• Title/Summary/Keyword: 섬유강화유리플라스틱

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Strength Characteristics and Non-Destructive Evaluation of Composites with Heat Damage (국부열손상을 받은 복합재료의 강도특성 및 비파괴평가)

  • Nam, Ki-Woo;Kim, Young-Un
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2002.05a
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    • pp.173-178
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    • 2002
  • Fourier transform has been one of the most common tools to study the frequency characteristics of signals. With the Fourier transform alone, it is difficult to tell whether signal's frequency contents evolve in time or not. Except for a few special cases, the frequency contents of most signals encountered in the real world change with time. Time-frequency methods are developed recently to overcome the drawbacks of Fourier transform, which can represent the information of signals in time and frequency at the same time. In this study, heat damage process of a carbon fiber reinforced plastic(CFRP) and glass fiber reinforced plastic(GFRP) under monotonic tensile loading was characterized by acoustic emission. Different kinds of specimens were used to determine the characteristics of Strength and AE signals. Time-frequency analysis methods were employed for the analysis of fracture mechanism in CFRP such as matrix cracking, debonding and fiber fracture.

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A Study on the Structural Design of Effective Composite Joint and Light Weight in Body Floor (Body Floor의 복합재 접합방식 및 경량화 설계에 관한 연구)

  • Kim, Hong Gun;Oh, Sang Yeob;Kim, Kwang Choul;Kim, Hyun Woo;Kwac, Lee Ku
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.6
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    • pp.920-925
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    • 2012
  • A study of vehicle weight lightening has been progressed to reduce the fuel consumption. In this paper, the body floor in an EV (Electric Vehicle) bus has been applied by composites as CFRP and GFRP. In order to analyse a various reliability and safety, an experiment and FEM analysis was carried out to obtain weight lightening. Especially, the joint. An effective design is obtained through an experiment as well as FEM analysis. Results of stress analysis of GFRP material showed twice as much displacement than those of CFRP material. Among three kinds of joint methods, the bond joint method is occurred to a substantial shape change in the body and floor. It is found that the rivet joints are fairly suitable for stress sustaining capability.

Strength toss of F-Fiber Obtained from Recycling FRP Ship in a Basic Solution (폐 FRP 선박에서 분리하여 얻은 F섬유의 염기성 용액에서의 강도저하)

  • Lee, Seung-Hee;Kim, Yong-Seop;Yoon, Koo-Young
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.11 no.1
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    • pp.42-45
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    • 2008
  • It has been reported that FRP (fiber reinforced plastic) can be recycled by separating into layers instead of crushing into powder. F-fiber obtained from roving layer separated from FRP, has bigger tensile strength than the bundle of glass fibers of which FRP was made (more than 90%). SEM image of F-fiber shows the presence of some resin. Under the proposition of usage of F-fiber in the concrete material, tensile strength is examined after soaking in a basic solution (NaOH+KOH). The reaction mechanism of strength loss may be considered as an attack of hydroxide ion ($OH^-$) on a chemical bond of Si-O-Si of glass fiber. The simulation graph of the strength loss data implies certain reaction mechanism. While in the early stage kinetically controlled reaction results in a fast drop of tensile strength, after 30 days dispersion rate of hydroxide ion plays a major role in strength loss. This result is similar to the one for the AR glass. An extrapolation of the graph would make an assumption about the lift time of F-fiber possible.

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Structural Changes of Nylon 6/Clay Nanocomposite Film on Drawing Condition (Nylon 6/Clay 나노복합재 필름의 연신조건에 따른 구조적 변화)

  • 강영아;김경효;이양헌;조현혹
    • Proceedings of the Korean Fiber Society Conference
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    • 2003.04a
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    • pp.352-353
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    • 2003
  • Clay 분산 유/무기 나노복합재 제조기술은 실리케이트 층상구조의 점토광물을 나노 스케일의 시트상의 기본 단위로 박리(exfoliation)하여 고분자수지에 분산시킴으로써 범용 고분자의 낮은 기계적 물성의 한계를 엔지니어링 플라스틱 수준으로까지 올리고자 하는 것으로서, 기존의 무기 충진재 및 강화재의 입자크기(〉1 $\mu\textrm{m}$)를 나노 스케일까지 분산시켜 기존 무기물 충진 복합재의 단점을 한층 보완하는 것을 목표로 하고 있어 성능 및 원가 면에서 매우 유리한 방법으로 21세기의 복합재료 생산시장의 판도에 상당한 변화를 가져오게 할 수 있는 핵심기술이라 할 수 있다. (중략)

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Bending Strength of FRP According to the Winding Orientation of Glass Fiber (와인딩 각도에 따른 FRP의 굽힘강도)

  • Park, Hoy-Yul;Kang, Dong-Pil;Han, Dong-Hee;Kim, In-Sung;Pyo, Hyun-Dong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.05b
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    • pp.242-245
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    • 2000
  • The fiber contributes the high strength and modulus to the composite. The fiber orientation in FRP has a great effect on the strength of FRP because the strength of FRP mainly depends on the strength of fiber. In this study, FRP was made unidirectionally by pultrusion method and outer part of FRP was made by filament winding method to give fiber orientation to the FRP. The bending strength and bending stresses of FRP rods were simulated according to the winding orientation of glass fiber. The bending strength of FRP was also evaluated. The results of simulation and evaluation Were compared each other to investigate main stresses which affect the fracture of FRP. The main stresses which had a great effect on the strength of FRP were shear stresses.

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A Study For The Simple Method In Dividing The Layers of Fiber-reinforced Plastic (폐 FRP선박의 재활용공정에서 용이한 면포추출공정을 위한 화학적 처리 방법에 관한 연구)

  • Lee, Seung-Hee;Kim, Yong-Seop;Yoon, Koo-Young
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.13 no.1
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    • pp.43-46
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    • 2010
  • As one of the methods for recycling the FRP used for the small and medium-sized waste ships, separation of the roving layer from the mat has some merit in a sense of the recycling energy and the environmental effects. Similar characteristics between the roving and the mat make the mechanically automatic differentiation difficult. They, however, contain different ratio of the resin and the glass and the thickness. In this study photo physical differentiation between the two layers has been made using (1) boiling concentrated sulfuric acid which can dissolve the resin in the FRP layer and (2) hydrogen fluoride(HF) solution which can reacts with $SiO_2$ fragments of the glass. Furthermore coloring the FRP sample with water-soluble dye following the HF treatment makes the roving layer more distinguishable photophysically. The implementation of HF treatment has been successfully tested in this study.

A Study on Stress Corrosion Cracking of Fiber Reinforced Composite by Slow Strain Rate Test (저변형률시험법에 의한 섬유강화 복합재료의 응력부식균열에 관한 연구)

  • Lim, Jae-Gyu;Choi, Tae-Su
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.11
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    • pp.3433-3440
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    • 1996
  • This paper was investigation of the stres corrosion cracking(SCC) mechanism and the properties of corrosion fracture surface of glass fiber reinforced plastics(GFRP) produced by hand lay up(HLU) method in synthetic sea water. Test material is GFRP, that was used vinylester type epoxy acrylate resin and an unsaturated polyester as the matrix and the chopped strand mat(CSM) type E-glss fiber as the reinforcement. The slow strain rate test(SSRT) was performed on dry, wet and saturated wet specimens in sea water. Here the pH concentration of synthetic sea water was 8.2 and the strain rate is 1 x $10^{-6}$($sec^{-1}$) and test temperature ranges varied from $-60^{\circ}C$ to $80^{\circ}C$. It could be confirmed the fact that wet specimens tested at a particular test temperature ranges were appeared the eviences of SCC such as con-planar, mirror and hackle zone. Moreover, SCC of GFRP in sea water was characterised by falt fracture surfaces with only small amounts of fiber pull-out, in partial.

Self-Diagnosis for Fracture Prediction of Concrete Reinforced by New Type Rib CFGFRP Rod and CF Sheet (신형 리브재 CFGFRP 보강근 및 CF 보강시트로 보강된 콘크리트의 파괴예측 자가진단)

  • Park, Seok-Kyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.2
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    • pp.115-123
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    • 2007
  • For investigating self-diagnosis applicability, a method based on monitoring the changes in the electrical resistance of carbon fiber reinforced concrete has been tested. Then after examining change in the value of electrical resistance at each flexural weight-stage of carbon fiber in CFGFRP (carbon fiber and glass fiber reinforcing plastic) with new type rib and carbon sheet for concrete reinforcing, the correlations of electrical resistance and load as a function of strain, deflection were analyzed. As the results, it is clarified that when carbon fiber rod, rib and sheet fracture, the electrical resistance of it increase largely, and specially in case of CFGFRP, afterwards glass fiber tows can be resist the load due to the presence of the hybrid (carbon and glass) reinforced fiber. Therefore, it can be recognized that reinforcing bar and new type rib of CFGFRP and sheet of CF could be applied for self-diagnosis of fracture in reinforced FRP concrete.

Prediction of Spring Rate and Initial Failure Load due to Material Properties of Composite Leaf Spring (복합재 판스프링의 재료특성에 따른 스프링 강성변화와 초기 파단하중 예측)

  • Oh, Sung Ha;Choi, Bok Lok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.38 no.12
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    • pp.1345-1350
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    • 2014
  • This paper presented analysis methods for adapting E-glass fiber/epoxy composite (GFRP) materials to an automotive leaf spring. It focused on the static behaviors of the leaf spring due to the material composition and its fiber orientation. The material properties of the GFRP composite were directly measured based on the ASTM standard test. A reverse implementation was performed to obtain the complete set of in-situ fiber and matrix properties from the ply test results. Next, the spring rates of the composite leaf spring were examined according to the variation of material parameters such as the fiber angles and resin contents of the composite material. Finally, progressive failure analysis was conducted to identify the initial failure load by means of an elastic stress analysis and specific damage criteria. As a result, it was found that damage first occurred along the edge of the leaf spring owing to the shear stresses.

Low Cycle Fatigue Life Behavior of GFRP Coated Aluminum Plates According to Layup Number (적층수에 따른 GFRP 피막 Al 평활재의 저주기 피로수명 평가)

  • Myung, Nohjun;Seo, Jihye;Lee, Eunkyun;Choi, Nak-Sam
    • Composites Research
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    • v.31 no.6
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    • pp.332-339
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    • 2018
  • Fiber metal hybrid laminate (FML) can be used as an economic material with superior mechanical properties and light weight than conventional metal by bonding of metal and FRP. However, there are disadvantages that it is difficult to predict fracture behavior because of the large difference in properties depending on the type of fiber and lamination conditions. In this paper, we study the failure behavior of hybrid materials with laminated glass fiber reinforced plastics (GFRP, GEP118, woven type) in Al6061-T6 alloy. The Al alloys were coated with GFRP 1, 3, and 5 layers, and fracture behavior was analyzed by using a static test and a low cycle fatigue test. In the low cycle fatigue test, strain - life analysis and the total strain energy density method were used to analyze and predict the fatigue life. The Al alloy did not have tensile properties strengthening effect due to the GFRP coating. The fatigue hysteresis geometry followed the behavior of the Al alloy, the base material, regardless of the GFRP coating and number of coatings. As a result of the low cycle fatigue test, the fatigue strength was increased by the coating of GFRP, but it did not increase proportionally with the number of GFRP layers.