• The Korean Journal of Ecology
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• 제24권1호
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• pp.19-26
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• 2001

대형조선소가 위치한 옥포만내 퇴적물, 해수, 참굴(Crassostrea gigas) 중의tributyltin(TBT)과 triphenyltin(TPhT), 그리고 분해산물의 농도를 분석하였다. 퇴적물과 참굴 내 TBT 농도는 각각 5~2,650 ng/g, 387~l,190ng/g dry wt.(as Sn)으로 검출되었다. 해수 중의 TBT 화합물은 19~84 ng/ $\ell$ 농도범위를 나타내었다. 조선소 내 dry-dock에 인접한 정점에서 최고값을 보이며, 조선소로부터 거리가 멀어질수록 감소하는 농토분포를 나타내었다. 이는 조선소가 옥포만내 주 오염원임을 의미한다. 퇴적물 중의 TBT 화합물의 구성비는 약 57%로 dibu-tyltin(DBT)와 monobutyltin(MBT)보다 높게 나타났다 만을 가로지르는 방파제를 경계로 하여 부틸주석 화합물(butyltin)의 농도가 급격하게 감소하여, 방파제가 옥포만 내 유기주석 화합물의 분포에 영향을 미치고 있음을 나타내었다. 페닐주석화합물은 참굴 중 nd-52 ng/g으로 검출되었으며, 퇴적물과 해수의 전 정점에서 검출한계 이하의 값을 보였다. 참굴 중의 TBT 농도는 대조구인 해금강의 시료보다 높은 값을 보였고, 생물농축계수(biological concentration factor, BCF)는 1.1$\times$$10^4$의 값을 보였다.

• 해양환경안전학회지
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• 제19권3호
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• pp.290-301
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• 2013

The docking analysis of a global ship structure is requested to evaluate its structural safety against the reaction forces at supports during docking works inside a dry dock. That problem becomes more important recently as the size of ships is getting larger and larger. The docking supports are appropriately arranged in a dock to avoid their excessive reaction forces which primarily cause the structural damages in docking a ship and, up to now, the structural safety has been assessed against the support arrangement by the finite element analysis (FEA) of a global ship structure. However, it is complicated to establish the finite element model of the ship in the current structural design environment of a shipyard and it takes over a month to finish the work. This paper investigates a simple and fast approach to carry out a ship docking analysis by a simplified grillage model and to assign the docking supports position on the model. The grillage analysis was considered from the motivation that only the reaction forces at supports are sufficient to assess their arrangement. Since the simplified grillage model of the ship cannot guarantee its accuracy quantitatively, modeling strategies are proposed to improve the accuracy. In this paper, comparisons between the proposed approach and three-dimensional FEA for typical types of ships show that the results from the present grillage model have reasonably good agreement with the FEA model. Finally, an integrated program developed for docking supports planning and its evaluation by the proposed approach is briefly described.

• Structural Engineering and Mechanics
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• 제23권3호
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• pp.309-323
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• 2006

In this paper, seismic response of a free-standing ship located in a dry dock and supported by an arrangement of n keel blocks due to base excitation is addressed. Formulation of the problem including derivation of governing equations in various modes of motion as well as transition conditions from one mode to another is given in Moghaddasi and Bargi (2006) by same authors. On the base of numerical solution for presented formulation, several numbers of analyses are conducted to study sensitivity of system's responses to some major contributing parameters. These parameters include friction coefficients between contacting surfaces, block dimensions, peak ground acceleration, and the magnitude of vertical ground acceleration. Finally, performance of a system with usual parameters normally encountered in design is investigated.

• 한국해안·해양공학회논문집
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• 제24권4호
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• pp.235-246
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• 2012

연안방재계획 수립을 위한 기초자료 생성의 일환으로 태풍에 의한 해일 범람모의를 수행하였다. 통상적인 침수-노출 처리가 불가한 직립안벽을 갖는 항만역의 특징이 반영되도록 가상의 내부제방 개념을 도입하여 해석하였다. 목포항에 대한 실제해역 적용에 앞서 단순해역에서 다수의 적용성 평가를 통해 내부제방의 폭은 1 m가 적정한 것으로 평가되었다. 해일범람으로 인한 침수면적과 침수심 산정에 민감하게 작용하는 육역의 침수-노출 처리기법에서의 최소침수심은 격자에 의존적이나 10 m 내외의 유한요소 상세격자에서는 0.01 m가 적정한 것으로 판단된다. 기존 태풍경로에 준거한 100년 빈도급 중심기압과 최대풍속을 가지며 비대칭 경도풍과 파랑효과가 고려된 가상태풍의 내습에 따른 목포해역의 침수예상역이 모의되었다. 침수면적은 기존 연구결과와 유사성을 나타내지만 항만권역 일부에서 확대 가능성이 있는 것으로 평가된다.

• 한국해양공학회지
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• 제17권2호
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• pp.72-76
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• 2003

This paper presents the design concept and operation results of float-off for FSO (340,000 DWT Class, ELF AMENAM KPONO Project) built on the ground, without dry dock facilities. It was the first attempt to build FSO, completely, on the ground and launch it using DBU (Double Barge Unit, which was connected by rigid frame structure.) The major characteristics of FSO, which are similar to general VLCC type hull, including topside structure, weigh 51,000 metric ton. In order to have sufficient stability during the deck immersion of DBU, while passing through a minimum water plane area zone, proper trim control was completed with LMC (Load Master Computer). The major features of the monitoring system include calculation for transverse bending moment, shear force, local strength check of each connector, based on component stress, and deformation check during the load-out and float-off. Another major concern during the operation was to avoid damages at the bottom and sides of FSO, due to motion & movement after free-floating; therefore, adequate clearances between DBU and FSO were to be provided, and guide posts were installed to prevent side damage of the DBU casings. This paper also presents various measures that indecate the connector bending moment, damage stability analysis, and mooring of DBU during float off.

• 대한조선학회논문집
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• 제45권1호
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• pp.93-100
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• 2008

There are two ways of conventional thermal distortion analysis. One is the thermal elasto-plastic analysis and the other is the equivalent forces method based on inherent strain. The former needs exorbitant analysis time, while the latter cannot obtain results of stress field and it needs much time consumption with loads modeling on curved plates. Such faults in two methods have made difficulties in thermal distortion analysis of a large structure like ship hull. In order to solve them, new kind of thermal distortion analysis method was developed. We devised that the inherent strains was used as direct input factors in forms of boundary conditions. It was embodied by using thermal expansion coefficient in commercial code. We used the pre-calculated inherent strain as thermal expansion coefficient, and endowed nodes with imaginary temperatures. This method was already adopted at hull block welding distortion analysis which was considered as impossible, and gave productive results such as reduction of work time in the dry dock.

• 대한조선학회 특별논문집
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• 대한조선학회 2005년도 특별논문집
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• pp.144-150
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• 2005

The size of ship is being larger than the past in the shipping industry thanks to the increased quantity of goods transported by ship. Therefore, HHIC (Hanjin Heavy industries & Construction co., LTD) invented innovative construction method, so called 'DAM', to build a ship which is longer than the length of the HHIC's dry dock. On Erection at the sea by the application of DAM Method, Squeezing & Detachment of A/F film may occur as a result of the wave and the constriction between A/F film pre-applied on the side shell and DAM's Rubber Packing. Thus, the test for finding the minimum curing time of A/F film was performed to protect Squeezing & Detachment of A/F film on the hull. To verify the soundness of paint and to find the optimum condition during the erection period of the DAM, laboratory test was carried out under no immersion condition through the application of various coatings on the Rubber Packing. And two methods were selected from the results of laboratory test for actual MOCK-UP Test. In addition, the test for the film profile per temperature of silicone A/F coat and the film Squeezing was performed.

• 대한조선학회논문집
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• 제44권6호
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• pp.666-674
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• 2007

It is very important to estimate static squeezing pressure distributions for lining material of sterntube after bearing at dry dock stage since the maximum squeezing pressure value can be one of the significant characteristics representing coming navigation performances of the propulsion system. Moderate oil film pressure between lining material and propulsion shaft is also essential for safe ship service. In this paper, Hertz contact theory is explained to derive static squeezing pressure. Reynolds equation simplified from Navier-Stokes equation is centrally differentiated to numerically obtain dynamic oil film pressures. New shaft alignment technology of nonlinear elastic multi-support bearing elements is also used in order to obtain external forces acting on lining material of bearing. For 300K DWT class VLCC with synthetic bush of sterntube after bearing, static squeezing pressures are calculated using derived external forces and Hertz contact theory. Optimum partial slope of the after bush is presented by parametric shaft alignment analyses. Dynamic oil film pressures are comparatively evaluated for partially bored and unbored after bush. Finally it is proved that the partial slope can drastically reduce oil film pressure during engine running.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.28-41
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• 2009

We know the several construction methods for underwater tunnel, but properly submerged concrete box type tunnel was mostly good structure stability and mostly shot length of tunnels. Submerged box type tunnel was buildup the unit segments in dry dock or ship yard by 10 to 20meters. The submerged box was composed with segments was join each together. It was installing the gate and waterproofing the coupling the front hull of a box. The complete submerged box rise up to the surface water, tow in the submerged box by tugboat, going to the destination of tunnel construction site. Beforehand dredge up soil at the bottom of a underwater, sinking the submerged box, connection together complete submerged box in underwater. The research and development ILM tunneling method is receiving careful study. Biggest weakness in submerged concrete box type tunnel was pressure waterproofing, box to box connecting, complete submerged boxes navigation and installation, after operation the submerged tunnel and management concrete box structure. It was positive evidence in submerged concrete box type tunnel. We make a practical application of the principle "the ILM tunneling method in underwater construction methods."

• Journal of Advanced Marine Engineering and Technology
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• 제33권6호
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• pp.880-885
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• 2009

The ships have a lot of electric machinery needed to supply electricity from the moment of launching coming out of dry dock to docking at jetty. Thus, the ships always have to use alternator and electric machinery that has low efficiency under the low load. Many government service ships like the MMU training ship have been spending lots of time at jetty rather than sailing at sea. These ships are operated under the condition of low load due to the operation of basic machinery at jetty and electric machineries are driven with the status of low efficiency. This paper would suggest the energy saving method for these ships. The investigation describes that shore connection is a great asset to these ships and that the flow rate control by adjusting revolution with the adoption of inverter is better than flow rate control by using throttle valve to save energy. The result is based on the investigation of cooling pump at MMU training ship.