• Title/Summary/Keyword: Moment

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Analysis and Experimental Verification of Linear Motor Moment for Precision Machine Tools (정밀 공작기계용 리니어모터 모멘트의 해석 및 실험적 검증)

  • Cho, Young-Taek;Cho, Han-Wook;Lee, Seung-Han
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.884-885
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    • 2015
  • This paper presents the characteristic analysis and experiment of pitching moment in permanent magnet linear synchronous motor (PMLSM) for precision machine tools. In this paper, we define force characteristics of the moment and the moment analysis by the finite element method. Manufacture experiment and we will compare the results of finite element analysis and experimental results.

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The General Mornent of Non-central Wishart Distribution

  • Chul Kang;Kim, Byung-Chun
    • Journal of the Korean Statistical Society
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    • v.25 no.3
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    • pp.393-406
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    • 1996
  • We obtain the general moment of non-central Wishart distribu-tion, using the J-th moment of a matrix quadratic form and the 2J-th moment of the matrix normal distribution. As an example, the second moment and kurtosis of non-central Wishart distribution are also investigated.

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Analysis of Statically Indeterminate Bearing-Shaft System Prediction of the Behavior of Ball Bearing (부정정 베어링-축계의 해석 및 볼베어링의 거동예측)

  • 김완두;한동철
    • Tribology and Lubricants
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    • v.10 no.1
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    • pp.62-68
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    • 1994
  • The analysis of statically indeterminate bearing-shaft system was investigated. The moment loads and misalignment angles which were induced in the ball bearings were determined, and the influence of span length of this system on the moment loads and fatigue lives was identified. The sliding and spinning speeds between balls and raceways which affected the performance of ball bearing evaluated. The equation to estimate the cage speed of ball bearing under moment loads was proposed. This equation had been verified by the test results of measuring of cage speed, which was useful to the prediction of ball bearing under moment loads.

Two Method for Evaluation of the Dipole Moment Matrix Elements (쌍극자모멘트 행렬요소를 계산하는 두가지 방법)

  • Sangwoon Ahn
    • Journal of the Korean Chemical Society
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    • v.22 no.4
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    • pp.229-238
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    • 1978
  • Two methods for evaluation of the dipole moment matrix elements are developed, one using the expansion method for spherical harmonics and the other the transformation method of the dipole moment matrix elements into overlap integrals for Mulliken. The numerical values of the dipole moment matrix elements evaluated by two methods are in agreement with each other.

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A Study on the Longitudinal Strength of the Ship Hull(I) (선체 종강도에 관한 연구(I))

  • 고윤섭
    • Journal of the Korean Institute of Navigation
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    • v.8 no.2
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    • pp.43-50
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    • 1984
  • When the static load is applied to the ship's hull the deflection due to the bending moment from longitudinal direction has not been considered in the usual calculation of maximum bending moment. In fact, however, the deflection of ship's hull must be affected by the above-stated bending moment, and in this case the value of the maximum bending moment would be lessened in comparision with the result of usual calculation. In this paper, the author at first calculated the difference between the two values in case of rectangular barge, and suggested a practical criterion of longitudinal strength.

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AN ERROR ESTIMATION FOR MOMENT CLOSURE APPROXIMATION OF CHEMICAL REACTION SYSTEMS

  • KIM, KYEONG-HUN;LEE, CHANG HYEONG
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.21 no.4
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    • pp.215-224
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    • 2017
  • The moment closure method is an approximation method to compute the moments for stochastic models of chemical reaction systems. In this paper, we develop an analytic estimation of errors generated from the approximation of an infinite system of differential equations into a finite system truncated by the moment closure method. As an example, we apply the result to an essential bimolecular reaction system, the dimerization model.

An Examination on the Singularoty of Grad Moment Equation for Shock Wave Problems

  • 오영기
    • Bulletin of the Korean Chemical Society
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    • v.17 no.4
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    • pp.385-390
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    • 1996
  • It has been well known that the Grad thirteen-moment equations have solutions only when the Mach number is less than a limiting value for the stationary plane shock-waves. The limit of Mach number has been re-examined by including successive terms in the series expansion of distribution function. The method employed is the linear analysis of moment equations near up-streaming and down-streaming flows. For the thirteen moment case, it has been confirmed that equations have solutions only when the Mach number is less than 1.6503, which is consistent with the literature value. For the case of twenty moments, the limit of Mach number is decreased to 1.3416.

3D Object Recognition Using SOFM (3D Object Recognition Using SOFM)

  • Cho, Hyun-Chul;Shon, Ho-Woong
    • Journal of the Korean Geophysical Society
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    • v.9 no.2
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    • pp.99-103
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    • 2006
  • 3D object recognition independent of translation and rotation using an ultrasonic sensor array, invariant moment vectors and SOFM(Self Organizing Feature Map) neural networks is presented. Using invariant moment vectors of the acquired 16×8 pixel data of square, rectangular, cylindric and regular triangular blocks, 3D objects could be classified by SOFM neural networks. Invariant moment vectors are constant independent of translation and rotation. The recognition rates for the training and testing data were 95.91% and 92.13%, respectively.

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Investigation on the Effective Moment of Inertia of Reinforced Concrete Flexural Members Under Service Load (사용하중 상태에서 철근콘크리트 휨부재의 유효 단면2차모멘트에 대한 고찰)

  • Lee, Seung-Bea;Park, Mi-Young;Jang, Su-Youn;Kim, Kang-Su;Kim, Sang-Sik
    • Journal of the Korea Concrete Institute
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    • v.20 no.3
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    • pp.393-404
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    • 2008
  • The approaches in many design codes for the estimation of the deflection of flexural reinforced concrete (RC) members utilize the concept of the effective moment of inertia which considers the reduction of flexural rigidity of RC beams after cracking. However, the effective moment of inertia in design codes are primarily based on the ratio of maximum moment and cracking moment of beam subjected to loading without proper consideration on many other possible influencing factors such as span length, member end condition, sectional size, loading geometry, materials, sectional properties, amount of cracks and its distribution, and etc. In this study, therefore, an experimental investigation was conducted to provide fundamental test data on the effective moment of inertia of RC beams for the evaluation of flexural deflection, and to develop a modified method on the estimation of the effective moment of inertia based on test results. 14 specimens were fabricated with the primary test parameters of concrete strength, cover thickness, reinforcement ratio, and bar diameters, and the effective moments of inertia obtained from the test results were compared with those by design codes, existing equations, and the modified equation proposed in this study. The proposed method considered the effect of the length of cracking region, reinforcement ratio, and the effective concrete area per bar on the effective moment of inertia, which estimated the effective moment of inertia more close to the test results compared to other approaches.

3-Dimensional Gait analysis and the relationship between lower limb alignment and knee adduction moment in elderly healthy women (3차원적 동작 분석기를 이용한 건강한 여자 노인의 하지 정렬 상태와 슬관절 내전 모멘트의 상관 관계에 관한 연구)

  • Cho, You-Mi;Lee, Wan-Hee
    • Journal of Korean Physical Therapy Science
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    • v.10 no.1
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    • pp.90-101
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    • 2003
  • Gait analysis can provide a better understanding of how the alignment of the lower limb and foot can contribute to force observed at the knee. Anatomic and mechanical factors that affect loading in the knee pint can contribute to pathologic change seen at the knee in degenerative pint disease and should be considered in treatment plan. The purpose of this study is to present the gait analysis data and to determine whether there is any relationships between alignment of the lower limb, foot progression angle and knee pint moments in elderly healthy women with 3-dimensional motion analyzer. The results were as follows; 1. Cadence showed 114.8 steps/min, gait speed showed 1.05 m/s, time per a stride showed 1.06 sec, time per a step showed 0.53 sec, single-supporting phase was 0.41 sec, double-supporting phase was 0.24 sec, stride length was 1.04 m, Step length was 0.56 m. 2. According to the parameters of kinematics, the maximal knee flexion angle through swing phase showed left $46.82^{\circ}$, right $40.19^{\circ}$ and the maximal knee extension angle showed left $-1.32^{\circ}$, right $2.01^{\circ}$. knee varus showed left $26.90^{\circ}$, right $30.93^{\circ}$. 3. Moment, one of kinetic parameters of knee pint the maximal flexion moment showed left 0.363. Nm/kg, right 0.464 Nm/kg and maximal extension moment showed left 0.389 Nm/kg, right 0.463 Nm/kg. The maximal. adduction moment showed left 0.332 Nm/kg, right 0.379 Nm/kg and the maximal internal rotatory moment showed left 0.13 Nm/kg, right 0.140 Nm/kg. 4. On sagittal plane, the maximal power of knee joint showed left 0.571 J/kg, right 0.629 J/kg. On coronal plane, the maximal power of knee joint showed left 0.11 J/kg, right 0.12 J/kg. On transverse plane, the maximal power of knee joint showed left 0.058 J/kg, right 0.072 J/kg. 5. The subject who had varus alignment of the lower extremity had statistically higher in knee adduction moment in mid stance phase. 6. The subject who had large foot progression angle had statistically lower in knee adduction moment in late stance phase. A relationship was observed between the alignment of the lower extremity and the adduction moment of the knee joint during stance phase. Hence, we need some research to figure, out the change of adduction moment according to the sort of knee joint osteoarthritis and the normal geriatrics as well. And we also require more effective, specific therapeutic program by making use of those background of researches.

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