• 제목/요약/키워드: Strength evaluation method

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Fuzzy logic approach for estimating bond behavior of lightweight concrete

  • Arslan, Mehmet E.;Durmus, Ahmet
    • Computers and Concrete
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    • 제14권3호
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    • pp.233-245
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    • 2014
  • In this paper, a rule based Mamdani type fuzzy logic model for prediction of slippage at maximum tensile strength and slippage at rupture of structural lightweight concretes were discussed. In the model steel rebar diameters and development lengths were used as inputs. The FL model and experimental results, the coefficient of determination R2, the Root Mean Square Error were used as evaluation criteria for comparison. It was concluded that FL was practical method for predicting slippage at maximum tensile strength and slippage at rupture of structural lightweight concretes.

환경영향을 고려한 WELD BONDING 시험편의 강도평가(인장전단의 경우) (Evaluation of Strength of Weld Bonding Specimen Considering Effects of Environments (In Case of Tensile Shear))

  • Lim, Ki-Chang;Kuen Ha, Shin;S.H. Lim
    • 한국안전학회지
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    • 제7권3호
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    • pp.99-107
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    • 1992
  • Weld bonding can be applied as a combined method of spot welding and adhesive to have more advantages than those. Weld bonding has many merits that enlarge the fatigue strength of spot Welding and also improve the creep of adhesive. But it has not beer proved well in the various environmental conditions. In this study, weld bonding test for fatigue properties and tensile strength is presented under such various coditions as temperatures, humidity, and etc.

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철도차량용 완충기 요크 구조강도 평가 (Structure and Strength Analysis of Yoke for Railway Vehicles)

  • 우창수;박현성;박동철
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2008년도 추계학술대회 논문집
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    • pp.1634-1641
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    • 2008
  • The shock absorbing equipment for railway rolling is one of the most important components. It's effects on the safety of both passengers and vehicle itself and reduce shock, vibration and noise. The shock absorber equipment is mainly consisted of the yoke, plate and rubber draft gear. The objective of the this paper is to evaluation of structure and strength for the yoke in railway vehicles. Structure and strength analysis has been performed by use of finite element method and experimental stress analysis.

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기존 철근콘크리트 건물 내진진단법의 강도지표 (Strength Index in Seismic Performance Evaluation Method of Existing Reinforced Concrete Buildings)

  • 이원호
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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    • pp.278-287
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    • 2000
  • In Korea, countermeasures against earthquake disasters such as the seismic performance evaluation and/or retrofit scheme of buildings have not been fully performed since Korea had not been experienced many destructive earthquakes in the past. However, due to more than four hundred earthquakes with slight/medium intensity occurred in the off-coastal and inland of Korea during the past 20 years, and due to the great earthquakes occurred recently in neighboring countries, such as the 1995 Hyogoken-Nambu Earthquake with more than 6,500 fatalities in Japan and the 1999 Ji-Ji Earthquake with more than 2,500 fatalities in Taiwan, the importance of the future earthquake preparedness measures in Korea is highly recognized. The main objective of this paper is to provide the basic data for development of a methodology for the future earthquake preparedness in Korea by investigating the concept and applicabilities of the Japanese Standard for Evaluation of Seismic Performance of Existing RC Buildings developed in Japan among the methodologies of all over the world. In this paper, a seismic performance evaluation method of the existing reinforced concrete buildings is proposed based on experimental data of columns and walls carried out in Korea by referring the Japanese Standard, especially focusing on the Strength Index(C) among the indices in the seismic capacity index(IS) equations. Also, the seismic capacities of two existing reinforced concrete buildings in Korea are evaluated based on the proposed methodology and the Japanese Standard, and the correlations between the seismic capacities by the proposed methodology and the Japanese Standard are discussed.

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ASIL에 기초하여 수정된 안전시스템 FMEA 위험평가척도 (A Modified Metric of FMEA for Risk Evaluation Based on ASIL of Safety System)

  • 백명식;장현애;권혁무
    • 품질경영학회지
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    • 제42권4호
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    • pp.543-562
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    • 2014
  • Purpose: The purpose of this study is to suggest a modified approach that compensates some shortcomings of RPN with relevant strength of ASIL for Safety System and suggests systematic and logical approach for FMEA. Methods: By comparing the objectives, determination procedures, and key conceptual differences of RPN and ASIL, a refined method of risk evaluation and a new risk metric are devised. Results: While the traditional FMEA provides only rough evaluation of relative risk for each failure, the proposed method compensates its shortcomings with relevant strength of ASIL and provides a more logical and practical procedure of risk evaluation. Conclusion: The new metric RPM provides not only a comparative priority rank but also the degree of physical seriousness. Besides, it may have even more benefits for various applications if the severity can be expressed as mone tary amount of losses.

분체계 고유동 콘크리트의 재료분리 판정방법 분석 (Segregation Evaluation Method for Powder Based High Fluidity Concrete)

  • 이혁주;한준희;이재진;한동엽;한인덕;한민철
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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    • pp.140-141
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    • 2018
  • There are three types of high fluidity concrete: powder based, VMA based, and combined. In the case of the powder based high fluidity concrete mixture, according to the textbook, increased viscosity due to the replaced fly ash can prevent segregation of coarse aggregate. On the other hand, decreased density of the powder due to the fly ash replacement can causes segregation but there is no report on this issue. Therefore, in this research, the segregation resistance and segregation evaluation method for powder based high fluid concrete mixture are evaluated. As a result, with increased replacing ration of supplementary materials, EIS value was decreased and apparently segregation resistance was increased. However, from the compressive strength evaluation depending on height of the cylindrical specimen, it was confirmed that the different of strength difference between top and bottom part of the specimen. Thus, following research regarding vertical segregation should be studied.

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Nondestructive Evaluation of Strength Performance for Heat-Treated Wood Using Impact Hammer & Transducer

  • Won, Kyung-Rok;Chong, Song-Ho;Hong, Nam-Euy;Kang, Sang-Uk;Byeon, Hee-Seop
    • Journal of the Korean Wood Science and Technology
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    • 제41권5호
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    • pp.466-473
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    • 2013
  • Nondestructive evaluation (NDE) technique method using a resonance frequency mode was carried out for heat-treated wood under different conditions. The effect of heat treatment on the bending strength and NDE technique using the resonance frequency by impact hammer and force transducer mode for Korean paulownia, Pinus densiflora, Lidiodendron tulipifera and Betula costata were measured. The heat treatment temperature has been investigated at $175^{\circ}C$ and $200^{\circ}C$, respectively. There were a close relationship of dynamic modulus of elasticity and static bending modulus of elasticity to MOR. In all conditions, It was found that there were a high correlation at 1% level between dynamic modulus of elasticity and MOR, and static modulus of elasticity and MOR. However, the result indicated that correlation coefficient is higher in dynamic modulus of elasticity to MOR than that in static modulus of elasticity to MOR. Therefore, the dynamic modulus of elasticity using resonance frequency by impact hammer mode is more useful as a nondestructive evaluation method for predicting the MOR of heat-treated wood under different temperature and species conditions.

멤브레인 방식 LNG탱크의 피로강도 평가법에 관한 연구 (I) (A Study on the Evaluation Method of Fatigue Strength of Membrane Type LNG Tank(I))

  • 김종호
    • Journal of Advanced Marine Engineering and Technology
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    • 제21권1호
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    • pp.49-58
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    • 1997
  • The membrane type LNG tank is non self-supporting tank which consists of both primary and secondary membrane supported through the insulation boxes by the adjacent hull struc¬ture. Although the membranes are not structural member. They are subject to periodical cyclic loads due to the thermal expansion and other expansions or contraction of membrane. At the design stage of the tank, an analytical and experimental approach on the fatigue strengths of membrane and its welds is necessary in order to assist the designer and the inpector. In this study the evaluation method of fatigue strength of membrane type LNG tank is pre¬sented with FEM analysis and fatigue test of lap welds and it contains the following:1) The fatigue tests and preparation of design S - N curve for lap welds 2) FEM analysis of test specimens 3) Estimation of cumulative damage factor of lap welds 4) Guideline for inspection of lap welds of membrane type LNG tank As the results of analytical and experimental approaches in this study, the evaluation method of fatigue strengths of membrane type LNG tank is proposed, which is expected to be useful for design and inspection of membrane type LNG tank.

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기존시설물 내진성능평가를 위한 평가항목 분류체계와 평가방법 (Seismic Performance Level Criteria and Evaluation Methods)

  • 김남희
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2000년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2000
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    • pp.251-260
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    • 2000
  • Seismic performance evaluation systems require rational classification of structure systems, proper evaluation criteria, and their scoring index for synthesis. Current seismic performance systems need expert judgments based on collection of available data, approximate analysis of important items, and various scoring system. This study presents a three-step seismic performance evaluation system for building structures in Korea. Each evaluation step determines the seismic performance and the method depends on the degree of refinement of analysis. The preliminary step evaluation involves the global attributes of structures such as vertical irregularity, asymmetric plan, redundancy, and age of structures. The second step requires an elastic analysis for estimation of forces acting on critical sections and checks the strength and ductility. The final step requires inelastic capacity of structures. Each stephas own evaluation scheme with proper weighing factor dependent on the importance and consequence. This study applies the fuzzy theory to a scoring method that synthesizes the individual quantity to a representative value.

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Self-evaluation model for TQM activity

  • Osada, Hiroshi;Yamazaki, Masahiko
    • International Journal of Quality Innovation
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    • 제1권1호
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    • pp.75-80
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    • 2000
  • Objective evaluation is necessary for the company to know the level of its TQM activity and to improve it. This article proposes self-evaluation model for TQM activity through comparison study of the examination viewpoints for the Deming Prize with criteria of the Malcolm Baldridge National Quality Award. Proposed self-valuation model consists of three evaluation categories i.e. management system, management performance and survey/audit system. Evaluation on these categories is done for process and performance by using scoring method. This self-evaluation model is useful for checking the progress of TQM and make company recognize the strength and weakness of its TQM activity, namely, positioning analysis.

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