• Title/Summary/Keyword: 절점좌표

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Comparative study of the nodal and the modal approach in the flexible dynamics (탄성체 동역학에서 절점좌표계와 모우드좌표계 방법의 비교)

  • 신상훈;유완석
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1994.04a
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    • pp.51-55
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    • 1994
  • 탄성체 동역학 해석에 있어서 변형을 나타내기 위해 사용되는 좌표로는 크게 절점좌표와 모우드좌표로 구분된다. 상대적으로 적은 좌표수를 사용하는 모우드좌표가 기계나 항공, 우주 분야에선 일반적으로 많이 사용된다. 그러나, 모우드를 선정함에 있어서의 기준의 불확실함 등으로 인해, 모우드좌표는 많은 경험을 요구하게 된다. 모우드좌표에 비해 많은 시간이 걸리지만, 절점 좌표의 사용은 누구나 쉽게 사용할 수 있음을 장점으로 한다. 본 연구에서는 두 가지 좌표로 탄성체 동역학의 운동방정식을 유도한 뒤, 슬라이더-크랭크 기구의 해석을 수행하여 그 결과를 서로 비교해 보고자 한다.

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A study on the transformation of cadastral map using Geo-Spatial Information System (지형공간정보체계를 활용한 지적도의 변환에 관한 연구)

  • Kim, Jung-Sik
    • Journal of Korean Society for Geospatial Information Science
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    • v.8 no.1 s.15
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    • pp.111-120
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    • 2000
  • A cadastral map that is base map on Land Information System is divided by two categories, graphical and digital cadastre. And digital cadastre can be displayed with location coordinates of nodes that depict parcel boundary on digital cadastral records. The transformation of digital cadastral records means that imported text data of node coordinate would be transformed into system data. This study was implemented to search reasons of errors resulted from transformation of graphic data and then to analyze the accuracy in terms of Position and area. For this, checking of software used in Geo-Spatial Information System was implemented at first and it was found that the accuracy is up by using double precision in coordinate transformation. On the position accuracy the errors at nodes was erased during making topology and the errors did not effect other nodes. On the area may the area errors because of being in error limit of allowable area had no problems in using of system.

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Flexible Multibody Dynamic Analysis of the Wiper System for Automotives (자동차 와이퍼 시스템의 유연 다물체 동역학 해석)

  • Jung, Sung-Pil;Park, Tae-Won;Cheong, Won-Sun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.2
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    • pp.175-181
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    • 2010
  • This paper presents the dynamic analysis method for estimating the performance of flat-type blades in wiper systems. The blade has nonlinear characteristics since the rubber is a hyper-elastic material. Thus, modal coordinate and absolute nodal coordinate formulations were used to describe the dynamic characteristic of the blade. The blade was structurally analyzed to find the bending characteristics of the cross section of the blade. According to the analysis results, the blade section is divided into three deformation bodies: rigid, small, and large. For the small deformation body, the modal coordinate formulation is used, while the absolute nodal coordinate formulation is used for the large deformation body. To verify the dynamic analysis result, an experiment was performed. The simulation and experiment results were compared to verify the flexible multi-body dynamic model.

Study on the Dynamic Analysis Method using the Modal Coordinates and the Absolute Nodal Coordinates (모드좌표와 절대절점좌표를 혼용한 동역학 해석기법에 관한 연구)

  • Sohn, Jeon-Hyun;Yoo, Wan-Suk
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1730-1735
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    • 2003
  • In this paper, the absolute nodal coordinate formulation was introduced to describe the large deformation problems. And also, the modal coordinates were employed to represent the small elastic deformation. A new hybrid formulation was developed to combine the modal coordinates and the absolute nodal coordinates. A spherical joint and the DOT1 constraint were developed to carry out the numerical simulation of mechanical systems with kinematic joints. A beam example was suggested to show the new formulation. The simulation results using the modal coordinates and the absolute nodal coordinates show a good agreement to the experiments.

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Three-Dimensional Sheet Modeling Using Relative Coordinate (상대 좌표를 이용한 종이류 모델링 기법)

  • Cho Heui Je;Bae Dae Sung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.2 s.233
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    • pp.247-252
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    • 2005
  • This research presents a three-dimensional modeling technique for a flexible sheet. A relative coordinate formulation is used to represent the kinematics of the sheet. The three-dimensional flexible sheet is modeled by multi-rigid bodies interconnected by out-of-plane joints and plate force elements. A parent node is designated as a master body and is connected to the ground by a floating joint to cover the rigid motion of the flexible sheet in space. Since the in-plane deformation of a sheet such as a paper and a film is relatively small, compared to out-of-plane deformation, only the out-of-plane deformation is accounted for in this research. The recursive formulation has been adopted to solve the equations of motion efficiently. An example is presented to show the validity of the proposed method.

Simulation and Experimental Methods for Three-Dimensional Sheet Media Transport System Using Relative Coordinate (상대좌표를 이용한 3차원 미디어 이송장치에 대한 실험방법과 Simulation에 대한 연구)

  • Dae, Dae-Sung;Cho, Heui-Je
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.573-576
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    • 2005
  • This research presents a three-dimensional modeling technique for a flexible sheet. A relative coordinate formulation is used to represent the kinematics of the sheet. The three-dimensional flexible sheet is modeled by multi-rigid bodies interconnected by out-of-plane joints and plate force elements. A parent node is designated as a master body and is connected to the ground by a floating joint to cover the rigid motion of the flexible sheet in space. Since the in-plane deformation of a sheet such as a paper and a film is relatively small, compared to out-of-plane deformation, only the out-of-plane deformation is accounted for in this research. The recursive formulation has been adopted to solve the equations of motion efficiently. An example is presented to show the validity of the proposed method.

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A Study on the Stiffness of Frustum-shaped Coil Spring (원추형 코일스프링의 강성에 대한 연구)

  • Lee, S.J.;Kim, J.H.
    • Journal of Power System Engineering
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    • v.7 no.4
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    • pp.49-54
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    • 2003
  • 스프링은 가장 널리 이용되어지고 있는 기계요소이다. 본 논문에서는 원추형 코일스프링의 강성을 구하기 위하여, 빔요소를 이용한 유한요소법을 사용하였다. 가상일의 법칙을 이용하였고, 코일스프링의 하중벡터를 압축 분포하중으로 대체하였다. 하중의 증가에 의한 절점에서의 변위는 유한요소법를 이용하여 계산하였다. 단계법으로 결점의 변위를 중첩하여 전체 강성행렬을 구하였다. 유한요소법에 의한 해석치는 실험치와 잘 일치하였다. 본 논문에서 제시한 프로그램을 사용하여, 스프링 강성과 응력을 예측할 수 있을 것으로 사료된다.

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Development and Verification of a Dynamic Analysis Model for the Current-Collection Performance of High-Speed Trains Using the Absolute Nodal Coordinate Formulation (절대절점좌표를 이용한 고속철도 집전성능 동역학 해석 모델 개발 및 검증)

  • Lee, Jin-Hee;Park, Tae-Won
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.3
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    • pp.339-346
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    • 2012
  • The pre-evaluation of the current-collection performance is an important issue for high-speed railway vehicles. In this paper, using flexible multibody dynamic analysis techniques, a simulation model of the dynamic interaction between the catenary and pantograph is developed. In the analysis model, the pantograph is modeled as a rigid body, and the catenary wire is developed using the absolute nodal coordinate formulation, which can analyze large deformable parts effectively. Moreover, for the representation of the dynamic interaction between these parts, their relative motions are constrained by a sliding joint. Using this analysis model, the contact force and loss of contact can be calculated for a given vehicle speed. The results are evaluated by EN 50318, which is the international standard with regard to analysis model validation. This analysis model may contribute to the evaluation of high-speed railway vehicles that are under development.