• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 추계학술대회 논문집
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• pp.809-810
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• 2012

• 한국강구조학회 논문집
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• 제26권2호
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• pp.69-79
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• 2014

본 연구에서는 콘크리트 섬유보강플라스틱(FRP)로 보강된 철골보의 정적 휨하중상태에서 휨거동에 관한 실험결과를 제시하였다. 아라미드섬유 스트립과 탄소섬유 스트립으로 보강된 4개의 실험체를 제작하였으며, 1개의 기준실험체를 제작하였다. 이중 두 실험체는 부분보강방식으로 보강되었다. H빔은 두 종류의 파괴모드를 가지고 있는데, (1) 부분보강 실험체에서는 FRP 스트립이 탈락(debonding)되는 파괴모드를 보이고 있으며, 전면보강 실험체에서는 FRP 스트립이 파단(rupture)되는 거동을 보이고 있다. 실험결과 16%의 휨내력 상승효과를 관찰하였다.

• 복합신소재구조학회 논문집
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• 제4권2호
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• pp.1-7
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• 2013

In recent years, fiber reinforced polymer plastic composites are readily available in the construction industry. Fiber reinforced polymer composite has many advantages such as high specific strength and high specific stiffness, high corrosion resistance, light-weight, magnetic transparency, etc. In this paper, we present the result of investigation pertaining to the flexural behavior of flange strengthened I-shape pultruded fiber reinforced polymer plastic (PFRP) member using carbon fiber sheet (CFRP sheet). Test variable is consisted of the number of layers of strengthening CFRP sheet from 0 to 3. From the experimental results, flexural strengthening effect of flange strengthened I-shape PFRP member using CFRP sheet is evaluated and it was found that 2 layers of strengthening CFRP sheet are appropriate considering efficiency and workability.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 추계학술발표대회 논문집
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• pp.153-157
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• 2001

Interfacial properties and microfailure modes of electrodeposition (ED) treated carbon fiber reinforced polyetherimide (PEI) toughened epoxy composite were investigated using microdroplet test and the measurement of surface wettability. As PEI content increased, Interfacial shear strength (IFSS) increased due to enhanced toughness and plastic deformation of PEI. In the untreated case, IFSS increased with adding PEI content, and IFSS of pure PEI matrix showed the highest. On the other hand, for ED-treated case IFSS increased with PEI content with rather low improvement rate. The work of adhesion between fiber and matrix was not directly proportional to IFSS for both the untreated and ED-treated cases. The matrix toughness might contribute to IFSS more likely than the surface wettability. Interfacial properties of epoxy-PEI composite can be affected efficiently by both the control of matrix toughness and ED treatment.

• 한국기계가공학회지
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• 제21권5호
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• pp.77-83
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• 2022

A high-hardness tool material is required to reduce extreme abrasive wear when drilling carbon fiber reinforced plastic (CFRP). Single-crystal diamond is the hardest material in the world, but it is very expensive to be used as a cutting tool. Polycrystalline diamond (PCD) is a diamond grit fused at a high temperature and pressure, and diamond-like carbon (DLC) is an amorphous carbon with high hardness. This study compares DLC coatings and PCD inserts to conventional TiAlN-coated tungsten carbide drills. In fiberglass and carbon fiber reinforced polymer drilling, the tool wear of DLC-coated carbide was approximately half that of TiAlN-coated tools, and slight tool wear occurred in the case of PCD insert end drills.

• Computers and Concrete
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• 제33권4호
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• pp.385-398
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• 2024

As concrete dominates the construction industry, alternatives to traditionally used steel reinforcement are being sought. This study explored the suitability of carbon fiber-reinforced polymer (CFRP) as a substitute within rigid frames, focusing on its impact on section ductility and overall structural durability against seismic events. However, current design guidelines address quasi-static loads, leaving a gap for dynamic or extreme circumstances. Our approach included multiscale simulations, parametric study, and energy dissipation analyses, drawing upon a unique adaptation of modified compression field theory. In our efforts to optimize macro and microparameters to improve yield strength, manage brittleness, and govern failure modes, we also recognized the potential of CFRP's high corrosion resistance. This characteristic of CFRP could significantly reduce the frequency of required repairs, thereby contributing to enhanced durability of the structures. The research reveals that CFRP's durability and seismic resistance are attributed to plastic joints within compressed fibers. Notably, CFRP can impart ductility to structural designs, effectively balancing its inherent brittleness, particularly when integrated with quasi-brittle materials. This research challenges the notion that designing bendable components with carbon fiber reinforcement is impractical. It shows that creating ductile bending components with CFRP in concrete is feasible despite the material's brittleness. This funding overturns conventional assumptions and opens new avenues for using CFRP in structural applications where ductility and resilience are crucial.

• 한국소음진동공학회논문집
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• 제26권4호
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• pp.375-382
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• 2016

The mechanical property of a carbon-fiber-reinforced plastic (CFRP) is subjected to two elements, carbon fiber and polymer resin, in a first step and the selection of multi-layered structure is second one. Many combination of fabric layers, i.e. plainweave, twillweave, can be derived for candidates of test specimen used for a basic mechanical components so that a reliable identification of dynamic nature of possible multi-layered structures are essential during the development of CFRP based component system. In this paper, three kinds of multi-layered structure specimens were prepared and the dynamic characteristics of service specimens were conducted through classical modal test process with impact hammer. In addition, the design sensitivity analysis based on transmissibility function was applied for the measured response data so that the response sensitivity for each resonance frequency were compared for three CFRP test specimens. Finally, the evaluation of CFRP specimen over different multi-layered fabric structures are commented from the experimental consequences.

• 한국농공학회지
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• 제45권2호
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• pp.58-67
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• 2003

Over the last decade fiber-reinforced polymer (FRP) reinforcement consisting of glass, carbon, or aramid fibers embedded in a resin such as vinyl ester, epoxy, or polyester has emerged as one of the most promising and affordable solutions to the corrosion problems of steel reinforcement in structural concrete. But reinforcing rebar for concrete made of FRP rebar has linear elastic behavior up to tensile failure. For safety a certain plastic strain and an elongation greater than 3% at maximum load is usually required for steel reinforcement in concrete structures. The same should be required for FRP rebar. Thus, the main object of this study was to develop new type of hybrid FRP rebar Also, this study was evaluated to the mechanical properties of Hybrid FRP rebar. The Manufacture of the hybrid FRP rebar was achieved by pultrusion, and braiding and filament winding techniques. Tensile and interlaminar shear test results of Hybrid FRP rebar can provide its excellent tensile strength-strain behavior and interlaminar stress-strain behavior.

• Advanced Composite Materials
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• 제18권3호
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• pp.251-264
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• 2009

Nonlinear mechanical behaviors of unidirectional carbon fiber-reinforced plastic (CFRP) laminates using cup-stacked carbon nanotubes (CSCNTs) dispersed epoxy are evaluated and compared with those of CFRP laminates without CSCNTs. Off-axis compression tests are performed to obtain the stress-strain relations. One-parameter plasticity model is applied to characterize the nonlinear response of unidirectional laminates, and nonlinear behaviors of laminates with and without CSCNTs are compared. Clear improvement in stiffness of off-axis specimens by using CSCNTs is demonstrated, which is considered to contribute the enhancement of the longitudinal compressive strength of unidirectional laminates and compressive strength of multidirectional laminates. Finally, longitudinal compressive strengths are predicted based on a kink band model including the nonlinear responses in order to demonstrate the improvement in longitudinal strength of CFRP by dispersing CSCNTs.

• Composites Research
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• 제35권2호
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• pp.115-119
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• 2022

탄소섬유의 성능은 탄소 섬유 강화 플라스틱(CFRP)과 같은 고품질 고분자 복합재료에 매우 중요하다. 이를 위해 탄소섬유 물성에 큰 영향을 주는 전구체 섬유의 기계적, 물리적, 구조적 특성을 개선할 수 있는 최적화된 방사공정과 이를 위한 적합한 전구체 공중합 고분자를 사용하는 것은 필수적이다. 본 연구에서는 메타크릴산(MAA)의 함량과 주입시간, 2,2'-아조비스(2-메틸프로피오니트릴) (AIBN)의 농도를 합성공정 변수로 설정하였으며, 용액 중합법(solution polymerization)에 의해 Poly(AN-co-MAA)가 합성되었다. 305,138 g/mol의 분자량과 4.2%의 MAA 비율을 가지는 Poly(AN-co-MAA)를 N,N-디메틸포름아미드(DMF)에 16.0 wt% 농도로 용해시킨 후 기격습식방사법(dry-jet-wet spinning)으로 전구체 섬유를 제조하였다. 섬유의 인장강도는 ~1.06 GPa, 인장탄성률은 ~22.01 GPa였으며, 섬유에서의 공극 및 구조적 결함은 관찰되지 않았다.