• Title, Summary, Keyword: structural dynamic

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Reliability-Based Dynamic Load Model for Bridges (교량 충격하중의 확률론적 모델)

  • 황의승
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.69-72
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    • 1991
  • The purpose of this study is to develop the reliability-based dynamic load model for bridges. Analytial procedure to calculate the dynamic load is developed. Truck traffic is simulated using Monte Carlo method. Static and dynamic loads(deflections) are plotted on the normal probability paper to estimate the mean maximum dynamic load in bridge lifetime. The results may be served as a basis for new LRFD bridge design code.

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Study on the Dynamic Instability of Star-Dome Structures (스타돔의 동적 불안정 현상에 관한 연구)

  • Han, Sang-Eul;Hou, Xiao-Wu
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.72-77
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    • 2008
  • Stability is a very important part which we must consider in structural design. In this paper, we take advantage of finite element method, and study about parametrical instability of star-dome structures, which is subjected to harmonically pulsating load. When calculating stiffness matrix, we consider elastic stiffness and geometrical stiffness simultaneously. In equation of motion, we represent displacements and accelerations by trigonometric series expansions, and then obtain Hill's infinite determinants. After first order approximation, we can get first and second order dynamic instability region finally.

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Moving force identification from bridge dynamic responses

  • Yu, Ling;Chan, Tommy H.T.
    • Structural Engineering and Mechanics
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    • v.21 no.3
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    • pp.369-374
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    • 2005
  • A big progress has been made for moving force identification from bridge dynamic responses in recent years. Current knowledge and the potentials on moving force identification methods are reviewed in this paper under main headings below: background of moving force identification, experimental verification in laboratory and its application in field.

Dynamic interaction analysis of vehicle-bridge system using transfer matrix method

  • Xiang, Tianyu;Zhao, Renda
    • Structural Engineering and Mechanics
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    • v.20 no.1
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    • pp.111-121
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    • 2005
  • The dynamic interaction of vehicle-bridge is studied by using transfer matrix method in this paper. The vehicle model is simplified as a spring-damping-mass system. By adopting the idea of Newmark-${\beta}$ method, the partial differential equation of structure vibration is transformed into a differential equation irrelevant to time. Then, this differential equation is solved by transfer matrix method. The prospective application of this method in real engineering is finally demonstrated by several examples.

System identification of steel framed structures with semi-rigid connections

  • Katkhuda, Hasan N.;Dwairi, Hazim M.;Shatarat, Nasim
    • Structural Engineering and Mechanics
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    • v.34 no.3
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    • pp.351-366
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    • 2010
  • A novel system identification and structural health assessment procedure of steel framed structures with semi-rigid connections is presented in this paper. It is capable of detecting damages at the local element level under normal operating conditions; i.e., serviceability limit state. The procedure is a linear time-domain system identification technique in which the structure responses are required, whereas the dynamic excitation force is not required to identify the structural parameters. The procedure tracks changes in the stiffness properties of all the elements in a structure. It can identify damage-free and damaged structural elements very accurately when excited by different types of dynamic loadings. The method is elaborated with the help of several numerical examples. The results indicate that the proposed algorithm identified the structures correctly and detected the pre-imposed damages in the frames when excited by earthquake, impact, and harmonic loadings. The algorithm can potentially be used for structural health assessment and monitoring of existing structures with minimum disruption of operations. Since the procedure requires only a few time points of response information, it is expected to be economic and efficient.

Time Domain Identification of Nonlinear Structural Dynamic Systems Using Unscented Kalman Filter (Unscented Kalman Filter를 이용한 비선형 동적 구조계의 시간영역 규명기법)

  • Yun, Chung-Bang;Koo, Ki-Young
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.117-126
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    • 2001
  • In this study, the recently developed unscented Kalman filter (UKF) technique is studied for identification of nonlinear structural dynamic systems as an alternative to the extended Kalman filter (EKF). The EKF, which was originally developed as a state estimator for nonlinear systems, has been frequently employed for parameter identification by introducing the state vector augmented with the unknown parameters to be identified. However, the EKF has several drawbacks such as biased estimations and erroneous estimations especially for highly nonlinear dynamic systems due to its crude linearization scheme. To overcome the weak points of the EKF, the UKF was recently developed as a state estimator. Numerical simulation studies have been carried out on nonlinear SDOF system and nonlinear MDOF system. The results from a series of numerical simulations indicate that the UKF is superior to the EKF in the system identification of nonlinear dynamic systems especially highly nonlinear systems.

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Experimental Structural Dynamic Modification of Fixture for Environmental Vibration Test Control (환경진동시험제어를 위한 치구의 실험적 구조변경 설계)

  • 김준엽;정의봉
    • Journal of KSNVE
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    • v.6 no.3
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    • pp.317-323
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    • 1996
  • This paper proposes the method of experimental structural dynamic modification of fixture for environmental vibration test control. This method can predict the responses at any points on the fixture utilizing the experimental data, and structural dynamic modification of fixture is made using the predicted responses for the spectra at the specimen attachment points to meet the specified reference spectrum. From the results of controlling the fixture before and after modification by conventional control method and optimal reference spectrum, which has been previously reported by the authors, the proposed method is shown to be an effective one.

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Geometrically Nonlinear Dynamic Analysis of Suspension Bridges Considering Construction Sequences (현수교의 기하학적 비선형을 고려한 동적 밀 시공단계별 해석)

  • 방명석
    • Journal of the Korean Society of Safety
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    • v.14 no.4
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    • pp.148-157
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    • 1999
  • Dynamic structural behavior in long span bridges, especially cable structures, is very sophisticated due to their flexibility and structural members are sequentially erected in each construction step. In this study, the consistent mass matrix for dynamic analysis is formulated and computational program considering construction sequences is developed where structural members can be builded or removed by command language and automatically reanalyzed in the moment when structural system is changed. The dynamic analysis, i.e. eigenvalue and time series analysis and the geometrically nonlinear analysis considering construction sequence are conducted to the Namhae Bridge. The analytical results are satisfactory compared with measuring values and the developed computational program can successfully be applied to design and safety check.

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Identification of One-Dimensional Structural Joints Using Spectral Element Method (스펙트럴요소법을 이용한 1차원 구조물 결합부의 규명)

  • Kang, Tae-Ho;Lee, U-Sik
    • Journal of the Korean Society for Precision Engineering
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    • v.16 no.11
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    • pp.183-190
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    • 1999
  • In this paper, a dynamic modeling approach is introduced to identify the dynamic characteristics of the structural/mechanical joints within an one-dimensional structure. A structural joint is represented by the four-pole parameters and the four-pole parameters are determined from the measured frequency response functions by using the spectral element method. As the illustrative examples, a cantilevered beam a clamped-clamped beam, both consist of two beams connected by a bolted joint, are investigated to evaluate the present modeling approach. It is found that the dynamic responses predicted by using the identified for-pole parameters for the bolted joint are well agreed with the measured dynamic responses measured

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Structural and Vibration Analysis of Large Windturbine Rotor Considering the Rotational and Aero Load Effect (회전 및 풍하중 가진 효과를 고려한 대형 풍력발전 로터의 구조 및 진동해석)

  • Kim, Dong-Man;Kim, Dong-Hyun;Park, Kang-Kyun;Kim, Yu-Sung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.270-275
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    • 2008
  • In this study, computer applied engineering (CAE) techniques are full? used to conduct structural and dynamic analyses of a huge composite rotor blade. Computational fluid dynamics is used to predict aerodynamic load of the rotating wind-turbine blade model. Static and dynamic structural analyses are conducted based on the non-linear finite element method for composite laminates and multi-body dynamic simulation tools. Various numerical results for aerodynamic load, dynamic analyses are presented and characteristics of structural behaviors are investigated herein.

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