• Journal of Industrial Technology
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• v.19
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• pp.301-312
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• 1999

The purpose of this paper is to study the effects of container size with multi-stage and multi-item on average inventory and customer service level in Kanban systems. We use the different distributions of demand and interarrival time for each item to show that we had better to change the container size depending on different type of item for this simulation study. The small lot size can be used for container size of a single item if there is no setup time. The container size should be identical with average order size as setup time increases. The fill rate increases if the container size is large with multi-item. However, it is difficult to establish the effective container size because the effects of the container size on the order queue time are not clear. It is suitable to use the average order size as the container size for each item if the variance of demand and interarrival time of each item is relatively small. It is effective to sue the average container size if the variance of them is relatively large.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.13 no.5
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• pp.96-102
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• 2004

In this study, we have developed the simulation tool in order to investigate driving trajectory of AGV for container transport. AGV for container transport is different from the indoor AGV in that it is a large size structure at being loaded the weight of 40 ton. and AGV for container transport is applied to front wheel steering, rear wheel steering, all wheel steering, and crap steering. Therefore, we have developed the simulation tool considering dynamic problems and a center of turning in accordance with fourth ways of steering mode. As the result of this study, we have confirmed that this tool is useful and cost-effective in the dynamic analysis or large size vehicles. Also, it is useful to calculate the minimum radius of turning for large size vehicles.

• Transactions of Materials Processing
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• v.19 no.1
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• pp.50-58
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• 2010

In order to successfully implement hot die forging process for the large-size titanium alloy products, it is necessary to devise a customized heating method for the billets and the die tools, as well as the die tool design. This study aims at establishing a hot die forging process of the large-size titanium alloy container products by applying the warm die, semi-hot die and hot die forging process step-wise. To accomplish this purpose, forging mechanism and the die tools were designed considering the strength of die materials at the given die heating temperature. The movable heating devices for the billet and the die tools were also introduced to prevent overcooling of billet and die tools. To verify the applicability of the designed forging process, real-size forging tests were carried out and the quality of forged products, including dimension, surface condition, microstructure and the mechanical properties was evaluated.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1076-1081
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• 2004

In this study, we have developed the simulation tool in order to investigate driving trajectory of AGV for container transport. AGV for container transport is different from the indoor AGV in that it is a large size structure at being loaded the weight of 40 ton. And AGV for container transport is applied to front wheel steering, rear wheel steering, all wheel steering, and crap steering. Therefore, we have developed the simulation tool considering dynamic problems and center of turning in accordance with four way of steering modes. Throughout some computer simulations, we have confirmed that this tool is useful to analysis dynamic problems and to calculate minimum radius of turning for large size vehicles.

• Journal of Ocean Engineering and Technology
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• v.35 no.6
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• pp.403-413
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• 2021

As the size of ships increases, the size and output power of their thrusters also increase. When a large ship berths or unberths, the jet flow produced from its thruster has an adverse effect on the stability of quay walls. In this study, we conducted a numerical analysis to examine the impact of the thruster jet flow of a 30,000 TEU container ship, which is expected to be built in the near future, on the stability of a quay wall. In the numerical simulation, we used the fluid-structure interaction analysis technique of LS-DYNA, which is calculated by the overlapping capability using an arbitrary Lagrangian Eulerian formulation and Euler-Lagrange coupling algorithm with an explicit finite element method. As the ship approached the quay wall and the vertical position of the thruster approached the mound of the quay wall, the jet flow directly affected the foot-protection blocks and armor stones. The movement and separation of the foot-protection blocks and armor stones were confirmed in the area affected directly by the thruster jet flow of the container ship. Therefore, the thruster jet flows of ultra-large ships must be considered when planning and designing ports. In addition, the stability of existing port structures must be evaluated.

• International Journal of Ocean System Engineering
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• v.2 no.3
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• pp.170-175
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• 2012

Currently, most logistics use containers. The construction of new port and high speed medium size container ship for the transportation of merchandise have become very important. The problem of ship stability is also important because of its direct influence on the loss of human life, ships, and merchandise. The stability of a container ship during its operation is not a large problem because it is well considered in the design process. However, the assessment of ship stability during container loading/unloading in port still depends on the expertise of experienced personnel. In this paper, a model based simulation system is introduced, which is able to assess ship stability during container loading/unloading, using ENVISION, a general purpose simulation system.

• Journal of Ship and Ocean Technology
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• v.11 no.4
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• pp.1-20
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• 2007

After the introduction of the World Trade Organization, large scale container ships are being used as a means of transportation for international trade. Therefore, improving the loading and unloading capability of container quays is the most economic way, considering the cost needed for the establishment or expansion of container quays. In this paper, a new container cargo handing system that is equipped with a high performance container crane is suggested. A structural analysis on the container crane is also conducted to decide the form and size of structural member scantlings, using NASTRAN, which is a general structure analysis program.

• Journal of Navigation and Port Research
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• v.29 no.6 s.102
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• pp.529-536
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• 2005

Recently the building of ultra large container ship are discussed among ship building companies and ship operating company who have a tendency to pursue the advantage of large scale of economy. These tendency will be continued for the time being, if ship-building skill and economical efficiency are available. As the enlargement of container ship size becomes hot issues in ship-building markets, the needs for re-arrangement of accommodation house in large container ship are proposed carefully in some researches. This study examined economical efficiency of re-arrangement of accommodation house in ultra large container ship. The separation between accommodation and engine room is proposed through out drawing works in initial design stage and we examined the merits and demerits of the separation in the view of economical efficiency. The RFR(Required Freight Rate) is considered as the objective function to evaluate the re-designed vessel. The economical benefits are analyzed in the view of ship operator and shipyard respectively.

• Journal of Ship and Ocean Technology
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• v.5 no.4
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• pp.44-50
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• 2001

Large container carriers are suffering from lack of knowledge on reliable correlation allowances between model tests and full-scale trials, especially at fully loaded condition, Careful full-scale sea trial with a full loading of containers both in holds and on decks was carried out to clarify it. Model test results were analyzed by different methods but with the same measuring data to figure out appropriated correlations factors for each analysis methods, Even if it is no doubt that model test technique is one of the most reliable tool to predict full scale powering performance, its assumptions and simplifications which have been applied on the course of data manipulation and analysis need a feedback from sea trial data for a fine tuning, so called correlation factor. It can be stated that the best correlation allowances at fully loaded condition for both 2-dimensional and 3-dimensional analysis methods are fecund through the careful sea trial results and relevant study on the large size container carriers.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.1 s.145
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• pp.15-21
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• 2006

Recently, the attention to large container ships whose size is greater than 10,000 TEU container ship has been increased due to their increasing demand. The large container ship has twin skegs because of the engine capacity and large beam-draft ratio. In this paper, the maneuvering characteristics of a container ship with twin skegs were investigated through 4DOF(four degree of freedom) HPMM(Horizontal Planar Motion Mechanism) test and computer simulation. A mathematical model for maneuvering motion with 4DOF of twin skegs system was established to include effects of roll motion on the maneuvering motion. And to obtain roll-coupling hydrodynamic coefficients of a container ship, 4DOF HPMM system of MOERI which has a roll moment measurement system was used. HPMM tests were carried out for a 12,000 TEU class container ship with twin skegs at scantling load condition. Using the hydrodynamic coefficients obtained, simulations were made to predict the maneuvering motion. Rudder forces of twin-rudders were measured at the angles of drift and rudder. The neutral rudder angles with drift angles of ship was quite different with those of single skeg ship. So other treatment of flow straightening coefficient $\gamma_R$ was used and the simulation results was compared with general simulation result. The treatment of experimental result at static drift and rudder test was very important to predict the maneuverability of a container ship with twin skegs.