• Title/Summary/Keyword: Mooring dolphin

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Numerical Design Optimization of Mooring Dolphin of Steel Pile Type (강관말뚝식 계류돌핀의 수치적 설계최적화)

  • Lee, Na-Ry;Ryu, Yeon-Sun;Kim, Jeong-Tae;Seo, Kyung-Min;Cho, Hyun-Man
    • Journal of Ocean Engineering and Technology
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    • v.13 no.3 s.33
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    • pp.3-11
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    • 1999
  • Optimum design of mooring dolphin is numerically investigated. Design optimization problem of moring dolphin is first formulated. Geometry and cross sections of piles are used as design variables. Design objective is the total weight of steel piles of mooring dolphin, and the constraints of stress, penetration depth, lower and upper bounds on design variables are imposed. Based on the design variable linking and fixing, several class of design variations are sought. For the numerical optimization, both PLBA(Pshenichny - Lim - Belegundu - Arora) program and DNCONF subroutine code in IMSL library are used. For a dolphin structure with 20 steel piles, vertical and inclined, optimum designs for different cases are successfully obtained, which can be applied for the mooring of a very large floating structure.

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Numerical Design Optimization of Mooring Dolphin of Steel Pile Type (강관말뚝식 계류돌핀의 수치적 설계최적화)

  • 이나리;류연선;김정태;서경민
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1998.04a
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    • pp.237-244
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    • 1998
  • Optimum design of mooring dolphin is numerically investigated. Design optimization problem of mooring dolphin is first formulated. Geometry and cross sections of piles are used as design variables. Design objective is the total weight of steel piles of mooring dolphin and the constraints of stress, penetration depth, lower and upper bounds on design variables are imposed. Based on the design variable linking and fixing, several class of design variations are sought. For the numerical optimization, both PLBA( Pshenichny-Lim-Belegundu-Arora) program and DNCONF subroutine code in IMSL library are used. For a dolphin with 20 steel piles, vertical and inclined, optimum designs for different cases are successfully obtained, which can be applied for the mooring of a large floating structure.

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A Study on the Design of Dolphin System for VLFS (부유식 해양구조물을 위한 돌핀 계류시스템의 설계 연구)

  • Cho Kyo-Nam
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.19 no.1 s.71
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    • pp.105-111
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    • 2006
  • Dolphin mooring system can be a good candidate for the VLFS fastening system in view point of strength and effectiveness. In the design process of the dolphin system, precise calculation of the wave forces and the subsequent selecting the proper number of the piles adopted are one of the main factors. In this paper, one of the design process of the dolphin system is investigated and a proper configuration of the system is derived based on the structural characteristics of the system that was obtained through the structural analysis of the basic pile element confronted to the external loadings including wave impact load. It was found that lot the better design of ihe mooring system for VLFS, mono pile mooring system is more recommendable in a specific condition than other multi piles mooring system.

Experimental Study on a Dolphin-Fender Mooring System for Pontoon-Type Structure (초대형 부유식 구조물의 돌핀-펜더계류시스템에 관한 실험연구)

  • Kim, Jin-Ha;Cho, Seok-Kyu;Hong, Sa-Young;Kim, Young-Shik
    • Journal of the Society of Naval Architects of Korea
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    • v.42 no.1 s.139
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    • pp.43-49
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    • 2005
  • in this paper a dolphin-fender moored pontoon-type floating structure in shallow water depth is studied focusing on mooring force. The pontoon-type floating structure is 500m long, 300m wide. The structure has partially non-uniform drafts of 2.0m and 3.0m. The employed mooring system is a guyed frame type dolphin-fender system. The 1/125 scale model fender system is made of rubber tube to have hi-linear load deflection characteristics. A series of model tests has been conducted focusing on motion and fender force responses in regular and irregular waves at KRISO's ocean engineering basin Non-linear numerical simulation of fender reaction force has been carried out and the results are compared with those of model tests. The simulated rigid body motion and mooring forces also have been compared with the test results.

Motion Analyses for a Very Large Floating Structure with Dolphin Mooring Systems in Irregular Waves (불규칙파 중에서 돌핀 계류된 해상공항에 대한 운동 해석)

  • 이호영;신현경;임춘규;강점문;윤명철
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2000.10a
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    • pp.57-62
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    • 2000
  • The very large flcating structure which am be used for as airport may be as large as several kilomet wide. The first order wave forces as well as wave drift forces are very important forces on such a very large floating In the present studv, the time simulation of motion responses with dolphin-moored VLFS in waves is presented The coeffcients and wave forces involved in the equations are obtained from a three-dimensionul panel method in the frequc The horizontal drift forces and mooring forces for dolphin systems are taken into account. As for numerical example, analyses are carried out for a VLFS in irregular wave condition

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Nonlinear Response Analyses for a Barge-Mounted Plant with Dolphin Mooring Systems in Irregular Waves (불규칙파 중에서 돌핀 계류된 바아지식 해상공장에 대한 비선형 응답 해석)

  • 이호영;신현경;염재선
    • Journal of Ocean Engineering and Technology
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    • v.14 no.4
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    • pp.1-8
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    • 2000
  • The time simulation of motion responses of dolphin-moored BMP in waves is presented. The equation of motion based on Cummin's theory of impulse responses are employed, and solved in time domain by using the Newmark $\beta$ method. The hydrodynamic coefficient and first order wave exciting forces involved in the equations are obtained from a three-dimensional panel method in the frequency domain. The second order wave drift forces and mooring for dolphin system are taken into account. As for numerical example, time domain analysis are carried out for a BMP in irregular wave condition.

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Dynamic Analysis of Mooring Dolphin System Considering Soil Properties (지반의 강성특성을 고려한 지반-돌핀구조계의 동적해석)

  • Yi, Jin-Hak;Oh, Se-Boong;Yun, Chung-Bang;Hong, Sup;Kim, Jin-Ha
    • Journal of Ocean Engineering and Technology
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    • v.12 no.3 s.29
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    • pp.19-30
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    • 1998
  • In this paper, the dynamic analysis of a dolphin system for mooring a floating structure such as barge mounted plant is studied. The characteristics of the soil-pile system are simplified by a set of equivalent spring elements at the mudline. To evaluate the equivalent spring constants, the finite difference method is used. Since the characteristics of the soil-pile system are nonlinear in case of soft foundation, the nonlinear dynamic analysis technique is needed. The Newmark $beta$ method incorporating the modified Newton-Raphson method(initial stiffness method) is used. A numerical analysis is performed on two mooring dolphin systems on soft foundation and rock foundation. In case of the rock foundation, the characteristics are found to be nearly linear, so the linear dynamic analysis may be sufficient to consider the foundation effect. But in case of soft foundation, the non-linearity of the foundation appears to be very signigicant, so the nonlinear dynamic analysis si needed.

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Nonlinear Subgrade Reaction Analysis of the Soil-Pile System for Mooring Dolphin Structures (계류식 돌핀구조물에 대한 지반-말뚝계의 비선형 지반반력 해석)

  • 오세붕;이진학;이상순;김동수;정태영
    • Journal of the Korean Geotechnical Society
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    • v.15 no.2
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    • pp.3-16
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    • 1999
  • The objective of BMP( Barge Mounted Plant) project is to construct plants on mooring floating structures at sea. To analyze the pile behavior under mooring dolphins, generally, axial or lateral behavior of soil-pile system is evaluated by using a nonlinear subgrade reaction method which models the pile as a structural element and the soil as series of nonlinear springs along the depth. As a result, load-displacement curves at pile head can be solved by finite difference method and the equivalent stiffness of bottom boundaries of dolphin structure is evaluated. In this study off-shore site investigation was performed on the marine area of Koje Island and axial and lateral load transfer curves of the ground were modeled with depth. The subgrade reaction analysis was performed for piles under axial or lateral loadings, and the required penetration depth and section of the pile were determined. Subsequently, the spring boundaries under the dolphin structure could be modeled from the calculated load-displacement curve and then the dynamic response of the dolphin structure was analyzed reasonably by considering ground conditions. The analysis considering the stiffness of the soil-pile system has resulted in larger displacement amplitudes than those for rigid foundations. Furthermore, moment distributions of the casing were dependent on the soil-pile system so that deformable foundation induces the larger moment of top section of casing and the smaller moment of pile head.

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Analyses on the Behaviour of Ocean Structure Due to Ship Collision (선박의 충돌로 인한 해양구조물의 거동 해석)

  • 이호영;박종환;곽영기
    • Journal of Ocean Engineering and Technology
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    • v.15 no.4
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    • pp.115-119
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    • 2001
  • The simulation of motion responses of a dolphin-moored ocean structure in shallow water when it cllides with a ship, has been carried out. The equation of motion in the time domain according to Cummin's theory is employed, and solved by making use of the Newmark-${\beta}$ method. The added mass and damping coefficients involved in the equations are abtained from a three-dimensional panel method in the frequency domain. The impact forces due to ship collision are calculated using both the elastic and non-elastic modelings. The mooring forces for dolphin systems of ocean structure are regarded as linear spring forces.

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Behaviour Analyses of Ocean Structure Due to Ship Collision (선박의 충돌로 인한 해양구조물의 거동 해석)

  • 이호영
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.05a
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    • pp.103-107
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    • 2001
  • When ship claps against the ocean structure sited at shallow water, the time simulation of motion responses of dolphin-moored ocean structure is presented. The equatien of motion based on Cummin's theory of impulse responses are employed, and solved in time domain by using the Newmark $\beta$ method. The added mass and damping coefficients involved in the equations are obtained from a three-dimensional panel method in the frequency domain. The impact forces due to ship collision are modeled as two method, and those are elastic and non-elastic collisions. The mooring forces for dolphin systems of scean structure are considered as linear spring system.

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