• 한국지반공학회논문집
• /
• 제22권3호
• /
• pp.37-43
• /
• 2006

이 연구는 선박을 정착하기 위하여, 해성점토에 관입된 앵커 및 닻줄의 변형, 인장력 및 지반거동을 해석할 수 있는 방법에 대한 연구로써, 앵커와 닻줄을 multi-segment로 나누어, 일차원 유한 요소 해석을 하였다. 각 element와 지반거동에 대한 힘과 모멘트의 평형조건을 만족시키면서, 앵커와 닻줄의 변형과 인장력을 해석하는 방법으로, 앵커 및 선박 상판에서 구할 수 있는 특정경계조건을 구한 후, 지속적인 반복작업을 이용하여 각 element의 변형과 인장력을 구하는 방법을 채택하였다. 이러한 연구결과는 앵커 및 닻줄이 사용된 해양구조물의 설계 및 시공에 반영될 수 있으며, 이 연구의 예측결과는 실제 현장 건ta와 비교 분석되었으며, 비교를 위한 항목으로는 anchor의 지지력, 닻줄길이, 선박에 연결된 닻줄의 각도 및 인장력 등이 사용되었다. 각 항목의 비교결과, 실제 현장 data와 상당히 일치하여, 이 방법으로 지반 및 선체의 거동을 예측할 수 있다는 것이 증명되었다.

• 한국해양공학회지
• /
• 제17권3호
• /
• pp.7-12
• /
• 2003

The Navy has tested the holding capacity of many kinds of anchors in order to propose the design chart for the holding capacity of drag-embedment anchors. The design chart is only applicable up to the cable bottom angle 60 when load is raised to the ultimate weight. However, the anchor experiences a significant uplift force when the angle is above 60 in shallow seas. In this paper, the procedure for the estimation of the holding capacity of anchors in mud is proposed. Drag-embedment anchors do not function well when there is a significant uplift component of load in soft seafloor materials, such as mud. Under these loading and seafloor conditions, gravity anchors seems to be more efficient. However, they are too heavy for their holding capacity. Therefore, suction pile (hollow concrete block) is more beneficial to the foundntion of silt protector in shallow sea with mud seafloor materials.

• 한국해안해양공학회지
• /
• 제5권1호
• /
• pp.25-38
• /
• 1993

해양구조물의 케이블 반응 분석을 위한 다방향 파람 스펙트라의 수치모델이 조사되었다. 여러 형태의 전파모델을 파랑으로 인한 물입자의 흐름과 계류시스템을 예측하기 위해 사용하였다. 케이블에 작용하는 수동역학적 파력은 케이블의 경사에 평행한 방향과 접선방향에서의 항력과 관성력을 고려한 Morison 공식에 의해 평가되었다. 변위와 속도, 궤적, 위상면의 반응, 그리고 장력을 고려한 다방향 불규칙 파랑의 수치해석에 의하여 부체의 tether pc와 anchor point에서 계류시스템 케이블의 반응을 나타내었다. 서로 다른 항력 계수와 다양한 유의 파고, 그리고 선택된 파랑계수들이 이 분석에 고려되었다. 예제에서 고려된 특정 시스템을 통하여 파랑의 전파함수계수와 항력계수 뿐만 아니라 파랑의 주기와 높이가 케이블-부체시스템의 동적반응에 중요한 영향을 미침을 알 수 있었다.

• 수산해양기술연구
• /
• 제46권3호
• /
• pp.214-222
• /
• 2010

The paper presents investigations on to which degree the sinking speed of longlines is influenced by type of bait, bait sinking orientations and anchor weights. The main aim of this study is to obtain further insight in the ocean current displacement phenomena in demersal longlining. The sinking speed is one of the main factors deciding the current displacement. In an ongoing project, sinking speed experiments with longlines with 6 kg and 10 kg anchor weights have been carried out in the Trondheim fjord. The longlines used in the first experiments were rigged without bait and hook. The results of these experiments with two different anchor weights have revealed only a slight difference in the sinking speed, except for the part near to the anchors, even though the sinking speed of longlines in general is supposed to be much influenced by the anchor weights. The reason for the obtained result is supposed to be that the experiments have been carried out at relative shallow waters. Further studies have included bait sinking experiments in the flume tank. The experiments showed that the drag coefficient of "fillet type (flat)" bait varied from 0.763 to 1.735, while it for "elliptic type" bait varied from 0.62 to 1.483. Other activities have included calculation of the sinking speed of longlines as a function of the established resistance coefficients of bait of various shape and size for commercial longlining. The calculated sinking speed of a longline with the fillet type bait was found to be 12.4 to 16.5% lower than for a longline without bait.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2000년도 봄 학술발표회 논문집
• /
• pp.58-76
• /
• 2000

An analytical solution method capable of determining the geometric configuration and developed tensile forces of mooring lines associated with fixed plate/pile or drag anchors is presented. The solution method, satisfying complete equilibrium conditions, is capable of analyzing multi-segmented mooring lines that can consist of either chains, cables, or wires embedded in layered seafloor soils. Centrifuge model tests and full -scale field tests were used to calibrate and validate the analytical solution.

• 한국항해항만학회:학술대회논문집
• /
• 한국항해항만학회 2010년도 춘계학술대회
• /
• pp.219-220
• /
• 2010

A new concept of ocean transport system, called mobile harbor, was introduced as a feasibility study in Korea in 2009. Target of the mobile harbor is a smart distance transport of containers with or without cargo handling cranes. Although the mobile harbor project has a lot of topics to deal with, this paper is to focus on only ship-to-ship stabilized mooring, which plays a key role in cargo handling. The ship-to-ship stabilized mooring system was developed and installed on beard a barge of LOA 32m and breadth 12m. The dockside tests as sea test were carried out so as to ascertain ascertained whether the systems can work well to control the barge's motion. The results of dockside test showed that the heave motion of the barge's motion can be reduced by more than 45%.

• 한국항해항만학회지
• /
• 제34권4호
• /
• pp.281-286
• /
• 2010

A new concept of ocean transport system, called mobile harbor, was introduced as a feasibility study in Korea in 2009. Target of the mobile harbor is a short distance transport of containers with or without cargo handling cranes. Although the mobile harbor project has a lot of topics to deal with, this paper is to focus on only ship-to-ship stabilized mooring, which plays a key role in cargo handling. The ship-to-ship stabilized mooring system was developed and installed on board a barge of LOA 32m and breadth 12m. The dockside tests as sea test were carried out so as to ascertain whether the systems can work well to control the barge’s motion. The results of dockside test showed that the heave motion of the barge's motion can be reduced by more than 45%.

• 대한토목학회논문집
• /
• 제9권1호
• /
• pp.11-23
• /
• 1989

본 논문에서는 guyed tower의 mooring system에 관한 수치해석결과를 제시하였다. 가상일의 원리와 유한요소법을 사용하여 기본식을 유도하였으며 케이블의 기하학적 비선형성을 고려하였다. 유체의 항력과 관성력은 Morrison식을 사용하여 고려하였으며 비선형 운동방정식의 해는 Newton-Raphson방법과 Newmark-${\beta}$ 방법을 사용하여 구하였다. Tower와 mooring line의 부착점에서의 초기경사각, 인장력, clump weight를 집중하중으로 이상화 시키는 종래의 해석방법의 문제점도 아울러 고찰하였다. 수치해석 예를 통하여 본 논문에서의 해석방법의 정당성을 입증하였다.

• 수산해양기술연구
• /
• 제51권4호
• /
• pp.600-613
• /
• 2015

The Fishing gear loss has been repeated every year in the West Sea; however, there has been no solution. So fisher men have undergone economic loss every year. Thus it is required to reduce the loss of fishing gear. In this study to find out the reason that the fishing gear is lost in the Sea, 10 years data of wave and current for 6 locations in the West Sea were investigated and a numerical modelling were conducted into the behaviour of a gillnet in wave and current. The fishing gear was modelled with the mass spring model. As a result, it came out into the open that the location where fishing gear loss occurred most frequently was Choongnam province. The height of the maximum significant wave in this province was 6.7 m and the period of that was 4.4 second. The maximum current speed was 0.7 m/s. As a result of simulation with these data, it was revealed that the buoy is one of the reasons to decrease the holding power of the gillnet. For example, the tension of anchor rope was decreased to 50% while the drag coefficient or volume of buoy was decreased to 25%. So it is predicted that an improvement of the buoy contributes to the reduction of the gillnet loss.

• 해양환경안전학회:학술대회논문집
• /
• 해양환경안전학회 2007년도 춘계학술발표회
• /
• pp.169-174
• /
• 2007

부표시스템 침수체의 주요형상인 원형실린더에 제어봉을 부착하여 2차원 단면의 유동특성에 대해서 수치해석을 수행하였다. 유속을 0.1m/s에서 0.5m/s로 변화시키면서 부표시스템 주위의 유동현상을 파악하고 부표시스템의 효과적인 유통제어를 위해 실린더 (D=50mm)에 제어봉의 직경을 0.1D 에서 O.5D 까지 부착하여 조류에 의한 영향을 조사하였다. 유동장내의 속도분포는 PIV계측기법 중 2 프레림 입자추적법을 사용하여 수치해석의 정도를 높이고자 0.3m/s에서 비교 평가하였다. 실린더 주위의 압력분포는 0.2D 의 제어봉을 부착하였을 경우, 유속의 변화에 관계없이 가장 양호한 경향을 보이는 것을 알 수 있었다.