• Title/Summary/Keyword: fiber composite

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A New Evaluation Method for Interfacial Properties of Composites using the Gradual Multi-Fiber Fragmentation Test (단계적 다섬유 Fragmentation 시험법을 이용한 복합재료의 계면적 특성에 대한 새로운 평가방법)

  • ;;Koichi Goda
    • Composites Research
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    • v.12 no.2
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    • pp.10-25
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    • 1999
  • A new evaluation method for the interfacial properties of fibrous composites based on a fragmentation technique is proposed by using the gradual multi-fiber composite, in which the inter-fiber spacing is gradually changed. The results showed that as the inter-fiber distance increased, the aspect ratio of broken fibers decreased while the interfacial shear strength between the fiber and matrix increased. When the reciprocal of the inter-fiber destance was taken for the above relations, both the aspect ratio and interfacial shear strength showed a saturated value. This means that the gradual multi-fiber composite indicates an upper bound in aspect ratio and an upper bound in interfacial shear strength. It was concluded that this fragmentation test could be a new method for composite evaluation, since reducing a difference between these two bounds is effective for composite strengthening. In addition an elastoplastic finite element analysis was carried out to relate the above results with fiber stress a distribution around fiber breaks. It was proved that the bound obtained in the gradual multi-fiber composite test is closely related to stress concentrations caused by a group of multi-fiber breaks.

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An Experimental Study on the Development of Hybrid Discontinuous Fiber Reinforced Cementitious Composite (하이브리드형 단섬유보강 시멘트복합재료의 개발에 관한 실험적 연구)

  • 김영덕;조봉석;김재환;김용로;윤현도;김무한
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2003.05a
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    • pp.57-60
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    • 2003
  • Generally, normal concrete has the disadvantages of low tensile strength, low ductility and volume instability. To improve its performance, fiber reinforced cimentitious composite(FRCC) have been development. These composites are composed of cement, sand, water, a small amount of admixtures, and an optimal amount of fiber like synthetic fiber and steel fiber. This research investigates influence of sand, hybrid fiber and fiber volume fraction, and reports the test results of mechanical properties, fracture behavior and failure pattern of the FRCC. Our experiment was observed that sand mixed FRCC has lower compressive strength and higher bending strength than no sand mixed FRCC, and more steel fiber mixed FRCC has higher compressive strength and bending strength. Hybrid FRCC of steel and polypropylene had superior properties than FRCC of polypropylene only in same fiber volume fraction.

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Thermal Conductivity and Thermal Expansion Behavior of Pseudo-Unidirectional and 2-Directional Quasi-Carbon Fiber/Phenolic Composites

  • Cho, Donghwan;Choi, Yusong;Park, Jong Kyoo;Lee, Jinyong;Yoon, Byung Il;Lim, Yun Soo
    • Fibers and Polymers
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    • v.5 no.1
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    • pp.31-38
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    • 2004
  • In the present paper, a variety of fiber reinforcements, for instance, stabilized OXI-PAN fibers, quasi-carbon fibers, commercial carbon fibers, and their woven fabric forms, have been utilized to fabricate pseudo-unidirectional (pseudo-UD) and 2-directional (2D) phenolic matrix composites using a compression molding method. Prior to fabricating quasi-carbon fiber/phenolic (QC/P) composites, stabilized OXI-PAN fibers and fabrics were heat-treated under low temperature carbonization processes to prepare quasi-carbon fibers and fabrics. The thermal conductivity and thermal expansion/contraction behavior of QC/P composites have been investigated and compared with those of carbon fiber/phenolic (C/P) and stabilized fiber/phenolic composites. Also, the chemical compositions of the fibers used have been characterized. The results suggest that use of proper quasi-carbonization process may control effectively not only the chemical compositions of resulting quasi-carbon fibers but also the thermal conductivity and thermal expansion behavior of quasi-carbon fibers/phenolic composites in the intermediate range between stabilized PAN fiber- and carbon fiber-reinforced phenolic composites.

Structural Evaluation of Glass-fiber Reinforced 3-Layer Polymer Composite Pipe (GFRP 보강 폴리머 모르터 3중복합관의 구조적 특성)

  • Yeon, Kyu-Seok;Kwon, Yoon-Hwan;Ryu, Keun-Woo;Jin, Nan-Ji
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 2001.10a
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    • pp.147-151
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    • 2001
  • This study was performed to evaluate the internal and external factors affecting external strength of the 3-layer polymer composite pipes made of polymer mortar and fiber-glass reinforced plastic. Twenty four sandwich type 3-layer polymer composite pipes were made of polymer mortar and fiber-glass reinforced plastic by centrifugal method. The objective of this study was to evaluate the effects the of polymer mortar thickness for and core fiber-glass contents per unit area on external strength of 3-layer polymer composite pipes. For the more economical and practical design of 3-layer polymer composite pipe, further study should be done for the various polymer mortar, fiber-glass and different ratio of the inside/outside FRP thickness.

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Investigation on Mechanical Properties of Natural-Fiber Composite Manufactured using VARTM Method (VARTM 공법으로 제작된 자연섬유 복합재료의 기계적 특성 분석)

  • Park, Hyunbum
    • Journal of Aerospace System Engineering
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    • v.10 no.3
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    • pp.59-62
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    • 2016
  • In this study, an investigation was performed on the mechanical properties of the natural-fiber-composite structure. The specimen was manufactured using the Vacuum Assisted Resin Transfer Molding (VARTM) method. The flax-fiber materials were adopted for the natural fiber composite, and vinyl-ester resin was also adopted. After a manufactured specimen was obtained, a mechanical test was carried out. The mechanical properties of the experiment results were compared with those of the natural-composite data cited from a number of other references.

Repair and Retrofit System of Concrete Structures using Fiber Glass and Epoxy Composite Sheets, Improved Through Utilization of Silica fume and Mechanical Saturator (실리카흄과 현장기계함침을 이용한 유리섬유 복합재(CAF)의 콘크리트 구조물 보수보강공법)

  • 유용하;권성준
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.10a
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    • pp.785-792
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    • 2000
  • Repair and retrofit system of concrete structures has been developed from conventional reinforced concrete overlaying, steel plate bonding and recently to fiber composite systems. Research and study on carbon, aramid, and glass fiber composite system has been actively carried out from all over the world Glass fiber composite is proved to be competitive technically and enconomically, among fiber composite system. CAF system is a system developed locally using all domestic materal, glass fabric and epoxy, and improved in shear bonding property by utilizing silica fume mixed with epoxy. All the tests on material properties, structural behavior, constructiveness at site and quality control procedure proved to be most appropriate system so far developed. Futher research work is and will be under progress for utilization of this system which will be applied to more adverse situation.

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Binary Mixture Rule for Predicting the Dielectric Properties of Unidirectional E-glass/Epoxy Composite Materials (일방향 유리섬유/에폭시 복합재료의 유전성질 예측을 위한 혼합법칙)

  • Chin Woo Seok;Lee Dai Gil
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2004.10a
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    • pp.175-179
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    • 2004
  • Since the electromagnetic properties of fiber reinforced polymeric composites can be tailored effectively by adding small amount of electromagnetic powders to the matrix of composites, they are plausible materials for fabricating the radar absorbing structures (RAS) of desired performance. In order to design the effective electromagnetic wave (EM) absorber with the fiber reinforced polymeric composites, the electromagnetic characteristics with respect to the constituents of the composite should be available in the target frequency band. In order to describe the dielectric behavior of low loss unidirectional fiber reinforced composite, theoretical models and mixture equations for estimating its dielectric constant were proposed with respect to the fiber, matrix volume fractions and fiber orientations, and verified by the experiments. From the investigation, it was found that the suggested binary mixture rules agreed well with the experimental results.

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Structural Behavior of Glass-Fiber Reinforced Plastic Composite Pipes (유리섬유 강화플라스틱 복합관의 구조적 특성)

  • 연규석;김남길;조규우;김동준;최종윤;백종만
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.05a
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    • pp.822-827
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    • 2003
  • This study was performed to evaluate the internal and external factors affecting external strength of the 3-layer polymer composite pipes made of polymer mortar and fiber-glass reinforced plastic. Twenty four sandwich type 3-layer polymer composite pipes were made of polymer mortar and fiber-glass reinforced plastic by centrifugal method. The objective of this study was to evaluate the effects the of polymer mortar thickness for and core fiber-glass contents per unit area on external strength of 3-layer polymer composite pipes. For the more economical and practical design of 3-layer polymer composite pipe, further study should be done for the various polymer mortar, fiber-glass and different ratio of the inside/outside FRP thickness.

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An Improvement of Optical Fiber Composite Power Cable On-Line Monitoring System for Underground Distribution Network (지중 배전계통 적용을 위한 광복합 케이블 실시간 감시시스템 개선)

  • Cho, Jin-Tae;Kim, Ju-Yong;Lee, Hak-Ju;Park, Jung-Sung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.7
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    • pp.77-83
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    • 2012
  • Since power system is switching to smart grid, on-line monitoring technology has become necessary for underground distribution power cable. Therefore, the application of DTS(Distributed Temperature Sensing) technology using OFCPC(Optical Fiber Composite Power Cable) capable of monitoring underground distribution power cables has been developed. These can bring about reductions in faults and increases in operating capacity of underground distribution system. To date, the test-bed of optical fiber composite power cable on-line monitoring system has been constructed. Then, matters to be improved have been drawn through verification experiments. This paper presents the improvement and experiment results of the optical fiber composite power cable on-line monitoring system to apply to underground distribution lines in the field.

Study on Manufacture of Korean Paper(Hanji) Sludge-Wood Fiber Composite Boards I. Physical Properties of Korean Paper(Hanji) Sludge-Wood Fiber Composite Boards (한지슬러지-목재섬유 복합보드의 제조연구 I. 한지슬러지-목재섬유 복합보드의 물리적 성질)

  • Lee, Phil-Woo;Lee, Hak-Lae
    • Journal of the Korean Wood Science and Technology
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    • v.27 no.2
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    • pp.23-30
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    • 1999
  • This study was carried out to develop the Korean paper(Hanji) sludge-wood fiber composite boards utilizing the relinquished sludges occurring from the making process of Korean classic paper Hanji. The bark of paper mulberry(Broussonetia kazinoki Sieb.) has been used as a raw material since past hundreds and thousands years. Korean paper(Hanji) sludge was divided into two kinds, the one was the white sludge from the first stage and the other was the black sludge occurring from the final stage of Korean paper(Hanji) making. Four levels of the mixed ratio of each white or black sludge to wood fiber(10:90, 20:80, 30:70 and 40:60), three levels of the resin adhesives(PMDI, urea and phenol resin) and three levels of the density(0.60, 0.75 and 0.90) were designed to investigate the physical properties of Korean paper(Hanji) sludge-wood fiber composite boards. From the results and discussion, it could be concluded as follows : 1. In the white sludge-wood fiber composite board, the thickness swelling was not affected by the specific gravity and sludge additive of composite boards, but among the resin adhesives PMDI resin showed the best dimensional stability. Water absorption was superior in urea resin, secondly PMDI resin and very poor in phenol resin. 2. In the black sludge-wood fiber composite board, thickness swelling was superior in PMDI resin but very poor in phenol resin. In water absorption, PMDI and urea resin showed good results, regardless of specific gravity or sludge additive, but phenol resin showed poor results. 3. From the results and discussion of physical properties it is suggested that the white sludge-wood fiber composite boards bonded with PMDI or black sludge-wood fiber composite boards bonded with urea resin were made possibly with similar or better properties. compared with general fiberboard until the addition of 20% sludge into wood fiber.

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