• Journal of Ship and Ocean Technology
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• 제3권4호
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• pp.35-51
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• 1999

Fatigue strength assessment procedures have been implemented in the ship design rules by many classification societies. However, a large variation tin the details of the different approaches exists in practically all aspects influding load history assessment, stress evaluation and fatigue strength assessment. In order to assess the influences of thesd variations on the prediction of fatigue lives. a comparative study is organized by the ISSC Committee III.2 Fatigue and Fracture. A pad detail on the top of longitudinal hatch coaming of a panamax container vessel is selected for fatigue calculation. The work described in this paper is one set of results of this comparative study in which the ABS dynamics approach is applied. Through this analysis the following conclusions can be drawn. (1) With the original ABS approach, the fatigue life of this pad detail is very low, only 2.398 years. (2) The treatment of the stillwater bending moment in the ABS approach might be a source of conservatism. If the influence of stillwater bending moment is ignored, then the fatigue life for this pad detail is 7.036 years. (3) The difference between the nominal stress approach and the hot spot stress approach for this pad detail is about 26%.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.15-21
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• 2005

In this paper, the procedure of generation and application of nonlinear wave loads for structural design of large container carrier was described. Ship motion and wave load was calculated by modified strip method. Pressure acting on wetted hull surface was calculated taking into account of relative hull motion to the wave. Design wave height was determined based on the most sensitive wave length considering rule vertical wave bending moment at head sea or fellowing sea condition. And the enforced heeling angie concept which was introduced by Germanischer Lloyd (GL) classification had been used to simulate high torsional moment in way of fore hold parts similar to actual sea going condition. Using wave load generated from this dynamic load calculation, FE analyses were performed. With this result, yielding, buckling, hatch diagonal deflection and fatigue strength of hatch corners were reviewed based on the requirement of GL classification. The results of FE analysis show good compatibility with GL classification.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.22-30
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• 2005

Sloshing loads, produced by the violent liquid free-surface motions inside the cargo tank have become an important design parameter in ship building industry since there have been demands for the increased sizes of the cargo containment system of LNG carriers. In this study, sloshing impact pressure acting on the shell of the spherical cargo tank of an LNG carrier as well as dynamic pressure and flow behavior around the pump tower located at the center of the tank have been calculated. Comparative numerical sloshing simulations for a spherical LNG tank using 2-D LR.FLUIDS which is based on the finite difference method and 3-D MSC.DYTRAN which is capable of calculating nonlinear fluid-structure interaction have been carried out. A method of calculating sloshing-induced dynamic loads and the subsequent structural strength analysis for pump tower of a spherical LNG carrier using MSC. DYTRAN and MSC.NASTRAN have been presented.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.31-37
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• 2005

An attempt to improve the speed performance through the minimizing in wave resistance has been done by an application of gooseneck and no bulb type to bulbous bow for the DSME 78,500 Class LPG Carrier on the basis of the CFD calculation and comparatives model tests. The hydrodynamic characteristics according to the variation of the shape of Cp-curve, design load water line, frame line and bulbous bow that have an important effect on the wave resistance has been evaluated/calculated by ship-flow code. A wide variety in hull variation have been tried to have a good hull form with three types of fore-body hull forms mainly classified by the shape of bulbous bow. The speed performances for the three final hull forms with different bulbous bows have been evaluated through the model tests.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2004년도 추계학술대회
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• pp.297-302
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• 2004

본 연구에서는 수직배치형 블록을 가지는 컨테이너 터미널을 대상으로 안벽에서 컨테이너의 양${\cdot}$적하 작업을 담당하는 안벽크레인(Q/C)에 대한 하역생산성을 비교분석하였다. 분석 대상이 되는 안벽크레인의 유형은 기존의 싱글트롤리 타입외에 차세대 안벽크레인으로 인식되고 있는 듀얼트롤리, 더블트롤리, 수직순환식의 하역방식을 가지는 장비에 대한 하역생산성을 순작업시간당 생산성 측면에서 이들 하역장비의 성능을 측정해 보았다. 이들 차세대 컨테이너 크레인은 기존의 싱글트롤리 타입의 장비에 비해 기계적 싸이클 타임이 짧으며, 선회방식이 상이하여 현재의 싱글 트롤리타입보다 하역생산성이 매우 높을 것으로 보고 있다. 본 연구의 결과로 제시된 4가지 유형의 안벽크레인에 대해 작업싸이클타임과 시뮬레이션 기법을 이용하여 기계적생산성과 순작업생산성을 산출하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권4호
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• pp.1130-1147
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• 2014

Large size ships have a very flexible construction resulting in low resonance frequencies of the structural eigen-modes. This feature increases the dynamic response of the structure on short period waves (springing) and on impulsive wave loads (whipping). This dynamic response in its turn increases both the fatigue damage and the ultimate load on the structure; these aspects illustrate the importance of including the dynamic response into the design loads for these ship types. Experiments have been carried out using a segmented scaled model of a container ship in a Seakeeping Basin. This paper describes the development of the model for these experiments; the choice was made to divide the hull into six rigid segments connected with a flexible beam. In order to model the typical feature of the open structure of the containership that the shear center is well below the keel line of the vessel, the beam was built into the model as low as possible. The model was instrumented with accelerometers and rotation rate gyroscopes on each segment, relative wave height meters and pressure gauges in the bow area. The beam was instrumented with strain gauges to measure the internal loads at the position of each of the cuts. Experiments have been carried out in regular waves at different amplitudes for the same wave period and in long crested irregular waves for a matrix of wave heights and periods. The results of the experiments are compared to results of calculations with a linear model based on potential flow theory that includes the effects of the flexural modes. Some of the tests were repeated with additional links between the segments to increase the model rigidity by several orders of magnitude, in order to compare the loads between a rigid and a flexible model.

• 한국항해항만학회지
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• 제34권10호
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• pp.781-786
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• 2010

본 연구에서 하역크레인을 장착하여 모선과 연안항만간 컨테이너를 단거리 운송하는 것으로 새로운 개념의 해상운송시스템인 모바일하버를 소개하였다. 초대형 컨테이너선박이 직접 연안항만에 접이안하는 대신에 모바일하버가 해안에서 일정거리 이격되어 모선이 정박하기에 수심여건이 양호한 작업장까지만 이동한다. 따라서, 모바일하버의 적용을 위한 국내 무역항의 해안환경, 기술적 조건 및 한계에 대한 조사는 필연적 과정이다. 모바일하버의 접근성을 파악하기 위하여 환경조건, 화물하역처리능력, 해상교통량 및 교통류를 해상교통시뮬레이션 및 가상항로표지시스템의 툴을 사용하여 분석하였다. 수집한 정보의 분석과 적용서의 평가를 통해 최적수준의 남해안 및 동해안 무역항에 대한 모바일하버 정박장은 (1) 기상 및 해상자연환경조건면에서 마산항, 울산항, 부산신항의 순으로, (2) 해상교통 및 수역시설여건의 조건에서는 목포, 부산신항, 동해묵호항의 순으로, (3) 화물처리의 현장능력 및 지역무역항의 운영실태분석으로는 부산권, 여수광양권, 목포권으로 나타났다. 본 연구를 통해 최적의 항만 및 작업장 선정을 위한 기준을 제시하였으며, 모바일하버가 현장에 적용되기 위해서는 초대형선박과 모바일하버의 접안 및 화물작업이 이루어지는 해역에서 해상교통안전을 확보하기 위한 선박자동식별시스템 등 가상항행보조시설이 도입되어야 할 것으로 본다.