• Title/Summary/Keyword: rigid body analysis

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Dynamic Analysis of a Three-Axis Mechanism for Transfer Robots (3축 이송용 로봇의 동적 해석)

  • Lee, Suk Young
    • Journal of Energy Engineering
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    • v.24 no.3
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    • pp.128-134
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    • 2015
  • This research is that analyze multi-body system that have flexible and rigid body. Transfer robots are widely used mainly in automobile industry owing to its capability to handle heavy parts with high speed in wide range of movement. For the transfer robots to widen the application area, a new three-axis mechanism with heavy payload has been recently developed in consideration of the strength and stiffness. For the purpose, transient dynamic analysis is carried out to find the component position yielding a certain time. Though this research, we can analysis stress distribution and deformation of robot component.

Comparison of simplified model and FEM model in coupled analysis of floating wind turbine

  • Kim, Byoung Wan;Hong, Sa Young;Sung, Hong Gun;Hong, Seok Won
    • Ocean Systems Engineering
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    • v.5 no.3
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    • pp.221-243
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    • 2015
  • This paper compares simplified and finite element method (FEM) models for tower and blade in dynamic coupled analysis of floating wind turbine. A SPAR type wind turbine with catenary mooring lines is considered in numerical analysis. Floating body equation is derived using boundary element method (BEM) and convolution. Equations for mooring line, tower and blade are formulated with theories of catenary, elastic beam and aerodynamic rotating beam, respectively and FEM is applied in the formulation. By combining the equations, coupled solutions are calculated. Tower or blade may be assumed rigid or lumped body for simplicity in modeling. By comparing floating body motions, mooring line tensions and tower stresses with the simple model and original FEM model, the effect of including or neglecting elastic, rotating and aerodynamic behavior of tower and blade is discussed.

Dynamic Analysis of Constrained Multibody Systems Undergoing Collision (충돌하는 구속 다물체계의 동역학 해석)

  • Park, Jeong-Hun;Yu, Hong-Hui;Yang, Hyeon-Ik;Hwang, Yo-Ha
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.2 s.173
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    • pp.535-542
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    • 2000
  • This paper presents a method for the dynamic analysis of constrained multibody systems undergoing abrupt collision. The proposed method uses a longer time interval to check collision than that of c onventional method. This reduces the computational effort significantly. To calculate collision points on two colliding rigid bodies, one may introduce constraints of contact. However, this causes reduction of degree of freedom and difficulty of numerical analysis. The proposed method can calculate collision points without above mentioned problems. Three numerical examples are given to demonstrate the computational efficiency and the usefulness of the proposed method.

Vibration Analysis of a Flexible Structure in a Motion (유연 구조물의 운동중 발생하는 진동의 해석)

  • 이신영
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.6
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    • pp.1503-1509
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    • 1994
  • An analysis method is suggested and experimentally studied in order to solve a vibration problem of a flexible structure while it is moving. In this method, substructure synthesis method, modal analysis method and Newmark's integral method were used. Total deformation of a structure was composed of quasistatic component and dynamic component. Rigid body modes were considered in calculation of dynamic component. Combining those two component, deformation behavior and a real structural model of a transfer feeder showed good agreements with computational results.

Near-resonant attitude motion analysis of a spinning satellite via multiple scales method

  • Kang, Ja-Young
    • 제어로봇시스템학회:학술대회논문집
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    • 1994.10a
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    • pp.213-217
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    • 1994
  • The attitude stability of a satellite in spin-stabilized injection mode which contains a liquid pool is investigated. The satellite model for investigation is a two-body system consisting of a the main body, which is symmetric and rigid, representing the spacecraft, and a spherical pendulum, representing the liquid pool. Assuming that both spacecraft and pendulum are in states of steady spin about the symmetry axis of the spacecraft, the coupled nonlinear equations of motion for the system are simplified. In this paper, by using the multiple scales method, the possible resonance conditions in terms of the system parameters are determined and the corresponding near-resonant solutions are derived.

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Dynamic modeling and structural reliability of an aeroelastic launch vehicle

  • Pourtakdoust, Seid H.;Khodabaksh, A.H.
    • Advances in aircraft and spacecraft science
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    • v.9 no.3
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    • pp.263-278
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    • 2022
  • The time-varying structural reliability of an aeroelastic launch vehicle subjected to stochastic parameters is investigated. The launch vehicle structure is under the combined action of several stochastic loads that include aerodynamics, thrust as well as internal combustion pressure. The launch vehicle's main body structural flexibility is modeled via the normal mode shapes of a free-free Euler beam, where the aerodynamic loadings on the vehicle are due to force on each incremental section of the vehicle. The rigid and elastic coupled nonlinear equations of motion are derived following the Lagrangian approach that results in a complete aeroelastic simulation for the prediction of the instantaneous launch vehicle rigid-body motion as well as the body elastic deformations. Reliability analysis has been performed based on two distinct limit state functions, defined as the maximum launch vehicle tip elastic deformation and also the maximum allowable stress occurring along the launch vehicle total length. In this fashion, the time-dependent reliability problem can be converted into an equivalent time-invariant reliability problem. Subsequently, the first-order reliability method, as well as the Monte Carlo simulation schemes, are employed to determine and verify the aeroelastic launch vehicle dynamic failure probability for a given flight time.

A Study on Dynamic Responses of Tracked Vehicle on Extremely Soft Cohesive Soil (점착성 연약지반 주행차량의 동적거동 연구)

  • Kim, Hyung-Woo;Hong, Sup;Choi, Jong-Su
    • Ocean and Polar Research
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    • v.26 no.2
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    • pp.323-332
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    • 2004
  • This paper concerns about a study on dynamic responses of tracked vehicle on soft cohesive soil. For dynamic analyses of tracked vehicle, two different models were adopted, i.e. a single-body model and a multi-body model. The single-body vehicle model was assumed as a rigid body with 6-dof. The multi-body vehicle was modeled by using a commercial software, RecurDyn-LM. For the both models properties of cohesive soft soil were modeled by means of three relationships: pressure to sinkage, shear displacement to shear stress, and shear displacement to dynamic sinkage. Traveling performances of the two tracked vehicle models were compared through dynamic analyses in time domain.

Human Motion Control Using Dynamic Model (동력학 모델을 이용한 인체 동작 제어)

  • Kim, Chang-Hoe;O, Byeong-Ju;Kim, Seung-Ho
    • Journal of the Ergonomics Society of Korea
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    • v.18 no.3
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    • pp.141-152
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    • 1999
  • In this paper, We performed the human body dynamic modelling for the realistic animation based on the dynamical behavior of human body, and designed controller for the effective control of complicate human dynamic model. The human body was simplified as a rigid body which consists of 18 actuated degrees of freedom for the real time computation. Complex human kinematic mechanism was regarded as a composition of 6 serial kinematic chains : left arm, right arm, support leg, free leg, body, and head. Based on the this kinematic analysis, dynamic model of human body was determined using Newton-Euler formulation recursively. The balance controller was designed in order to control the nonlinear dynamics model of human body. The effectiveness of designed controller was examined by the graphical simulation of human walking motion. The simulation results were compared with the model base control results. And it was demonstrated that, the balance controller showed better performance in mimicking the dynamic motion of human walking.

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