• 제목, 요약, 키워드: structural dynamic

검색결과 4,271건 처리시간 0.042초

Evaluation of structural dynamic responses by stochastic finite element method

  • Li, Q.S.;Fang, J.Q.;Liu, D.K.
    • Structural Engineering and Mechanics
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    • v.8 no.5
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    • pp.477-490
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    • 1999
  • The uncertainties associated with structural parameters and dynamic loading are identified and discussed. Structural parametric uncertainties are treated as random variables and dynamic wind load is simulated as a random process. Dynamic wind-induced responses of structures with parametric uncertainties are investigated by using stochastic finite element method. The formulas for structural dynamic reliability analysis considering the randomness of structural resistance and loading are proposed. Two numerical examples of high-rise structures are presented to illustrate the proposed methodology. The calculated results demonstrate that the variation in structural parameters indeed influences the dynamic response and the first passage probability evaluation of structures.

FE model updating method incorporating damping matrices for structural dynamic modifications

  • Arora, Vikas
    • Structural Engineering and Mechanics
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    • v.52 no.2
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    • pp.261-274
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    • 2014
  • An accurate finite element (FE) model of a structure is essential for predicting reliably its dynamic characteristics. Such a model is used to predict the effects of structural modifications for dynamic design of the structure. These modifications may be imposed by design alterations for operating reasons. Most of the model updating techniques neglect damping and so these updated models can't be used for accurate prediction of vibration amplitudes. This paper deals with the basic formulation of damped finite element model updating method and its use for structural dynamic modifications. In this damped damped finite element model updating method, damping matrices are updated along with mass and stiffness matrices. The damping matrices are updated by updating the damping coefficients. A case involving actual measured data for the case of F-shaped test structure, which resembles the skeleton of a drilling machine is used to evaluate the effectiveness of damped FE model updating method for accurate prediction of the vibration levels and thus its use for structural dynamic modifications. It can be concluded from the study that damped updated FE model updating can be used for structural dynamic modifications with confidence.

Dynamic sensitivity analysis and optimum design of aerospace structures

  • Gu, Yuanxian;Kang, Zhan;Guan, Zhenqun;Jia, Zhiwen
    • Structural Engineering and Mechanics
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    • v.6 no.1
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    • pp.31-40
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    • 1998
  • The research and applications of numerical methods of design optimization on structural dynamic behaviors are presented in this paper. The emphasis is focused on the dynamic design optimization of aerospace structures, particularly those composed of composite laminate and sandwich plates. The methods of design modeling, sensitivity analysis on structural dynamic responses, and the optimization solution approaches are presented. The numerical examples of sensitivity analysis and dynamic structural design optimization are given to demonstrate the effectiveness of the numerical methods.

Topological optimized design considering dynamic problem with non-stochastic structural uncertainty

  • Lee, Dong-Kyu;Starossek, Uwe;Shin, Soo-Mi
    • Structural Engineering and Mechanics
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    • v.36 no.1
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    • pp.79-94
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    • 2010
  • This study shows how uncertainties of data like material properties quantitatively have an influence on structural topology optimization results for dynamic problems, here such as both optimal topology and shape. In general, the data uncertainties may result in uncertainties of structural behaviors like deflection or stress in structural analyses. Therefore optimization solutions naturally depend on the uncertainties in structural behaviors, since structural behaviors estimated by the structural analysis method like FEM need to execute optimization procedures. In order to quantitatively estimate the effect of data uncertainties on topology optimization solutions of dynamic problems, a so-called interval analysis is utilized in this study, and it is a well-known non-stochastic approach for uncertainty estimate. Topology optimization is realized by using a typical SIMP method, and for dynamic problems the optimization seeks to maximize the first-order eigenfrequency subject to a given material limit like a volume. Numerical applications topologically optimizing dynamic wall structures with varied supports are studied to verify the non-stochastic interval analysis is also suitable to estimate topology optimization results with dynamic problems.

풍하중을 받는 구조물의 풍방향 동적응답해석 (Dynamic Alongwind Response of the Structure under the Wind Load)

  • 도혜경;권택진
    • 한국전산구조공학회:학술대회논문집
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    • pp.451-458
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    • 2001
  • The structural dynamic responses by wind load consist of alongwind, acrosswind and torsional behavior. Specially, dynamic alongwind response can be obtained from theoretical approach presented by Davenport, Vellozzi and Cohen. Generally the structural dynamic alongwind response can be obtained using the approximate analysis, under the condition that only the first mode shape of the structure is considered and the mode shape is assumed to be a linear function. In this paper, the dynamic alongwind responses are performed by using spectrum of longitudinal velocity fluctuations presented by Davenport and Kaimal, respectively.

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Dynamically Adaptive Finite Element Mesh Generation Schemes

  • Yoon, Chong-Yul;Park, Joon-Seok
    • 한국전산구조공학회논문집
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    • v.23 no.6
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    • pp.659-665
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    • 2010
  • The finite element method(FEM) is proven to be an effective approximate method of structural analysis if proper element types and meshes are chosen, and recently, the method is often applied to solve complex dynamic and nonlinear problems. A properly chosen element type and mesh yields reliable results for dynamic finite element structural analysis. However, dynamic behavior of a structure may include unpredictably large strains in some parts of the structure, and using the initial mesh throughout the duration of a dynamic analysis may include some elements to go through strains beyond the elements' reliable limits. Thus, the finite element mesh for a dynamic analysis must be dynamically adaptive, and considering the rapid process of analysis in real time, the dynamically adaptive finite element mesh generating schemes must be computationally efficient. In this paper, a computationally efficient dynamically adaptive finite element mesh generation scheme for dynamic analyses of structures is described. The concept of representative strain value is used for error estimates and the refinements of meshes use combinations of the h-method(node movement) and the r-method(element division). The shape coefficient for element mesh is used to correct overly distorted elements. The validity of the scheme is shown through a cantilever beam example under a concentrated load with varying values. The example shows reasonable accuracy and efficient computing time. Furthermore, the study shows the potential for the scheme's effective use in complex structural dynamic problems such as those under seismic or erratic wind loads.

Dynamic torsional response measurement model using motion capture system

  • Park, Hyo Seon;Kim, Doyoung;Lim, Su Ah;Oh, Byung Kwan
    • Smart Structures and Systems
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    • v.19 no.6
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    • pp.679-694
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    • 2017
  • The complexity, enlargement and irregularity of structures and multi-directional dynamic loads acting on the structures can lead to unexpected structural behavior, such as torsion. Continuous torsion of the structure causes unexpected changes in the structure's stress distribution, reduces the performance of the structural members, and shortens the structure's lifespan. Therefore, a method of monitoring the torsional behavior is required to ensure structural safety. Structural torsion typically occurs accompanied by displacement, but no model has yet been developed to measure this type of structural response. This research proposes a model for measuring dynamic torsional response of structure accompanied by displacement and for identifying the torsional modal parameter using vision-based displacement measurement equipment, a motion capture system (MCS). In the present model, dynamic torsional responses including pure rotation and translation displacements are measured and used to calculate the torsional angle and displacements. To apply the proposed model, vibration tests for a shear-type structure were performed. The torsional responses were obtained from measured dynamic displacements. The torsional angle and displacements obtained by the proposed model using MCS were compared with the torsional response measured using laser displacement sensors (LDSs), which have been widely used for displacement measurement. In addition, torsional modal parameters were obtained using the dynamic torsional angle and displacements obtained from the tests.

Equivalent static wind loads for stability design of large span roof structures

  • Gu, Ming;Huang, Youqin
    • Wind and Structures
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    • v.20 no.1
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    • pp.95-115
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    • 2015
  • Wind effects on roofs are usually considered by equivalent static wind loads based on the equivalence of displacement or internal force for structural design. However, for large-span spatial structures that are prone to dynamic instability under strong winds, such equivalent static wind loads may be inapplicable. The dynamic stability of spatial structures under unsteady wind forces is therefore studied in this paper. A new concept and its corresponding method for dynamic instability-aimed equivalent static wind loads are proposed for structural engineers. The method is applied in the dynamic stability design of an actual double-layer cylindrical reticulated shell under wind actions. An experimental-numerical method is adopted to study the dynamic stability of the shell and the dynamic instability originating from critical wind velocity. The dynamic instability-aimed equivalent static wind loads of the shell are obtained.

차세대 반도체 FAB의 동적 구조 설계를 위한 PC형 격자보 구조물의 동적 특성 평가 (A Dynamic Structural Design of PC type Sub-Structure for Next-Generation FAB based on Dynamic Test and Simulation)

  • 전종균;김강부;손성완;이홍기
    • 반도체디스플레이기술학회지
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    • v.3 no.4
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    • pp.51-55
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    • 2004
  • In the design stage of high precision manufacturing/inspection FAB facilities, it is necessary to investigate the allowable vibration limits of high precision equipments and to study structural dynamic characteristics of C/R and Sub-structure in order to provide structural vibration criteria to satisfy these allowable limits. The goal of this study is to investigate the dynamic characteristics of PC-Type mock-up structures designed for next generation TFT-LCD FAB through experiments and analysis procedures. Therefore, in order to provide a proper dynamic structural design for high precision manufacturing/inspection work process, these allowable limits must be satisfied.

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Structural dynamic optimization with probability constraints of frequency and mode

  • Chen, Jian-Jun;Che, Jian-Wen;Sun, Huai-An;Ma, Hong-Bo;Cui, Ming-Tao
    • Structural Engineering and Mechanics
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    • v.13 no.5
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    • pp.479-490
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    • 2002
  • The structural dynamic optimization problem based on probability is studied. Considering the randomness of structural physical parameters and the given constraint values, we develop a dynamic optimization mathematical model of engineering structures with the probability constraints of frequency, forbidden frequency domain and the vibration mode. The sensitivity of structural dynamic characteristics based on probability is derived. Two examples illustrate that the optimization model and the method applied are rational and efficient.