• Title/Summary/Keyword: 비선형 다물체 동역학

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Calculation of Critical Speed of Railway Vehicle by Multibody Dynamics Analysis (다물체 동역학 해석방법을 이용한 철도차량의 임계속도 계산)

  • Kang, Juseok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.37 no.11
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    • pp.1371-1377
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    • 2013
  • In this analysis, a method is presented to calculate the critical speed of a railway vehicle by using a multibody dynamic model. The contact conditions and contact forces between the wheel and the rail are formularized for the wheelset model. This is combined with the bogie model to obtain a multibody dynamic model of a railway vehicle with constraint conditions. First-order linear dynamic equations with independent coordinates are derived from the constraint equations and dynamic equations of railway vehicles using the QR decomposition method. Critical speeds are calculated for the wheelset and bogie dynamic models through an eigenvalue analysis. The influences of the design parameters on the critical speed are presented.

Study of Effect of Tractive Force on Bicycle Self-Stability (구동력을 고려한 자전거 안정성에 관한 연구)

  • Souh, Byung-Yil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.11
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    • pp.1319-1326
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    • 2012
  • This study focuses on the influence of tractive forces on the self-stability of a bicycle. The eigen-value analysis of the self-stability of a passive rider control linear bicycle model can be used to analyze the self-stability. A linear bicycle model with front and rear driving forces is developed. The influence of tractive forces on the self-stability is identified by using the developed model. A nonlinear multi-body bicycle model is used to confirm the results of the linear analysis.

Wind Turbine Simulation Program Development using an Aerodynamics Code and a Multi-Body Dynamics Code (풍력발전시스템의 유연체 다물체 동역학 시뮬레이션 프로그램 개발)

  • Song, Jin-Seop;Rim, Chae-Whan;Nam, Yong-Yun;Bae, Dae-Sung
    • New & Renewable Energy
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    • v.7 no.4
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    • pp.50-57
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    • 2011
  • A wind turbine simulation program for the coupled dynamics of aerodynamics, elasticity, multi-body dynamics and controls of turbine is newly developed by combining an aero-elastic code and a multi-body dynamics code. The aero-elastic code, based on the blade momentum theory and generalized dynamic wake theory, is developed by NREL(National Renewable Energy Laboratory, USA). The multi-body dynamics code is commercial one which is capable of accounting for geometric nonlinearity and twist deflection. A turbulent wind load case is simulated for the NREL 5-MW baseline wind turbine model by the developed program and FAST. As a result, the two results agree well enough to verify the reliability of the developed program.

Study on a 2-Dimensional Dynamic Modeling Technique to Analyze the Overriding Phenomena of Rollingstock (열차의 타고오름 해석을 위한 2차원 충돌동역학 모델링 기법 연구)

  • Kim, Geo-Young;Koo, Jeong-Seo;Kwon, Tae-Soo
    • Journal of the Korean Society for Railway
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    • v.14 no.1
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    • pp.11-18
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    • 2011
  • This paper proposed a new 2-D multi-body dynamic modeling technique to analyze overriding behaviors taking place during train collision. This dynamic model is composed of nonlinear springs, dampers and masses by considering the deformable characteristics of carbodies as well as energy absorbing structures and components. By solving this dynamic model for rollingstock, energy absorbing capacities of collision elements, accelerations of passenger sections, impact forces applied to interconnecting devices, and overriding displacements can be well estimated. For a case study, we chose KHST (Korean High Speed Train), obtained crush characteristic data of each carbody section from 3-D finite element analysis, and established a 2-D multi-body dynamic model. This 2-D dynamic model was simulated under the train-to-train collision scenarios, and evaluated with 3-D virtual testing model. It was founded from the simulation results that this 2-D dynamic model could well predict overriding behaviors, and the modeling technique of carbody deformation was very important in overriding estimation.

Computational Algorithm for Nonlinear Large-scale/Multibody Structural Analysis Based on Co-rotational Formulation with FETI-local Method (Co-rotational 비선형 정식화 및 FETI-local 기법을 결합한 비선형 대용량/다물체 구조 해석 알고리듬 개발)

  • Cho, Haeseong;Joo, HyunShig;Lee, Younghun;Gwak, Min-cheol;Shin, SangJoon;Yoh, Jack J.
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.44 no.9
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    • pp.775-780
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    • 2016
  • In this paper, a computational algorithm of an improved and versatile structural analysis applicable for large-size flexible nonlinear structures is developed. In more detail, nonlinear finite element based on the co-rotational (CR) framework is developed. Then, a finite element tearing and interconnecting method using local Lagrange multipliers (FETI-local) is combined with the nonlinear CR finite element. The resulting computational algorithm is presented and applied for nonlinear static analyses, i.e., cantilevered beam and multibody structure. Finally, the proposed analysis is evaluated with regard to its parallel computation performance, and it is compared with those obtained by serial computation using the sparse matrix linear solver, PARDISO.

Nonlinear Analysis of Beam Using Linear Finite Element Method and Dynamic Analysis (선형 유한요소법과 동역학을 연계한 보의 비선형 거동 해석)

  • Jang, Sung-Hee;Lee, Seoung-Soo;Kim, Chang-Wan
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2010.04a
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    • pp.754-755
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    • 2010
  • 본 논문에서는 선형 유한요소법과 동역학적 해석방법을 연계하여 유연 다물체 보의 거동을 해석하였다. 이 방법은 절대 절점 좌표계를 사용하였고, 몇 가지 수치 예제를 해석해 본 논문에서 설명하는 선형 유한 요소법과 동역학적 연계 해석방법의 타당함을 확인하였다.

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Dynamics Analysis for Flexible Systems using Finite Elements and Algebraic Quaternions (4원법과 유한요소를 이용한 유연체 동역학의 해석기법)

  • Lee, Dong-Hyun;Yun, Seong-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.18 no.2
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    • pp.141-149
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    • 2005
  • This paper deals with formulations of the energy equilibrium equation by an introduction of the algebraic description, quarternion, which meets conservations of system energy for the equation of motion. Then the equation is discretized to analyze the dynamits analysis of flexible multibody systems in such a way that the work done by the constrained force completely is eliminated. Meanwhile, Rodrigues parameters we used to express the finite rotation lot the proposed method. This method lot the initial essential step to a guarantee of developments of the 3D dynamical problem provides unconditionally stable conditions for the nonlinear problems through the numerical examples.

Prediction of the Out-of-plane Motion due to the In-plane Excitation (평면내 방향 기진력에 의한 평면밖 방향 운동의 예측)

  • Oh, Il-Geun
    • Journal of Ocean Engineering and Technology
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    • v.7 no.2
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    • pp.141-149
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    • 1993
  • 삼 자유도를 가진 부유물체의 동적 응답을 이론적으로 연구하였다. 평면내 방향 운동모우드에 대한 지배방정식을 선형화한 후, 그들의 조화해를 평명밖 방향 운동모우드의 방정식과 연성시켰다. 그렇게 해서 주어지는 방정식은 시간에 따라 변화하는 계수를 가진 형태로서, 평면밖 방향의 운동만을 보일 것으로 예측되는 부유물체가 평면밖 방향의 운동을 보일 수도 있음을 밝혔다. 동역학적 불안정성과 그 결과로 나타나는 평면밖 방향의 대진폭 운동을 보이고 있다. 본 결과는 주기적으로 동요하는 부유물체가 서로 연성된 운동을 하는 현상으로도 해석할 수 있다.

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Analysis of Dynamic Behaviors for the Korea High Speed Train(KHST) by Using Non-Linear Creep Theory (비선형 크립이론을 이용한 한국형 고속전철의 동특성 해석)

  • 박찬경;김석원;김회선
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1093-1098
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    • 2002
  • Dynamic behaviors of the Korean High-speed Train(KHST) have been analyzed to investigate the performance on the stability, the safety and the ride comfort. Multi-body dynamics analysis program using Recursive method, called RecurDyn, have been employed in the numerical simulation. To model the wheel-rail contact, the RecurDyn uses its built-in module which uses the square root creep law. The accuracy of the rail module in RecurDyn. however, decreases in the analysis of flange contact because it linearizes the shape of the wheel and rail. To solve this problem, a nonlinear contact theory have been developed that considers the profiles of the wheel and rail. The results show that the KHST still needs more stability. The problem should be solved by the examinations of module and modeling.

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Multi-Body Dynamic Response Analysis of a MW-Class Wind Turbine System Considering Rotating and Flexibility (로터 회전 및 타워의 탄성력을 고려한 MW 급 풍력발전기의 비선형 다물체 동적 응답 해석)

  • Kim, Dong-Man;Kim, Dong-Hyun;Kim, Yo-Han;Kim, Su-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.78-83
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    • 2009
  • In this study, computer applied engineering (CAE) techniques are fully used to conduct structural and dynamic analyses of a whole huge wind turbine system including composite blades, tower and nacelle. For this study, computational fluid dynamics (CFD) is used to predict aerodynamic loads of the rotating wind-turbine blade model. Multi-body dynamic structural analyses are conducted based on the non-linear finite element method (FEM) by using super-element method for composite laminates blade. Three-dimensional finite element model of a wind turbine system is constructed including power train(main shaft, gear box, coupling, generator), bedplate and tower. The results for multi-body dynamic simulations on the wind turbine's critical operating conditions are presented in detail.

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