• Title/Summary/Keyword: 인장강화

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Characteristics of Thermal Degradation for Carbon Fiber/Epoxy Composite using Strand Specimen (스트랜드 인장시편을 적용한 탄소섬유/에폭시 복합재의 열화특성 연구)

  • Oh, Jin-Oh;Kil, Hyung-Bae;Yoon, Sung-Ho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2012.05a
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    • pp.408-410
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    • 2012
  • In this study, High temperature properties of carbon fiber reinforced composites is performed using strand specimens and resin specimens. As for the tensile test at the different temperature, the tensile modulus of resin specimens decreases slightly until the temperature reaches the glass transition temperature. but the tensile modulus of strand specimens maintains tensile modulus at the room temperature. The tensile strength of resin and strand specimens decreases rapidly until the temperature reaches the glass transition temperature.

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Development of a Prediction Model for the Mechanical Properties of Polypropylene Composites Reinforced by Talc and Short Glass Fibers (탈크 및 유리단섬유로 강화된 폴리프로필렌 복합재료의 기계적 물성 예측 모델 개발)

  • Kim, Soon;Son, Dongil;Choi, Donghyuk;Jeong, Inchan;Park, Young-Bin;Kim, Sung Youb
    • Composites Research
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    • v.26 no.4
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    • pp.245-253
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    • 2013
  • In this paper, we developed a theoretical model which is able to predict the tensile strength and elastic modulus of hybrid composites reinforced by two types of randomly distributed discontinuous reinforcements. For this, we considered two known models; One is a prediction model based on the assumption that the composite is reinforced by two types of well aligned continuous reinforcements. The other is a statistical model for the composite which is reinforced by only one type of randomly distributed discontinuous reinforcements. In order to evaluate the validity of accuracy of our prediction model, we measured the strength and elastic modulus of polypropylene hybrid composite reinforced by talc and short glass fiber. We found that the present model drastically enhances the accuracy of strength prediction compared to an existing model, and predicts the elastic modulus within the same order with experimentally measured values.

Evaluation on the Bending Behavior After Yield of RC Beam by Using Image Processing Method(II): Focused on the Tensile Part (영상 분석 기법을 이용한 RC 부재의 항복 후 휨 거동 분석(II): 인장부를 중심으로)

  • Kim, Kun-Soo;Park, Ki-Tae;Woo, Tae-Ryeon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.6
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    • pp.47-53
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    • 2022
  • As the limit state design method is applied as a method of designing concrete structures, the ultimate state is considered in the analysis or design. In fact, when the reinforced concrete member bears tensile force, the force is transmitted from the rebar to the concrete, and the structure bears the tensile force to the ultimate state even after yield. Therefore, the accurate evaluation of behavior after yield, it is necessary to study the tension stiffening effect after yield of the flexural member. In this study, a 4-point bending test was conducted on the RC simple beam having a rectangular cross section of the double reinforcement, and the behavior of the member was analyzed in detail using the image analysis method. Using the analysis results, the estimation formula for the tension stiffening effect after yield was proposed, and the applicability of this was verified through the experimental results of existing study. The difference between the ultimate strain and the yield strain representing the ductile behavior of the member is similar to the experimental results. The prediction of the proposed formula is relatively accurate.

Tensile Properties of CERP Composite with Different Resin Composition under Cryogenic Temperature (극저온 환경에서 탄소섬유강화 복합재료의 수지조성변화에 따른 인장 물성 측정)

  • Kim, Myung-Gon;Kang, Sang-Guk;Kong, Cheol-Won;Kim, Chun-Gon
    • Composites Research
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    • v.20 no.4
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    • pp.1-8
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    • 2007
  • In this study, carbon fiber reinforced polymeric (CFRP) composites with different resin composition were manufactured and resin formulation in composite materials were presented through tensile tests for cryogenic use. Thermo-mechanical cyclic loading (up to 6 cycles) was applied to CFRP unidirectional laminate specimens from room temperature to $-150^{\circ}C$. Tensile tests were then performed at $-150^{\circ}C$ using an environmental test chamber. In addition, matrix-dominant properties such as the transverse and in-plane shear characteristics of each composite model were measured at $-150^{\circ}C$ to examine the effects of resin formulation on their interfacial properties. The tensile tests showed that the composite models with large amounts of bisphenol-A epoxy and CTBN modified rubber in their resin composition had good mechanical performance at cryogenic temperature (CT).

Numerical Analysis of Ultra High Performance Fiber Reinforced Concrete I-beam

  • Han, Sang-Mook;Guo, Yi-Hong;Kim, Sung-Wook;Kang, Su-Tae
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.817-820
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    • 2008
  • 이 논문은 초고강도 섬유보강 I형 보의 거동을 Diana를 사용하여 3차원 유한요소해석을 수행하였다. 보통 또는 고강도 콘크리트의 구성방정식과 달리 초고강도 섬유보강 콘크리트의 재료적 특성 즉, 인장 변형률 강화를 고려한 탄-소성 파괴 역학적 모델을 제안하여 해석에 반영하였다. 인장영역에서는 인장 변형률 강화를 고려한 다차원 고정 균열 규준을 사용하였고, 압축영역에서는 associated flow rule을 고려한 Drucker-Prager Criterion을 채택하였다. UHPFRC(Ultra-High Performance Fiber Reinforced Concrete) I형 보의 하중변형관계, 최초 균열, 최초 대각 균열, 극한상태 등의 결과를 실험결과와 비교하여 해석법의 유용성을 입증하였다.

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섬유함유율에 따른 GF/PP 복합재료의 인장강도

  • 엄윤성;고성위
    • Proceedings of the Korean Society of Fisheries Technology Conference
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    • 2003.10a
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    • pp.39-42
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    • 2003
  • 최근에 널리 쓰이고 있는 섬유강화 복합재료는 플라스틱 재료가 갖고 있는 가공성의 장점을 충분히 발휘한 재료로서 모재인 수지와 강화재인 강화섬유로 구성되며 사용된 섬유의 종류에 따라 유리섬유강화플라스틱(GFRP : glass fiber reinforced plastic)과 탄소섬유강화플라스틱(CFRP : carbon fiber reinforced plastic)으로 구분된다. 이 두 복합재료가 건설, 선박, 자동차 그리고 우주항공분야에 이르기까지 거의 모든 산업에서 다양하게 이용되고 있다. (중략)

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Effect of Temperature on Tensile Fracture Behavior of Glass Fiber Polypropylene Composites (온도변화에 따른 GF/PP복합재료의 인장파괴거동)

  • 고성위;엄윤성;허경환;김엄기;김형진
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.37 no.3
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    • pp.240-245
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    • 2001
  • The tensile strength and failure mechanisms of glass fiber polypropylene (GF/PP) composites are investigated in the temperature range from ambient to 8$0^{\circ}C$. The tensile strength increases as fiber volume fraction ratio increase. The tensile strength shows a maximum at ambient temperature, and it tens to decrease as temperature goes up. Major failure mechanisms of GF/PP composites can be classified as fiber matrix debonding, fiber pull-out, delamination and matrix deformation.

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위편성물 강화 열가소성 복합재료의 인장특성 연구

  • 이덕래;김학용;최종주;서민강
    • Proceedings of the Korean Fiber Society Conference
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    • 1998.10a
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    • pp.435-438
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    • 1998
  • Textile composites란 직물, 편성물, 브레이드 등을 사용한 섬유강화 복합재료의 총칭으로서 텍스타일이 지닌 뛰어난 기능을 매트릭스에 부가함에 따라 단일재료로는 얻지 못하는 뛰어난 공업재료를 만들 수 있다. 편성물은 직물이나 브레이드에 비해서, 변형특성도 매우 우수하고 고생산성이다. 복합재료에서 강화재로 편성물을 사용하는 경우, 섬유소재, 편조직, 편환 밀도 등을 고려하는 것에 의하여 편성물 강화 복합재료의 역학적 특성이 달라진다. (중략)

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Effect of Surface Treatments with Flame Plasma and Silane on Mechanical Properties of Silica Reinforced Elastomeric Composites (화염 플라즈마 및 실란 표면처리가 실리카 강화 고무복합재료의 기계적 특성에 미치는 영향)

  • Lee, Jun-Man;Ryu, Sang-Ryeoul;Lee, Dong-Joo
    • Composites Research
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    • v.24 no.6
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    • pp.18-24
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    • 2011
  • The effect of surface treatments with the atmospheric pressure flame plasma (APFP) and epoxy silane (ES) is experimentally investigated to yield the best mechanical properties of silica ($V_f=40%$) reinforced elastomeric composites. The tensile strength of the composites is increased significantly with decrease the mean diameter. When the diameter is $2.2{\mu}m$, that of the composite is increased about 1.4 times compared to the matrix (2.52 MPa). Also, the tensile strength of silica reinforced composites with APFP and ES treated is increased 8.8~13.3%, 9.9~12.5%, respectively. When the diameter is $26.6{\mu}m$, the tensile modulus of the composite is increased about 2 times compared to the matrix (0.88MPa), and the tensile modulus of silica reinforced composites with APFP and ES treated is increased 15.6~22.8%, 21.1~5.8%, respectively. Conventional silane coupling agent treatment have a few disadvantages because of using organic solvents. However APFP treatment is a fast, economic and eco-friendly method to improve the mechanical properties.

Cracking Analysis of RC Tension Members Using Polynomial Strain Distribution Function (다항식 변형률 분포함수를 이용한 철근콘크리트 인장부재의 균열 해석)

  • 곽효경;송종영;김한수
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.1
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    • pp.69-84
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    • 2002
  • In this papers, an analytical model which can simulate the post-cracking behavior and tension stiffening effect in a reinforced concrete(RC) tension member is proposed. Unlike the classical approaches using the bond stress-slip relationship or the assumed bond stress distribution, the tension stiffening effect at post-cracking stage is quantified on the basis of polynomial strain distribution functions of steel and concrete, and its contribution is implemented into the reinforcing steel. The introduced model can be effectively used in constructing the stress-strain curve of concrete at post-cracking stage, and the loads carried by concrete and reinforcing steel along the member axis can be directly evaluated on the basis of the introduced model. In advance, the prediction of cracking loads and elongations of reinforced steel using the introduced model shows good agreement with results from the previous analytical studies and experimental data.