since this structure ought to endure wave loads for long periods at sea, it is essential to analyze the wave response characteristics. Direct-method is used to analyze the fluid-structure problem and the coupled motion of equation is used to obtain response results. The structural part is calculated by using finite element method (FEM) and the fluid part is analyzed by using boundary element method (BEM). Dynamic responses caused by the elastic deformation and rigid motion of structure are analyzed by numerical calculation. To investigate response characteristics of the pier in regular waves, several factors such as the wavelength, water depth, wave direction and flexural rigidity of structure are considered. As a result, wave response of pier changed at the point of $L/{\lambda}$ 1.5 and represented the torsional phenomenon according to the various incident waves. And the responses showed increasing tendency as the water depths increase at the incident point in case of $L/{\lambda}=8.0$ and peak point of vertical displacement amplitude moved from side to side as the flexural rigidity of structure changes.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.125-126
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• 2007

In this paper, the floating body with vertical plate is introduced with a study on the flow patterns and characteristics in around the floating body by using 2 frame particle tracking method. This paper introduce an analysis method to predict the characteristics if flow around the neighboring fields if Floating Body with vertical plate in order to investigate a high performance model. Flow visualization has conducted in a drcu1ating water channel by a high speed camera and etc. Flow phenomena according to turbulence intensity distribution and flow separation around the floating body with vertical plate were obtained by two-dimensional PIV system.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.5
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• pp.604-610
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• 2018

Recently, due to the rapid growth of the leisure industry, demand for small-scale flotation and mooring pontoon platforms has been increasing rapidly. Standard rules for the design and structural safety of such structures have become necessary. This paper provides criteria that can be referenced when designing pontoon platforms, and also introduces structural safety evaluation procedures. In this study, the structural safety and stability of a 15-meter pontoon platform were investigated through structural design and finite element analysis. For platforms of less than 10 meters in length, a simple structural calculation can be used, but for platforms over 10 meters, a detailed structural strength review must be considered to meet safety guidelines defined in existing regulations. The structural strength of the initial design was examined and its structural safety was verified. For future research, it is an evaluative system was developed that can be used to examine the various loading conditions during design.