• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.214-215
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• 2021

The existing evaluation method could not apply the effect of zero span tension generated in the waterproofing layer attached to the surface of the structure at the moment of cracking as the waterproofing layer was constructed in the state where the cracks were formed. The test apparatus developed through this study is expected to be able to conduct tests closer to the environment occurring in actual structures as it is possible to simultaneously create a pressurized (constrained) condition and an environment for zero span tension.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.828-833
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• 2003

In this paper, a study on fracture characteristics of chemically prestressed mortar with addition of expansive additives was carried out. Uni-axial tension tests with reinforced mortar specimen restrained by embedded reinforcing bar and three point bending tests with notched steel fiber reinforced beams were carried out to verify the characteristics of the cracking behavior, the tension stiffening effect due to bond between rebar and mortar, and fracture characteristic. Tension stiffening curve for the chemically prestressed mortar was obtained from uni-axial tension test. And increased fracture energy due to the chemical prestress was also obtained from bending test and tension softening curve for chemically prestressed mortar was also obtained.

• 소성∙가공
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• 제22권6호
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• pp.303-309
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• 2013

Spring-back of MS1470 steel sheets was numerically predicted using a non-linear kinematic hardening material behavior based on the Yoshida-Uemori model. From uniaxial tension and uniaxial tension-compression-tension data as well as the uniaxial tension-unloading-tension data, the parameters of the Yoshida-Uemori model were obtained. For the numerical simulations, the Yoshida-Uemori model was implemented into the commercial finite element program, ABAQUS/Explicit and ABAQUS/Standard using the user-defined material subroutines. The model performance was validated against the measured spring-back from the benchmark problems of NUMISHEET 2008 and NUMISHEET 2011, the 2-D draw bending test and the S-rail forming test, respectively.

• 로봇학회논문지
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• 제17권2호
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• pp.178-182
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• 2022

Post-tension duct in nuclear reactor containment building is filled with grease to prevent steel strand from corroding. If grease leaks by break of duct, steel strand will corrode and cause problem in building safety. Therefore, grease leak should be checked preventatively. But currently used method is inefficient, since it has to remove grease and strand to check. And other methods for checking post-tension dust are not well-researched. In this paper, we develop screw-propelled robot that can move in grease and detect grease duct directly. Also, we make the test environment that is similar to real post-tension duct of containment building and test robot in that environment to verify that our robot is feasible in the post-tension duct. The robot can move forward and backward in grease duct by twin screw mechanism and has mount for sensors to detect grease leakage and strand corrosion.

• 한국항공우주학회지
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• 제37권9호
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• pp.939-945
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• 2009

액체로켓 연소기 재생냉각 챔버의 제작에 사용되는 구리합금의 성형한계 곡선을 얻기 위하여 돔 장출 시험과 인장시험을 수행하였다. 성형한계 곡선에 대한 실험적인 연구를 위하여 인장시편을 사용하여 인장-압축 변형률 상태의 데이터를 얻었으며, 인장-인장의 변형률 상태를 얻기 위하여 돔 장출 시험용 시편을 사용한 돔 장출 시험 또한 수행하였다. 시험에 사용한 모든 시편은 제작방향에 따라 종 방향과 횡 방향시편으로 구분하였다. 시험 결과 인장-인장 변형률 상태에서 최대 주 변형률과 부 변형률은 62.3%와 58.6%이며, 인장-압축 상태에서는 60.5%와 25.8%로 나타났다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.1003-1008
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• 2002

The purpose of this research was to obtain fatigue property of pavement concrete by split tension fatigue test. The specimens of pavement concrete were fabricated using the concrete at jop site. The fatigue tests of split tension were performed by 4 stress levels(90%, 80%, 70%, 60%) and 3 stress ratio(0.1, 0.3, 0.5). From this research, the S-N relationship, S-N-P relationship was derived and Weibull probability density functions was plotted using the distribution parameters.

• 대한기계학회논문집A
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• 제21권2호
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• pp.261-271
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• 1997

This paper presents the design process and characteristic test results of tension sensors for measuring the ultimate tension forces of surgical wires. Three types of sensor were designed and tested for calibration. The first two types which transfer the wire tension to the sensing element by direct contact have too much hysterisis errors due to the firctional effect. This error can be considerably reduced in the modified structure, where a cover and a loading button is used to transfer force and moment to the sensing element. The strains predicted by theoretical equations agree well with those by finite element calculations neglecting friction and the strains by finite element analysis considering friction are in good agreement with those measured by four strain gages. The modified ring type tension sensor developed in this paper is expected to be useful for measuring the tension of surgical wires with nonlinearity of 1.31%FS, hysterisis of 5.74%FS and repeatability of 0.19%FS.

• Journal of the Korean Wood Science and Technology
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• 제18권3호
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• pp.6-16
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• 1990

The objectives of this study were to investigate the relative effects of specific gravity and particle size on internal bond and tensile strengths and fracture toughness of particleboard and to compare mechanical strength with fracture toughness. The particleboard was manufactured with three different particle sizes at specific gravity levels of 0.6, 0.7, and 0.8 with a resin content of 10% based on oven dry weight. The results were summarized as follows: 1. Internal bond strength. fracture toughness in internal bond test. maximum tensile strength, and fracture toughness in tension test increased with the increase of specific gravity of particleboard. 2. As partcle size increased, internal bond strength, fracture toughness. maximum tensile strength. and fracture toughness in tension test increased. 3. The maximum tensile strength and fracture toughness appeared to be in a direct relationship, and then maximum tensile strength could be used for predicition of fracture toughness for tension test. 4. The fracture toughness in internal bond test was somewhat independent on induced crack length.

• 한국재료학회지
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• 제15권2호
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• pp.126-133
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• 2005

Mechanical properties of zirconium cladding were evaluated by ring tension test to simulate Reactivity-Initiated Accident (RIA) at high burnup situation as an out-reactor test. Zircaloy-4 cladding was hydrided up to 1000 ppm as well as oxidized up to $100\;{\mu}m$ to simulate high-burnup situation. After simulated high-burnup treatment, ring tension test was carried out from 0.01 to 1/sec to correlate with actual RIA event. The results showed that ductility and circumferential toughness decreased with the hydrogen content and oxide thickness. Hydride generated inside cladding acted as brittle failure. Oxygen influenced cladding tube by the reduction of load bearing area, oxygen embrittlement, and thermal aging. Correlation between in-reactor RIA parameter like fuel enthalpy and out-reactor toughness was performed and showed a reasonable result.

• 가정과삶의질연구
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• 제16권4호
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• pp.83-83
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• 1998

The purpose of this study is to investigate interpersonal support, tension in lifechanges & satisfaction. The selected sample is composed of 387 housewives in ChongJoo city. SAS pc program was used for the statistical analysis of the data. Data was analyzed by frequency, F-test, percentage, mean, Duncan's Multiple Range Test, Pearson's correlation coefficient, Regression Analysis. Major findings as follows: 1)At wedding & funeral ceremony, kin networks of her parents & parents-in law side were variables to have influence on tension in life changes. And the number of social organization participated were a variable to have influence on the satisfaction. The age of couple, education of couple, duration of marriage, income, family lifecycle, the number of children, pattern of family were variables to influence tension in life changes, but were not variables to influence on the satisfaction. 2) At usual or wedding & funeral ceremony, kin networks of her parents side were variables to influence on instrumental & companionship support. And the number of friends was a variable to influence on companionship & informational support. The number of neighbors was a variable to influence on instrumental, companionship & informational support. The number of social organization participated was a variable to influence on companionship & emotional support. The age of couple, education of couple,income, duration of marriage, family life cycle, number of children, family size, family type were variables to influence on interpersonal support. 3)The relationship between tension and satisfaction in life changes was negative, and between instrumental support and satisfaction was negative also. But between companionship support and satisfaction was positive relationship and between tension of personal &social life and instrumental support was positive relationship. The relationship between tension of marriage life and companionship support was negative and between tension of family life and information support was negative relationships. The received companionship support was lower tension in life changes than not received it. But the received instrumental support was higher tension of personal & social life. The received companionship & informational support was higher satisfaction than not received them. But the received instrumental support was lower satisfaction than not received it. 4) Instrumental & companionship support, at usual kin network of her parents in taw side, at wedding & funeral ceremony kin network of her parents side,were variables to influence on tension in life changes. Instrumental, companionship& informational support, at wedding & funeral ceremony kin network of her parents side, were variables to influence on the satisfaction