• 제목/요약/키워드: Short fiber-reinforced composite

검색결과 112건 처리시간 0.02초

선형보강재와 평면보강재를 적용한 토체의 전단강도 및 투수특성 (Shear Strength and Permeability Characteristics of Soil Body Reinforced with Linear and Planar Reinforcing Materials)

  • 차경섭;장병욱;우철웅;박영곤
    • 한국농공학회지
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    • 제45권6호
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    • pp.162-171
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    • 2003
  • Traditional methods of earth reinforcement consist of introducing strips, fabrics, or grids into an earth mass. Recently, discrete fibers are simply added and mixed with the soil, much the same as cement, lime or other additives. The advantages of randomly distributed fibers is the maintenance of strength isotropy, low decrease in post-peak shear strength and high stability at failure. In this study, new composite reinforcement structures which consist of geotextile and randomly distributed discrete fibers were examined their engineering properties, such as shear strength of the composite reinforced soil and permeability of short fiber reinforced soil. The increments of shear strength of composite reinforced soils were the sum of increments by fiber and woven geotextile, respectively. The permeability of short fiber reinforced soil was increased with fiber mixing ratio.

Partially encased composite columns using fiber reinforced concrete: experimental study

  • Pereira, Margot F.;De Nardin, Silvana;El. Debs, Ana L.H.C.
    • Steel and Composite Structures
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    • 제34권6호
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    • pp.909-927
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    • 2020
  • This paper addresses the results of an experimental study involving 10 partially encased composite columns under concentric and eccentric compressive loads. Parameters such as slenderness ratio, ordinary reinforced concrete and fiber reinforced concrete, load eccentricity and bending axis were investigated. The specimens were tested to investigate the effects of replacing the ordinary reinforced concrete by fiber reinforced concrete on the load capacity and behavior of short and slender composite columns. Various characteristics such as load capacity, axial strains behavior, stiffness, strains on steel and concrete and failure mode are discussed. The main conclusions that may be drawn from all the test results is that the behavior and ultimate load are rather sensitive to the slenderness of the columns and to the eccentricity of loading, specially the bending axis. Experimental results also indicate that replacing the ordinary reinforced concrete by steel fiber reinforced concrete has no considerable effects on the load capacity and behavior of the short and slender columns and the proposed replacement presented very good results.

분산형 복합재료의 손상 메커니즘 (Damage Mechanics in Particle or short-Fiber Reinforced Composite)

  • 조영태
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 1998년도 추계학술대회 논문집
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    • pp.287-292
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    • 1998
  • In particle or short-fiber reinforced composites. cracking of the reinforcements is a significant damage mode because the broken reinforcements lose load carrying capacity. This paper deals with the load carrying capacity of intact and broken ellipsoidal inhomogeneities embedded in an infinite body and a damage theory of particle or short-fiber reinforce composites. The average stress in the inhomogeneity represents its load carrying capacity. and the difference between the average stresses of the intact t and broken inhomogeneities indicates the loss of load carrying capacity due to cracking damage. The composite in damage process contains intact and broken reinforcements in a matrix. An incremental constitutive relation of particle or short-fiber reinforced composites including the progressive cracking damage of the reinforcements have been developed based on the Eshelby's equivalent inclusion method and Mori and Tanaka's mean field concept. Influence of the cracking damage on the stress-strain response of the composites is demonstrated.

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옹벽 배면토체 적용을 위한 단섬유 보강토의 전단강도 특성 (Shear Strength Characteristics of Short-fiber Reinforced Soil for the Application of Retaining Wall Backfill)

  • 박영곤;차경섭;장병욱
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2003년도 추계학술대회 논문집(II)
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    • pp.73-78
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    • 2003
  • As a fundamental study to develop the retaining wall of new type, short-fibers are mixed with soils and a series of compaction tests and triaxial compression tests for short-fiber reinforced soils are performed. From the results of compaction tests, optimum moisture content is increased and maximum dry unit weight is decreased with fiber mixing ratio. When 60mm fibrillated fiber of 0.2$\%$ mixing ratio is added to SM soil, strength increment of short-fiber reinforced soil is above 1.2 times compared to soil only. Strength increment shows maximum value for composite reinforced soil, namely, soil+short-fiber+planar reinforcement. But in case of mixing with ML soil and short-fiber, the strength of short-fiber reinforced soil is nearly the same as soil only. Internal angle of short-fiber reinforced soil is increased about $2\~3$ degrees and cohesion is also increased above 10kPa compared to soil only. Therefore, it is judged that short-fiber is a good material to strengthen the soil.

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콘크리트 충전 유리섬유 복합소재 기둥의 세장비 특성에 관한 실험적 연구 (Experimental Study on Slenderness Effects in Concrete-Filled Glass Fiber Reinforced Polymer Composite Columns)

  • 최석환;이성우;손기훈;이명
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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    • pp.585-590
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    • 2001
  • The structural characteristics of concrete-filled glass fiber reinforced polymer tubes were studied. The concept of concrete-filled composite columns was introduced to overcome the corrosion problems associated with steel and concrete piles under severe environments. Other benefits of composite columns include low maintenance cost, high earthquake resistance, and long expected endurance period. Several experiments were conducted; 1) compression test for short-length composite columns, 2) uniaxial compression tests on a total of 7 columns with various slenderness ratios. Short-length columns give higher strength and ductility revealing high confinement action in concrete. Failure strengths, failure patterns, confinement effects, and stress-strains relations were analyzed for slender columns. Current study will show the feasibility of concrete-filled glass fiber reinforced polymer composite columns in corrosive environments, and will provide an experimental database for columns that are externally reinforced by multidirectional fibers.

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단섬유 보강 복합재료에서의 열탄성 거동에 관한 해석 (An lnvestigation of the thermoelastic Behavior in Short Fiber Reinforced Composite Materials)

  • 김홍건
    • 한국생산제조학회지
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    • 제6권3호
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    • pp.89-95
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    • 1997
  • A simulation to investigate the thermal behavior in short fiber or whisker reinforced composite materials has been performed for the application to the thermoelastic stress analysis using Finite Element Method (FEM). To obtain the internal field quantities of composite material, the procedure of micromechanical modeling and the principle of virtual work were implemented. For the numerical illustration, an aligned axisymmetric single fiber model has been employed to assess field quantities. It was found that the proposed simulation methodology for thermoelastic stress analysis is applicable to the complicated inhomogeneous solid for the investigation of micromechanical thermoelastic behavior.

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가압소결법으로 제조된 알루미나 단섬유 보강 청동기지 복합재의 마모특성 (Wear Properties of the Alumina Short Fiber Reinforced Tin-Bronze Matrix Composites manufactured by Hot Pressing)

  • 최준호;허무영
    • 소성∙가공
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    • 제4권4호
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    • pp.398-409
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    • 1995
  • The wear properties of the alumina short fiber reinforced tin-bronze matrix composites manufactured by hot pressing was studied at the room temperature and $350^{\circ}C.$ The wear loss of various specimens having different constituent and different density was examined by a pin-on-disc type wear testing machine. The results were discussed by the observation of the worn surface morphology and the analysis of the composition on the worn surfaces. Since the reinforced effect of the alumina fiber on the wear resistance was dependent on the strength of alloy matrix, the pressureless sintered composites having a lower matrix strength showed a marked increase in wear resistance by the fiber reinforcement. As the wear condition became severe, the fiber reinforcement was more effective. The delamination on the wear surface was observed in the pressureless sintered specimens having pores which are related to the initiation and the propagation of cracks. However, the wear mechanism acting on a big failure area was not found on the wear surfaces of the hot pressed specimens having a few pores.

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Incremental Damage Mechanics of Particle or Short-Fiber Reinforced Composites Including Cracking Damage

  • Cho, Young-Tae
    • Journal of Mechanical Science and Technology
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    • 제16권2호
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    • pp.192-202
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    • 2002
  • In particle or short-fiber reinforced composites, cracking of the reinforcements is a significant damage mode because the cracked reinforcements lose load carrying capacity. This paper deals with an incremental damage theory of particle or short-fiber reinforced composites. The composite undergoing damage process contains intact and broken reinforcements in a matrix. To describe the load carrying capacity of cracked reinforcement, the average stress of cracked ellipsoidal inhomogeneity in an infinite body as proposed in the previous paper is introduced. An incremental constitutive relation on particle or short-fiber reinforced composites including progressive cracking of the reinforcements is developed based on Eshelby's (1957) equivalent inclusion method and Mori and Tanaka\`s (1973) mean field concept. Influence of the cracking damage on the stress-strain response of composites is demonstrated.

노반 토구조물로서의 이용을 위한 새로운 단섬유 복합보강토 옹벽구조 개발 (Development of Short-fiber Composite Reinforced Retaining Wall for Railroad Soil Structure)

  • 박영곤;박태순;장병욱;이영제
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2004년도 춘계학술대회 논문집
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    • pp.1014-1019
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    • 2004
  • The development of both economical and consistent structure is strongly required for the whole reorganization of the railway network in Korea. Retaining wall is one of the major structures in the vicinity of the railway, which needs improving its external appearance and stability. Therefore, this study presents a new type of retaining wall, so called short-fiber composite reinforced retaining wall, as an alternative of retaining walls, which can be used for constructing the slope and roadbed soil structures. The results from real-scale test and dynamic numerical analysis for developed new one, which helps both the improvement of the external appearance and also the optimum use of the limited space near the railway, show excellent performance. On the basis of these results, it is judged that short-fiber composite reinforced retaining wall has the advantages of choosing the front wall freely and having a chance to use any low quality soil as backfill.

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전단지연 이론을 이용한 단섬유 형태의 SMA 보강 고분자 복합재료의 열변형 거동 해석 (Thermo-Mechanical Behavior of Short SMA Reinforced Polymeric Composite Using Shear tag Theory)

  • 정태헌;이동주
    • 대한기계학회논문집A
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    • 제23권6호
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    • pp.1001-1010
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    • 1999
  • Thermo-mechanical behavior of discontinuous shape memory alloy(SMA) reinforced polymeric composite has been studied using modified shear lag theory and finite element(FE) analysis with 2-D multi-fiber model. The aligned and staggered models of short-fiber arrangement are employed. The effects of fiber overlap and aspect ratio on the thermomechanical responses such as the thermal expansion coefficient are investigated. It is found that the increase of both tensile stress(resistance stress) in SMA fiber and compressive stress in polymer matrix with increasing aspect ratio is the main cause of low thermal deformation of the composite.