• Title, Summary, Keyword: 조화하중

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Investigation on Seismic-Response Characteristics and Optimal Design Parameters of Tuned Mass Damper Considering Site Effects (지반특성에 따른 동조질량감쇠기의 지진응답특성 및 최적설계변수)

  • Kang, Kyung-Soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.12 no.11
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    • pp.5306-5313
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    • 2011
  • Most previous studies for finding optimal design parameters of a tuned mass damper(TMD) have been focused on the harmonic excited single-degree-of freedom system. In this study, optimal values of damping ratio and tuning frequency ratio of a TMD applied to control a seismically excited structure are investigated through numerical analyses. Considering that the structural responses due to earthquake loads are strongly dependent on the soil condition, the site effects on the optimal parameters of the TMD are studied and compared to those presented by previous studies. Numerical analyses results indicate that better control performance can be obtained by using the parameters proposed by this study in the seismic application of the TMD.

Design Sensitivity Analysis and Optimal Design to Control Forced Vibration of Structure (구조물 진동제어를 위한 민감도해석 및 최적설계)

  • 이재환;이광한;송의준
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.39-44
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    • 1994
  • 본 문에서는 조화기진력(harmonic force) 하에서 보조변수법을 적용한 연속법이 사용되어 선형구조물의 변위, 응력에 대한 치수 설계 민감도가 계산되었다. 또한 최적설계가 조화 하중의 경우에 시도되어 주어진 제한조건들을 만족하며 최소 중량이 계산되었다.

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Dynamic Instability of Arch Structures Considering Geometric Nonlinearity by Sinusoidal Harmonic Excitation (기하학적 비선형을 고려한 아치 구조물의 정현형 조화하중에 의한 동적 불안정 현상에 관한 연구)

  • 윤태영;김승덕
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.69-76
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    • 2003
  • We investigate the fundamental mechanisms of the dynamic instability when the sinusoidal shaped arch structures subjected to sinusoidal harmonic excitation with pin-ends. In nonlinear dynamics, examining the characteristics of attractor on the phase plane and investigating the dynamic buckling process are very important thing for understanding why unstable phenomena are sensitively originated by various initial conditions. In this study, the direct and the indirect snap-buckling of shallow arches considering geometrical nonlinearity are investigated numerically and compared with the step excitation critical load.

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Study on Adaptive Higher Harmonic Control Using Neural Networks (신경회로망을 이용한 적응 고차조화제어 기법 연구)

  • Park, Bum-Jin;Park, Hyun-Jun;Hong, Chang-Ho
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.3
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    • pp.39-46
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    • 2005
  • In this paper, adaptive higher harmonic control technique using Neural Networks (NN) is proposed. First, linear transfer function is estimated to relate the input harmonics and output harmonics, then NN which has the universal function approximation property is applied to expand application range of the transfer function. Optimal control gain matrix computed from the transfer function is used to train NN weights. Online weight adaptation laws are derived from Lyapunov's direct method to guarantee internal stability. Results of the simulation of 6-input 2-output nonlinear system show that adaptive HHC is applicable to the system with uncertain transfer function.

Nonlinear Characteristics Evaluation of Tuned Liquid Damper with White Noise Amplitude (백색잡음 하중 크기에 따른 TLD의 비선형 특성 평가)

  • Woo, Sung-Sik;Lee, Sang-Hyun;Choi, Ki-Young;Chung, Lan;Park, Tae-Won
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.21 no.2
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    • pp.135-143
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    • 2008
  • In this study, it was investigated for dynamic nonlinear characteristics using dynamic data obtained by shaking table test. The design of Tuned Liquid Damper(TLD) has limitation to plan based on Tuned Mass Damper(TMD) analogy and linear wave theory. Also, while there are many studies regarding properties of TLD under harmonic load, there are not estimated for dynamic non-linear characteristics of TLD under the load that is not governed by particular frequency like a white noise. This paper investigated dynamic non-linear characteristics of TLD varied with load amplitude using a white noise and suggested equations that can estimate damping ratio, natural frequency ratio and effective mass ratio of TLD.

Harmonic Excitation of Shear Building with Force-Controlled Shaking Table (힘-제어 진동대를 이용한 전단건물의 조화진동)

  • Lee, Sang Ho
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.1
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    • pp.853-859
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    • 2015
  • 1-DOF shear building was designed, built and tested to investigate the interactions between the shear building and the shaking table excited harmonically by the electro-magnetic forces. In the experiments horizontal accelerations of the shaking table and the shear building were measured. To understand the experimental results experimental setting was modeled as an unconstrained 2-DOF system under the hormonic forces. The responses of the shear building and the shaking table of the unconstrained 2-DOF system were found with the equations of motions. The magnification factors of the table and the shear building with respect to the amplitude of the harmonic forces and the transmission of the shear building with respect to the table excitations were found and compared with the experimental results.

Excitation and System Identification of a Full-Scale Five-Story Structure for the Application of Viscoelastic Dampers (점탄성 감쇠기 적용을 위한 실물크기 5층 건물의 가진 및 시스템 식별)

  • 민경원;이상현;김진구;이영철;이승준;최현훈
    • Journal of the Earthquake Engineering Society of Korea
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    • v.7 no.3
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    • pp.1-7
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    • 2003
  • Excitation and system identification are carried out for a full-scale five-story structure to obtain fundamental data which will be used for the design of viscoelastic dampers, The hybrid mass driver(HMD) installed on the fifth floor was employed as external exciter to provide excitation for the building, Each floor response was measured and processed to find out where and how the viscoelastic dampers are located and designed. The sine-sweep and white noise loadings were applied to the structure by the HMD to obtain dynamic characteristics such as natural frequencies, damping ratios, and modes, The identified building was experimentally investigated again with the designed viscoelastic dampers installed at inter-stories to obtain the response behavior in the companion paper.

Seismic Response of Structures with Buckling-Restrained Braces (좌굴방지 가새가 설치된 건물의 지진응답)

  • 김진구;최현훈
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.2
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    • pp.197-207
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    • 2002
  • Energy dissipation capacity and earthquake responses of steel structures installed with unbonded braces(UB) were investigated. Parametric studies were performed for a single-degree-of-freedom structure under harmonic loads, and optimum yield strength of unbonded braces were derived. Nonlinear dynamic time history analyses were carried out to investigate the seismic response of multi-story model structures with UB having various size and strength. Various techniques were applied to determine proper story-wise distribution of UB in multi-story structures. The analysis results show that the maximum displacements of structures generally decrease as the stiffness of UB increases. However for some natural frequencies and seismic loads the maximum displacement and accumulated damage increases as the stiffness of UB increases.

Identification of Stiffness and Damping Matrix of Building Structures using Modal Characteristics (모드 특성을 이용한 건축 구조물의 강성 및 감쇠 행렬식별)

  • 강경수
    • Journal of the Earthquake Engineering Society of Korea
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    • v.8 no.2
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    • pp.45-53
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    • 2004
  • In this paper, the stiffness and damping matrix are experimentally constructed using the structural modal information on frequencies, damping ratio and modal vectors, which are obtained by shaking table tests. Free vibration, harmonic and white noise vibration tests are performed. The acceleration of the shaking table was used as the input signal, and the corresponding accelerations of each floor were measured as output signals. The characteristics and limitations of modal information from each test are compared. The results of this study would be a basic resource of the analytical and experimental studies on the system identification of structures.