• 대한조선학회 특별논문집
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• 대한조선학회 2017년도 특별논문집
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• pp.88-92
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• 2017

As the considerable request of the fast and accurate way of the selection of circuit breaker is increased, we introduce the development of software of circuit breaker selection for the marine use. Originally, the selection of circuit breaker has been carried out by manual in the marine project. It is not the easy work to select the proper type of circuit breaker to check the time-current characteristic curves of each type of circuit breakers for the various type of loads. In this regards, we developed the software to select the proper type of circuit breaker to confirm fast and accurately. And, we introduce the course of the development of the software for the selection of circuit breaker.

• 한국CDE학회논문집
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• 제16권3호
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• pp.207-215
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• 2011

Due to its large size, a ship is first divided into scores of blocks and then each block is constructed through various shops, such as the assembly shop, the painting shop, and the outfitting shop. However, each block may not be directly moved to the next shop and may be temporarily laid on a block stockyard because the working time in each shop is different. If blocks are laid on the block stockyard without any planning, the rearrangement of the blocks by a transporter are required because the blocks have the different in and out time. In this study, an optimal layout method based on the genetic algorithm was proposed in order to minimize the rearrangement of the blocks in the block stockyard. To evaluate the applicability of the proposed method, it was applied to a simple layout problem of the block stockyard.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1036-1041
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• 2007

In this paper, we studied the optimized design of roof structure to be separable roof structure. Also, the design have to satisfy with the GM/RT 2100' missile protection tests to verify the safety of railway vehicle structure. The separable roof structure design could have easier assembly process than whole roof structure in case of the interior outfitting and so on. Optimized design have to have as good as whole roof structure about results from the structure analysis. We studied separable roof structure to be optimized along with GM/RT 2100. The separable roof structure showed that the results have the same level of structure analysis

• 대한조선학회 특별논문집
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• 대한조선학회 2011년도 특별논문집
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• pp.70-74
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• 2011

This paper describes the quay mooring analysis to verify the safety of a moored drillship in typhoon conditions. Mooring system consists of mooring equipments(deck bollards, shore bitts, mooring lines, fenders) to resist the extreme environmental condition. Wind force acting on the drillship is obtained from the wind tunnel test results. The strength of quay mooring system has been checked. The static mooring analysis shows that the designed mooring system satisfies the mooring design criteria. Vertical displacements of the drillship have been calculated considering the dynamic wave motions and static heelings due to the wind force acting on the ship. With the vertical displacements and the hull draft of drillship, the required water depth for quay mooring has been derived.

• Ocean Systems Engineering
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• 제2권4호
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• pp.271-287
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• 2012

Due to its large size, a ship is first divided into scores of blocks and then each block is constructed through various shops, such as the assembly shop, the painting shop, and the outfitting shop. However, each block may not be directly moved to the next shop and may be temporarily laid at a block stockyard because the working time in each shop is different from each other. If blocks are laid at the block stockyard without any planning, the rearrangement of the blocks by a transporter is required because the blocks have the different in and out time. In this study, a block layout method based on the genetic algorithm was proposed in order to minimize the rearrangement of the blocks in the block stockyard. To evaluate the applicability of the proposed method, it was applied to simple layout problems of the block stockyard. The result shows that the proposed method can yield a block layout that minimizes the total relocation cost of moving obstacle blocks in the block stockyard.

• 대한조선학회 특별논문집
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• 대한조선학회 2009년도 특별논문집
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• pp.93-96
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• 2009

Foundation structure for the main engine heavy spare parts in the engine room is susceptible to resonance problem due to outfitting weight. In addition the deck floor has a large opening for the main engine installation and maintenance, which further weakens the foundation structure. To reinforce the weak structure, two types of approaches have been used; 1) insert an H-pillar below or above the floor and 2) increase the stiffener size. In this paper, the H-pillar approach is used to solve the vibration problem of the foundation structure in the engine room opening area. A commercial program is used to analyze the vibration problem ad to find the location and the size of the H-pillar. Modal test at the quay and on-board vibration measurement during the sea trial have confirmed the validity of inserting an H-pillar below the floor.

• 한국안전학회지
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• 제19권2호
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• pp.1-5
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• 2004

Al-brass is the raw material of mnufacturing tubes for heat exchanger of vessel where seawater is used to coolant because it has high level of heat coductivity and excellent mechanical properties and high level of corrosion resistance due to cuprous oxide($Cu_2O$) layer against seawater. However, damage of Al-brass tubes for heat exchanger of vessel is reported that local corrosion such as stress corrosion cracking occurred by synergism effect between mechanical factor and corrosion environment. In this study, to investigate on the effect of stress on the polarization characteristics of Al-brass. At the stress of 0% and 95% yield strength by constant displacement tester, in 3.5% NaCl + 0.1% $NH_4OH$ solution, the polarization tests were carried out. And thus open circuit potential, corrosion current density, anodic polarization, cyclic polarization and dezincification behavior of Al-brass are investigated.

• 산업공학
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• 제12권3호
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• pp.395-400
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• 1999

Shipbuilding process is composed of hull construction, in which the structural body of a ship is formed, and outfitting, in which all the non-structural parts such as pipes, derricks, engines, machinery, electrical cable, etc. are manufactured, added and assembled. Hull construction can be classified into parts fabrication, block assembly and hull erection. Among them, the parts fabrication is the first manufacturing stage that produces components or zones needed for block assembly and hull construction. More specifically, the parts fabrication is performed through machining processes including marking, cutting, pressing, and/or forming. When material is entering into the parts fabrication stage, it is important for achieving the total efficiency of production to select one of production division, so-called 'bay,' as well as machine tools on which the part is fabricated. In this paper, given production quantities of parts in the fabrication stage, the problem is to optimally select machine tools and production division, such that the total flow-time is minimized as well as the workload among machines is balanced. Specifically, three mathematical models for flow-time minimization, load balance, and simultaneously considering both objectives, and a numerical example are analyzed and presented.

• 한국시뮬레이션학회논문지
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• 제25권2호
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• pp.75-81
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• 2016

고정위치 생산 방식과 이를 개선한 흐름 생산 방식의 생산성을 비교하기 위해 데크하우스 선행의장 공정의 사례를 이용하여 이를 비교 분석하였다. 현재의 선행의장 공정 시스템은 고정위치 생산을 하고 있으며, 여기서는 블록이 한 구역을 점유하고, 작업이 완료 될 때까지 이동하지 않는다. 반면 개선된 흐름생산시스템에서는 블록이 이동하며 작업자와 장비는 움직이지 않는다. 시뮬레이션 결과 제안된 생산시스템에서 블록의 이동시간과 대기시간을 고려하지 않았을 때는 블록의 생산량이 거의 증가하지 않았다. 그러나 흐름생산에서는 작업을 위한 장비와 작업자의 이동과 대기시간이 거의 없어, 작업장의 작업시간의 변동성을 줄일 수 있다면 흐름생산이 고정위치 생산 시스템을 대체하는 보다 더 우수한 대안이 될 수 있음을 보였다.

• 대한조선학회 특별논문집
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• 대한조선학회 2017년도 특별논문집
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• pp.32-37
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• 2017

Due to the nature of semi-submergible drilling rig, various equipments are arranged in a limited space, and therefore the many types of outfitting holes passing through the hull structure are densely arranged and that is required the detailed structural strength evaluation in terms of ULS and FLS by class or client. Particularly, semi-submergible drilling rig has a variety of global load which affects the structure strength around holes compared to general commercial ship, and its response of stress is also complicated, so it is difficult to carry out the prediction design of structural strength evaluation and reinforcement. In this regard, this paper presents a case study on the evaluation of structural strength for the various holes and large openings of semi-submergible drilling rig conducted by our company, as well as an established hole verification procedure.