• 한국해안·해양공학회논문집
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• 제31권6호
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• pp.478-484
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• 2019

용수 파력발전소의 해저케이블이 단락되는 사고가 2014년 겨울에 발생했다. 그 원인을 밝히기 위해서 재현기간 50년 이상의 고파랑 발생 가능성과 케이블 보호공의 설계중량 과소 산정 여부를 검토하였다. 기상청에서 운용하는 부이의 관측자료와 파랑추산자료를 검토하여 겨울동안 발생한 고파랑의 재현기간을 살펴보았다. 케이블 보호공의 설계중량을 검토하기 위해서 항만 및 어항 설계기준 뿐만 아니라 파의 입사각이 큰 경우의 연구결과를 참조해서 직접 안정중량을 계산하였다. 분석 결과, 2014년 겨울동안 재현빈도 50년 이상의 고파랑은 발생하지 않았으며, 경사지게 입사하는 파랑에 대한 케이블 보호공의 중량이 부족해서 보호공이 이탈한 것으로 나타났다.

• 한국해양공학회지
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• 제23권1호
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• pp.96-103
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• 2009

In 2006, Jeju Island in South Korea experienced a crisis, no electricity for three hours anywhere in the entire island. This incident was caused by a domino effect that occurred after one of the submarine power cables connecting the island to Haenam, a coastal city on the mainland, was damaged by an external load, probably from a ship anchor or a steel pile being used in marine farming. This study presents a collision analysis of a new submarine power cable protector called arch type reinforced concrete. For the analysis, a dynamic finite element program, ANSYS AUTODYN, was used to examine the displacement and stress of the submarine power cable protector using different material models (RHT concrete model, Mohr.Coulomb concrete model). In addition, two reinforcing bar spacings, 75 mm and 150 mm, were considered. From the analyses, the effects of the parameters (concrete model and spacing) on the results (displacement and stress) were analyzed, and the relations between the damage and parameters were found.

• 한국해양공학회지
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• 제30권2호
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• pp.109-116
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• 2016

A flexible concrete mattress (FCM) is a structural system for protecting submarine power or communication cables under various load types. To evaluate its of protection performance, a numerical analysis of an FCM under an anchor collision was performed. The explicit dynamics of the finite element analysis program ANSYS were used for the collision analysis. The influences of the steel reinforcement modeling and collision angle of the anchor on the collision behavior of the FCM were estimated. The FCM damage was evaluated based on the results of the numerical analysis considering the numerical modeling and collision environment.

• 한국해양공학회지
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• 제29권1호
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• pp.70-77
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• 2015

The purpose of this study was to provide fundamental data for an anchor collision simulation of an FCM (flexible concrete mattress). Numerical material models (elastic-perfectly plastic model, Drucker-Prager model, and RHT concrete model) were compared. ANSYS Explicit Dynamics was used for collision analyses. An FE model was used for the anchor, FCM, andreinforcement bars. The results showed that the behavior of the FCM was verydifferent that those ofthe material models. In particular, the effect of the pressure dependent strength was most noticeable among the properties of concrete.

• 한국전산구조공학회논문집
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• 제24권6호
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• pp.609-616
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• 2011

콘크리트와 철근의 재료모델 그리고 스톡앵커의 낙하거리 변화에 따른 아치형 해저 케이블 보호구조물의 충돌특성을 분석하였다. 콘크리트의 재료모델로는 plastic kinematic모델과 Johnson-Holmquist Concrete모델이, 철근의 재료모델은 선형탄성모델과 plastic kinematic모델이 고려되었다. 스톡앵커의 무게는 2ton이며 낙하거리는 3, 5, 8.83m로 선정되었다. 충돌해석을 위해 유한요소해석 프로그램 ANSYS가 사용되었고, 해석시간 단축을 위해 낙하거리를 초기속도로 변화하는 기법을 사용하였다. 낙하거리 변화에 따른 재료모델의 민감성을 분석한 결과, 콘크리트의 충돌응답은 콘크리트모델에 민감하고 철근의 충돌응답은 일차적으로 철근모델에 이차적으로 콘크리트모델에 민감함을 알 수 있었다.

• 한국해양공학회지
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• 제32권5호
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• pp.324-332
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• 2018

It is known that damages to the subsea cables used for electric power transmission between islands and countries, including renewable energy from offshore wind power, current, tides, etc., cost much to restore, which causes social and economic losses. Various types of fishing rigs and anchors have been reported to be the greatest hazards to subsea cables. It is possible to design and construct a suitable protection facility for a subsea cable by precisely estimating the underwater behavior of such hazardous apparatuses. In this study, numerical simulations of the underwater behaviors of various hazardous apparatuses were carried out using fluid-structure interaction (FSI) analysis as a basic study to simulate the actual behavior phenomena of hazardous apparatuses in relation to a subsea cable. In addition, the underwater drop characteristics according to the types of hazardous apparatuses were compared. In order to verify the accuracy of the FSI analysis method used in this study, we compared the test results for underwater drops of a steel ball bearing. Stock anchors, stockless anchors, and rocket piles, which were actually reported to be the cases of damage to subsea cables along the southwest coast of Korea, were considered as the hazardous apparatuses for the numerical simulations. Each hazardous apparatus was generated by a Lagrangian model and coupled with the fluid domain idealized by the Eulerian equation to construct the three-dimensional FSI analysis model. The accuracy of the numerical simulation results was verified by comparing them with the analytical solutions, and the underwater drop characteristics according to the types of hazard apparatuses were compared.