• Title/Summary/Keyword: structural material.

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A Strategy for Building BIM+PMIS System (BIM+PMIS 시스템 구축 전략)

  • Yoon, Su-Won;Chin, Sang-Yoon;Shin, Tae-Hong;Choi, Cheol-Ho
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2008.11a
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    • pp.61-67
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    • 2008
  • BIM has been increasingly deployed to the construction industry in order to minimize ambiguity and to reduce errors of the communicated engineering information, for which poor communication due to fragmented industrial structure is mainly responsible. Known BIM use cases and related researches are focusing either (1) on a specialized solution for a given specialty area (e.g. structural engineering planning and early design, material take-off, constructability simulation, etc.), or (2) on handling interoperabillty issues with Industrial Foundation Classes (IFC); Neither of these approaches have sufficiently catered for collaboration and information management in actual construction projects. This paper proposes the strategy for BIM+PMIS (project management information system) system focused on improving PMIS which has been commercially provided with ASP(Application Service Provider). It also describes the architecture of the BIM-based information management module prototype, which is a key component of the BIM+PMIS system.

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Static and Dynamic Analysis of Reinforced Concrete Axisymmetric Shell on the Elastic Foundation -With Application to an Static Behavior Analysis of Axisymmetric Shell- (탄성지반상에 놓인 철근콘크리트 축대칭 쉘의 정적 및 동적 해석 (III) -비선형 정적거동을 중심으로-)

  • 조진구
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.39 no.3
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    • pp.72-82
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    • 1997
  • In all inelastic deformations time rate effects are always present to some degree. Whether or not their exclusion has a significant influence on the prediction of the material behaviour depends upon several factors. In the study of structural components under static loading conditions at normal temperature it is accepted that time rate effects are generally not important. However metals, especially under high temperatures, exhibit simultaneously the phenomena of creep and viscoplasticity. In this study, elastoplastic and elasto-viscoplastic models include nonlinear geometrical effects were developed and several numerical examples are also included to verify the computer programming work developed here in this work. Comparisons of the calculated results, for the elasto-viscoplastic analysis of an internally pressurised thick cylinder under plane strain condition, have shown that the model yields excellent results. The results obtained from the numerical examples for an elasto-viscoplastic analysis of the Nuclear Reinforced Concrete Containment Structure(NRCCS) subjected to an incrementally applied internal pressure were summarized as follows : 1. The steady state hoop stress distribution along the shell layer of dome and dome wall junction part of NRCCS were linearly behave and the stress in interior surfaces was larger than that in exterior. 2.However in the upper part of the wall of NRCCS the steady state hoop stress in creased linearly from its inner to outer surfaces, being the exact reverse to the previous case of dome/dome-wall junction part. 3.At the lower part of wall of NRCCS, the linear change of steady state hoop stress along its wall layer began to disturb above a certain level of load increase.

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Effect of Local Strain on Low Cycle Fatigue using ESPI System (ESPI System을 이용하여 측정한 국부 변형률이 저사이클 피로수명에 미치는 영향에 관한 연구)

  • Kim, Kyung-Su;Kim, Ki-Sung;Kwon, Jung-Min;Park, Seong-Mo;Kim, Beom-Il
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.2 s.146
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    • pp.213-219
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    • 2006
  • Low cycle fatigue cracks are mainly detected at discontinuous welded locations with high stresses under repeated cyclic static loads due to cargo leading and unloading. Theoretical and analytical methods have been used for evaluation of local stress and strain which have an effect on a prediction of fatigue life, but those have difficulties of considering stress concentration at notched location and complicated material behavior of welded joint or heat affected zone. Electronic speckle pattern interferometry(ESPI) system is nondestructive and non-contact measurement system which can get the relatively accurate full field strain at critical positions such as welded zone and structural discontinuous location. In this study, local strain was measured on welded cruciform joint by ESPI system and then low cycle fatigue test was performed. Effect of local strain on low cycle fatigue life was examined by measured values using ESPI system. Moreover, experimental fatigue life was compared with established S-N curves using theoretical local strain and stress calculated by Neuber's rule.

Life Experiences and Prospects of Welfare/Poverty Exit of the Poor with Work Ability: Mixed Methodology using Sequential Exploratory Design (근로능력이 있는 빈곤층의 경험과 탈수급/탈빈곤 전망에 대한 연구: 순차적 탐구전략에 따른 방법론적 융합)

  • Jo, Joon-Yong
    • Journal of Digital Convergence
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    • v.14 no.9
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    • pp.19-29
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    • 2016
  • This study analyzes life experiences and prospects of poverty/welfare exit of the poor with work ability utilizing Mixed methodology. Based on Sequential Exploratory Design, it qualitatively analyzes 3 waves of qualitative panel data linked to Korea Welfare Panel Study(KWPS) and presents life changes of 14 poor in the context of their prospects of welfare/poverty exit. Then it proposes hypotheses on the role of education, household economy expectation, self-esteem in the prospects of poverty/welfare exit following the sequential exploratory design to quantitatively test qualitative findings utilizing KWPS(7th). The outcomes of the Structural Equation Model(SEM) suggest that household economy expectation plays mediating role between education and the prospects of welfare/poverty exit. This implies that anti-poverty policy needs to consider a psychological approach to enhance household economy expectations of the poor as well as other material support.

Synthesis of Ga2O3 powders by precipitation method (침전법을 이용한 Ga2O3 분말의 합성)

  • Jung, Jong-Yeol;Kim, Sang-Hun;Kang, Eun-Tae;Kim, Jin-Ho;Han, Kyu-Sung;Hwang, Kwang-Teak;Cho, Woo-Seok
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.24 no.1
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    • pp.8-14
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    • 2014
  • In this study, we investigated synthesis and characteristics of gallium oxide ($Ga_2O_3$) powders prepared by precipitation method. $Ga_2O_3$ powders were synthesized using $Ga(NO_3)_3$ as a starting material and $NH_4OH$ as a precipitant. The oxidation temperature of $Ga(OH)_3$ and phase transition temperature of $Ga_2O_3$ was revealed using TG-DSC analysis. The crystal structural change of $Ga_2O_3$ powders was investigated by XRD analysis. The morphologies and size distributions of $Ga_2O_3$ particles were analyzed using SEM.

The mediating effect of innovation and information sharing, in the relationship between the strategic supply chain and the supply chain performance of the raw material export-import firm (원자재 수출입 기업의 전략적 공급사슬지향성과 공급사슬 성과의 관계에서 혁신활동과 정보공유 활동의 매개역할)

  • Cho, Yeon Sung
    • International Commerce and Information Review
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    • v.17 no.1
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    • pp.193-214
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    • 2015
  • This study was conducted to explore the impact of the strategic supply chain orientation on the supply chain performance of raw materials export-import firms. In addition, this study analyzed the mediated effect of innovation and information sharing between the strategic supply chain orientation and supply chain performance of the firms. In the research model of this study considered the strategic supply chain orientation, innovation, information sharing and supply chain performance as the characteristics of the raw materials export-import firms by dividing the learning performance and market performance. The sample firms be analyzed were 445 firms. The 7 hypothesis including moderated effect were analyzed by using LISREL as structural equation modeling. According to the path analysis, the strategic supply chain orientation had a positive impact on the innovation activity. However, it did not have a positive influence on the information sharing. In the analysis of the mediated effect, the innovation activity of supply chain showed a full mediated effect between the strategic supply chain orientation and the information sharing. And the information sharing showed a partial mediated effect between the strategic supply chain orientation of these firms and the supply chain performance.

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Study on Analysis of RTM Process to Manufacture Bogie Frame Skin Depending on Thickness (대차 프레임 스킨의 두께에 따른 RTM 공정 특성 분석 연구)

  • Kim, Moosun;Kim, Jung-Seok;Kim, Seung Mo
    • Composites Research
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    • v.28 no.6
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    • pp.372-377
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    • 2015
  • In this study, we analyzed process numerically when a bogie frame skin is manufactured by applying resin transfer molding process using composite material instead of steel. Processing time was compared based on the various thickness of bogie frame skin and the weight variation of a skin was also considered. As a result, RTM processing time decreases and the weight of a bogie reduces as the thickness of frame skin increases with the assumption that fiber volume is constant inside the skin. By considering these results as the information to estimate the production cost, trade-off between two fields, processing time and structural properties, can be performed in design optimization to produce bogie frame.

Numerical Homogenization in Concrete Materials Using Multi-Resolution Analysis (다중해상도해석을 이용한 콘크리트 재료의 수치적 동질화)

  • Rhee In-Kyu;Roh Young-Sook
    • Journal of the Korea Concrete Institute
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    • v.17 no.6 s.90
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    • pp.939-946
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    • 2005
  • The stiffness properties of heterogeneous concrete materials and their degradation were investigated at different-levels of observations with aids of the opportunities and limitations of multi-resolution wavelet analysis. The successive Haw transformations lead to a recursive separation of the stiffness properties and the response into coarse-and fine-scale features. In the limit, this recursive process results in a homogenization parameter which is an average measure of stiffness and strain energy capacity at the coarse scale. The basic concept of multi-resolution analysis is illustrated with one and two-dimensional model problems of a two-phase particulate composite representative of the morphology of concrete materials. The computational studies include the meso-structural features of concrete in the form of a hi-material system of aggregate particles which are immersed in a hardened cement paste taking due to account of the mismatch of the two elastic constituents.

An Experimental Study on the Drying Shrinkage and Creep of High Strength Eco Lightweight Aggregate Concrete (고강도 에코인공경량골재콘크리트의 건조수축 및 크리프에 관한 실험적 연구)

  • Lee, Jin-Woo;Park, Hee-Gon;Kim, Woo-Jae;Bae, Yeoun-Ki;Lee, Hyoung-Woo;Lee, Jae-Sam
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.425-428
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    • 2008
  • To use lightweight aggregate concrete with the structural material, it was need to evaluate property of mechanic and drying shrinkage and creep of the lightweight aggregate concrete, but these weren't. So the purpose of this study which it sees follows the mechanical property of the eco lightweight aggregate concrete according to the water binder ration in the high strength concrete. Eco lightweight aggregate was made with clay and crushed rock in this study. To make experiment, water binder ratio was divided 35% and 39%. And the fresh concrete properties were that slump flow was 500${\pm}$50mm, air contents was 2.0${\pm}$1.0%. It evaluated the hold a drying shrinkage and the creep the effect, it analyzed quality and reliability of the eco lightweight aggregate concrete.

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An Experiment on Bond Behaviours of Reinforcements Embedded in Geopolymer Concrete Using Direct Pull-out Test (직접 인발 시험을 이용한 지오폴리머 콘크리트의 부착 특성 실험)

  • Kim, Jee-Sang;Park, Jong-Ho
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.4 no.4
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    • pp.454-462
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    • 2016
  • Geopolymer concrete is a new class of construction materials that has emerged as an alternative to ordinary Portland cement concrete to reduce the emission of $CO_2$ in the production of concrete. Many researches have been carried out on material developments of geopolymer concrete, however a few studies have been reported on the structural use of them. This paper presents an experiment on the bond behaviors of reinforcements embedded in fly ash based geopolymer concrete. The development lengths of reinforcement for various compressive strength levels of geopolymer concrete, 20, 30 and 40 MPa, and reinforcement diameters, 10, 16 and 25 mm, are investigated. Total 27 specimens were manufactured and pull-out test according to EN 10080 was applied to measure the bond strength and slips between concrete and reinforcements. As the compressive strength levels of geopolymer concrete increase, the bond strength between geopolymer concrete and reinforcement increase. The bond strengths decrease as the diameters of reinforcements increase, which is similar in normal concrete. Also, an estimation equation for the basic development length of reinforcement embedded in geopolymer concrete is proposed based on the experimental results in this study.