• 대한조선학회 특별논문집
• /
• 대한조선학회 2015년도 특별논문집
• /
• pp.79-84
• /
• 2015

A BC-B type bulk carrier is rarely built, so the structural characteristics is not reported and familiar so far. The biggest difference between BC-B and BC-A type vessel is applying alternate cargo loading, which density is over $1.0ton/m^3$. In this paper, 150K DWT class BC-B type bulk carrier is calculated and compared with BC-A type vessel, which has same condition such as main dimension and deadweight, about prescriptive rule and FEA based on CSR. And aspect ratio of target vessel is smaller than typical capsize bulk carrier, so 150K and 180K bulk carrier, which applied BC-A type, are also compared to find feature of wide beam vessel.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2007년도 춘계학술대회B
• /
• pp.3080-3085
• /
• 2007

Shape optimization of the 3-dimensional WIG airfoil with 3.0-aspect ratio has been performed by using the multi-objective genetic algorithm. The WIG ship effectively floating above the surface by the ram effect and the virtual additional aspect ratio by a ground is one of next-generation and cost-effective transportations. Unlike the airplane flying out of the ground effect, a WIG ship has possibility to capsize because of unsatisfying the static stability. The WIG ship should satisfy aerodynamic properties as well as a static stability. They tend to strong contradict and it is difficult to satisfy aerodynamic properties and static stability simultaneously. It is inevitable that lift force has to scarify to obtain a static stability. Multi-objective optimization technique that the individual objectives are considered separately instead of weighting can overcome the conflict. Due to handling individual objectives, the optimum cannot be unique but a set of nondominated potential solutions: pareto optimum. There are three objectives; lift coefficient, lift-to-drag ratio and static stability. After a few evolutions, the non-dominated pareto individuals can be obtained. Pareto sets are all the set of possible and excellent solution across the design space. At any selections of the pareto set, these are no better solutions in all design space

• 해양환경안전학회지
• /
• 제24권3호
• /
• pp.325-331
• /
• 2018

This paper deals with the dynamical analysis of a vessel that leads to capsize in regular beam seas. The complete investigation of nonlinear behaviors includes sub-harmonic motion, bifurcation, and chaos under variations of control parameters. The vessel rolling motions can exhibit various undesirable nonlinear phenomena. We have employed a linear-plus-cubic type damping term (LPCD) in a nonlinear rolling equation. Using the fourth order Runge-Kutta algorithm with the phase portraits, various dynamical behaviors (limit cycles, bifurcations, and chaos) are presented in beam seas. On increasing the value of control parameter ${\Omega}$, chaotic behavior interspersed with intermittent periodic windows are clearly observed in the numerical simulations. The chaotic region is widely spread according to system parameter ${\Omega}$ in the range of 0.1 to 0.9. When the value of the control parameter is increased beyond the chaotic region, periodic solutions are dominant in the range of frequency ratio ${\Omega}=1.01{\sim}1.6$. In addition, one more important feature is that different types of stable harmonic motions such as periodicity of 2T, 3T, 4T and 5T exist in the range of ${\Omega}=0.34{\sim}0.83$.

• 대한조선학회논문집
• /
• 제44권1호
• /
• pp.1-7
• /
• 2007

Recently, researches to find rational mathematical model for prediction of capsizing have been progressed by ITTC. Lee(1997) developed a mathematical model which describes 6 DOF transient motions, such as capsizing, of a ship in regular waves. In this study a mathematical model for prediction of capsizing in following and quartering seas is developed based on Lee's model. And factors affecting prediction of capsizing are analyzed through comparing simulation results with experimental results. Present simulation results are compared with ITTC bench mark test results. In rolling tests with beam seas and tree runs with stern quartering seas, capsizing events are predicted well. But calculated roll angle is larger than experimental one. It is found that nonlinear manoeuvring coefficients don't affect the prediction of capsizing events.

• 한국항해항만학회지
• /
• 제33권4호
• /
• pp.255-261
• /
• 2009

Prediction of the stability for ships is very complex in reality. In this paper, risk based approach is applied to predict the probability of capsize for a certified ship, which is effected by the forces of sea especially the wave loading Safety assessment and risk analysis process are also applied for the probabilistic prediction of stability for ships. The probability of shipsencountering different waves at sea is calculated by the existed statistics data and risk based models. Finally, ship capsizing probability is calculated according to single degree of freedom(SDF) rolling differential equation and basin erosion theory of nonlinear dynamics. Calculation results show that the survival probabilities of ship excited by the forces of the seas, especially in the beam seas status, can be predicted by the risk based method.

• 한국해양공학회지
• /
• 제22권4호
• /
• pp.78-83
• /
• 2008

In recent years, small boats used for marine leisure have been steadily increasing because of the increase in national income and the desire for marine leisure. But the repair of such small boats in dry dock has pointed out many faults in small FRP-shipbuilding in terms if workspace and manpower. Lifting a boat from the water to land is done with a crane or by hand using a sling around the bottom of the boat. But dry dock work is limited by the scale of the boat, which corresponds to the crane capacity, with carelessness making it possible to capsize a boat and endanger life. The purpose of this study was the development of a marine docking system that would improve economical efficiency and safety, for which we carried out concept design, model tests, structural analysis, etc.

• Journal of Advanced Research in Ocean Engineering
• /
• 제2권3호
• /
• pp.112-128
• /
• 2016

Capsize and sinking of a coastal car ferry has occurred in a Korean offshore area and has caused hundreds of human casualties. The rapid turn and improper cargo loading are inferred as the main reasons of the accident. It has motivated to develop a new system of cargo securing with improved safety of Korean coastal ferries. This paper provides a new approach regarding cargo securing safety assessment which is purely based on force equilibrium conditions, because IMO CSS is suitable for the ocean-going vessels. The mathematical formulations are presented for the new approach. This paper also introduces a newly developed safety assessment system based on the new approach. Most outstanding features are that it can utilize acceleration data produced from hydrodynamic motion analyses or assumed maximum extents of ship motion components and that securing safety assessment is simultaneously possible for unlimited number of cargoes with finite number of lashings.

• 한국항해항만학회지
• /
• 제26권2호
• /
• pp.189-192
• /
• 2002

우리나라 대부분의 어선은 침수 및 전복에 의해 야기되는 해양사고에 있어 그 빈도가 높으며, 특히 24m이하의 소형어선에서 두드러진다. 그럼에도 불구하고 소형어선에 대한 복원성 기준이 없을 뿐 아니라 소형어선의 복원성 자료를 찾기란 그리 쉽지 않다. 이에 본 연구에서는 90년 이후 표준어선으로 고시되어 건조 실적이 있는 실적선 10척에 대해 계측된 자료를 활용하여 이를 기초로 Genetic Programming을 이용한 GM 추정식을 도출하였다. 또한 국외 복원성 기준과 GP 추정식을 이용 각각에 대해서 GM을 평가하여, Genetic Programming에 의한 GM추정의 타당성을 보였다. 하지만, 이러한 결과값이 사용되기 위해서는 보다 많은 실적선 Data를 이용한 추론이 요구된다.

• 한국해양환경ㆍ에너지학회지
• /
• 제8권4호
• /
• pp.193-202
• /
• 2005

본 논문에서는 침몰선박이 보유하고 있는 모든 위해요인을 체계적으로 규명하고, 위해요인으로 인한 손실정도를 정량적으로 산출하여 효과적이고 일관된 침몰선박 관리와 과학적이고 경제적인 침몰선박 처리 의사결정에 활용할 수 있는 침몰선박 위해도 평가모델 및 정보시스템의 개발내용을 소개하고자 한다.

• 수산해양기술연구
• /
• 제51권4호
• /
• pp.520-526
• /
• 2015

A tragic disaster happened by capsizing O-Ryong 501 trawler at Western Bering Sea in 1st, Dec. 2014. The disaster was caused by the severe weather and the long deferred escape from the storm in fully developed high sea. Lots of sea water from poop deck rushed into the fish ponder with fishes all together after hauling net and then remove the fishes from codend. The vessel became to incline to the one side caused by the weight and the free surface effect of flood sea waters and fishes at initial stage. In spite of crews all effort to discharge the waters, but the work was not achieved successfully. For the worse thing, the order of abandon ship was issued too late. After all, the ship capsized and sank, then almost crews became to the victims of the casualty including captain. In this paper, author carried out restrictively the calculation of dynamic factors influenced on the disaster including the weather condition and effects of the flood sea waters, and found out that the most important causes of the disaster were the decrease of stabilities, GM was decreased from 0.9m to 0.08 m, and the high waves which led to the vessel disaster.