• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.12-14
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• 2002

In this paper, magnetic force on acting arc was analyzed by 3-D FEM for three DC arc-quenching rooms having different magnetic flux paths. We measured arc breaking time in prototypes by experiment so that we compared the relation of magnetic force and arc breaking time. Finally, we present the techniques for magnetically-driven arc and for the prediction of arc breaking time.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.339-344
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• 2011

In the past much effort has been made to utilize advanced computational fluid dynamic (CFD) programs for aeroelastic simulations and analysis. However, it is limited in the field of unsteady aeroelasticity due to enormous size of computer memory and unreasonably long CPU time. Recently, AAEMS(Aerodynamics is Aeroelasticity minus Structure) was developed for linear time-invariant, coupled fluid-structure systems. In this paper, to demonstrate further the efficiency and accuracy of the new model reduction method, we successfully examine AGARD 445.6 wing modeled by FLUENT CFD, FSIPRO3D and NASTRAN FEM(Finite Element Method) programs. Using the ROM(Reduced Order Modeling) one can predict flutter boundary as a function of the dynamic pressure.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.329-332
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• 2002

The upper bound analysis by stream function is used to study the torsional forward extrusion. The torsional forward extrusion process not only reduces forming load but also increase optimal die angle. Optimal die angle is determined by the optimization technique. The advantages of this process are that the low capacity of pressing machine can be used and the process with a large die angle can be applied. To verify the theoretical result, we have carried out experiments using model material (plasticine) and FE simulations using DEFORM3D.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.277-280
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• 2005

A shape optimization is applied to achieve a design objective in three-dimensional forging processes. In multi-stage forging processes, among the important design aspects, the die shape fur preforming is regarded as the design variable since it influences the forged part relatively higher than the others. The rigid-plastic finite element method and the sensitivity method are employed and formulated to solve a formulated optimization problem. An approximation scheme is also used for the direction search during the optimization. The upset forging of a square box is selected as a test example in order to demonstrate and verify the optimization process of this study. After the optimization, the optimized shape of the die yields a finial product of desire shape.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.10a
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• pp.398-401
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• 2005

The characteristic of sheet metal process is the few loss of material during process, the short processing time and the excellent price and strength. Such press-forming process are the used machine ability and the characteristic, used material, the accuracy of the part which becomes processing and side condition of a process are considered and the designed. The purpose of this study is apply efficiently sheet metal forming processing by 3D formation-analyzed program simulations in the site. By a study, forming process was simulation to drawing and trimming and cam process using static-implicit method software. By making apply this to an industrial site the productivity improvement and cost reduction etc. effect able was predicted.

• The Journal of Engineering Geology
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• v.26 no.2
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• pp.169-175
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• 2016

Estimations of regional stress are demonstrated in this paper. Firstly, regional stress is defined and the characteristics of regional stress are then discussed based on the local stresses measured by the Compact Conical-ended Borehole Overcoring (CCBO) technique and the results from the earthquake focal mechanism. Secondly, the regional stresses are estimated by a back analysis of three-dimensional finite element models, using the local stresses measured by the CCBO and hydraulic fracturing.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.163-166
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• 2001

It leaves much room for improvement that UTM-01 is of practical use. Therefor we will design of longitudinal pole magnet for UTM-02 system. The design of new magnet is based on light weight for bogie system. The new magnet for UTM-02 was reduced weight of magnet is 18kg per one, then it was ratio lift to weight is 10.13.

• Proceedings of the KIEE Conference
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• 1998.07e
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• pp.1828-1830
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• 1998

In this paper, an analysis of microstrip-slotline transiton is performed using a 3D vector Finite Element Method(FEM). On the base of the analysis, power divider/combiner is designed. The optimal structure for equal power division in Ka band is also proposed.

• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.21-23
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• 2004

The claw-pole PM(Permanent Magnet) stepping motor has the advantage of the positioning machine because of a relatively little step angle, facility of control, and detent torque characteristics. Although the research about this motor has been progressed, it was difficult to analyze because of three-dimensional magnetic circuit. This paper performed analysis of the static and dynamic characteristics of the claw-pole PM stepping motor using 3D-FEM(Finite Element Method). We also manufactured the test products and practiced performance tests for verification of the analysis results.

• International Journal of Railway
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• v.5 no.4
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• pp.163-166
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• 2012

Many different types of floating slab track have been developed and installed around the world to reduce vibrations and noise originating in the surrounding environment. The main objective of this study is to examine the influence of slab length on behavior of floating slab track based on rail-slab-isolator interaction. The floating slab track is modeled by the connection between rail, slab, isolator, and slab mat in the transition zone. All elements were assembled in a simplified two-dimensional (2D) finite element model (FEM). The maximum length of FST is then investigated based on the maximum additional rail stress criterion as described in UIC 774-3R since no fully accepted design criteria for the slab length in FST systems currently exist.