• Title/Summary/Keyword: Static coefficient of stiffness

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Static Analysis of Two Dimensional Curbed Beam Structure by Finite Element-Transfer Stiffness Coefficent Method (유한요소-전달강성계수법에 의한 2차원 곡선 보 구조물의 정적해석)

  • Choi, Myung-Soo
    • Journal of Power System Engineering
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    • v.21 no.6
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    • pp.40-45
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    • 2017
  • The objective of this study is the finite element-transfer stiffness coefficient method, which is the combination of the modeling technique of finite element method and the transfer technique of transfer stiffness coefficient method, is applied in the static analyses of two dimensional curved beam structures. To confirm the effectiveness of the applied method, two computational models are selected and analyzed by using finite element method, finite element-transfer stiffness coefficient method and exact solution. The computational results of the static analyses for two computational models using finite element-transfer stiffness coefficient method are equal to those using finite element method. When the element partition number of curved beam structure is increased, the computational results of the static analyses using both methods approach the exact solution. We confirmed that the finite element-transfer stiffness coefficient method is superior to finite element method when the number of the curved beam elements is increased from the viewpoints of the computational speed and the utility of computer memory.

A Theoretical Study on the Dynamic Characteristics of Damping Flexible Coupling(I) (유체감쇠 커플링의 동특성에 관한 이론적 연구(I))

  • 김종수;제양규;정재현;전효중
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.1
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    • pp.11-22
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    • 1994
  • The present works are the theoretical results of the study to develope a damping flexible coupling which has a high performance of control for the torsional vibrations of power shafts in a large machinery. It is established the analysis scheme of the multiple-leaf spring, to obtain the static coefficient of stiffness of the coupling. Also, the dynamic coefficient of stiffness and the damping coefficient of the coupling are indentified through the flow analysis for a induced flow of working fluid by the deflection of multiple-leaf springs. This paper dealt with damping contributions by the friction between each plate of the multiple-leaf spring. In this paper, it is found that the dynamic characteristics of the damping flexible coupling are strongly dependent on the stiffness and the number of the multiple-leaf spring, and also vary with the viscosity of working fluid and the vibration speed of the inner star.

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Static Analysis of Axisymmetric Circular Plates under Lateral Loading Using Transfer of Stiffness Coefficient (강성계수의 전달을 이용한 횡방향 하중을 받는 축대칭 원판의 정적해석)

  • Choi, Myung-Soo;Yeo, Dong-Jun
    • Journal of Power System Engineering
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    • v.18 no.6
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    • pp.64-69
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    • 2014
  • A circular plate is one of the important structures in many industrial fields. In static analysis of a circular plate, we may obtain an exact solution by analytical method, but it is limited to a simple circular plate. Thus, many researchers and designers have used numerical methods such as the finite element method. The authors of this paper developed the finite element-transfer stiffness coefficient method (FE-TSCM) for static and dynamic analyses of various structures. FE-TSCM is the combination of the modeling technique of the finite element method (FEM) and the transfer technique of the transfer stiffness coefficient method (TSCM). FE-TSCM has the advantages of both FEM and FE-TSCM. In this paper, the authors formulate the computational algorithm for the static analysis of axisymmetric circular plates under lateral loading using FE-TSCM. The computational results for three computational models obtained by FE-TSCM are compared with those obtained by FEM in order to confirm the accuracy of FE-TSCM.

Static Stiffness Tuning Method of Rotational Joint of Machining Center (머시닝센터 회전 결합부의 정강성 Tuning 기법)

  • Kim, Yang-Jin;Lee, Chan-Hong
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.19 no.6
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    • pp.797-803
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    • 2010
  • A method has been developed to tune the static stiffness at a rotation joint considering the whole machine tool system by interactive use of finite element method and experiment. This paper describes the procedure of this method and shows the results. The method uses the static experiment on measurement model which is set-up so that the effects of uncertain factors can be excluded. For FEM simulation, the rotation joint model is simplified using only spindle, bearing and spring. At the rotation joint, the damping coefficient is ignored, The spindle and bearing is connected by only spring. By static experiment, 500 N is forced to the front and behind portion of spindle and the deformation is measured by capacitive sensor. The deformation by FEM simulation is extracted with changing the static stiffness from the initial static stiffness considering only rotation joint. The tuning static stiffness is obtained by exploring the static stiffness directly trusting the deformation from the static experiment. Finally, the general tuning method of the static stiffness of machine tool joint is proposed using the force stream and the modal analysis of machine tool.

Static Analysis of Three Dimensional Solid Structure by Finite Element-Transfer Stiffness Coefficent Method Introducing Hexahedral Element (육면체 요소를 도입한 유한요소-전달강성계수법에 의한 3차원 고체 구조물의 정적 해석)

  • Choi, Myung-Soo;Moon, Deok-Hong
    • Journal of Power System Engineering
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    • v.16 no.1
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    • pp.78-83
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    • 2012
  • The authors suggest the algorithm for the static analysis of a three dimensional solid structure by using the finite element-transfer stiffness coefficient method (FE-TSCM) and the hexahedral element of the finite element method (FEM). MATLAB codes were made by both FE-TSCM and FEM for the static analysis of three dimensional solid structure. They were applied to the static analyses of a very thick plate structure and a three dimensional solid structure. In this paper, as we compare the results of FE-TSCM with those of FEM, we confirm that FE-TSCM introducing the hexahedral element for the static analysis of a three dimensional solid structure is very effective from the viewpoint of the computational accuracy, speed, and storage.

Static Analysis of Frame Structures Using Transfer of Stiffness Coefficient (강성계수의 전달을 이용한 골조구조물의 정적해석)

  • 문덕홍;최명수;정하용
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2001.10a
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    • pp.287-294
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    • 2001
  • In static analysis of a variety of structures, the matrix method of structural analysis is the most widely used and powerful analysis method. However, this method has drawback requiring high-performance computers with many memory units and fast processing units in the case of analyzing complex and large structures accurately. Therefore, it's very difficult to analyze these structures accurately in personal computers. For overcoming the drawback of the matrix method of structural analysis, authors suggest transfer stiffness coefficient method(TSCM). The TSCM is very suitable to a personal computer because the concept of the TSCM is based on the transfer of the stiffness coefficient for an analytical structure. In this paper, the static analysis algorithm for frame structures is formulated by the TSCM. We confirm the validity of the proposed method through the compare of computation results by the TSCM and the NASTRAN.

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An Experimental Study on the Dynamic Characteristics of Damping Flexible Coupling( II ) (유체감쇠 커플링의 동특성에 관한 실험적 연구(II))

  • 김종수;제양규;정재현;전효중
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.1
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    • pp.23-31
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    • 1994
  • The present works are the experimental results of the study to develope a damping flexible coupling which has a high performance of control for the torsional vibrations of power shafts in a large machinery. The damping flexible coupling is manufactured and is compared for dynamic characteristics with other type coupling which is the Geislinger coupling. The static coefficient of stiffness and the damping coefficient allows the control of excitation frequency through a cam driver. The experimental results obtained from the two couplings are compared with the theoretically results.

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A Study on the Static Sensitivity Analysis Algorithm Using the Transfer of Stiffness Coefficient (강성계수의 전달을 이용한 정적 감도해석 알고리즘에 관한 연구)

  • Choi, Myung-Soo
    • Journal of Power System Engineering
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    • v.5 no.4
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    • pp.82-89
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    • 2001
  • To design a structural or a mechanical system with the best performance, the main procedure of a typical design usually consists of repeated modifications of design parameters and the investigation of the system response for each set of these parameters. But this procedure requires much time, effort and experience. Sensitivity analysis can provide systematic information for improving performance of a system. The author has studied on the development of the structural analysis algorithm and suggested recently the transfer stiffness coefficient method(TSCM). This method is very suitable algorithm to a personal computer because the concept of the TSCM is based on the transfer of the nodal stiffness coefficients which are related to force and displacement vectors at each node. In this paper, a new sensitivity analysis algorithm using the concept of the TSCM is formulated for the computation of state variable sensitivity in static problems. The trust of the proposed algorithm is confirmed through the comparison with the computation results using existent sensitivity analysis algorithm and reanalysis for computation models.

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Static Analysis of Frame Structures Using Transfer of Stiffness Coefficient (강성계수의 전달을 이용한 골조구조물의 정적해석)

  • 최명수;문덕홍;정하용
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.16 no.1
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    • pp.9-18
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    • 2003
  • In static analysis of a variety of structures, the matrix method of structural analysis is the most widely used and powerful analysis method. However, this method has drawback requiring high-performance computers with many memory units and fast processing units in the case of analyzing accurately structures with a large number of degrees-of- freedom. Therefore, it's very difficult to analyze these structures accurately in personal computers. For overcoming the drawback of the matrix method of structural analysis, authors suggest the transfer stiffness coefficient method(TSCM). The TSCM is very suitable to a personal computer because the concept of the TSCM is based on the transfer of the stiffness coefficient for an analytical structure. In this paper, the static analysis algorithm for frame structures is formulated by the TSCM. We confirm the validity of the TSCM through the comparison of computation results by the TSCM, the NASTRAN, the matrix method of structural analysis and the analytical solution.

An Analysis of Characteristics of Air-Lubricated Foil Journal Bearings (공기윤활 포일 베어링의 특성해석)

  • 김종수;이준형;최상규
    • Tribology and Lubricants
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    • v.17 no.2
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    • pp.97-108
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    • 2001
  • This paper describes the development of performance analysis technique for a leaf-type gas lubricated fail bearing. Stiffness coefficient and frictional damping due to the slip between all contacts of leaves are evaluated for various leaf structures. The fluid film thickness and pressure distribution are computed but it is not considered the elastic deformation by film pressure. The analysis results include the effects that the curvature radius and the length of leaf and the friction coefficient have on the static and dynamic characteristics of the foil bearings.