• Title/Summary/Keyword: Beam structure

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Three-Dimensional Shape Estimation of Beam Structure Using Fiber Bragg Grating Sensors (광섬유 브래그 격자 센서를 이용한 보 구조물의 3차원 형상 추정)

  • Lee, Jin-Hyuk;Kim, Heon-Young;Kim, Dae-Hyun
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.39 no.3
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    • pp.241-247
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    • 2015
  • Deflection and deformation occur easily in structures with long length, such as bridges and pipelines. Shape monitoring is required for ensuring their structural health. A fiber Bragg grating (FBG) sensor can be used for monitoring a large-scale structure because of its advantage of multiplexing. In this study, FBG sensors were used for monitoring a composite beam structure, and its strains were measured at multiple points. Thereafter, a shape estimation technique based on the strains was studied. Particularly, a three-dimensional shape estimation technique was proposed for accurate structural health monitoring. A simple experiment was conducted to verify the performance of the shape estimation technique. The result revealed that the estimated shape of the composite beam structure was in agreement with the actual shape obtained after the deformation of the specimen. Additionally, the deflection at a specific point was verified by comparing the estimated and actual deformations measured using a micrometer.

On complex flutter and buckling analysis of a beam structure subjected to static follower force

  • Wang, Q.
    • Structural Engineering and Mechanics
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    • v.16 no.5
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    • pp.533-556
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    • 2003
  • The flutter and buckling analysis of a beam structure subjected to a static follower force is completely studied in the paper. The beam is fixed in the transverse direction and constrained by a rotational spring at one end, and by a translational spring and a rotational spring at the other end. The co-existence of flutter and buckling in this beam due to the presence of the follower force is an interesting and important phenomenon. The results from this theoretical analysis will be useful for the stability design of structures in engineering applications, such as the potential of flutter control of aircrafts by smart materials. The transition-curve surface for differentiating the two distinct instability regions of the beam is first obtained with respect to the variations of the stiffness of the springs at the two ends. Second, the capacity of the follower force is derived for flutter and buckling of the beam as a function of the stiffness of the springs by observing the variation of the first two frequencies obtained from dynamic analysis of the beam. The research in the paper may be used as a benchmark for the flutter and buckling analysis of beams.

Damped dynamic responses of a layered functionally graded thick beam under a pulse load

  • Asiri, Saeed A.;Akbas, Seref D.;Eltaher, Mohamed A.
    • Structural Engineering and Mechanics
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    • v.75 no.6
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    • pp.713-722
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    • 2020
  • This article aims to illustrate the damped dynamic responses of layered functionally graded (FG) thick 2D beam under dynamic pulse sinusoidal load by using finite element method, for the first time. To investigate the response of thick beam accurately, two-dimensional plane stress problem is assumed to describe the constitutive behavior of thick beam structure. The material is distributed gradually through the thickness of each layer by generalized power law function. The Kelvin-Voigt viscoelastic constitutive model is exploited to include the material internal damping effect. The governing equations are obtained by using Lagrange's equations and solved by using finite element method with twelve -node 2D plane element. The dynamic equation of motion is solved numerically by Newmark implicit time integration procedure. Numerical studies are presented to illustrate stacking sequence and material gradation index on the displacement-time response of cantilever beam structure. It is found that, the number of waves increases by increasing the graduation distribution parameter. The presented mathematical model is useful in analysis and design of nuclear, marine, vehicle and aerospace structures those manufactured from functionally graded materials (FGM).

Finite Element Eigen Analysis of Undamped Beam Structure with Composite Sections (복합단면을 갖는 비 감쇠 보 구조물의 유한요소 고유치 해석)

  • Park, Keun-Man;Cho, Jin-Rae;Jung, Weui-Bong;Bae, Soo-Ryong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.6
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    • pp.691-697
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    • 2007
  • Numerical eigen analysis of beam-like structure can be easily and effectively done by various conventional beam theory-based methods. However, in case of the structures composed of composite-sectioned beams, the application of conventional numerical methods requires one to derive both equivalent material and geometry properties. In the present paper, these equivalent properties are derived by the transformed section method and the test FEM program is coded. The numerical accuracy of the proposed method is verified through the comparison with the ANSYS 3-D model.