• Title/Summary/Keyword: 편심도

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Initial Imperfection Sencitivity in Stiffened Plates (보강판의 초기결함 민감성 연구)

  • 김천욱;원종진
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.8 no.3
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    • pp.264-273
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    • 1984
  • 초기경향이 있는 보강평판의 비선형 운동 방정식을 Galerkin method에 의하여 유도하였다. Runge Kutta method를 사용하여 step-load를 받고 있는 보강평판의 동적 좌굴문제의 수치해를 구하였다. 정적 좌굴실험에 의하여 좌굴하중을 결정함에 있어 동적 해석법을 응용할 수 있음을 입증하였으며, step-load를 받는 보강평판의 동적 좌굴해석으로 정적좌굴의 초기결함 민감성을 해 석하였다. 보강평판의 초기결함민강성은 평판보다 훨씬 낮으며 보강재의 편심비가 높을수록 민감 성은 둔화된다.

A Design of Self-Acting Air Lubricated Spindle (공기동압 스핀들의 설계)

  • Song, Museok;Jang, Dong-Seob;Lee, Young-Ze
    • Tribology and Lubricants
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    • v.12 no.2
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    • pp.41-47
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    • 1996
  • 고속에서 작동하는 공기동압 스핀들을 개발하기 위해 축방향 하중을 포함하여 설계와 관련된 문제들을 살펴보았다. 협곡이론에 근거한 지배방정식을 사용하였고, 차분법을 사용하여 해석하였다. 설계인자인 홈의 형상, 홈의 각도, 회전수, 그리고 편심량 등을 사용하여 축방향과 원주방향의 압력분포를 수치해석적으로 구하였다.

An Experimental Study on Eccentrically Loaded Steel Fiber Reinforced Concrete Columns (편심축하중을 받는 강섬유보강 콘크리트 기둥의 실험적 연구)

  • 박홍용;안영진
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10b
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    • pp.857-860
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    • 2000
  • An experimental study on the behavior of Steel Fiber Reinforced Concrete Columns under eccentric compression are presented. Forth-one columns were tested; the variables were column type, eccentricity of load, fiber contents, and longitudinal reinforcement ratio. The column size was 250×160 mm in cross section with an effective length of 1150 mm. Eccentricity of load was varied in the range from 1/6 to 1/2 times the column depth. This paper is to provides a framework for basic understanding of the steel fiber concrete columns.

유도전동기의 자기적 소음에 대한 고찰

  • 황영문
    • 전기의세계
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    • v.25 no.2
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    • pp.40-45
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    • 1976
  • 유도전동기의 고주파진동토오크의 산정법에 대하여는 Morrill, Chang, Puchstein Kimball 및 Veinott씨 등에 의한 불평형공간자속분포의 대칭좌표법 또는 2회전자계법해석으로 많은 연구가 거듭되어 기계정수가 고주파토오크에 미치는 영향의 관계를 풀이하고 있다. 또한 Jordan과 Lax씨에 의하여 편심 및 기계적진동에 따른 전자력파의 분포력 mode수 및 그 주파수를 개발함으로서 소음방지대책에 많은 진전을 보았다. 소음진동측정방법으로는 원래 진동측정이 정밀한 장치에 의존하여야 하며 그 방법 또한 어려운 점이 많아 method of 1-point measurement of electromagnetic-force waves로 처리되어 왔으나 요즈음에는 anechoic chamber와 같은 장치에서의 특별한 조작에 의하여 method of resultant measurement of accoustic noise powers에 의하여 보다 합리적인 소음측정 및 해석이 가능하게 되었다.

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A Study on Detection of Runout Eccentric Error Using CCS Sensor at CNC Lathe (CNC선반에서 주축변위센서를 이용한 가공편심오차의 검출에 관한 연구)

  • 양재생;맹희영
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2002.10a
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    • pp.468-473
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    • 2002
  • This paper presents the methodology for measuring eccentricity of the cylindricaliy machined part using CCS(Cylindrical Capacity Spindle Sensor) signal in the CNC turning process. In order to investigate the relationships between CCS orbits and eccentricities, the initial conditions for various eccentricity state and machining process is applied to the experimental strategy. AS a result, it is considered the linearities of CCS signal and magnitude of eccentricity of machined cylindrical surfaces based on the possibility as a automatic detection apparatus for the CNC lathe.

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Development of Digital Load Cell (디지털 로드 셀 개발)

  • Bae, In-Ho;Park, Heung-Joon;Park, Chan-Won;Min, Nam-Ki
    • Proceedings of the KIEE Conference
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    • 2003.07d
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    • pp.2726-2728
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    • 2003
  • 본 논문에서는 디지털 로드 셀의 국산화 결과를 보고한다. 개발된 로드 셀의 특성은 다음과 같다. A/D분해도: 20 bit, 변환속도: 100 Hz, 정도: < 0.02% R.O., 반복특성: < 0.01% R.O. 사용온도범위: 2080C, 온도특성: < 0.03% R.O./10C, 진단기능: 자체내장, 자체보정기능: 온도, 편심오차, 크리프 보정기능 내장, 보호회로: surge lightening.

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Development of an Improved Point Load Apparatus (개량형 점하중강도시험기의 개발)

  • Kim, Yong-Phil;Um, Jeong-Gi
    • Tunnel and Underground Space
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    • v.19 no.6
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    • pp.473-478
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    • 2009
  • The accuracy of point load apparatus is depend on point to point coaxial fitting. Also, the estimation of applied point load using the pressure gauge frequently lead to erroneous results. An improved point load apparatus has been developed in this study by mounting linear bearing on polished support rod, and eccentric error of point to point axis has been sustained less than 0.1 mm even under series of extreme work load conditions. Two digital displacement gauges are attached to measure the distance from point to point with sample specimen. A load cell mounted at the end of upper conical platen measure the applied net load on sample instead of preassure gauge. Total of 107 point load tests has been achieved to assure the quality and performance of developed apparatus. This exercise turned out to be successful.

Transverse Stress of Slabs due tp Longitudinal Prestressing in Prestressed Concrete Box Girders (프리스트레스트 콘크리트 박스 거더의 종방향 프리스트레싱에 의한 슬래브의 횡방향 응력)

  • Yang, In-Hwan
    • Journal of the Korea Concrete Institute
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    • v.15 no.5
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    • pp.679-688
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    • 2003
  • For box girders in which the longitudinal tendon is profiled in the inclined webs, longitudinal prestressing force will induce transverse effects as well as longitudinal ones. In this paper, the method to estimate transverse effects induced by longitudinal prestressing is proposed. The concept of transverse equivalent loading which is calculated through longitudinal prestressing analysis is developed. The transverse stress in slabs of box girders due to longitudinal prestressing are investigated. The comparison of numerical results of the proposed method and those of folded plate method represents that the method is reasonable. Numerical analyses are carried out depending on the parameters such as web inclination and ratio of girder length to tendon eccentricity. Analysis results show that when only prestressing are considered the magnitude of transverse stress in slabs of box girder is not so large. However, if the other stresses due to dead and live load et al. are superposed on these stresses, it may be that the longitudinal prestressing effects are significant.

A study on the effects of intake port eccentricity and a partition between the two intake ports on the in-cylinder swirl characteristics in a valve diesel engine (4밸브 디젤기관의 흡기포트 편심과 두 흡기포트 사이의 격막이 실린더 내 선회 특성에 미치는 영향에 관한 연구)

  • Lee, Ji-Geun;Gang, Sin-Jae;No, Byeong-Jun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.7
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    • pp.948-961
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    • 1997
  • The effects of intake port eccentricity and a partition between the two intake ports on the incylinder swirl characteristics in a 4 valve diesel engine having the two intake ports, one is a helical intake port and the other is a tangential intake port, were investigated by using the impulse swirl meter(ISM) in a steady flow test rig. Mean flow coefficient ( Cf(mean), swirl ratio ( Rs) and the mass flowrate through the two intake ports with and without intake port partition were measured. The results showed that the characteristics of in-cylinder swirl ratio formed by a 4-valve cylinder head were largely affected by valve eccentricity ratio ( Ny) and the existence of an intake port partition between the two intake ports. Mean flow coefficient ( Cf(mean)) increases and swirl ratio ( Rs) decreases in case of being the partition between the two intake ports. And also the mass flowrate through the tangential intake port is 19.0% and 7.7% more than that of the helical intake port in case of the two intake ports with and without partition respectively.ively.

A study on the analysis and identification of error motion in planetary gear system (유성치차장치의 회전오차 해석과 그 진단에 관한 연구)

  • 박천경;박동삼
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.14 no.1
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    • pp.43-53
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    • 1990
  • The manufacturing errors such as pitch error and run-out error in planetary gear system bring about the irregular displacement of the center of each gear, which cause the torqe variation, vibration and noise. In this study, the relation between manufacturing errors and error motions of the center of gear was analyzed, and it can be applied to identyfy the errors of gears by investigating the measured locus of the center of each gear. Also, another identification method of power spectrum estimation using FFT algorithm was introduced, which analyze the frequency of the measured error motions. The results show that the error of each gear had a corresponding unique frequency, therefore, this method proved to be more effective.