• Proceedings of the KWS Conference
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• 2006.10a
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• pp.225-227
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• 2006

As rail steel at a crossing area must undergo much higher loading than those at regular railway, Mn-alloyed steel is normally used for its high load-carrying capability and reduced wear rate. However, as these Mn-alloyed steel is tend to have casting defects, manufacturing cost to produce defect-free Mn-alloyed steel becomes quite expensive. Therefore, in order to replace Mn-alloyed steel, we performed build-up welding using CH-90 and investigated regarding to wear characteristics of build-up weld metal.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.842-847
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• 2005

In recent railroad markets, the use of steel sleepers is gradually increased due to various advantages in resistance for impact as well as economical efficiency for production, construction. maintenance and recycle. The typical steel sleepers which are successfully used in railroad markets are n-type of Corus Inc. in England and Y-type of ThyssenKrupp Gft Gleistechnik in Germany. Both types have merits and demerits in safety and economical efficiency. In 1990, n-type steel sleeper was developed in Korea, but was failed in putting into practical use, due to the subsidence into the ballast by Jive loads and welding crack, etc.. In this paper, in order to develop optimal shape of n-type steel sleepers for domestic rail mads, parametric studies for cross section, thickness, are performed.

• Computational Structural Engineering
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• v.9 no.2
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• pp.143-151
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• 1996

The optimal design for Electro-magnetic Launcher (EML : Rail Gun) considering structural and electrical constraints are presented. For the structure of EML under high pulsed currency, the cross section is minimized subject to maximum stress of each element(rail, side wall, ceramic, and steel) within allowable stress and preload limits. The electrical constraint is the effective ceramic thickness which prevents the eddy current effect reducing the performance of EML. The stress analysis and optimization procedure of 90mm EML is conducted with ANSYS Code. The optimal design under preload is reduced to 53% of area compared with optimal design without preload. In case of rail with arc angle .theta.=45.deg., the performance of EML is the best among the other rail arc angles. The optimal design for rail with arc angle .theta.=45.deg., results in the reduction of 9% of area and 10.4% of deformation compared with Fahrenthold's design. The optimal preload 59.8MPa is much lower than Fahrenthold's design(186MPa). The results show that the optimal design of EML meets the design requirements.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1243-1244
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• 2010

• Proceedings of the KSR Conference
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• 2006.05b
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• pp.619-629
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1285-1286
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• 2011

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.1197-1204
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• 2004

The metropolitan cities and operation companies of urban transit railway are driving to construct the LRT(light rail transit) system because of the advantage of construction cost and environmental serviceability. This study suggests the optimal design method of steel box girder considering dynamic characteristics of LRT with rubber wheel. The behavior and design constraints are formulated based on the structural design criteria for LRT. Genetic algorithm is applied to the minimum weight design of structural system. A typical example is solved to illustrate the applicability of the proposed minimization algorithm. From the results of application example, the optimum design of steel box girder is successfully accomplished. Therefore, this system can act as a consultant to assist novice designers in the design of steel box girder for LRT with rubber wheel.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.706-711
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• 2005

From the using CWR (Continuously Welded Rail) on steel plate girder bridges without ballast, axial forces are occurred from a temperature on CWR and girders. Because of the additional axial forces, studies in order to CWR and developments of devices are proceeding. The track system of steel plate girder bridges is poor. When CWR is used for the system, the resistance on sleepers is increased from a temperature. So it is increasing an effect on CWR and, for solving the effect, longitudinal forces for buckle are being decreased. It is possible that opposite cases can be happened and it is also compared and studied. Therefore, we present a reasonable model for analyzing CWR within the property of steel plate girder railway bridges in Korea. Furthermore, the results analyzed for stability is compared and evaluated with tests. Finally, a reasonable method for the installation of CWR on bridges without ballast is suggested.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.205-210
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• 2001

Fatigue crack growth tests were carried out using high manganese cast steel under constant amplitude loading. Average crystal grain sizes of the material are $200{\mu}m$ and $1000{\mu}m$. For this material, ${\Delta}K_{th}$ is about $8MPa{\sqrt{m}}$ which is quiet large as compared to the general structural steels and the crack growth rate is lower than the general structural steels especilly in the low ${\Delta}K$ regsion. The reason of this behavior is crack closure due to fracture surface roughness and fretting oxide. The relationship between da/dN and the ${\Delta}K_{eq}$ was represented by narrow band regardless of the stress ratio.

• Steel and Composite Structures
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• v.24 no.1
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• pp.113-128
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• 2017

This paper highlights a study undertaken on the free vibration of a precast steel-concrete composite slab panel for track support. The steel-concrete composite slab track is an evolvement from the slab track, a form of ballastless track which is becoming increasingly attractive to asset owners as they seek to reduce lifecycle costs and deal with increasing rail traffic speeds. The slender nature of the slab panel due to its reduced depth of construction makes it susceptible to vibration problems. The aim of the study is driven by the need to address the limited research available to date on the dynamic behaviour of steel-concrete composite slab panels for track support. Free vibration analysis of the track slab has been carried out using ABAQUS. Both eigenfrequencies and eigenmodes have been extracted using the Lanczos method. The fundamental natural frequencies of the slab panel have been identified together with corresponding mode shapes. To investigate the sensitivity of the natural frequencies and mode shapes, parametric studies have been established, considering concrete strength and mass and steel's modulus of elasticity. This study is the world first to observe crossover phenomena that result in the inversion of the natural orders without interaction. It also reveals that replacement of the steel with aluminium or carbon fibre sheeting can only marginally reduce the natural frequencies of the slab panel.