• Title, Summary, Keyword: Static Equilibrium Analysis

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Static equilibrium and linear vibration analysis of a high speed electric train system (고속전철 시스템의 정적평형 및 선형진동 해석)

  • 김종인;유홍희;황요하
    • Journal of the Korean Society for Railway
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    • v.2 no.4
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    • pp.1-8
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    • 1999
  • A formulation to perform static equilibrium and linear vibration analysis is presented in this paper. The formulation employs minimum number of equations of motion which are derived by using a partial velocity matrix. The static equilibrium analysis is performed first, then the linear vibration analysis is performed at the static equilibrium position. By using the formulation presented in this paper, static equilibrium and linear vibration analysis of a high speed electric train system are performed. A single bogie system, a power car vehicle, and a train system which consists of five vehicles are analyzed, respectively. Natural frequencies and a few lowest mode shapes of the two are identified in this paper.

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Static equilibrium and linear vibration analysis of a high speed electric train system (고속 전철 시스템의 정적 평형 및 선형 진동 해석)

  • 김종인;유홍희;황요하
    • Proceedings of the KSR Conference
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    • pp.305-312
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    • 1998
  • A formulation to perform static equilibrium and linear vibration analysis is presented in this paper. The formulation employs minimum number of equations of motion which are derived by using a partial velocity matrix, The static equilibrium analysis is performed first, then the linear vibration analysis is performed at the static equilibrium position. By using the formulation presented in this paper, static equilibrium and linear vibration analysis of a high speed electric train system are performed. A single bogie system, a power vehicle, and a train system which consists of five vehicles are analyzed, respectively. Natural frequencies and a few lowest mode shapes of the three are identified in this paper.

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An Optimization Algorithm to Compute Pre-Loads of the Given Static Equilibrium State in Train Dynamics (열차동역학에서 주어진 정적평형상태의 초기하중을 계산하기 위한 최적화 알고리즘)

  • 김종인;박정훈;유홍희;황요하
    • Journal of the Korean Society for Railway
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    • v.2 no.3
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    • pp.9-17
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    • 1999
  • This paper presents a new algorithm to determine the pre-loads that sustain the static equilibrium state in a given position. The algorithm which uses a partial velocity matrix leads to an unconstrained optimization problem to compute the pre-loads of the suspensions. To demonstrate the validity of the proposed algorithm, the static analysis results that employ the pre-loads of three examples are presented using a reliable commercial program. Results of the analysis confirm the validity of the proposed algorithm.

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A Study on the Analysis of Multi-let Spread Mooring Systems (다점지지 계류시스템의 정적해석에 대한 연구)

  • Sin, Hyeon-Gyeong;Kim, Deok-Su
    • Journal of Ocean Engineering and Technology
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    • v.9 no.2
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    • pp.53-60
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    • 1995
  • A multi-leg spread mooring system for floating offshore structures is important, but the multi-leg static analysis is complicated due to the nonlinear behavior of each line and the effect of current which affects each line differently. The pretensioned position of the multi-leg mooring system obtained from the static equilibrium condition changes into a different position due to external loads and current. In this paper, the new position and the static tension at each line are caculated. The relation between the initial static equilibrium position and the new position due to the external loads is expressed in terms of the Taylor's series expansion. The Runge-Kutta $4^{th}$ method is employed in analyzing the 3-dimensional static cable nonlinear equations.

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Modal Analysis of Human Leg with Respect to Hip Joint Position by Using Multibody Modeling (다물체 모델링을 통한 Hip Joint 위치에 따른 인체 Leg부의 고유진동특성 분석)

  • NamGoong, Hong;Yoo, Hong-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.8
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    • pp.761-766
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    • 2010
  • The goal of this study is to analysis natural frequency for different static postures of human leg. To perform this research human leg is modeled by multi-body modeling for the musculoskeletal system. This leg model has biarticular muscles which acting on two joints and the muscles represents some of the major muscles, such as hamstring, of the upper and lower limbs. To obtain each static equilibrium position energy method is employed and to analysis natural frequency linearization method for constrained mechanical system is employed. Static equilibrium position depends on some parameter or condition such as hamstring stiffness or external force. Making a change these parameter the aim of this research can be performed.

Static and dynamic analysis of circular beams using explicit stiffness matrix

  • Rezaiee-Pajand, Mohammad;Rajabzadeh-Safaei, Niloofar
    • Structural Engineering and Mechanics
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    • v.60 no.1
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    • pp.111-130
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    • 2016
  • Two new elements with six degrees of freedom are proposed by applying the equilibrium conditions and strain-displacement equations. The first element is formulated for the infinite ratio of beam radius to thickness. In the second one, theory of the thick beam is used. Advantage of these elements is that by utilizing only one element, the exact solution will be obtained. Due to incorporating equilibrium conditions in the presented formulations, both proposed elements gave the precise internal forces. By solving some numerical tests, the high performance of the recommended formulations and also, interaction effects of the bending and axial forces will be demonstrated. While the second element has less error than the first one in thick regimes, the first element can be used for all regimes due to simplicity and good convergence. Based on static responses, it can be deduced that the first element is efficient for all the range of structural characteristics. The free vibration analysis will be performed using the first element. The results of static and dynamic tests show no deficiency, such as, shear and membrane locking and excessive stiff structural behavior.

Numerical analysis of plasma MHD equilibrium (플라즈마 MHD 평형의 수치해석)

  • Lee, Hong-Sik;Whang, Ki-Woong
    • Proceedings of the KIEE Conference
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    • pp.206-209
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    • 1988
  • Fixed boundary MHD static equilibrium for the axisymmetric toroidal plasma is analyzed numerically. The Grad-Shafranov equation is solved using FFM. The toroidal current tenn is expressed by plasma pressure p($\psi$) and toroidal field function g($\psi$). The numerical results are compared to the Solovev analytic equilibrium for the verification of the analysis. For SNUT-79 tokamak device in Seoul National University, flux surfaces and toroidal current profiles according to the variation of p and g profiles are observed. Also the safety factor q and average beta are obtained.

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Development of a Computer Program for the Dynamic Analysis of Mount System with Flexible Bodies (탄성체를 포함하는 마운트계의 동역학 해석 프로그램 개발)

  • Lee, Byeong-Hun;Kim, Gyeong-U;Jeong, U-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.1
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    • pp.94-102
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    • 2000
  • A computer program for three dimensional dynamic analysis of a mount system composed of rigid or flexible bodies and mount elements is developed. Cartesian coordinates and Euler parameters are used to specify the positions and orientations of the bodies. The equations of motion are formulated using Langrange equation and Langrange multiplier technique. The developed program includes routine, for inclined mount elements, several kinds of driving constrains, and external forces. The Static equilibrium analysis routine is also developed using iterative method.

Desorption Equilibrium Moisture Content of Rough Rice , Brown Rice, White Rice and Rice Hull (벼, 현미, 백미 및 왕겨의 방습평형함수율)

  • Keum, D. H.;Kim, H.;Cho, Y. K.
    • Journal of Biosystems Engineering
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    • v.25 no.1
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    • pp.47-54
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    • 2000
  • This study was performed to determine desorption equilibrium moisture contents of rough rice, brown rice, white rice and rice hull grown in Korea. EMC values were measured by static method using saturated salt solutions at three temperature levels of 2$0^{\circ}C$, 3$0^{\circ}C$ and 4$0^{\circ}C$ and eight relative humidity levels in the range from 11.2% to 85.0%. The measured EMC values were fitted to modified Henderson, Chung-Pfost , and modified Oswin models by using nonlinear regression analysis. The results of comparing root mean square errors for three models showed that modified Henderson and CHung -Pfost models could serve as good models, and that modified Oswin model could not be available for rough rice, brown rice, white rice and rice hull.

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Nonlinear analysis of thin shallow arches subject to snap-through using truss models

  • Xenidis, H.;Morfidis, K.;Papadopoulos, P.G.
    • Structural Engineering and Mechanics
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    • v.45 no.4
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    • pp.521-542
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    • 2013
  • In this study a truss model is used for the geometrically nonlinear static and dynamic analysis of a thin shallow arch subject to snap-through. Thanks to the very simple geometry of a truss, the equilibrium conditions can be easily written and the global stiffness matrix can be easily updated with respect to the deformed structure, within each step of the analysis. A very coarse discretization is applied; so, in a very simple way, the high frequency modes are suppressed from the beginning and there is no need to develop a complicated reduced-order technique. Two short computer programs have been developed for the geometrically nonlinear static analysis by displacement control of a plane truss model of a structure as well as for its dynamic analysis by the step-by-step time integration algorithm of trapezoidal rule, combined with a predictor-corrector technique. These two short, fully documented computer programs are applied on the geometrically nonlinear static and dynamic analysis of a specific thin shallow arch subject to snap-through.