• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.561-562
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• 2009

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.22-29
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• 2011

고추력 액체 로켓 엔진용 터보펌프의 무부하 회전 시험을 통하여 얻어진 임계속도를 회전체동역학 해석으로부터 예측된 임계속도와 상호 비교하여 해석 모델의 타당성을 검토하였다. 질량 불평형 하중만을 고려한 베어링 무부하 하중조건에서 해석으로부터 얻어지는 1차 임계속도의 예측치는 시험에서 얻어진 결과와 잘 일치하였다. 상기 회전체동역학 모델을 이용하여 유동해석 및 성능시험 결과를 바탕으로 얻어진 펌프와 터빈의 반경하중으로부터, 반경하중 상대 각도에 따른 베어링 강성 변화를 고려하여 임계속도 변화를 예측하였다. 수치해석 결과 펌프와 터빈의 반경하중 상대 각도는 임계속도에 지대한 영향을 미치고 있는 것으로 나타났다. 반면 추가로 축하중이 부과되는 경우 반경하중의 상대 각도에 대한 영향은 감소하는 것으로 나타났다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.274-277
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• 1997

Eddy current effect in a high speed rotor suspended by a mangnetic bearing is invstigated using electromagnetic field analysis technique. The non-zero conductivity model of a laminated rotor sleeve is proposed to concern electrical shorting of laminates due to rub, handling or press fit assembly,et al. As the rotating speed increase, the distibution of magnetic flux line is changed and the magnetic forces decrease remarkably. ANSYS Magnetics (version 5.3) is used for the magnetic field analysis.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1764-1773
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• 2011

This study is about how to handle very soft grounds consisted of coal and household garbage(organic soil), clay, silt and so on, through examining Seoul-Busan High-Speed railway 6-2nd section. The soft soil might induce long term settlement and lead to structure's differential settlement eventually. So, we performed the boring test for characteristic of railway ground, laboratory test and field survey for mechanical property. And we also collected the engineering data of ground and the data for the establishment arrangement. These data were examined thoroughly considering residual settlement and strength by high-speed railway design standard. As a result of this study, we can say high-speed railway ground must have enough bearing capacity and be settled under allowable residual settlement(10cm). And also it needs to replace soft ground with high quality sand for the fundamental solution. With the application of replacement method on this study, we expect enough condition to construct stable high-speed railway.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.182-183
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• 2008

In this study, rotor dynamic analysis have been conducted using three-dimensional solid model. Analysis object has smaller size and higher speed than any general CNC spindle. It is important to consider the real supporting conditions and external forces for whirl behavior analysis. As a results, the bearing stiffness is higher, whirl motion is less than before.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.80-82
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• 2008

This paper deals with the design of an 870 krpm class high-speed permanent magnet synchronous generator (PMSG) applied to micro turbine system. Since space where the high-speed PMSG coupled with the micro turbine occupies in the system is strictly limited, the work described in this paper is motivated by the desire to make maximum output power of the generator considering the rotor and stator structures, winding methods and bearing system under restricted space.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 춘계학술대회 논문집
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• pp.1180-1187
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• 2004

Relative displacements between decks should be within the allowable limit under horizontal forces in high-speed railway bridges. Longitudinal force transmitters(LFT) have been introduced ih high-speed railway bridges for test track. The horizontal forces on the pier supporting the fixed bearing are transmitted to the near piers supporting the sliding bearings by LFT, The performance of LFT was investigated by field test in which the braking and acceleration tests using KTX were conducted in Baebang viaduct. The relative displacements between decks were measured infield test and were compared with the numerical results and the allowable limit.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1392-1394
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• 2007

By the examination of data collected by long-term measuring system on high-speed railway bridges, it has been known that the atmospheric temperature may affect the responses of maximum deflection and acceleration of bridge deck. Collected data show a tendency by seasonal factor to that, by the decrease of temperature, the response of acceleration of bridge deck increases, and the response of deflection decreases. To trace the cause of this tendency, parametric analysis on the stiffness of bridge bearing and track ballast has been performed, and the in-site measurement has been achieved in high-speed railway line to understand seasonal influences.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.415-422
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• 1999

The general concept of reinforced roadbed in the high-speed railway is to cope with the soft ground for the bearing capacity and settlement of foundation soil. The cyclic plate load tests were performed to determine the behavior of reinforced ground with multiple layers of geogrid underlying by soft soil. Five series of test were conducted with varying the soil profile conditions including the ground level, type of soil, and the thickness of each soil layer. Based on these plate load tests, laboratory model tests under cyclic loading were conducted to know the effect of geogrid reinforcement in particular for the high-speed rail roadbed. The permanent settlement and the behavior of earth pressure in reinforced roadbed subjected to a combination of static and dynamic loading are presented.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2004년도 학술대회지
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• pp.186-194
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• 2004

Experiments were conducted to determine the structural static and dynamic characteristics of air foil bearings. The housing of the bearing on the journal was driven by an impact hammer which was used to simulate dynamic forces acting on the bump loll with various leading condition. Two different bump foils (Cu-coated bump and viscoelastic bump) were tested and the static and dynamic coefficients of two bump foils compared, based on the experimental measurements for a wide range of operating conditions. The static and dynamic characteristics of air foil bearings were extracted 0rpm the frequency response function by least square method and IV(Instrumental Variable) method. The experiment was tested at 0rpm and $10,000\~16,000rpm$, and loaded on $50\~150N$. From the test results, the possibility of the application of high load and high speed condition is suggested.