• 제목/요약/키워드: 집중 질량

검색결과 194건 처리시간 0.034초

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

  • 윤경재
    • 한국군사과학기술학회지
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    • 제7권4호
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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.

자유단에 집중질량을 갖는 캔틸레버형 변단면 보의 자유진동 (Free Vibrations of Tapered Cantilever-Type Beams with Tip Mass at the Free End)

  • 오상진;이재영;박광규;모정만
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문집
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    • pp.965-970
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    • 2002
  • The purpose of this paper is to investigate the free vibration characteristics of tapered beams with general boundary condition(translational and rotational elastic support) at one end and carrying a tip mass with translational elastic support at the other end. The beam model is based on the classical Bernoulli-Euler beam theory which neglects the effects of rotatory inertia and shear deformation. The governing differential equation for the free vibrations of linearly tapered beams is solved numerically using the corresponding boundary conditions. Numerical results are compared with existing solutions by other methods for cases in which they are available. The lowest four natural frequencies are calculated over a wide range of section ratio, dimensionless spring constant and mass ratio.

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집중 질량및 관성 모멘트를 갖는 회전하는 티모센코 보의 면외굽힘 진동 (Flapwise Bending Vibration of Rotating Timpshenko Beams with Concentrated Mass and Mass Moment of Inertia)

  • 박정훈;유홍희
    • 소음진동
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    • 제8권2호
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    • pp.353-360
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    • 1998
  • In this paper, a modeling method for the bending vibration analysis of rotating Timoshenko beams with concentrated mass and mass moment of inertia is presented. The shear and rotary inertia effects become critical for the accurate estimation of the natural frequencies and mode shapes as the slenderness ratio decreases. The natural frequencies obtained by using the Timoshenko beam theory are lower than those by using the Euler beam theory. The critical angular speed, which does not exist only with the concentrated mass, exists with the concentrated mass moment of inertia.

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상단에 집중질량을 갖는 유체에 잠긴 기둥의 자유진동 특성 (Free Vibration Characteristics of Columns Immersed in Fluid with a Concentrated Mass at the Top)

  • 오상진
    • 한국농공학회지
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    • 제42권1호
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    • pp.105-112
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    • 2000
  • This paper deals with the free vibrations of columns immersed in fluid. The column model is based on the classical Bernoulli-euler theory which neblects the effects of rotatory inerital and shear deformation. The eccentricity and rotatory inertial of the concentrated mass at the top are taken into accuont. In the governing equation for the free vibration of column, thedensity of immersed part was midified to account for theadded fluid mass. The govering differential equations are solved numerically using the corresponding boundary conditions. The lowest four natural frequencies and corresponding mode shapes are calculated over a range of non-dimensional system parameters ; the mas density ration of fluid to column, the ratio of fluid depth to span length, the ratio of tip mass to total column mass, the dimensionless mass moment of inertia, and the eccentricity.

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열 잉크젯 프린트헤드의 집중질량 모델링 (Lumped Modeling of Thermal Inkjet Print Head)

  • 이유섭
    • 대한기계학회논문집B
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    • 제30권10호
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    • pp.942-949
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    • 2006
  • A lumped model is proposed to predict liquid ejection characteristics of a thermally driven inkjet print head. The model is based on a two-dimensional heat conduction equation, an empirical pressure-temperature equation and a nonlinear hydraulic flow-pressure equation. It has been simulated through the construction of an equivalent R-C circuit, and subsequently analyzed using SIMULINK and a circuit simulation tool, PLECS. Using the model, heating and cooling characteristics of the head are predicted to be in agreement with the IR temperature measurements. The effects of the head geometry on the drop ejection are also analyzed using the nonlinear hydraulic model. The present model can be used as a design tool for a better design of thermal inkjet print heads.

집중질량을 갖는 회전중심방향 자유단 외팔보의 진동해석 (Vibration Analysis of Rotating Inward Cantilever Beams With a Tip-Mass)

  • 이건호;유홍희
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2014년도 추계학술대회 논문집
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    • pp.389-391
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    • 2014
  • The Vibration Analysis of Rotating Inward Beams Considering The Tip-Mass is presented based on Euler-Bernoulli beam theory. The frequency equations, which are coupled through gyroscopic coupling terms, 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 results.

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Pasternak지반에 지지된 집중질량을 갖는 보강된 변단면 후판의 동적안정해석 (Dynamic Stability Analysis of Stiffened Tapered Thick Plate with Concentrated Mass on Pasternak Foundations)

  • 이용수;김일중
    • 한국소음진동공학회논문집
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    • 제19권12호
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    • pp.1296-1305
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    • 2009
  • This paper has the object of investigating dynamic stability of stiffened tapered thick plate with concentrated mass on Pasternak foundation by means of finite element method and providing kinematic design data for mat of building structures. Finite element analysis of stiffened tapered thick plate is done by use of rectangular finite element with 8-nodes. In order to analysis plate which is supported on Pasternak foundation, the Winkler foundation parameter is varied with 10, 100, 1000 and the shear foundation parameter is 5, 10, concentrated mass is $0.25m_c$, $1.0m_c$, tapered ratio is 0.25, 0.5. The ratio of In-plane force to critical load is applied as $0.4\sigma_{cr},\;0.6\sigma_{cr},\;0.8\sigma_{cr}$ respectively. This paper analyzed varying tapered ratio.

상단 집중질량을 갖는 근입 말뚝의 진동 특성 (Vibration Characteristics of Embedded Piles Carrying a Tip Mass)

  • 최동찬;변요셉;오상진;천병식
    • 한국소음진동공학회논문집
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    • 제20권4호
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    • pp.405-413
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    • 2010
  • The vibration characteristics of fully and partially embedded piles with flexibly supported end carrying an eccentric tip mass are investigated. The pile model is based on the Bernoulli-Euler theory and the soil is idealized as a Winkler model for mathematical simplicity. The governing differential equations for the free vibrations of such members are solved numerically using the corresponding boundary conditions. The lowest three natural frequencies and corresponding mode shapes are calculated over a wide range of non-dimensional system parameters: the rotational spring parameter, the relative stiffness, the embedded ratio, the mass ratio, the dimensionless mass moment of inertia, and the tip mass eccentricity.

축방향 왕복운동을 하는 집중질량을 가진 외팔보의 비선형 동적 모델링 및 안정성 해석 (Nonlinear Dynamic Modeling and Stability Analysis of an Axially Oscillating Cantilever Beam With a Concentrated Mass)

  • 홍정환;유홍희
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 춘계학술대회논문집
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    • pp.477-482
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    • 2003
  • A nonlinear modeling method for an axially oscillating cantilever beam with a concentrated mass is presented in this paper. Hybrid deformation variables are employed fur the modeling method with which frequency response characteristics of axially oscillating cantilever beams are investigated. The geometric nonlinear effects of stretching and curvature are considered to accurately predict the frequency response characteristics of the oscillating cantilever beam. The effects of the magnitude and the location on the concentrated mass on the frequency characteristics are investigated. It is found that the dynamic instability is significantly influenced by the two parameters.

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유체저장탱크 단순화 모델의 정확도 향상을 위한 내진설계변수 산출 (Accuracy Improvement of Simplified Liquid Storage Tanks Seismic Design)

  • 송수영;이강원;김준휘;임윤묵
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2010년도 정기 학술대회
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    • pp.285-288
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    • 2010
  • 유체저장탱크가 외부로부터 지진과 같은 동적하중을 받게 될 경우 유체와 구조물의 상호작용(Fluid-Structure Interaction)으로 인하여 일반적인 구조물과는 상이한 거동을 보이게 된다. 이러한 복잡한 상호작용을 고려하여 현재 내진 설계에서는 Housner와 Haroun의 이론을 적용한 단순화 모델들이 사용되고 있다. 이들 모델은 유체의 거동을 대류(convective) 성분과 충격(impulsive) 성분으로 구분하여 집중질량으로 단순화 한다. 하지만 점차 대형화되고 있는 유체저장탱크의 정확한 동적 거동 특성을 파악하고, 지진하중과 같은 방향성을 가진 하중에 대한 구조물의 정확한 응답을 해석하려면 단순화 모델의 적용성 검토가 필요하다. 본 연구에서는 지진하중을 받는 유체저장탱크의 동적거동을 집중질량 모델과 3차원 모델을 이용하여 해석하였다. 나아가 해석결과의 차이를 분석하여 단순화 모델의 정확도 향상을 위한 내진설계변수 산출에 관하여 향후 연구방향을 제시하였다.

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