• 한국해양공학회지
• /
• 제32권4호
• /
• pp.215-221
• /
• 2018

In this study, the optimal design of a mooring system was carried out. Unlike almost all design methods, which are based on the deterministic method, this study focused on the probabilistic method. The probabilistic method, especially the design of experiment (DOE), could be a good way to cover some of the drawbacks of the deterministic approach. There various parameters for a mooring system, as widely known, including the weight, length, and stiffness of line. Scenarios for the mooring system parameters were produced using the Latin Hypercube Sampling method of the probabilistic approach. Next, a vessel-mooring system coupled analysis was performed in Orcaflex. A total of 50 scenarios were used in this study to optimize the initial design by means of a genetic algorithm. Finally, after determining the optimal process, a reliability analysis was performed to understand the system validity.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 1998년도 봄 학술발표회 논문집
• /
• pp.237-244
• /
• 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.

• 한국해양공학회지
• /
• 제27권6호
• /
• pp.16-21
• /
• 2013

In this paper, the mooring system for a floating wave energy farm is designed based on a two-dimensional analysis. The mooring system uses an anchorless mooring line linking two floaters in a floating wave energy farm. The basic equation to determine the length of the mooring line between the two floaters is proposed. The other properties such as the diameter and pretension are taken from the mooring line for a single floater. The dynamic behavior and safety of the designed mooring system under extreme ocean conditions are analyzed with the commercial software Orcaflex. A numerical study shows the stability and high safety in tension of the designed mooring lines for a floating wave energy farm. The proposed anchorless mooring system for a floating wave energy farm results in a considerable reduction in the length of the mooring line, contributing to the economics of a floating wave energy farm.

• 한국정보기술학회논문지
• /
• 제16권12호
• /
• pp.41-47
• /
• 2018

부이형 수중감시 시스템은 필요시 특정해역에 설치되어 일정기간 운용하고 회수이후, 다른 해역으로 이동하여 수중감시를 수행하는 장비이다. 본 논문에서는 부이형 수중감시 시스템에 적용되는 계류라인에 대하여 설치성을 유지하고 안정적인 운용이 가능하도록 계류방법을 선정하고 계류라인의 구조를 설계하였다. 부이형 수중감시 시스템의 구성요소인 배열센서조립체의 신호전송 케이블의 간섭을 고려하여 2점 계류방법을 선정하였고, 계류라인은 해역 이동에 따른 설치/회수성을 고려하여 부이체인, 나일론 로프, 그리고 앵커체인의 3단 복합구조를 기본 구성으로 설계하였다. 설계 유효성을 검증하기 위하여 수치실험과 조파수조 시험을 수행하여 유사성을 확인하였으며, 최종적으로 해상시험 위치의 환경을 대상으로 계류라인의 설계를 수행하였다. 최종 설계에 의해 제작된 계류라인은 해상시험을 통하여 설계 시 고려한 유의파고 이상에서도 안정적인 계류를 수행함을 확인하였다.

• 수산해양기술연구
• /
• 제35권2호
• /
• pp.201-208
• /
• 1999

To develop a new fish cage which is required for offshore or moving cage culturing system has been gradually increased against being closely dense of fish cage in shallow water. Though submersible fish cage culturing system is essential technology for converting from shallow water into the offshore, it was pointed out the serious problem about stability of which are sinking and floating state. This study is presented conceptual design of submersible fish cage centered with a mooring steel pile to acquire stability and faculty. Design of mooring steel pile for submersible fish cage culturing system needs to carry out optimal design of mooring steel pile for which much efforts are required. Formulation and optimal design process of submersible fish cage are organized into using Sequential Quadratic Programming method of numerical optimization. For submersible fish cage system centered with a mooring steel pile, process of the optimal design is proposed and the optimal solutions are obtained.

• 한국해양학회지:바다
• /
• 제7권4호
• /
• pp.286-303
• /
• 2002

한국해양연구원에서는 1978년이래 해류계 계류에 의한 해류관측을 실시하였다. 본 단보에서는 한국주변의 연안역과 대륙붕해역에서 시도하였던 계류 형태와 계류 실패 사례를 소개하고자 한다. 천해역에서는 U-type 계류와 트롤방지 해저 계류장치를 이용한 해류관측 방법이 주로 이용되었다. 천해역에서 계류 실패를 피하기 위해서는 (1) 어로활동을 포함한 계류현장의 환경을 고려하여 적절한 계류 계획을 세워야 하며 (2) 계류기간과 수심 및 기타 예기치 않게 계류선에 영향을 줄 수 있는 제반 요인 등을 고려하여 적절한 계류용품이 사용되어야 한다

• International Journal of Ocean System Engineering
• /
• 제2권2호
• /
• pp.97-105
• /
• 2012

A all floating structures operating within a limited area require, stationkeeping to maintain the motions of the floating structure within permissible limits. In this study, methods for selecting and optimizing the mooring system Caisson for floating wind turbines in shallow water are investigated. The design of the mooring system is checked against the governing rules and standards. Adequately verifying the design of floating structures requires both numerical simulations and model testing, the combination of which is referred to as the hybrid method of design verification. The challenge in directly scaling moorings for model tests is the depth and spatial limitations of wave basins. It is therefore important to design and build equivalent mooring systems to ensure accurate static properties (global restoring forces and global stiffness).

• 해양환경안전학회지
• /
• 제29권2호
• /
• pp.248-253
• /
• 2023

대다수의 부유식 해양플랜트는 위치 유지의 방법으로서 체인 계류 시스템을 사용하나, 그 설계 변경 과정은 논문으로 찾아보기 힘들다. 본 연구는 FLBT를 대상 해양플랜트로 선정하여 계류 초기설계안과 모형시험을 수치해석으로 분석하고, 변경된 설계조건에 따라 새로운 계류 설계안을 제시하였다. 주된 환경 방향에 따라 계류선 묶음(bundle)의 주 방향을 조절하는 것이 계류 설계하중 감소에 크게 유효했다. 터렛 계류된 해양플랜트라도 횡파에 노출되며, 횡파 중 운동 때문에 높은 계류 인장력이 발생했다. 일치된 환경 방향 조건은 설계조건이 될 수 없으며, 바람, 파도, 조류의 각 환경 방향이 복잡한 조건에서 설계 계류 하중이 발생했다. 횡요 운동이 계류 인장력에 미치는 영향이 큼으로 적절한 횡요 감쇠 계수를 계류해석에 적용하는 것이 중요하다.

• Ocean Systems Engineering
• /
• 제1권2호
• /
• pp.157-169
• /
• 2011

To provide more rational design solutions at conceptual design level, axiomatic design method has been applied to solve critical part of a new engineering problem called Mobile Harbor. In the implementation, the Mobile Harbor, a functional harbor system that consists of a vessel with container crane approaches to a container ship anchored in the open sea and establishes a secure mooring between the two vessels to carry out loading and unloading of containers. For this moving harbor system to be able to operate successfully, a reliable and safe strategy to moor and maintain constant distance between the two vessels in winds and waves is required. The design process of automatic ship-to-ship mooring system to satisfy the requirements of establishing and maintaining secure mooring has been managed using axiomatic design principles. Properly defining and disseminating Functional Requirements, clarifying interface requirements between its subsystems, and identifying potential conflict, i.e. functional coupling, at the earliest stage of design as much as possible are all part of what need to be managed in a system design project. In this paper, we discuss the automatic docking system design project under the umbrella of KAIST mobile harbor project to illustrate how the Axiomatic Design process can facilitate design projects for a large and complex engineering system. The solidified design is presented as a result.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제11권1호
• /
• pp.178-201
• /
• 2019

The appropriate design of a mooring system to maintain the position of an offshore structure in deep sea under various environmental loads is important. Fatigue design of the mooring line considering OPB/IPB(out-of-plane bending/in-plane bending) became an essential factor after the incident of premature fatigue failure of the mooring chain due to OPB/IPB in the Girassol region in West Africa. In this study, mooring line fatigue analysis was performed considering the OPB/IPB of a spread moored FPSO in deep sea. The tension of the mooring line was derived by hydrodynamic analysis using the de-coupled analysis method. The floater motion time histories were calculated under the assumption that the mooring line behaves in quasi-static manner. Additional time domain analysis was carried out by prescribing the obtained motions on top of the selected critical mooring line, which was determined based on spectral fatigue analysis. In addition, nonlinear finite element analysis was performed considering the material nonlinearities, and both the interlink stiffness and stress concentration factors were derived. The fatigue damage to the chain surface was estimated by combining both the hydrodynamic and stress analysis results.