• 제목/요약/키워드: Bending Vibration Analysis

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집중 질량 및 관성모멘트를 갖는 회전하는 티모센코 보의 면외굽힘 진동 (Flapwise Bending Vibration of Rotating Timoshenko Beams with Concentrated Mass Moment of Inertia)

  • 박정훈;유홍희
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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    • pp.110-115
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    • 1997
  • 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 modeshapes as the slenderness ratio decreases. The effect of the concentrated mass and mass moment of inertia on the natural frequencies are also investigated with the modeling method.

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연성강성 효과를 고려한 회전하는 다중 블레이드 시스템의 굽힘진동 해석 (Bending Vibration Analysis of Rotating Multi-blade Systems Considering the Coupling Stiffness Effect)

  • 임하성;권성훈;유홍희
    • 한국소음진동공학회논문집
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    • 제16권9호
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    • pp.912-918
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    • 2006
  • A modeling method for the vibration analysis of rotating multi-blade systems considering the coupling stiffness effect is presented in this paper. Blades are assumed as cantilever beams and the coupling stiffness effect originates from disc or shroud between blades. As the angular speed, hub radius ratio, and the coupling stiffness vary, the natural frequencies of the system vary. Numerical results show that the coupling stiffness is very important to estimate the natural frequencies. Along with the natural frequencies, associated mode shapes, critical angular speed, and critical hub radius ratio are obtained through the analysis.

연성강성 효과를 고려한 회전하는 다중 블레이드 시스템의 굽힘진동 해석 (Bending Vibration Analysis of Rotating Multi-blade Systems Considering the Coupling Stiffness Effect)

  • 임하성;권성훈;유홍희
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2006년도 춘계학술대회논문집
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    • pp.1354-1359
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    • 2006
  • A modeling method for the vibration analysis of rotating multi-blade systems considering the coupling stiffness effect is presented in this paper. Blades are assumed as cantilever beams and the coupling stiffness effect originates from disc or shroud between blades. As the angular speed, hub radius ratio, and the coupling stiffness vary, the natural frequencies of the system vary. Numerical results show that the coupling stiffness is very important to estimate the natural frequencies. Along with the natural frequencies, associated mode shapes, critical angular speed, and critical hub radius ratio are obtained through the analysis.

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비국소 탄성 이론을 이용한 나노 판의 휨 및 자유진동해석 (Nonlocal elasticity theory for bending and free vibration analysis of nano plates)

  • 이원홍;한성천;박원태
    • 한국산학기술학회논문지
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    • 제13권7호
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    • pp.3207-3215
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    • 2012
  • 본 논문에서는 3차 전단변형이론이 고려된 비국소 탄성 이론을 이용한 나노 판의 휨 및 진동에 대하여 연구하였다. 비국소 탄성 이론은 미소 규모 효과를 고려할 수 있고 3차원 전단변형이론은 나노 판의 두께방향으로의 전단 변형률과 전단응력의 곡선변화 효과를 고려할 수 있다. 이러한 두 가지 이론을 이용하여 나노 판의 처짐과 고유진동수에 미치는 비국소 이론의 효과를 제시하였다. 국소 탄성이론과의 관계를 수치해석 결과를 통하여 고찰하였다. 또한 (i) 비국소 계수, (ii) 나노 판의 적층형태, (iii) 나노 판의 보강 방향 그리고 (iv) 나노 판의 적층 수 등이 나노 판의 무차원 처짐에 미치는 효과에 대하여 관찰하였다. 본 연구의 결과를 검증하기 위해 참고문헌의 결과들과 비교 분석하였으며 해석결과는 참고문헌의 결과들과 잘 일치함을 알 수 있었다. 비국소 이론에 의한 나노 판의 처짐에 관한 연구는 향후 관련연구에 비교자료로 활용될 수 있을 것이다.

High-rise Reinforced-concrete Building Incorporating an Oil Damper in an Outrigger Frame and Its Vibration Analysis

  • Omika, Yukihiro;Koshika, Norihide;Yamamoto, Yukimasa;Kawano, Kenichi;Shimizu, Kan
    • 국제초고층학회논문집
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    • 제5권1호
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    • pp.43-50
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    • 2016
  • The reinforced-concrete multi-story shear-wall structure, which can free a building from beams and columns to allow the planning of a vast room, has increasingly been used in Japan as a high-rise reinforced-concrete structure. Since this structural system concentrates the seismic force onto multi-story shear walls inside, the bending deformation of the walls may cause excessive deformation on the upper floors during an earthquake. However, it is possible to control the bending deformation to within a certain level by setting high-strength and rigid beams (outriggers) at the top of the multi-story shear walls; these outriggers restrain the bending behavior of the walls. Moreover, it is possible to achieve high energy dissipation by placing vibration control devices on the outriggers and thus restrain the bending behavior. This paper outlines the earthquake response analysis of a high-rise residential tower to demonstrate the effectiveness of the outrigger frame incorporating vibration control devices.

A new simple three-unknown sinusoidal shear deformation theory for functionally graded plates

  • Houari, Mohammed Sid Ahmed;Tounsi, Abdelouahed;Bessaim, Aicha;Mahmoud, S.R.
    • Steel and Composite Structures
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    • 제22권2호
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    • pp.257-276
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    • 2016
  • In this paper, a new simple higher-order shear deformation theory for bending and free vibration analysis of functionally graded (FG) plates is developed. The significant feature of this formulation is that, in addition to including a sinusoidal variation of transverse shear strains through the thickness of the plate, it deals with only three unknowns as the classical plate theory (CPT), instead of five as in the well-known first shear deformation theory (FSDT) and higher-order shear deformation theory (HSDT). A shear correction factor is, therefore, not required. Equations of motion are derived from Hamilton's principle. Analytical solutions for the bending and free vibration analysis are obtained for simply supported plates. The accuracy of the present solutions is verified by comparing the obtained results with those predicted by classical theory, first-order shear deformation theory, and higher-order shear deformation theory. Verification studies show that the proposed theory is not only accurate and simple in solving the bending and free vibration behaviours of FG plates, but also comparable with the other higher-order shear deformation theories which contain more number of unknowns.

마그네토스트릭션 효과를 이용한 비접촉 모달 테스팅 기법 (Noncontact Modal Testing Method Using Magnetostriction Effects)

  • 조승현;이호철;김윤영
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2000년도 추계학술대회논문집
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    • pp.701-707
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    • 2000
  • In this work, we propose to employ magnetostrictive sensors to develop a new non-contacting modal testing method. Specific applications are made in the modal testing of a beam in bending. The role of bias magnetic fields in measuring bending waves is addressed and an approximate analysis to explain the principle to measure bending signals is carried out. The measured modal data by the present method agree well with those by conventional methods using accelerometers.

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Bending, buckling, and free vibration analyses of carbon nanotube reinforced composite beams and experimental tensile test to obtain the mechanical properties of nanocomposite

  • Mohammadimehr, M.;Mohammadi-Dehabadi, A.A.;Akhavan Alavi, S.M.;Alambeigi, K.;Bamdad, M.;Yazdani, R.;Hanifehlou, S.
    • Steel and Composite Structures
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    • 제29권3호
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    • pp.405-422
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    • 2018
  • In this research, experimental tensile test and manufacturing of carbon nanotube reinforced composite beam (CNTRC) is presented. Also, bending, buckling, and vibration analysis of CNTRC based on various beam theories such as Euler-Bernoulli, Timoshenko and Reddy beams are considered. At first, the experimental tensile tests are carried out for CNTRC and composite beams in order to obtain mechanical properties and then using Hamilton's principle the governing equations of motion are derived for Euler Bernoulli, Timoshenko and Reddy theories. The results have a good agreement with the obtained results by similar researches and it is shown that adding just two percent of carbon nanotubes increases dimensionless fundamental frequency and critical buckling load as well as decreases transverse deflection of composite beams. Also, the influences of different manufacturing processes such as hand layup and industrial methods using vacuum pump on composite properties are investigated. In these composite beams, glass fibers used in an epoxy matrix and for producing CNTRC, CNTs are applied as reinforcement particles. Applying two percent of CNTs leads to increase the mechanical properties and increases natural frequencies and critical buckling load and decreases deflection. The obtained natural frequencies and critical buckling load by theoretical method are higher than other methods, because there are some inevitable errors in industrial and hand layup method. Also, the minimum deflection occurs for theoretical methods, in bending analysis. In this study, Young's and shear modulli as well as density are obtained by experimental test and have not been used from the results of other researches. Then the theoretical analysis such as bending, buckling and vibration are considered by using the obtained mechanical properties of this research.

모달해석기법을 이용한 판 구조물의 진동인텐시티 해석 (Structural Intensity Analysis of Plate Structures Using Modal Analysis)

  • 정상민;조대승;김사수
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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    • pp.319-326
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    • 1998
  • Structural intensity of plates experiencing bending vibration is analytically evaluated using the modal analysis based on the assumed mode method. In the analysis, material internal loss and localized damping are considered. The power obtained by structural intensity integration over the circle containing the excitation source is compared with the power injected into plates to verify the accuracy of the presented method and; to evaluate the convergence of mode superposition. The intensity integration is carried out varying the circle radius and the integral step to investigate their effects in case of the power estimation using structural intensities. In addition, the dominant component among internal forces in the energy transfer by the bending vibration of a stiffened plate is investigated.

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