• Title/Summary/Keyword: Fiber glass reinforced plastics(FRP)

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A Comparative Study on the Shear-Strengthening Effect of RC Beams Strengthened by FRP (FRP로 보강된 RC보의 전단보강효과 비교연구)

  • 심종성;김규선
    • Magazine of the Korea Concrete Institute
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    • v.10 no.4
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    • pp.101-111
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    • 1998
  • This study presents test results of RC beams strengthened by carbon fiber sheet(CFS), carbon fiber reinforced plastics(CFRP) or glass fiber reinforced plastics(GFRP) for increasing shear resistance. Nineteen specimens were tested, and the test was performed with different parameters including the type of strengthening materials(CFS, GFRP, CFRP), shear-strengthening methods(wing type, jacket type, strip type), strip-spacing, strengthening direction of FRP. The test results show that shear-damaged RC beams strengthened by FRP(CFS, GFRP, CFRP) have more improved the shear capacity. The mathematical model based on plastic theory was also developed to predict shear strength of shear-damaged RC beams strengthened by FRP. The predictions using the mathematical model. are agreed with the observations from the observed shear strengths for 19 test beams.

Tribological Characteristics of Fiber-Reinforced Plastics(FRP) (섬유강화복합재의 Tribological 특성에 관한 연구)

  • 성인하;여인완;김대은
    • Tribology and Lubricants
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    • v.12 no.1
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    • pp.6-14
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    • 1996
  • Experimental investigation on the tribological behavior of fiber-reinforced plastics(FRP) has been studied. It is shown that the frictional behavior of carbon FRP depends on the fiber-orientation while glass FRP does not. The friction coefficient values for carbon FRP were about 0.8, 0.3, and 0.2 for normal, 45$^{\circ}$ and 0$^{\circ}$ sliding directions respectively. Also, the applied load was found to affect the friction coefficient. In the case of this work, 50 gf resulted in the highest value while 200 gf resulted in the lowest value. The friction coefficients for higher loads fell in between the two extreme values.

Correlation between Probe Frequency and Echo-Pulse Velocity for Ultrasonic Testing of a Fiber-Reinforced Plastic Hull Plate (복합소재 선체 외판의 초음파 탐상을 위한 탐촉자 주파수와 수신기 음향 속력의 상관관계)

  • Lee, Sang-gyu;Han, Zhiqiang;Lee, Chang-woo;Oh, Daekyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.26 no.2
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    • pp.219-226
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    • 2020
  • Nondestructive testing is one of the most commonly used quality inspection methods for evaluating ship structures. However, accurate evaluation is dif icult because various composite materials, such as reinforcements, resin, and fiber-reinforced plastics (FRPs), are used in hulls, and manufacturing quality differences are likely to exist owing to the fabrication environment and the skill level of workers. This possibility is especially true for FRP ships because they are significantly thicker than other structures, such as automobiles and aircraft, and are mainly manufactured using the hand lay-up method. Because the density of a material is a critical condition for ultrasonic inspection, in this study, a hull plate was selected from a vessel manufactured using e-glass fiber, which is widely used in the manufacture of FRP vessels with the weight fraction of the glass content generally considered. The most suitable ultrasonic testing conditions for the glass FRP hull plate were investigated using a pulse-echo ultrasonic gauge. A-scans were performed with three probes (1.00, 2.25, and 5.00 MHz), and the results were compared with those of the hull plate thickness measured using a Vernier caliper. It was found that when the probe frequency was higher, the eco-pulse velocity of the receiver had to be lowered to obtain accurate measurement results, whereas fewer errors occurred at a relatively low probe frequency.

Developing a Study on the Extracting Method of Laminated Glass Fiber from FRP Boats (폐FRP 선박으로부터 섬유보강재 추출공정 개선 연구)

  • Yoon, Koo-Young
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.12 no.1
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    • pp.23-28
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    • 2009
  • There is several ways of recycling methods for waste FRP boats. The main one is mechanical recycling that is one of the simple and technically proven methods. It recently has been reported that FRP can be recycled by separating into laminated glass fiber layers instead of crushing into powder. Even though the mechanical recycling is a good way for the eligibility of laminated glass fiber reinforced material, the system should have another option which can collect resin of FRP. Because the resin is still very useful renewable energy source, that cannot be discarded, But FRP is made up of laminated glass fiber(roving cloth layer) which is fire retardant substances and very hard to break into each layer. Due to the high cost of fossil energy the waste plastics should be regenerated to the source of renewable energy. Laminated glass fiber which is recyclable in a very limited way, is currently a serious barrier to waste FRP boat regenerating. This study is to propose a new extracting method which is efficient and environment friendly FRP waste regenerating system. The recycled glass fiber which is obtained by the separation of the roving layer from FRP waste has been found to be useful for concrete(FRC) products or concrete(FRC) structures as fiber reinforced material. And it can be successively applied to renewable energy applications using the waste resins of FRP residue without laminated glass fiber.

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A Study on the Mechanical Characteristics of Ho1low Type Glass Fiber Reinforced Plastics Re-bar (중공형 GFRP리바의 기계적 특성에 관한 연구)

  • 한길영;이동기;오환교;홍석주;신용욱;배시연
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2000.10a
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    • pp.7-11
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    • 2000
  • In this paper was studied on the mechanical characteristics of Glass Fiber Reinforced Plastics(GFRP) of the steel bar it is to replace. The advantage of FRP such as high strength, low weight and chemical inertness or noncorrosiveness can be fully exploited. GFRP bar were successfully fabricated at l0mm nominal diameters of solid and hollow types using a pultrusion method. Tensile and bending specimens from this bar were tested and compared with behavior of GFRP rebar and steel bar.

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Analysis of EMF Mitigation Characteristic for Transmission Tower Using Compact Insulation Arm (Compact 절연암 송전 철탑의 전자계 저감특성 분석)

  • Song, Hong-Jun;Lee, Won-Kyo;Lee, Sang-Yun;Choi, In-Hyeok;Lee, Dong-Il;Byeon, Ki-Sik
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.2
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    • pp.349-355
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    • 2009
  • As electrical power demand is gradually increasing, the construction of power transmission facility is unavoidable. However difficulties which resulted from increasing of complaints and NYMBY make power transmission tower to be more environmentally friendly. As an alternative proposal, a new method which is changing conventional iron arm for insulation arm which is made of FRP(Fiber Glass Reinforced Plastics) is in progress. In this paper, we discussed environmentally friendly characteristic of domestic 154 kV testing transmission tower whose insulation arms have same mechanical and excellent electrical properties compare to conventional heavy iron arm.

Comparison of Machining Defects by Cutting Condition in Hybird FRP Drilling (유리탄소섬유 하이브리드 복합재의 절삭 조건에 따른 가공 결함 비교)

  • Baek, Jong-Hyun;Kim, Su-Jin
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.9
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    • pp.12-20
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    • 2022
  • Delamination and burr defects are important problems in drilling fiber reinforced plastics. A method for measuring FRP drilling defects has been studied. Delamination and burr factors were defined as the relative length or area. Using these factors, the effects of tool shape and drilling conditions on delamination and burr were studied. In this study, the defects that occur when drilling a glass-carbon fiber hybrid composite were compared in terms of three factors. In the glass-carbon fiber hybrid composite, the effects of the feed rate and tool point angle on the delamination and burr factors were similar to those in previous studies. The diameter of the tool did not affect the defect factor. A circular burr was generated in a drill tool with a point angle of 184°, and a relatively small deburring factor was observed compared with a tool with a point angle of 140°.

Developing Advanced Total Recycling Method of FRP Boats (FRP선박의 일괄 재처리 방법의 개선)

  • Lee, Seung Hee;Yoon, Koo Young
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.16 no.1
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    • pp.53-59
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    • 2013
  • Since 1990s, the major recycling methods for mechanical recycling of FRP(Fiber Reinforced Plastics)boats has involved shredding and grinding of the scrap FRP in a new recycled product. But still it leads to secondary problem such as air pollution, unacceptable shredding noise level and few limited applications. This study is to propose a newly advanced method which is more efficient and environment friendly waste FRP regenerating system. As extracting FRP layer and making the recycled fiber for recycled-fiber reinforced concrete(RFRC) from waste FRP, the recycling process has some merits in a sense of the recycling energy and the environmental effects. In this study, for those tasks, spectro-chemical differentiation method and coloring water-soluble dye treatment makes the roving layer more distinguishable photophysically. Also that has remarkably reduced safety hazards and energy. Using the mechanical properties of polymers and composite, FRP with the orthotropic and laminated plastic structure has been easily separated in the new extracting system. Also the new method has introduced five kind of separating manuals for the some different compositions of FRP boats. The roving fiber of laminated glass-fiber layer is as good as the polyvinyl fiber which is cost-high commercial fiber to increasing strength of concrete products. The early study has shown the effectiveness of laminated glass-fiber layer which also is chemical-resistant due to the resin coating. These results imply that more efficient and environment friendly recycled glass fiber can be better applied to the fiber reinforced concrete(FRC) substitute and this study also has shown wide concrete applications with RFRC from the waste FRP boat.

Effects of Heat Treatment on Electrical and Mechanical Properties of Glass Fiber Reinforced Epoxy (열처리가 유리섬유 강화 복합재료의 전기적 및 기계적 성질에 미치는 영향)

  • 이백수;이덕출
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.3
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    • pp.174-180
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    • 1998
  • In this work, the properties of FRP, which is applied recently in the composite insulating materials, by thermal treatment were investigated. The specimens were epoxy glass laminates fabricated by thermal press method and had the volume content of 46[%] cutted $45^{\circ}C$ in the fiber direction and 1.0[mm] thickness. The experimental results showed that the amount of weight loss, wettability, surface potential, and surface resistivity increased up to 200[$^{\circ}C$] as a function of temperature. Usually, most degradations caused the hydrophilic to decrease the contact angle. But, in this work on thermal-degradated FRP, we can confirm the introduction of hydrophobic properties by cross-linking and the ablation of polar small-molecules rather than chain scission and oxidation. Finally, weight loss and contact angle increased. These phenomena show the existence of hydrophobic surface. With the change to the hydrophobic surface and the electrical potential and resistivity on FRP surface increased. But, the dielectric properties and tensile stength are decreased.

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Evaluation of Fracture Detection Function for the FRP by Electrical Resistance Measurement (전기저항 측정에 의한 FRP의 파괴 예측 기능의 평가)

  • Sin, Sun-Gi;Kim, Yeong-Hui;Lee, Jun-Hui
    • Korean Journal of Materials Research
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    • v.12 no.2
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    • pp.135-139
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    • 2002
  • Carbon powders (CP) and carbon fiber (CF) were introduced info glass fiber reinforced plastics (FRP) composites to obtain fracture detection function. The composites were evaluated through the relation between a load-displacement curve and an electrical resistance change curve in three point bending test. CP containing FRP (CP-FRP) has a sensitivity of electrical resistance change at much lower load level than CF containing FRP (CF-FRP). In loading-unloading tests, CP-FRP showed a large amount of residual electrical resistance which enables the estimation of loading hysteresis.