• Title/Summary/Keyword: 강성효과

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Rotordynamic design of Pulse Generator (펄스발전기의 로터다이나믹 설계)

  • Kim, Yeong-Chun;Park, Cheol-Hyun;Park, Hei-Joo;Seon, Mun-Tae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.379.2-379
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    • 2002
  • The support bearing requires high DN to raise specific energy efficiency for the state of the art rotating machine with high speed. Especially for the system has a big rotor(750 kgf) with high speed(about one mi i lion DNs) such as the pulsed generator, tin selection of the bearing and lubrication method are very important. (omitted)

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Characteristics for rotordynamics of laminated rotor supported by rolling bearings (구름베어링으로 지지된 적층로터의 로터다이나믹 특성)

  • Kim, Yeong-Chun;Park, Cheol-Hyun;Park, Hei-Joo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.381.1-381
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    • 2002
  • The A lot of rotating machinery are generally used in industrial field and the electrical machinery such as the motor and generator account for the most of the part. Generally motor and generator have electrical loss because of eddy current. So silicon steel sheets are used in order to reduce the electrical loss and furthermore laminated rotor is used for motor and generator to eliminate the electrical loss and heat generation. (omitted)

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Nonlinearly Distributed Active Earth Pressure on a Translating Rigid Retaining Wall : II. Application (평행이동하는 강성옹벽에 작용하는 비선형 주동토압 : II. 적용성)

  • 백규호
    • Journal of the Korean Geotechnical Society
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    • v.19 no.1
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    • pp.191-199
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    • 2003
  • It is known that the distribution of the active earth pressure against a rigid wall is not triangular, but nonlinear, due to arching effects in the backfill. In the farmer paper, a new formulation was proposed for the nonlinear distribution of active earth pressure on a translating rigid retaining wall considering arching effects. In this paper, parametric study is performed to investigate the effect of ${\phi}, {\delta}$ and wall height on the magnitude and distribution of active earth pressure calculated from the proposed equations. In order to check the accuracy of the proposed formulation, the predictions from the equation are compared with both existing full-scale test results and values from existing equations. The comparisons between calculated and measured values show that the proposed equations satisfactorily predict both the earth pressure distribution and the lateral active earth force on the translating wall. Simplified design charts are also proposed for the modified active earth pressure coefficient and fur the height of application of the lateral active force in order to facilitate the use of the proposed equation.

Optimum Rigger Locations for Highrise Braced Frames with Facade Riggers (여러 개의 파사드리거를 갖는 고층구조물에서 리거의 최적위치)

  • Jung, Dong-Jo;Yuk, Min-Hye;Lim, Byung-Taeg;Kim, Seok-Koo
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.2
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    • pp.137-146
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    • 2007
  • Numerical analyses are performed to show the effect of stiffening facade riggers on the behavior of the structure and to investigate the optimum locations of facade riggers. Optimum locations of the facade riggers to minimize the drift at the top of the structure are obtained by maximizing the drift reduction caused by the facade riggers and are significantly influenced by the bending and shear stiffnesses of the braced frame and facade riggers. Three standard load cases of uniformal and triangularly distributed lateral loads as well as a lateral point load at the top of the structure are considered in this paper Optimum locations of facade riggers are plotted as functions of nondimensional relative stiffness parameters ${\omega}$ and ${\beta}$ for structures with one to four riggers. Although the analysis presented herein is based on certain simplifying assumptions, it is believed that the results do provide sufficiently accurate information for determining the optimum locations of facade riggers in highrise structures.

Tension Stiffening of Reinforced High Performance Fiber Reinforced Cementitious Composites (HPFRCC) (철근 보강 고성능 섬유보강 콘크리트의 인장 강성)

  • Lee, Seong-Cheol;Kim, Jae-Hwa;Cho, Jae-Yeol;Shin, Kyung-Joon
    • Journal of the Korea Concrete Institute
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    • v.22 no.6
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    • pp.859-866
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    • 2010
  • To overcome weak and brittle tensile characteristics of concrete, many studies have been conducted on fiber reinforced concrete (FRC). Recently, high performance fiber reinforced cementitious composites (HPFRCC), which shows strain hardening behavior, has been actively investigated. However, most of the studies focused on the material behavior of HPFRCC itself. Only a few studies have been conducted on the tensile behavior of HPFRCC with steel reinforcement. Therefore, a tension stiffening test for HPFRCC members has been conducted in this study in order to investigate the effect of a reinforcing bar on the tensile behavior of HPFRCC. Tensile stress-strain relationship of HPFRCC has been derived from the tests. The HPFRCC resisted tensile stress continuously from the first cracking to the yield of reinforcing bar. Through the comparison with the tensile behavior of HPFRCC members without a reinforcement, it was shown the tensile strength and capacity of HPFRCC were reduced due to the combined effect of the high shrinkage of HPFRCC, restraining effect of steel reinforcement, and the strain hardening behavior of HPFRCC. It is expected that the tension stiffening test results can be useful for an application of HPFRCC with steel reinforcement as structural members.

End-Shape Effect for Stress Concentration Reduction of Composite Single-Lap Bonded Joint (끝단형상에 따른 복합소재 단일겹치기 체결부의 응력집중 저감에 관한 연구)

  • Kim, Jung-Seok;Hwang, Jae-Yeon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.35 no.3
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    • pp.333-340
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    • 2011
  • We evaluated the stress-reduction effect for different shapes of a composite adherend with or without a spew fillet. Six different single-lap joint specimens were modeled and assessed using nonlinear finite element analysis. Moreover, we investigated the effect of the stiffness ratio of the adherend and adhesive. The single-lap joint with normal tapering had the highest stress values, and the single-lap joint with reverse tapering and a spew fillet had the lowest stress values. The composite adherends with higher stiffness had lower stress values, and the adhesives with lower stiffness had lower stress values.

Experimental Study on the Top- Lateral Bracing of U-Type Steel Box Girders Using Real Size Specimen: Torsional Stiffness (실물모형 시험를 이용한 U형 강박스거더의 상부 수평브레이싱에 관한 실험적 연구: 비틂강성)

  • Shim, Nak Hoon;Park, Young Suk
    • Journal of Korean Society of Steel Construction
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    • v.18 no.4
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    • pp.447-456
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    • 2006
  • In this study, a torsional test for U-type steel box girders was performed to observe the effects of the kind of panel for top lateral walateral bracings on the torsional behavior of the U-type steel girder system. For the structural tests, the test specimen with a two-thirds scale of the system actually constructed in the field was used. In the torsional test to observe the efects of top lateral bracings, the most economical arrangement of the top lateral bracing was found to be the panel width to length ratio of 1:1.5 with the inclined angle of $40^{\circ}$.