• Title, Summary, Keyword: 다물체 동역학

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Multi-body Dynamics and Structural Vibration Analyses of Smart UAV Ground Test Equipment (스마트 무인기 지상시험장치의 다물체 동역학 및 구조진동해석)

  • Park, Kang-Kyun;Kim, Dong-Hyun;Kim, Dong-Man;Choi, Hyun-Chul;Ahn, Oh-Sung
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.1
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    • pp.22-29
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    • 2010
  • In this study, computational multi-body dynamics and structural vibration analyses including some impact condition have been conducted for the ground flight test system of the developed smart UAV model. Designed ground test system has four degree-of-freedom motions with limited motion control mechanism. Design safety margin designs for several structural components are tested and verified considering expected critical motions (pitching and rolling) of the test smart UAV model. Computational results for various analysis conditions are practically presented in detail. Futhermore, proper design modifications of the initially designed test equipment in order to guarantee or increase structural safety have been successfully conducted in the design stage.

Improvement of Handrail Slippage Characteristics Using Multi-Body Dynamic Analysis Technique (다물체 동역학 해석기술을 이용한 핸드레일의 슬립특성 개선)

  • Park, Chan-Jong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.9
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    • pp.1422-1428
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    • 2004
  • In this paper, computer simulation model of handrail band including pulley-driving system is developed to calculate handrail slippage. This handrail simulation model is validated with test result within operating range and used to predict its slippage behavior with respect to variation of 4 different design parameters considering the applicability into the real handrail system. Based upon this parameter study, optimal condition for handrail slippage improvement is proposed without time-consuming and costly experiments of the real handrail system. And then performance improvement of handrail slippage complied with safety code is achieved after applying the optimal condition into the real handrail band system.

Experimental Verification of Flexible Multibody Dynamic Simulations for A Rotating Beam (회전 외팔보에 대한 유연 다물체 동역학 시뮬레이션의 실험적 검증)

  • Kim, Seong-Su;Gang, Yeon-Jun;Lee, Gyu-Il
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.2
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    • pp.267-274
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    • 2002
  • Using a flexible rotating beam test bed, experimental verification of a flexible multibody dynamic simulations for a rotating beam model has been carried out. The test bed consists of a flexible arm, harmonic driver reducer, AC servo motor and DSP board with PC. The mechanical ports of the test bed has been designed using 3D CAD program. For the simulation model, mass and moment of inertia of each part of the flexible rotating beam test bed are also obtained from 3D CAD model. In the flexible multibody dynamic simulations, the substructuring model has been established to capture nonlinear effects of the flexible rotating beam. Through the experimental verification, substructuring model provides better results than those from the linear model in the high speed rotation.

Approximate Function Method for Real Time Multibody Vehicle Dynamics Model (근사함수방법을 이용한 실시간 다물체 차량 동역학 모델)

  • Kim, Sung-Soo;Lee, Chang-Ho;Jeong, Wan-Hee;Lee, Sun-Ho
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.6
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    • pp.57-65
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    • 2006
  • An approximate function approach has been developed using the subsystem synthesis method for real-time multibody vehicle dynamics models. In this approach, instead of solving loop closure constraint equations of the suspension linkage, approximate functions are used. The approximate function represents the functional relationship between dependent coordinates and independent coordinates of the suspension subsystem. This kinematic relationship is also included in the suspension subsystem equations of motion. Different order of polynomial functions are tried to find out the best candidate functions. The proposed method is also compared with the conventional subsystem synthesis method to verify its efficiency and accuracy.

Dynamic Analysis of a Washing Machine Using a Multi-body Dynamic Model (다물체 동역학 모델을 이용한 세탁기의 동적 해석)

  • Kim, Tae-Jin;Kim, Byung-Jin;Kim, Seung-Oh;Min, Je-Hong;Chung, Jin-Tai
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.1
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    • pp.88-93
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    • 2012
  • In this study, a multi-body dynamic model is developed for a washing machine and the dynamic behaviors of the machine are investigated. The mechanical properties such as spring constants and damping factors are measured from vibrational experiments. With these experimentally obtained mechanical properties, a computer simulation model for the washing machine is established by using a commercial multi-body dynamics software DAFUL. In order to verify the developed simulation model, the dynamic responses computed from simulation are compared to the responses measured from vibration experiments. In addition, the effects of the stiffness and damping factors on the dynamic responses are also analyzed.

Real-Time Dynamic Analysis of Vehicle with Experimental Vehicle Model (실험기반 차량모델을 이용한 실시간 차량동역학 해석)

  • Yoo, Wan-Suk;Na, Sang-Do;Kim, Kwang-Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.9
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    • pp.1003-1008
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    • 2012
  • The paper presents an Experimental Vehicle Model (EVM), that utilizes the kinematic characteristics of suspensions from SPMD test data. The relative displacement and orientation of a wheel with respect to the body are represented as a function of the vertical displacement of the wheel. The equations of motion of the vehicle are formulated in terms of local coordinates that do not require coordinate transformation, which improves the efficiency of dynamic analysis. The EOM was modularized for each suspension model, and a $6{\times}6$ vehicle model was obtained by combining six suspensions. The analysis results were compared with ADAMS to verify the accuracy of the EVM. This study also verifies the feasibility of real-time simulation with the developed EVM. For a vehicle simulation for 1 ms, the real simulation time required within 20% of the prescribed time. This result shows that the EVM meets the real-time simulation requirements.

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.

A Non-recursive Formulation of Dynamic Force Analysis in Recursive Multibody Dynamics (순환 다물체동역학에서의 비순환적인 동하중해석 공식)

  • Kim, Seong-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.5
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    • pp.809-818
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    • 1997
  • An efficient non-recursive formulation of dynamic force analysis has been developed for serially connected multibody systems. Although derivation of equations of motion is based on a recursive dynamic formulation with joint relative coordinates, in the proposed formulation, dynamic forces such as joint reaction forces and driving force are computed non-recursively for specified joints. The efficiency of the proposed formulation has been proved by the operational count and the CPU time measure, comparing with that of the conventional recursive Newton-Euler formulation. A simulation of 7-DOF RRC robot arm has been carried out to validate solutions of reaction forces by comparing with those from a commercial dynamic analysis program DADS.

Dynamic Response Analysis for Upper Structure of 5MW Offshore Wind Turbine System based on Multi-Body Dynamics Simulation (다물체 동역학 시뮬레이션 기반 5MW급 해상풍력발전시스템의 상부구조물에 대한 동적 응답 해석)

  • Lee, Kangsu;Im, Jongsoon;Lee, Jangyong;Song, Chang Yong
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.16 no.4
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    • pp.239-247
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    • 2013
  • Recently renewable energy such as offshore wind energy takes a higher interest due to the depletion of fossil fuel and the environmental pollution. This paper deals with multi-body dynamics (MBD) analysis technique for offshore wind turbine system considering aerodynamic loads and Thevenin equation used for determination of electric generator torque. Dynamic responses of 5MW offshore wind turbine system are evaluated via the MBD analysis, and the system is the horizontal axis wind turbine (HAWT) which generates electricity from the three blades horizontally installed at upwind direction. The aerodynamic loads acting on the blades are computed by AeroDyn code, which is capable of accommodating a generalized dynamic wake using blade element momentum (BEM) theory. In order that the characteristics of dynamic loads and torques on the main joint parts of offshore wind turbine system are simulated similarly such an actual system, flexible body modeling including the actual structural properties are applied for both blade and tower in the multi-body dynamics model.

Study of Factor Causing Wear of a Barrel Cam in a Paper-Cup-Forming Machine by Using Multibody Dynamics Model (다물체 동역학 모델을 이용한 종이컵 성형기용 배럴캠의 마모 인자에 관한 연구)

  • Jun, Kab-Jin;Park, Tae-Won;Cheong, Kwang-Yeil;Kim, Young-Guk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.3
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    • pp.361-367
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    • 2010
  • The barrel cam, which is a type of cylindrical cam, has been widely used as a part of index drive units for automatic manufacturing machines. The axis of rotation of the barrel cam is orthogonal to the axis of rotation of the follower. The index drive rotates or dwells depending on the cam profile, while the cam rotates with a constant velocity. Continuous sliding contact between the barrel cam and the follower surfaces causes wearing of the adhesive between them. This study shows that the contact force between two sliding bodies is responsible for the wear of the barrel cam in the paper-cup-forming machine. This contact force is calculated by using the multibody dynamics model of the paper-cup-forming machine. The analytical result is validated by comparing it to the actual wear spots on the real product.