• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.308-315
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• 2008

극저온 유체를 운반하는 선박의 화물창은 보통 1차 방벽과 2차 방벽으로 구성되어 있다. 1차 방벽에 소량의 극저온 유체의 누출이 생기더라도, 액밀이 되는 2차 방벽에서 추가적인 극저온 유체의 누출을 방지할 수 있기 때문이다. 그러나 2차 방벽에 추가적인 손상이 생길 경우 유리솜으로 만들어진 Flat Joint를 거쳐 선체내벽까지 극저온 유체에 노출될 가능성이 있게 된다. 본 연구의 관심사는 2차 방벽의 손상 정도에 따라, 그리고 누출되는 극저온 유체의 양에 따라, 내측선체에 얼마나 영향이 미치는가를 알아보는 것이다. 이를 위해 본 연구에서는 극저온 유체를 운반하는 선박의 화물창을 구성하는 2차 방벽에 구멍을 뚫어 Flat Joint 사이로 극저온 유체가 흘러 들어가도록 격자를 생성한 후, CFD 소프트웨어를 이용하여 극저온 유체의 누출에 대한 계산을 수행 하였으며 이를 실험 결과와 비교 분석 하였다. 실험과 계산 결과를 살펴보면, 극저온 유체량에 따라 내측 선체에의 피해를 최소화 할 수 있음을 확인하였다.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.308-315
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• 2008

극저온 유체를 운반하는 선박의 화물창은 보통 1차 방벽과 2차 방벽으로 구성되어 있다. 1차 방벽에 소량의 극저온 유체의 누출이 생기더라도, 액밀이 되는 2차 방벽에서 추가적인 극저온 유체의 누출을 방지할 수 있기 때문이다. 그러나 2차 방벽에 추가적인 손상이 생길 경우 유리솜으로 만들어진 Flat Joint를 거쳐 선체내벽까지 극저온 유체에 노출될 가능성이 있게 된다. 본 연구의 관심사는 2차 방벽의 손상 정도에 따라, 그리고 누출되는 극저온 유체의 양에 따라, 내측선체에 얼마나 영향이 미치는가를 알아보는 것이다. 이를 위해 본 연구에서는 극저온 유체를 운반하는 선박의 화물창을 구성하는 2차 방벽에 구멍을 뚫어 Flat Joint 사이로 극저온 유체가 흘러 들어가도록 격자를 생성한 후, CFD 소프트웨어를 이용하여 극저온 유체의 누출에 대한 계산을 수행 하였으며 이를 실험 결과와 비교 분석 하였다. 실험과 계산 결과를 살펴보면, 극저온 유체량에 따라 내측 선체에의 피해를 최소화 할 수 있음을 확인하였다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.10
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• pp.791-797
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• 2003

A liquid storage rectangular tank structures are used In many fields of civil, mechanical and marine engineering. Especially, Ship structures have many tanks In contact with Inner or outer fluid, like ballast, fuel and cargo tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks in contact with fluid near engine or propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tank structures. In the previous report, we have developed numerical tool of vibration analysis of 3-dimensional tank structure using finite elements for plates and boundary elements for fluid region. In the present report, using the numerical analysis, vibrations characteristics In deep water tank are investigated and discussed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1079-1084
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• 2003

A liquid storage rectangular tank structures are used in many fields of civil, mechanical and marine engineering. Especially, Ship structures have many tanks in contact with inner or outer fluid, like ballast, fuel and cargo tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks ill contact with fluid near engine or propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tank structures. In the previous report, we have developed numerical tool of vibration analysis of 3-dimensional tank structure using finite elements for plates and boundary elements for fluid region. In the present report, using the numerical analysis, vibrations characteristics in deep water tank are investigated and discussed.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2002.03a
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• pp.145-153
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• 2002

A coastwise chemical tanker sailing at full speed has capsized in calm water and whole turing. In the precious paper, we investigated reasons of the accident by demonstrating the proper correction for the free surface effect of the liquid cargo and the bow-sinkage effect. In this paper, we also carry out model experiments of a transverse pressure under the seawater and an outward heel moment according to the heel angle and rudder angle, on the basis of radius of turning circle, ship's speed and drift angle of model ship occurring in turning. It is also shown that the flooding of seawater onto the deck occurring in turning generated a significant outward heel moment and the vertical distance between the center of gravity of the ship and the renter of lateral water drag.

• Journal of Navigation and Port Research
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• v.43 no.6
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• pp.469-474
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• 2019

One of the world's major resources is crude oil, the most fundamental part of the industry. There is no place that does not use crude oil. Petroleum refining products and chemical production industrial products are produced through nearby petrochemical complexes and ports after importing crude oil. There would be a possible relationship among the petrochemical complexes and nearby regional ports working with liquid cargoes. To confirm these relations, Ulsan Port, Daesan Port, and Yeosu Gwangyang Port were selected for this study. A Vector Auto Regressive model using time series data was applied. A Unit Root Test was performed. The relationship was confirmed through the Granger and Toda Yamamoto Causality Test.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.2
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• pp.114-121
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• 2014

Liquefied natural gas(LNG) cargo containment system(CCS) has the primary function of ensuring both adequate structural safety with respect to sloshing load which is defined as a violent behaviour of the liquid contents in CCS due to external forced motions and thermal insulation keeping natural gas below its boiling point. Among different LNG CCS types such as independent B-type and membrane ones, Mark III CCS is considered in this paper to perform its strength assessment. Mark III CCS plate is designed and constructed by stacking various non-metallic engineering materials such as plywood, triplex, reinforced PU foam that are supported by series of mastic upon inner steel hull structure. From the viewpoint of structural analysis, this plated structure is treated as a laminated composite structure showing complex structural behaviour under external load. Advanced finite element models of Mark III CCS plate is generated and used in conjunction with ultimate strength based failure criteria from laminated composite mechanics for the strength assessment. The strength assessment is performed within the initial failure state of Mark III CCS plate. Results provide failure details such as failure locations and loads. Finally obtained results are reviewed using the loads from acceptance criteria suggested by classification.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2004.11a
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• pp.62-67
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• 2004

Many ships in voyage experience weight and buoyancy distribution change by various reasons such as change of sea water density and waves, weather condition, and consumption of fuel, provisions, etc . The weight and buoyancy distribution change can bring the ships out of allowable trim, heeling angle. In these case, the ships should adjust trim and heeling angle by shifting of liquid cargo or ballasting, deballasting of ballast tanks for recovery of initial state or for a stable voyage. But, if the adjustment is performed incorrectly, ship's safety such as longitudinal strength, intact stability, propeller immersion, wide visibility, minimum forward draft cannot be secured correctly. So it is required that the adjustment of trim and heeling angle should be planned not by human operators but by optimization computer algorithm. To make an optimized plan to adjust trim and heeling angle guaranteeing the ship's safety and quickness of process, Uk! combined mechanical analysis and optimization algorithm. The candidate algorithms for the study were heuristic algorithm, meta-heuristic algorithm and uninformed searching algorithm. These are widely used in various kinds of optimization problems. Among them, heuristic algorithm $A^\ast$ was chosen for its optimality. The $A^\ast$ algorithm is then applied for the study. Three core elements of $A^\ast$ Algorithm consists of node, operator, evaluation function were modified and redefined. And we analyzed the $A^\ast$ algorithm by considering cooperation with loading instrument installed in most ships. Finally, the algorithm has been applied to tanker ship's various conditions such as Normal Ballast Condition, Homo Design Condition, Alternate Loading Condition, Also the test results are compared and discussed to confirm the efficiency and the usefulness of the methodology developed the system.

• Journal of the Society of Naval Architects of Korea
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• v.35 no.4
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• pp.27-37
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• 1998

The sloshing is very important in a safe transport of the liquid cargo by a ship. With the increasing number of supertanker and LNG carriers, this problem has become increasingly more important. In order to study the magnitude and characteristics of impact pressures due to sloshing, experiments ware performed with a rectangular tank and compared with numerical results. Structural responses of tank wall under impulsive pressures were measured. Structural vibrations induced by the sloshing load were analysed by including hydroelastic erects in terms of added mass and damping. To check the validity of the numerical model, the natural frequencies of plate in air and water were compared with measurements, and a good agreement was found. In the case that a plate vibrates under impulsive loads, the pressure on the flexible plate is larger than that on the rigid plate without hydroelastic effects, which was confirmed experimentally. The frequency of oscillatory pressure as well as accel%pion coincides with the natural frequency of plate in water.

• Journal of the Korea Society of Computer and Information
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• v.29 no.3
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• pp.191-198
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• 2024

Korea is an import and export-oriented economy that relies on shipping transportation, and sea ports play an important role in national economic growth. To secure and maintain the competitiveness of these ports, hardware and software investments are required, but policy support can also be expected to have an effect. This study identified the irrationality of the system by exploratory analysis of the port facility fee discount system for Ulsan Port, an energy hub port, and suggested improvement measures to resolve it.This study analyzed the volume of Ulsan Port and the reduction of port facility usage fees for about 10 years and identified irrational factors that despite a special port for liquid cargo, a considerable reduction for container cargo is concentrated, and even because it was a passing ship, 100% reduction for entrance and clearance fees were provided to them, which could cause serious moral hazard.. As a way to improve the port facility charge discount system at Ulsan Port, this study proposed strengthening support for eco-friendly activities to support containers, adjusting the reduction rate for passing ships, or improving the reduction and exemption application process.