• Journal of the Korean Society for Railway
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• v.15 no.5
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• pp.429-435
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• 2012

The HEMU-430X is a world-class railway vehicle which aimed the maximum speed of 430km/h and the operation speed of 370km/h. To maintain high-speed operation condition over 300km/h, various requirements for satisfy exist. However, one of the most important things is a reliable supply of electricity. Especially, the dynamic interaction between the pantograph and overhead contact line at high-speed is a significant matter to pre-evaluate. In this paper, using the dynamic interaction analysis program, current collection performance of the HEMU-430X was investigated. Firstly, based on the international standard, performance of the original specifications was evaluated. In addition, through study on changes in tension and span length, improvement of the performance was considered.

• Journal of the Korean Society for Railway
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• v.12 no.5
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• pp.678-686
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• 2009

A trial run of locally-developed tilting train has been in process on Chungbuk line since the test vehicle was first produced. For the system stabilization, interface verification among the systems including track, structure, catenary and signaling system, not to mention the rolling stock, is very crucial. Therefore, in this study, the dynamic rail force of the tilting (Hanvit 200), high-speed (KTX) and general (Mugunghwa) vehicle caused by driving in transition curve track was measured. And, it compared the tilting response with the other by using the measured rail force data in transition curve track, and then evaluated probability the range of load fluctuation for the variable dynamic vertical and lateral wheel load. As a result, a range of rail force by occurred a change of cant from the high-speed and general vehicle which had fixed bogie structure was distributed throughout small deviation. Otherwise, in case of the tilting train which was consisted of the pendulum bogie structure was distributed wide range about large deviation by changed of cant.

• Journal of Ocean Engineering and Technology
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• v.29 no.2
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• pp.143-153
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• 2015

This paper presents the results of an experimental study on the motion of an FPSO (Floating production storage and off-loading) and the characteristics of the mooring systejavascript:confirm_mark('abe', '1');m according to the turret position. Model tests of a turret-moored FPSO were carried out in the Ocean Engineering basin of KRISO. The FPSO was moored using an internal turret and catenary mooring. The models (1/60 scale) that were prepared included the FPSO, turret, and mooring lines. The experiments were conducted in irregular waves and combined environments, with waves, currents, and winds. A time-domain simulation was performed using OrcaFlex. The motion response and mooring line tension from the present calculations were compared with the results of experiments, and the agreement was fairly good. In addition, the results showed that the weathervaning stability was improved when the position of the turret was moved in the bow direction.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.1166-1169
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• 1998

The Load characteristic of electric railway requires the power demand of the high capacity which amplitude is spacial-temporally fluctuated due to frequent starting and stopping with large tractive force. The conventional electric railway mainly consists of the resistance controlled and the thyristor controlled locomotives, are compensated for their bad characteristics of the power factor$(70\sim80%)$ with installation of another capacitor improving power factor at the substation. Since 1994, VVVF train car with good characteristics of power factor(100%) have been introduced and operated in Kwa-Chon Line. From the present technical tendency, it is judged that introduction of the locomotive with various controlled methods is necessary. The protective equipments installed at the substation are complicated and various aspects to detect faults and reduce their extension, so the universal countermeasures are required. Specially in the case of the fault occurrence it is difficult to calculate the fault location because of the change in the contactline constant according to modifying the characteristics of the contactline (the dualized catenary wire and extension, etc), so much time is required for the detection of fault location. In BT-fed method distance-relays and fault-locators are not installed, we have so many difficulties in the quick accident recovery.

• Journal of Ocean Engineering and Technology
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• v.26 no.2
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• pp.48-57
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• 2012

This paper deals with numerical analyses in the context of estimations of hydrodynamic motions and dynamic loads for a floating type offshore platform using some exclusive simulation code such as code for the simulation of a floating type of offshore crane based on multi-body dynamics, along with the commercial code AQWA. Verifications of numerical models are carried out by comparing the RAO results from the simulation code. In the verification analyses, hydrodynamic motions are examined in the frequency domain for the floating type offshore platform according to the mooring lines. Both the hydrodynamic motions and dynamic loads are estimated for floating type offshore platforms equipped with the catenary type and taut mooring lines. A review and comparison are carried out for the numerically estimated results. The structural safety of the connection parts in an offshore structure such as a floating type offshore platform is one of the most important design criteria in view of fatigue life. The dynamic loads in the connecting area between a floating type offshore platform and its mooring lines are estimated in detail according to variations in the mechanical properties of the mooring lines. The dynamic tension load on the mooring lines is also estimated.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.58 no.3
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• pp.230-240
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• 2022

In general, a high tension on the anchor and chain is placed when a ship at anchor is subjected to heavy weather. Mariners have to pay attention to whether dragging anchor occurs to keep the safety of the ship at anchorage since it is difficult to maintain the stable motion of ship and it causes collisions with other ships nearby. In this paper, the ship motion against the external forces was shown to obtain the fundamental data about characteristic of holding power due to nature of seabed at anchor, so practical trials were carried out in rocky area and muddy area using a trial ship around coastal area of South Korea. In muddy seabed, holding power showed reasonable tension values depending on the distance from anchor position of continuing swing motions of a ship corresponding to wind force. Meanwhile in rocky seabed, tension values on the chain appeared very high occasionally regardless of the distance from the anchor position and seemed to exceed its holding power to be the breaking strain of the chain although weather was not in a severe condition. Therefore, some of the cables laid on the seabed were presumed to be caught in a crack on the rock. It is assumed that even a small amount of external force may cause the chain to break in a moment in rocky seabed. Additionally, wind and current forces had a somewhat contradictory effect on holding power of the ship between them.