• 제목/요약/키워드: Failure ratio

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접착이음의 파괴 기준 설정을 위한 연구 (Establishment for Failure Criterion of Adhesively Bonded Joint)

  • 이강용;공병석
    • 한국자동차공학회논문집
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    • 제8권1호
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    • pp.183-190
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    • 2000
  • The objective of this work is to develop a criterion for predicting the failure strength of the joints bonded by ductile adhesives. To obtain a criterion, first, fracture tests were carried out for T-peel joint and Single-lap joint with widely differing joints geometries. Then using the fracture loads obtained at tests, the finite element analysis were performed, in which the stresses in the adhesive bonds were calculated in great detail. After examining four epoxy adhesives, it is concluded that the fracture of adhesively bonded joint occurs when the maximum of the ratio of the mean to effective stresses exceeds a constant value which can be determined from analysis and test for each adhesive.

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배전용 자기제 현수애자의 고장 분석 (Failure Analysis of Porcelain Suspension Insulators for Distribution Line)

  • 김찬영;김추용;송일근;이병성;한용희
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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    • pp.157-160
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    • 1999
  • The paper provides the results of failure analysis for the porcelain suspension insulators. The comparisons of characteristics were made as a function of failed and unfailed isulators which had been used in real distribution line. This paper also described the failure modes which could be occurred in the fields. The cracks inside cap were detected though measuring the resistance or the leakage current. The ratio of open porosity was calculated from the Archimedes Method. The failure analyses of porcelain suspension insulators were conducted from the various analysis method.

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서비스 실패에 따른 서비스 회복과 고객행동에 관한 연구 (A Study on Service Recovery and Customer Behavior from Service Failure)

  • 박영배
    • 한국조리학회지
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    • 제13권1호
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    • pp.152-165
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    • 2007
  • The purpose of this study is to prove that the appropriate fit between service failure and recovery strategy can efficiently maximize customer satisfaction and behavioral intention, by using the prepared scenario through comprehensive approach concerning how the expectation level of service recovery has influence on perceived fairness, satisfaction and behavioral intention of service recovery based upon size in case of service failure. This study has been conducted by way of selection of filling-up type questionnaires for customers themselves who have experience in service failure out of customers who can easily visit family and hotel restaurants, that is, domestic restaurants in Seoul area, $June{\sim}August$ 2004, by setting factorial design of 2(control, severeness)$\times$3(distributive fairness, procedural fairness, mutual relational fairness)$\times$2(customer satisfaction, customer behavior). The survey was performed on the customers who visited common restaurants, family restaurants, hotel restaurants, etc. mainly in Seoul, and total 600 sheets of questionnaires were distributed and 496 sheets of them were returned(82.67% of return ratio). Research findings are as follows; First, perceived recovery justice has an effect on customer satisfaction and behavioral intention. Second, customer satisfaction and restaurant satisfaction have positive influence on behavioral intention. The results will be helpful for them to develop a further service failure and recovery framework. For service marketing managers, the results will suggest specific guidelines for establishing service recovery strategies.

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조기난소부전증 환자에서의 면역학적 연구;I. 입파구아형외 변화 (Immunologic Study in Women with Premature Ovarian Failure;I. Peripheral Blood Lymphocyte Subpopulations)

  • 김정구;이진용;장윤석
    • Clinical and Experimental Reproductive Medicine
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    • 제16권2호
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    • pp.147-152
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    • 1989
  • The purpose of this study is to detect certain change in peripheral blood lymphocyte subpopulations in women with premature ovarian failure. The B cells, T cells and subsets were counted in 21 women with premature ovarian failure and 30 age-matched normal control women. The B cells were measured by identifying lymphocyte with surface membrane immunoglobulin and T cells and subsets by indirect immunofluorescence technique with the monoclonal antibodies OK T3, OK T4, and OK T8. The results were as follows. 1. No significant difference in the absolute number of B cells, T cells and subsets between women with premature ovarian failure and normal control women was observed. 2. The percentage of B cells, T cells and OK T8(+) cells in women with premature ovarian failure was not significantly different from that in normal control subjects respectively. 3. The percentage of OK T4(+) cells and OK T4/0K T8(+) ratio was significantly higher in women with premature ovarian failure than in control subjects.

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Seismic behavior of steel frames with replaceable reinforced concrete wall panels

  • Wu, Hanheng;Zhou, Tianhua;Liao, Fangfang;Lv, Jing
    • Steel and Composite Structures
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    • 제22권5호
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    • pp.1055-1071
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    • 2016
  • The paper presents an innovative steel moment frame with the replaceable reinforced concrete wall panel (SRW) structural system, in which the replaceable concrete wall can play a role to increase the overall lateral stiffness of the frame system. Two full scale specimens composed of the steel frames and the replaceable reinforced concrete wall panels were tested under the cyclic horizontal load. The failure mode, load-displacement response, deformability, and the energy dissipation capacity of SRW specimens were investigated. Test results show that the two-stage failure mode is characterized by the sequential failure process of the replaceable RC wall panel and the steel moment frame. It can be found that the replaceable RC wall panels damage at the lateral drift ratio greater than 0.5%. After the replacement of a new RC wall panel, the new specimen maintained the similar capacity of resisting lateral load as the previous one. The decrease of the bearing capacity was presented between the two stages because of the connection failure on the top of the replaceable RC wall panel. With the increase of the lateral drift, the percentage of the lateral force and the overturning moment resisted by the wall panel decreased for the reason of the reduction of its lateral stiffness. After the failure of the wall panel, the steel moment frame shared almost all the lateral force and the overturning moment.

딤플형 내부 구조체를 가진 ISB 판넬의 굽힘 강성 특성 (Bending characteristics of ISB panel with dimple shapes as inner structures)

  • 안동규;이상훈;김진석;문경재;한길영;정창균;양동열
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2006년도 춘계학술대회 논문집
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    • pp.117-118
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    • 2006
  • The objective of this paper is to investigate into bending and failure characteristics of ISB panel with dimple shapes as inner structures. Through three-points bending test, the force-displacement curve and the failure shape are obtained to examine the deformation pattern, characteristic data including maximum load and displacement at the maximum load and failure pattern for the ISB panel. In addition, the influence of design parameters for ISB panel on the bending stiffness and failure mode has been found. From the results of the experiments, it has been shown that bending and failure characteristics of the ISB panel can be controlled by the ratio of radius and the direction of the material.

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Shear behaviour of RC beams retrofitted using UHPFRC panels epoxied to the sides

  • Al-Osta, Mohammed A.
    • Computers and Concrete
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    • 제24권1호
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    • pp.37-49
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    • 2019
  • In this study, the shear behaviour of reinforced concrete (RC) beams that were retrofitted using precast panels of ultra-high performance fiber reinforced concrete (UHPFRC) is presented. The precast UHPFRC panels were glued to the side surfaces of RC beams using epoxy adhesive in two different configurations: (i) retrofitting two sides, and (ii) retrofitting three sides. Experimental tests on the adhesive bond were conducted to estimate the bond capacity between the UHPFRC and normal concrete. All the specimens were tested in shear under varying levels of shear span-to-depth ratio (a/d=1.0; 1.5). For both types of configuration, the retrofitted specimens exhibited a significant improvement in terms of stiffness, load carrying capacity and failure mode. In addition, the UHPFRC retrofitting panels glued in three-sides shifted the failure from brittle shear to a more ductile flexural failure with enhancing the shear capacity up to 70%. This was more noticeable in beams that were tested with a/d=1.5. An approach for the approximation of the failure capacity of the retrofitted RC beams was evolved using a multi-level regression of the data obtained from the experimental work. The predicted values of strength have been validated by comparing them with the available test data. In addition, a 3-D finite element model (FEM) was developed to estimate the failure load and overall behaviour of the retrofitted beams. The FEM of the retrofitted beams was conducted using the non-linear finite element software ABAQUS.

Crack pattern and failure mode prediction of SFRC corbels: Experimental and numerical study

  • Gulsan, Mehmet Eren;Cevik, Abdulkadir;Mohmmad, Sarwar Hasan
    • Computers and Concrete
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    • 제28권5호
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    • pp.507-519
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    • 2021
  • In this study, a new procedure was proposed in order to predict the crack pattern and failure mode of steel fiber reinforced concrete (SFRC) corbels. Moreover, an experimental study was carried out in order to investigate the effect of several parameters, such as compressive strength, tensile strength, steel fiber ratio, shear span on the mechanical behavior of SFRC corbels in detail. Totally, 24 RC and SFRC corbels were prepared for the experimental study. Experimental results indicate that each investigated parameter has noticeable effect on the load capacity and failure mode of SFRC corbels. Moreover, finite element (FE) model of the tested corbels were prepared and efficiency of FE model was investigated for further studies. Comparison of FE and experimental results show that there is an acceptable fit between them regarding load capacity and crack patterns. Thereafter, parametric study was carried out via FE analyses in order to obtain a methodology for crack pattern and failure mode prediction of SFRC corbels. As a result of parametric studies, a new procedure was proposed as flowcharts in order to predict the failure mode of SFRC corbels for normal and high strength concrete class separately.

내력상태계수 개념을 도입한 철근콘크리트 보의 전단파괴 트러스모델에 관한 연구 (A Study on Truss Model Incorporated with Internal Force State Factor for Shear Failure Mechanism in slender RC Beam)

  • 정제평;김우
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 봄 학술발표회 논문집
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    • pp.609-614
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    • 2001
  • This paper is to explain reasonable shear behavior that can apply usually to reinforced concrete beams on the basic concepts of existent analysis and experimental research information. This study is succession $paper^{2) 3) 4) 5)}$ of treatise announced in existing and main control variable of reinforced concrete beams with stirrups used internal force state factor($\alpha$). Shear failure of reinforced concrete beams with stirrups is Influenced greatly because of the actual geometrical shape(a/d) of the concrete and flexural reinforcement steel ratio, stirrup reinforcement ratio and concrete compression strength, size effect etc. Therefore, shear behavior of reinforced concrete beams with stirrups that flexural crack is happened can be explained easily through proper extent proposal of internal force state factor($\alpha$) that express internal force state flowing. Use existent variable truss model by analysis model to explain arch action. Also, wish to compose each failure factors and correlation with internal force state factor by function, and when diagonal cracks happens, internal force state factor($\alpha$) study whether shear stress and some effect are.

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부착되지 않은 텐돈을 갖는 PS 콘크리트 연속부재의 해석적 연구 (Analysis of Prestressed Concrete Continuous Members with Unbonded Tendons)

  • 문정호;이리형
    • 콘크리트학회지
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    • 제7권6호
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    • pp.197-208
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    • 1995
  • 본 연구에서는 부착되지 않은 텐돈을 갖는 PS콘크리트 구조체에 대한 해석적 여구가 진행되었는데 해석결과는 기존의 실험결과들과 비교되었다. 기존의 실험 결과들로부터 하중변위 관계, 구조체의 파괴시 텐돈응력에 대한 설계식, 기존의 보통 철근량의 효과, 부재길이에 대한 부재두께의 효과, 하중의 종류에 따른 영향등을 해석적 연구와 병행하여 분석하였다. 총 12개의 실험결과가 분석되었는데, 그 중 6개는 2스팬 연속보이며, 나머지 6개는 3스팬 연속 슬래브였다. 해석 결과는 실험결과와 잘 일치함을 보여 주었으며, 구조체의 파괴시 텐돈의 응력은 기존의 보통 철근의 효과, 하중의 패턴, 텐돈의 형상 등에 따라 많은 영향을 받는 것으로 나타났다.