• Title, Summary, Keyword: 오일러 보이론

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Free vibration analysis of double split beams (이중 층상균열보의 자유진동해석)

  • Han, B.K;Lee, S.H
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.21 no.12
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    • pp.2008-2018
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    • 1997
  • In this study, free vibration analysis of double through-the-width split beam is studied based on the author's earlier work. Each segment which constructs double through-the-width split beam is considered as Timoshenko beam. The effect of coupling between longitudinal and transverse vibration on the natural frequencies of split beams is considered. Data acquisition and modal test of double split beam for clamped-free boundary condition are carried out. Experimental and numerical results obtained by ANSYS were compared with the calculated data by present theory and their comparisons give good agreement with one another. The influences of the size and location of double split, shear deformation, and boundary conditions on the natural frequencies are demonstrated for illustrative purpose. Effects of double split on the dynamic characteristics of beams can be used to detect the size and the location of damages in structures.

Influence of Crack on Dynamic Behavior of Simply Supported Beam with Moving Mass (이동질량을 가진 단순지지 보의 동특성에 미치는 크랙의 영향)

  • 윤한익;이용운;손인수
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.9
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    • pp.720-729
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    • 2003
  • An iterative modal analysis approach is developed to determine the effect of transverse open cracks on the dynamic behavior of simply supported Euler-Bernoulli beam with the moving mass. The influences of the depth and the position of the crack in the beam have been studied on the dynamic behavior of the simply supported beam system by numerical method. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments i.e. the crack is modelled as a rotational spring. This flexibility matrix defines the relationship between the displacements and forces across the crack section and is derived by applying fundamental fracture mechanics theory. As the depth of the crack is increased the frequency of the simply supported beam with the moving mass is increased.

Vibration Analysis of Rotating Pre-twisted Inward Beams with a Concentrated Mass (집중질량과 초기 비틀림을 갖는 회전중심방향 자유단 외팔보의 진동해석)

  • Lee, Gun Ho;Yoo, Hong Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.25 no.6
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    • pp.384-390
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    • 2015
  • The vibration analysis of rotating inward beams considering the pre-twisted is presented based on Euler-Bernoulli beam theory. The frequency equations, are calculated using hybrid deformation variable modeling along with the Rayleigh-Ritz assumed mode methods. In this study, resulting system of ordinary differential equations shows the effects of angular speed, and Young's modulus ratio. It is believed that the results will be a reference with which other researchers and commercial FE analysis program, ANSYS can compare their result.

Dynamic Behavior of Simply Supported Fluid Flow Pipe with Crack (크랙을 가진 유체유동 단순지지 파이프의 동특성 해석)

  • 윤한익;최창수;손인수
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.13 no.7
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    • pp.562-569
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    • 2003
  • An iterative modal analysis approach is developed to determine the effect of transverse open cracks on the dynamic behavior of simply supported pipe conveying fluid subject to the moving mass. The equation of motion Is derived by using Lagrange’s equation. The influences of the velocity of moving mass and the velocity of fluid flow and a crack have been studied on the dynamic behavior of a simply supported pipe system by numerical method. The presence of crack results In higher deflections of pipe. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments i.e. the crack is modelled as a rotational spring. Totally. as the velocity of fluid flow and the crack severity are increased, the mid-span deflection of simply supported pipe conveying fluid Is Increased. The time which produce the maximum dynamic deflection of the simply supported pipe Is delayed according to the increment of the crack severity.

Dynamic Behavior of a Simply Supported Fluid Flow Pipe with a Crack (크랙을 가진 유체유동 파이프의 동특성 해석)

  • 유진석;손인수;윤한익
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.689-694
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    • 2003
  • An iterative modal analysis approach is developed to determine the effect of transverse open cracks on the dynamic behavior of simply supported pipe conveying fluid subject to the moving mass. The equation of motion is derived by using Lagrange's equation. The influences of the velocity of moving mass and the velocity of fluid flow and a crack have been studied on the dynamic behavior of a simply supported pipe system by numerical method. The presence of crack results in higher deflections of pipe. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments i.e. the crack is modelled as a rotational spring. Totally, as the velocity of fluid flow and the crack severity are increased, the mid-span deflection of simply supported pipe conveying fluid is increased. The time which produce the maximum dynamic deflection of the simply supported pipe is delayed according to the increment of the crack severity.

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Influence of Serial Moving Masses on Dynamic Behavior of a Simply Support Beam with Crack (크랙을 가진 단순지지 보의 동특성에 미치는 이동질량의 영향)

  • 손인수;조정래;윤한익
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1085-1090
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    • 2003
  • An iterative modal analysis approach is developed to determine the effect of transverse open cracks on the dynamic behavior of simply supported Euler-Bernoulli beams with the moving masses. The influences of the velocities of moving masses, the distance between the moving masses and a crack have been studied on the dynamic behavior or a simply supported beam system by numerical method. no presence or crack results in large deflection of beam. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments i.e. the crack is modelled as a rotational spring. This flexibility matrix defines the relationship between the displacements and forces across the crack section and is derived by applying fundamental fracture mechanics theory. Totally, as the velocity of the moving masses and the distance between the moving masses are increased, the mid-span deflection of simply supported beam with the crack is decreased.

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A Study on Dynamic Behavior of Simply Supported Fluid Flow Pipe with Crack and Moving Mass (크랙과 이동질량을 가진 유체유동 단순지지 파이프의 동특성에 관한 연구)

  • Yoon, Han-Ik;Jin, Jong-Tae;Son, In-Soo
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.4
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    • pp.419-426
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    • 2004
  • In this paper, studied about the effect of open crack and the moving mass on the dynamic behavior of simply supported pipe conveying fluid. The equation of motion is derived by using Lagrange's equation. The influences of the velocity of moving mass, the velocity of fluid flow and a crack have been studied on the dynamic behavior of a simply supported pipe system by numerical method. The crack section is represented by a local flexibility matrix connecting two undamaged beam segments. Therefore, the crack is modelled as a rotational spring. Totally, as the velocity of fluid flow is increased, the mid-span deflection of simply supported pipe conveying fluid is increased. The position of the crack is located in the middle point of the pipe, the mid-span deflection of simply supported pipe presents maximum deflection.

Spectral Element Formulation for Analysis of Lamb Wave Propagation on a Plate Induced by Surface Bonded PZT Transducers (표면 부착형 PZT소자에 의해 유발된 판 구조물의 램파 전달 해석을 위한 스펙트럼 요소 정식화)

  • Lim, Ki-Lyong;Kim, Eun-Jin;Kang, Joo-Sung;Park, Hyun-Woo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.18 no.11
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    • pp.1157-1169
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    • 2008
  • This paper presents spectral element formulation which approximates Lamb wave propagation by PZT transducers bonded on a thin plate. A two layer beam model under 2-D plane strain condition is introduced to simulate high-frequency dynamic responses induced by a piezoelectric (PZT) layer rigidly bonded on a base plate. Mindlin-Herrmann and Timoshenko beam theories are employed to represent the first symmetric and anti-symmetric Lamb wave modes on a base plate, respectively. The Euler-Bernoulli beam theory and 1-D linear piezoelectricity are used to model the electro-mechanical behavior of a PZT layer. The equations of motions of a two layer beam model are derived through Hamilton's principle. The necessary boundary conditions associated with the electro-mechanical properties of a PZT layer are formulated in the context of dual functions of a PZT layer as an actuator and a sensor. General spectral shape functions of response field and the associated boundary conditions are obtained through equations of motions converted into frequency domain. Detailed spectrum element formulation for composing the dynamic stiffness matrix of a two layer beam model is presented as well. The validity of the proposed spectral element is demonstrated through numerical examples.