• Title/Summary/Keyword: Large structures

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Experimental study on lead extrusion damper and its earthquake mitigation effects for large-span reticulated shell

  • Yang, M.F.;Xu, Z.D.;Zhang, X.C.
    • Steel and Composite Structures
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    • v.18 no.2
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    • pp.481-496
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    • 2015
  • A Lead Extrusion Damper (LED) is experimentally studied under various frequencies and displacement amplitudes. Experimental results show that the force-displacement hysteresis loops of the LED are close to rectangular and the force-velocity hysteresis loops exhibit nonlinear hysteretic characteristic. Also, the LED can provide consistent energy dissipation without any stiffness degradation. Based on the experimental results, a mathematical model is then proposed to describe the effects of frequency and displacement on property of LED. It can be proved from the comparison between experimental and numerical results that the mathematical model can accurately describe the mechanical behavior of LED. Subsequently, the seismic responses of the Schwedler reticulated shell structure with LEDs are analyzed by ANSYS software, in which three different installation forms of LEDs are considered. It can be concluded that the LED can effectively reduce the displacement and acceleration responses of this type of structures.

Wave Response Analysis and Future Direction of Mega-Float

  • Park, Sung-Hyeon
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2001.10a
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    • pp.153-168
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    • 2001
  • In the country where the population concentrates in the metropolis with the narrow land, development of th ocean space is necessary. Recently, mega-float offshore structure is studied as one of the effective utilization of the ocean space. And very large floating structure are now being considered for various applications such as floating airports, offshore cities and so on. This very large structure is relatively flexible compared with real floating structures like large ships. when we estimate dynamic responses of these structures in waves, the elastic deformation is important, because vertical dimension is small compared with horizontal. And it is necessary to examine the effect of ocean wave eternal force received from the natural environment. In this study, the mat-type large floating structure is made to be analytical model. And the analysis of the dynamic response as it receives regular wave is studied. The finite element method is used in the analysis of structure part of this model. And the analysis is carried out using the boundary element method in the fluid part. In order to know the characteristics of the dynamic response of the large floating structures, effects of wavelength, bending rigidity of the structure, water depth, and wave direction on dynamic response of the floating structure are studied by use of numerical calculation.

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Distributed Structural Analysis Algorithms for Large-Scale Structures based on PCG Algorithms (대형구조물의 분산구조해석을 위한 PCG 알고리즘)

  • 권윤한;박효선
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.12 no.3
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    • pp.385-396
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    • 1999
  • In the process of structural design for large-scale structures with several thousands of degrees of freedom, a plethora of structural calculations with large amount of data storage are required to obtain the forces and displacements of the members. However, current computational environment with single microprocessor such as a personal computer or a workstation is not capable of generating a high-level of efficiency in structural analysis and design process for large-scale structures. In this paper, a high-performance parallel computing system interconnected by a network of personal computers is proposed for an efficient structural analysis. Two distributed structural analysis algorithms are developed in the form of distributed or parallel preconditioned conjugate gradient (DPCG) method. To enhance the performance of the developed distributed structural analysis algorithms, the number of communications and the size of data to be communicated are minimized. These algorithms are applied to the structural analyses of three large space structures as well as a 144-story tube-in-tube framed structure.

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Poisson's ratios of fabric materials in use for large-span membrane structures

  • Jianhui Hu;Wujun Chen;Chengjun Gao;Yibei Zhang;Yonglin Chen;Pujin Wang
    • Structural Engineering and Mechanics
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    • v.90 no.6
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    • pp.543-549
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    • 2024
  • The utilization of the fabric materials for lightweight building structures has attracted considerable attention due to the multiple functions and high strength-to-weight ratio. The mechanical properties of the fabric materials evolve with the loading cycle, especially for the Poisson's ratio that requires the full cyclic strain to determine the accurate values. The digital image correlation method has been justified but needs to meet the flexibility and complexity requirements of the fabric materials. This paper thus proposes a modified digital image correlation method to quantify the Poisson's ratio of fabric materials. To obtain the accurate Poisson's ratio of fabric materials in the cyclic experiments using non-contact measuring method, a speckle generation of the digital image correlation method is implemented to obtain the strain distribution and strain characteristics. The uniaxial cyclic experiments for the fabric materials are carried out in the warp, weft and 45° directions. The digital image correlation photos are taken when the material properties become stable in the cyclic loading. The results show that the strain distributions are non-uniform and dependent on the specimen directions. The reliable Poisson's ratios of the fabric materials in the warp, weft and 45° directions are 0.016, 1.2 and 2.6. The strain asymmetry at the maximum strain position is related with the weaving architecture. These observations and results are indispensable to understand the Poisson's ratios of fabric materials and to guide the proper analysis of the large-span membrane structures.