• Title/Summary/Keyword: Concentrated Mass

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Vibration Analysis of A Rotating Cantilever Blade with Multiple Concentrated Masses with an Elastically Restrained Root (다중 집중질량효과에 의한 탄성 회전 블레이드의 진동해석)

  • Yun Kyung-Jae
    • Journal of the Korea Institute of Military Science and Technology
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    • v.7 no.4 s.19
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    • pp.114-124
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    • 2004
  • In this paper, we have proposed a novel method which can analysis a rotating elastically restrained blade with concentrated masses located in an arbitrary position. 1:he equations of motion are derived and transformed into a dimensionless form to investigate general phenomena. For the modeling of the multi-concentrated masses, the Dirac delta function is used for the mass density function. Simulation results show that the vibration characteristics of elastic restrained blade of according to dimensionless variables for example, multiple masses magnitude and mass location ratio. This method can be applied to an practical rotating blade system required to more accurate results.

A Study on the Vibration Characteristics of Multi-span Beams (멀티스팬 빔의 진동특성에 관한 연구)

  • 홍진선
    • Journal of KSNVE
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    • v.8 no.5
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    • pp.856-861
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    • 1998
  • Several reactor system components, such as heat exchange tubes, fuel fins, controlrods, and various instruments are beam-like components. This study presents a simple solution method for calculating the natural frequencies and modes of beams supported by linear and torsional springs and attached concentrated mass and rotational inertia at some intermediate points. For a general multi-span beam, theoretical method is proposed to analyze the exact solution about vibrational characteristics with respect to the nondimensional parameters. And the results obtained using the numerical models are presented and discussed.

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Effect of Rotary Inertia of Concentrated Masses on the Natural Vibration of Fluid Conveying Pipe

  • Kang, Myeong-Gie
    • Nuclear Engineering and Technology
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    • v.31 no.2
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    • pp.202-213
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    • 1999
  • Effects of the rotary inertia of concentrated masses on the natural vibrations of fluid conveying pipes have been studied by theoretical modeling and computer simulation. For analysis, two boundary conditions for pipe ends, simply supported and clamped-clamped, are assumed and Galerkin's method is used for transformation of the governing equation to the eigenvalues problem and the natural frequencies and mode shapes for the system have been calculated by using the newly developed computer code. Moreover, the critical velocities related to a system instability have been investigated. The main conclusions for the present study are (1) Rotary inertia gives much change on the higher natural frequencies and mode shapes and its effect is visible when it has small value, (2) The number and location of nodes can be changed by rotary inertia, (3) By introducing rotary inertia, the second natural frequency approaches to the first as the location of the concentrated mass approaches to the midspan of the pipe, and (4) The critical fluid velocities to initiate the system unstable are unchanged by introduction of rotary inertia and the first three velocities are $\pi$, 2$\pi$, and 3$\pi$ for the simply supported pipe and 2$\pi$, 8.99, and 12.57 for the clamped-clamped pipe.

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Dynamic Stability of a Cantilevered Timoshenko Beam on Partial Elastic Foundations Subjected to a Follower Force

  • Ryu, Bong-Jo;Shin, Kwang-Bok;Yim, Kyung-Bin;Yoon, Young-Sik
    • Journal of Mechanical Science and Technology
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    • v.20 no.9
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    • pp.1355-1360
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    • 2006
  • This paper presents the dynamic stability of a cantilevered Timoshenko beam with a concentrated mass, partially attached to elastic foundations, and subjected to a follower force. Governing equations are derived from the extended Hamilton's principle, and FEM is applied to solve the discretized equation. The influence of some parameters such as the elastic foundation parameter, the positions of partial elastic foundations, shear deformations, the rotary inertia of the beam, and the mass and the rotary inertia of the concentrated mass on the critical flutter load is investigated. Finally, the optimal attachment ratio of partial elastic foundation that maximizes the critical flutter load is presented.

Nonlinear vibrations of axially moving beams with multiple concentrated masses Part I: primary resonance

  • Sarigul, M.;Boyaci, H.
    • Structural Engineering and Mechanics
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    • v.36 no.2
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    • pp.149-163
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    • 2010
  • Transverse vibrations of axially moving beams with multiple concentrated masses have been investigated. It is assumed that the beam is of Euler-Bernoulli type, and both ends of it have simply supports. Concentrated masses are equally distributed on the beam. This system is formulated mathematically and then sought to find out approximately solutions of the problem. Method of multiple scales has been used. It is assumed that axial velocity of the beam is harmonically varying around a mean-constant velocity. In case of primary resonance, an analytical solution is derived. Then, the effects of both magnitude and number of the concentrated masses on nonlinear vibrations are investigated numerically in detail.

On the Free Vibration of Immersed Linearly Tapered Beam with a Tip Mass (첨단 질량을 갖는 선형 원뿔대의 자유진동)

  • Shin, Young-Jae;Sung, Kyung-Yun;Yun, Jong-Hak
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.402.1-402
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    • 2002
  • A linearly tapered beam immersed partially in other material is considered and is modelled as a linearly tapered Bernoulli-Euler beam fixed at the bottom with a concentrated mass at the top. Its governing equations is derived and its free vibration analysis is performed for various boundary conditions. And the rotatory inertia of the eccentric lumped tip mass is considered. (omitted)

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Luxury Characteristics in Mass Fashion through the Historical Review of Fashion System (패션시스템의 사적 고찰을 통한 매스페션의 사치 특성)

  • Ko, Hyun-Zin
    • Fashion & Textile Research Journal
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    • v.10 no.5
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    • pp.739-747
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    • 2008
  • There have been increasing consumption of luxury fashion and recent marketing researches on luxury syndrome, trading up, etc. in mass fashion today. Historically the consumption of luxury had been concentrated on only upper class in the past. But since 20th century, the mass consumers of modern consumptive society show their interests in luxuries which had been preoccupation of few elite class. Accordingly, it can be thought that the historical review on the changes in the meaning of luxury should be necessary for a better understanding of modern luxury consumption in sociocultural context. The purpose of this study is to grasp the sociocultural meaning of luxury in modern fashion with a holistic viewpoint by examining the changes of luxury consumption in mass fashion. It will be helpful as a conceptual approach of modern luxury consumption. For this, the documentary study has been executed. It focused on since 20th century, which can be the root of mass productive and consumptive society in fashion history. The results are as follows. The luxury in court elite system before 20th century had been concentrated on few elite class exclusively but gradually began to be represented as inferior cheaper version by mass production according to their increasing interests since industrial revolution. The luxuries in elite designer system in the first half of 20th century were represented as illegal design piracy and legal genuine reproduction in spite of problems brought about between originality and copy. The concept of mass as consumer was virtually alienated in both systems. But in fashion system since the second half of 20th century, various types of consumer luxuries has appeared on account of the trading up phenomenon in drastic growth of mass culture.

Vibration Analysis of Vertical Pumps (수직펌프의 진동해석)

  • 홍진선
    • Journal of KSNVE
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    • v.9 no.5
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    • pp.928-935
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    • 1999
  • Vertical pumps are widely used owing to the fact that they occupy small floor space. In this type of pumps, however, the vibrational problems are very important, since, in many cases, they have less stiffness in comparison with lateral pumps. This study presents a simple solution method for calculating the natural frequencies and modes of vertical pumps. In this study, a mode of a vertical pump was developed and the nondimensional parameters for the vibrational characteristics of it were determined. Added mass was calculated for the effects of water and the transfer matrix method was used.

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Free Vibration Analysis of Thin Plate on Inhomogeneous Pasternak Foundation (비균질 Pasternak 지반위에 얹혀진 박판의 자유진동 해석)

  • Kim, Il-Jung;Lee, Young-Soo;Oh, Soog-Kyoung;Lee, Hoy-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.11a
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    • pp.395.2-395
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    • 2002
  • Recently, as size of building structure becomes larger, mat area of building structure is supported on Inhomogeneous foundation. The equipment machineries in building are mostly on basement story. The slab of the lowest basement story with equipment machineries is considerded as concentrated masses on plate supported on foundation. In this paper. vibration analysis of rectangular thin plate is done by use of rectangular finite element with 4 nodes. (omitted)

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Parametric instability of the nonconservative elastic system (비보존 탄성계의 파라미터 불안정)

  • 박영필;노광춘
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.11 no.1
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    • pp.124-131
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    • 1987
  • The parameteric instability of the cantilever beam carrying two concentrated masses subjected to a periodic follower force is investigated theoretically and experimentally. The effects of the constant follower force and the periodic follower force the mass ratio and the location of the concentrated mass on the parametric instability of the system are discussed. In experiment, the nonconservative follower force is produced by the magnetic force of the electromagnet. The theoretical and the experimental results on the parameteric instability are in good agreement each other.