• Title/Summary/Keyword: Compliant Forces Element

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Enhanced generalized modeling method for compliant mechanisms: Multi-Compliant-Body matrix method

  • Lim, Hyunho;Choi, Young-Man
    • Structural Engineering and Mechanics
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    • v.82 no.4
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    • pp.503-515
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    • 2022
  • The multi-rigid-body matrix method (MRBMM) is a generalized modeling method for obtaining the displacements, forces, and dynamic characteristics of a compliant mechanism without performing inner-force analysis. The method discretizes a compliant mechanism of any type into flexure hinges and rigid bodies by implementing a multi-body mass-spring model using coordinate transformations in a matrix form. However, in this method, the deformations of bodies that are assumed to be rigid are inherently omitted. Consequently, it may yield erroneous results in certain mechanisms. In this paper, we present a multi-compliant-body matrix-method (MCBMM) that considers a rigid body as a compliant element, while retaining the generalized framework of the MRBMM. In the MCBMM, a rigid body in the MRBMM is segmented into a certain number of body nodes and flexure hinges. The proposed method was verified using two examples: the first (an XY positioning stage) demonstrated that the MCBMM outperforms the MRBMM in estimating the static deformation and dynamic mode. In the second example (a bridge-type displacement amplification mechanism), the MCBMM estimated the displacement amplification ratio more accurately than several previously proposed modeling methods.

Dynamic Analysis of A High Mobility Tracked Vehicle Using Compliant Track Link Model (유연성 궤도 모델을 사용한 고기동성 궤도차량의 동역학 해석)

  • 백운경;최진환;배대성
    • Journal of KSNVE
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    • v.9 no.6
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    • pp.1259-1266
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    • 1999
  • The objective of this investigation is to develop a compliant track link model and apply this model to the multi-body dynamic analysis of high mobility tracked vehicles. Two major difficulties encountered in developing the compliant track models. The first one is that the integration step size must be kept small in order to maintain the numerical stability of the solution. This solution deals with high oscillatory signals resulting from the impulsive contact forces and stiff compliant elements to represent the joints between the track links. The second difficulty is due to the large number of the system equations of motion of the three dimensional multibody tracked vehicle model. This problem was sloved by decoupling the equations of motion of the chassis subsystem and the track subsystems. Recursive methods are used to obtain a minimum set of equations for the chassis subsystem. Several simulation scenarios were tested for the high mobility tracked vehicle including accelaeration, high speed cruising, braking, and turning motion in order to demonstrate the effectiveness and validity of the methods proposed in this investigation.

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Characteristics of Dynamic Track Tension for Three Dimensional High Mobility Tracked Vehicle (3차원 고기동 궤도차량의 동적 궤도장력 특성 연구)

  • 서문석;최진환;류한식;배대성
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.1
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    • pp.112-120
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    • 2003
  • In this paper, dynamic track tension fur high mobility tracked vehicle is investigated by multibody dynamic simulation techniques. This research focuses on a heavy military tracked vehicle which has sophisticated suspension and rubber bushed rack systems. In order to obtain accurate dynamic track tension of track subsystems, each track link is modeled as a body which has six degrees of freedom. A compliant bushing element is used to connect track links. Various virtual proving ground models are developed to observe dynamic changes of the track tension. Numerical studies of the dynamic track tension are validated against the experimental measurements. The effects of pre-tensions, traction forces, fuming resistances, sprocket torques, ground profiles, and vehicle speeds, for dynamic responses of track tensions are explored, respectively.

Behavior Analysis of a Tension Leg Platform in Current and Waves (조류와 파랑 중의 인장계류식 해양구조물의 거동해석)

  • Lee, S.C.;Park, C.H.;Bae, S.Y.;Goo, J.S.
    • Journal of Power System Engineering
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    • v.15 no.1
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    • pp.64-71
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    • 2011
  • The Tension Leg Platform(TLP) is restrained from oscillating vertically by tethers(or tendons), which are vertical anchor lines tensioned by the platform buoyancy larger than the platform weight. Thus a TLP is a compliant structure which allows lateral movements of surge, sway, and yaw but restrains heave, pitch, roll. In this paper, the motions of a TLP in current and waves were investigated. Hydrodynamic forces and wave exciting forces acting on the TLP were evaluated using the three dimensional source distribution method. The motion responses and tension variations of the TLP were analyzed in the case of including current or not including one in regular waves and effects of current on the TLP were investigated.