• 제목/요약/키워드: Euler-beam theory

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Stability of Water Tower with a Relatively Small Footing (상대적으로 작은 기초를 갖는 급수탑의 안정성)

  • Oh Sang-Jin;Jin Tae-Ki
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2006.04a
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    • pp.963-968
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    • 2006
  • The main purpose of this paper is to investigate the stability of water tower with a relatively small footing. The water tower is modeled that the column carrying a container is supported by a rotational spring at the base and is of constant cross-section, with a weight per unit length of column axis. The column model is based on the Bernoulli-Euler beam theory. The Runge-Kutta method and Determinant Search method are used to perform the integration of the governing differential equation and to determine the critical values(critical own weight. and critical buckling load), respectively. The critical buckling loads are calculated over a range of system parameters: the rotational stiffness parameter, the dimensionless radius of container and the own weight parameter of the column. The relation between the rotational stiffness parameter and the critical own weight parameter of the column is analyzed.

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Vibration Analyses and Design of Resonance Avoidance of the Unmanned Helicopter Master (무인 헬리콥터 마스터의 진동해석 및 공진회피 설계)

  • Lee, Seong-Chul;Son, In-Soo;Hur, Kwan-Do
    • Journal of the Korean Society for Precision Engineering
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    • v.28 no.8
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    • pp.951-958
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    • 2011
  • In this paper, the purpose is to investigate the vibration characteristics and the design of resonance avoidance of the unmanned helicopter master. Based on the Euler-Bernoulli beam theory for helicopter master, the equation of motion is derived by using extended Hamilton's principle. It was studied about the natural frequency of helicopter master as the design variances(tip mass, length and diameter of master). Also, it was compared the theoretical results for natural frequency with the results of FE analysis. The results of this study showed the vibration characteristics of helicopter master for the design of resonance avoidance.

Study on the Development of Noncontact Vibration Exciter for Thin Plates Using Magnetism (자력을 이용한 비접촉식 박판 가진장치 개발에 관한 연구)

  • Hur, Kwan-Do;Son, In-Soo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.1
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    • pp.104-109
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    • 2016
  • The noncontact vibration exciter system using the electro-magnet for a thin plate is studied in this paper. Based on the Euler-Bernoulli beam theory, the equation of motion of thin plate is derived. The main purpose of this experiment is to match the input-frequency and response frequency of thin plate. The test equipment is configured to vibrate on both sides of the thin plate using the electro-magnet. Two frequencies(input frequency and response frequency) in our experiments show very good agreement. This study results will contribute to basic investigate of an alternative air-knife system for the steel industry.

Theoretical Modeling and Dynamic Characteristics of a Cantilever IPMC Actuator (외팔보형 IPMC 구동기의 이론적 모델링과 구동특성)

  • Han, Dae-Woong;Lee, Seung-Yop;Cho, Sang-Ho
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1521-1526
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    • 2008
  • IPMC(Ionic Polymer-Metal Comosite) exhibits large deformation, having great attention in many application fields. It generates bending moment by ion exchange polymer film. It can be quickly bended by the applied voltage across the plated electrode of the polymer film. In the present paper, we derive the theoretical modeling and dynamic analysis of bending motions of IPMC actuators using the Euler-Bernoulli beam theory. The theoretical model of a cantilever IPMC actuator estimates the moment produced by the applied voltage. The dynamic characteristics, including natural frequencies and frequency response, are calculated by the theoretical model, and they are compared with the experimental results and finite element analysis. It is shown that the mathematical modeling allows precise estimation to the voltage-driven motion of the cantilever IPMC in air.

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Forced Vibration Analysis of Elastically Restrained Valve-pipe System (탄성지지된 밸브 배관계의 강제진동 특성)

  • Son, In-Soo;Yoon, Han-Ki;Min, Byoung-Hyun;Hur, Kwan-Do
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.11 no.4
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    • pp.90-96
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    • 2012
  • The forced vibration response characteristics of a elastically restrained pipe conveying fluid with attached mass are investigated in this paper. Based on the Euler-Bernoulli beam theory, the equation of motion is derived by using Hamilton's principle. The effects of attached mass and spring constant on the forced vibration characteristics of pipe at conveying fluid are studied. The forced deflection response of pipe with attached mass due to the variation of fluid velocity is also presented. The deflection response is the mid-span deflection of the pipe. The dimensionless forcing frequency is the range from 0 to 16 which is the first natural frequency of the pipe.

The End-Point Position Control of a Translational Flexible Arm by Inverse Dynamics (역동역학에 의한 병진운동 탄성 Arm 선단의 위치제어)

  • Lee, Seong-Cheol;Bang, Du-Yeol;S. Chonan;H. Inooka
    • Journal of the Korean Society for Precision Engineering
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    • v.9 no.4
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    • pp.136-146
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    • 1992
  • This paper provides the end-point positioning of a single-link flexible robot arm by inverse dynamics. The system is composed of a flexible arm, the mobile ballscrew stage as an arm base, a DC servomotor as an actuator, and a computer. Actuator voltages required for the model of a flexible arm to follow a given tip trajectory are formulated on the basis of the Bermoullie-Euler beam theory and solved by applying the Laplace transform method, and computed by the numerical inversion method proposed by Weeks. The mobile stage as the arm base is shifted so that the end-point follows the desired trajectories. Then the trajectory of end-point is measured by the laser displacement sensor. Here, two kinds of functions are chosen for the given tip trajectories. One is what is called the bang-bang acceleration profile and the other is the Gaussian velocity profile.

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Nonlinear Vibration Characteristics of a Curved Pipe with Fixed Ends and Steady Internal Flow (정상 상태 내부 유동이 있는 양단 고정 곡선 파이프의 비선형 진동 특성)

  • Lee, Su-Il;Jeong, Jin-Tae
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.1
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    • pp.61-66
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    • 2002
  • The nonlinear differential equations of motion of a fluid conveying curved pipe are derived by use of Hamiltonian approach. The extensible dynamics of curled pipe is based on the Euler-Bernoulli beam theory. Some significant differences between linear and nonlinear equations and the dynamic characteristics are discussed. Generally, it can be shown that the natural frequencies in curved pipes are changed with flow velocity. Linearized natural frequencies of nonlinear equations are slightly different from those of linear equations.

Stability Analysis of Pipe Conveying Fluid with Crack (크랙을 가진 유체유동 파이프의 안정성 해석)

  • Son, In-Soo;Ahn, Tae-Su;Yoon, Han-Ik
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.1 s.118
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    • pp.10-16
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    • 2007
  • In this paper, the dynamic stability of a cracked simply supported pipe conveying fluid is investigated. In addition, an analysis of the flutter and buckling instability of a cracked pipe conveying fluid due to the coupled mode(modes combined) is presented. Based on the Euler-Bernouli beam theory, the equation of motion can be constructed by using the Galerkin method. The crack section is represented by a local flexibility matrix connecting two undamaged pipe segments. The stiffness of the spring depends on the crack severity and the geometry of the cracked section. The crack is assumed to be in the first mode of fracture and to be always opened during the vibrations. This results of study will contribute to the safety test and a stability estimation of the structures of a cracked pipe conveying fluid.

Effects of Attached Mass on Stability of Pipe Conveying Fluid with Crack (크랙을 가진 유체유동 파이프의 안정성에 미치는 부가질량의 영향)

  • Son, In-Soo;Cho, Jeong-Rae;Yoon, Han-Ik
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.17 no.10
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    • pp.1002-1009
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    • 2007
  • In this paper, the dynamic stability of a cracked simply supported pipe conveying fluid with an attached mass is investigated. Also, the effect of attached mass on the dynamic stability of a simply supported pipe conveying fluid is presented for the different positions and depth of the crack. Based on the Euler-Bernouli beam theory, the equation of motion can be constructed by the energy expressions using extended Hamilton's principle. The crack section is represented by a local flexibility matrix connecting two undamaged pipe segments. The crack is assumed to be in the first mode of a fracture and to be always opened during the vibrations. Finally, the critical flow velocities and stability maps of the pipe conveying fluid are obtained by changing the attached mass and crack severity.

Characteristics of Forced Vibration of Valve-pipe Systems with a Crack (크랙을 가진 밸브 배관계의 강제진동 특성)

  • Son, In-Soo;Kim, Chang-Ho;Cho, Jeong-Rae
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.22 no.11
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    • pp.1049-1056
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    • 2012
  • The forced vibration response characteristics of a cracked pipe conveying fluid with a concentrated mass are investigated in this paper. Based on the Euler-Bernoulli beam theory, the equation of motion is derived by using Hamilton's principle. The effects of concentrated mass and fluid velocity on the forced vibration characteristics of a cracked pipe conveying fluid are studied. The deflection response is the mid-span deflection of a cracked pipe conveying fluid. As fluid velocity and crack depth are increased, the resonance frequency of the system is decreased. This study will contribute to the decision of optimum fluid velocity and crack detection for the valve-pipe systems.