• Title/Summary/Keyword: structural understanding

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Numerical studies on shear connectors in push-out tests under elevated temperatures

  • Wang, Aaron J.
    • Structural Engineering and Mechanics
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    • v.39 no.3
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    • pp.317-338
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    • 2011
  • Three-dimensional thermal and mechanical coupled finite element models are proposed to study the structural behaviours of shear connectors under fire. Concrete slabs, steel beams and shear connectors are modelled with eight-noded solid elements, and profiled steel deckings are modelled with eight-noded shell elements. Thermal, mechanical and geometrical nonlinearities are incorporated into the models. With the proper incorporation of thermal and mechanical contacts among steel beams, shear connectors, steel deckings and concrete slabs, both of the models are verified to be accurate after the validation against a series of push-out tests in the room temperature or under the standard fire. Various thermal and mechanical responses are also extracted and observed in details from the results of the numerical analyses, which gives a better understanding of the structural behavior of shear connectors under elevated temperatures.

The Design Concept and World-wide Trends for the Structural Design of Footbridge (보도육교 구조디자인의 세계적 추세와 설계개념)

  • Park, Sun-Woo;Lee, Ju-Na
    • Journal of Korean Association for Spatial Structures
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    • v.4 no.2 s.12
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    • pp.107-115
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    • 2004
  • A vocabulary for a understanding bridge has a different scope. The main characteristics of the modem footbridge are appropriateness, aesthetics and structural efficiency. Design concepts of footbridge design are investigated. There are functional concepts, aesthetical concepts like geometry, symbolism, lighting, and movement, and technical concepts. Futhermore, adaptation examples of these structural concepts for pedestrian bridges are presented.

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Finite Elements Analysis Application to the Structural Design of the Frame Type Furniture (골조형(骨造型) 가구구조설계(家具構造設計)에의 유한요소해석 응용)

  • Chung, Woo-Yang;Eckelman, Carl A.
    • Journal of the Korean Wood Science and Technology
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    • v.23 no.3
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    • pp.8-15
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    • 1995
  • This analytical study was carried out to make quality and productivity up in designing the frame-type furniture with semi-rigid joint by understanding the mechanical and structural behavior of the joint and by evaluating the validity of application of the time-saving Finite Element Method to its structural analysis. Slope deflection equation for rigid joint was modified to describe the moment-rotation behavior of semi-rigid joint and the joint stiffness factor(Z) could be calculated to lessen the experimental expense. It was proved that Finite Element Analysis with imaginary elements having equivalent MOE to the semi-rigid joint could be the alternative method for the structural analysis of the frame-type furniture, comparing the internal rotation of the 2-dimensional beam-to-column model with two-pin(wooden dowel) from the finite element method with other available theoretical and experimental rotation value.

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Coupling shape-memory alloy and embedded informatics toward a metallic self-healing material

  • Faravelli, Lucia;Marzi, Alessandro
    • Smart Structures and Systems
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    • v.6 no.9
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    • pp.1041-1056
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    • 2010
  • This paper investigates the possibility of a strategy for an automatic full recover of a structural component undergoing loading-unloading (fatigue) cycles: full recover means here that no replacement is required at the end of the mission. The goal is to obtain a material capable of self healing earlier before the damage becomes irreversible. Attention is focused on metallic materials, and in particular on shape memory alloys, for which the recovering policy just relies on thermal treatments. The results of several fatigue tests are first reported to acquire a deep understanding of the physical process. Then, for cycles of constant amplitude, the self-healing objective is achieved by mounting, on the structural component of interest, a suitable microcontroller. Its input, from suitable sensors, covers the current stress and strain in the alloy. The microcontroller elaborates from the input the value of a decisional parameter and activates the thermal process when a threshold is overcome.

Robust Design of Structural and Mechanical Systems using Concept of Allowable Load Set (허용하중집합 개념을 이용한 기계/구조 시스템의 강건 설계)

  • Kwak, Byung-Man
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.333-338
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    • 2007
  • The concept of "Allowable Load Set (ALS)" introduced by the author allows an easy understanding of load and strength characteristics of a structure in relation to its integrity under uncertainties. Two criteria of safety are introduced: A relative safety index denotes the distance to the boundary of the ALS and a normalized safety index is a distance in terms of functional value. They have been utilized in several examples, including multi-body mechanical systems such as a biomechanical system. Both formulations amount to robust designs in the sense that designs most insensitive to uncertainties are obtained in the context of newly defined safety indices, without using any input probability information.

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Shear Lag Phenomenon of Tube Structure with Core Wall in Relation to Nondimensional Structural Parameters (튜브-전단벽 구조의 무차원 구조변수에 따른 전단지연 현상)

  • 유은정;이강건;이리형
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2003.10a
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    • pp.325-332
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    • 2003
  • The tube structures act like cantilevered box beams and effectively resist lateral loads. In result, they are adopted as a high-rise buildings system. However, the shear lag in tube system prevents the idealized tube behavior such as a cantilevered box beam. Therefore, the studies on shear lag phenomena are necessarily requested. The presented papers are almost studied on framed tube structures and tube in tube structures. However, the study on the shear lag in the tube structure with core wall is lack. Thus, in this paper, the shear lag of the structure is studied. The shear lag coefficient is defined to investigate shear lag phenomena. However, existing shear lag coefficients are not adequate for understanding them. Therefore, on this study, new shear lag coefficient is suggested. In addition, the shear lag in the tube structure with core wall is analyzed by changing the five structural parameters of stiffness factor in frame, stiffness factor in wall, stiffness ratio, the number of stories and the number of bays.

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Brain Mapping Using Neuroimaging

  • Tae, Woo-Suk;Kang, Shin-Hyuk;Ham, Byung-Joo;Kim, Byung-Jo;Pyun, Sung-Bom
    • Applied Microscopy
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    • v.46 no.4
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    • pp.179-183
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    • 2016
  • Mapping brain structural and functional connections through the whole brain is essential for understanding brain mechanisms and the physiological bases of brain diseases. Although region specific structural or functional deficits cause brain diseases, the changes of interregional connections could also be important factors of brain diseases. This review will introduce common neuroimaging modalities, including structural magnetic resonance imaging (MRI), functional MRI (fMRI), diffusion tensor imaging, and other recent neuroimaging analyses methods, such as voxel-based morphometry, cortical thickness analysis, local gyrification index, and shape analysis for structural imaging. Tract-Based Spatial Statistics, TRActs Constrained by UnderLying Anatomy for diffusion MRI, and independent component analysis for fMRI also will also be introduced.

An Empirical Study on the Structural Relationship among Gender Discrimination, Organization Commitment and Organizational Citizenship Behavior in the Korean Shipping Firms

  • Shin Yong-John
    • Journal of Navigation and Port Research
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    • v.29 no.9
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    • pp.807-812
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    • 2005
  • The objective of this study is to empirically investigate the effect of gender discrimination to female workers in Korean shipping firms on the their organization commitment and organizational citizenship behavior. In carrying out the objective of this study, two hypotheses about the structural relationship among gender discrimination, organization commitment and organizational citizenship behaviors in the Korean shipping firms are established after reviewing the related studies. Survey questionnaires are distributed and analyzed to test the reliability and validity of the response. Also, a structural equation model is established and the model is analyzed by AMOS. In conclusion, there are a negative effect of gender discrimination on female workers' organizational commitment and a positive effect of their commitment on OCB. Through this paper, the comprehensive understanding of the structural relationship among gender discrimination, organization commitment and organizational citizenship behavior would be promoted.

Characterization of Structural Variations in the Context of 3D Chromatin Structure

  • Kim, Kyukwang;Eom, Junghyun;Jung, Inkyung
    • Molecules and Cells
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    • v.42 no.7
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    • pp.512-522
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    • 2019
  • Chromosomes located in the nucleus form discrete units of genetic material composed of DNA and protein complexes. The genetic information is encoded in linear DNA sequences, but its interpretation requires an understanding of three-dimensional (3D) structure of the chromosome, in which distant DNA sequences can be juxtaposed by highly condensed chromatin packing in the space of nucleus to precisely control gene expression. Recent technological innovations in exploring higher-order chromatin structure have uncovered organizational principles of the 3D genome and its various biological implications. Very recently, it has been reported that large-scale genomic variations may disrupt higher-order chromatin organization and as a consequence, greatly contribute to disease-specific gene regulation for a range of human diseases. Here, we review recent developments in studying the effect of structural variation in gene regulation, and the detection and the interpretation of structural variations in the context of 3D chromatin structure.

COST PERFORMANCE PREDICTION FOR INTERNATIONAL CONSTRUCTION PROJECTS USING MULTIPLE REGRESSION ANALYSIS AND STRUCTURAL EQUATION MODEL: A COMPARATIVE STUDY

  • D.Y. Kim;S.H. Han;H. Kim;H. Park
    • International conference on construction engineering and project management
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    • 2007.03a
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    • pp.653-661
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    • 2007
  • Overseas construction projects tend to be more complex than domestic projects, being exposed to more external risks, such as politics, economy, society, and culture, as well as more internal risks from the project itself. It is crucial to have an early understanding of the project condition, in order to be well prepared in various phases of the project. This study compares a structural equation model and multiple regression analysis, in their capacity to predict cost performance of international construction projects. The structural equation model shows a more accurate prediction of cost performance than does regression analysis, due to its intrinsic capability of considering various cost factors in a systematic way.

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