• Title/Summary/Keyword: 복합재 튜브

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Processing - Interlaminar Shear Strength Relationship of Carbon Fiber Composites Reinforced with Carbon Nanotubes (탄소나노튜브로 보강된 탄소섬유복합재의 제조공정과 층간전단강도)

  • Kim, Han-Sang
    • Composites Research
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    • v.24 no.5
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    • pp.34-38
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    • 2011
  • Carbon nanotubes (CNTs) have been widely investigated as reinforcements of CNT/polymer nanocomposites to enhance mechanical and electrical properties of polymer matrices since their discovery in the early 90's. Furthermore, the number of studies about incorporating CNTs into carbon fiber reinforced plastics (CFRP) to reinforce their polymer matrices is increasing recently. In this study, single-walled carbon nanotubes (SWNT) were dispersed in epoxy with 0.2 wt.% and 0.5 wt.%. Then, the SWNT/epoxy mixtures were processed to carbon fiber composites by a vacuum assisted resin transfer molding (VARTM) and a wet lay up method. The processed composite samples were tested for the interlaminar shear strength (ILSS). The relationship between the interlaminar shear strengths and processing, and the reinforcement mechanism of carbon nanotubes were investigated. CNT/epoxy nanocomposite specimens showed the increased tensile properties. However, the ILSS of carbon fiber composites was not enhanced by reinforcing the matrix with CNTs because of processing issues caused by increased viscosity of the matrix due to addition of CNTs particularly for a VARTM method.

Defect Detection of Impacted Composite Tubes by Lock-in Photo-Infrared Thermography Technique (위상잠금 열화상기법을 이용한 복합재 튜브 충격 손상 결함 측정)

  • Kim, Kyoung-Suk;Jeon, So-Young;Jung, Hyun-Chul
    • Journal of the Korean Society for Nondestructive Testing
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    • v.31 no.2
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    • pp.139-143
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    • 2011
  • The problem of delamination of composite tubes by impact has been acknowledged in aerospace and automobile industry. Non-destructive testing(NDT) methods in composite material structure are important to evaluate reliability of composite structure. There are many kinds of NDT methods which can detect the inside defect of the composite material such as Infrared Thermography(IRT). Infrared thermal imaging of object is different from that of a defect, in heated composite tubes with an internal defect, and then location and size of a defect can be measured by the analysis of thermal imaging pattern. In this study, Lock-in Infrared thermography detect internal defects of Impacted composite tubes by the inspection of infrared lay radiated from the surface of composite tubes.

Bending and Torsional Characteristics of Rectangular CFRP Tubes with Various Aspect Ratios (다양한 형상비를 갖는 사각 CFRP 튜브의 굽힘 및 비틀림 특성)

  • Lee, Yongsung;Cheong, Seong-Kyun
    • Composites Research
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    • v.27 no.2
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    • pp.37-41
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    • 2014
  • Fiber reinforced composite materials have outstanding specific strength and specific stiffness. So the use of composite materials increases in various kinds of industrial fields including sports goods such as bicycles. Composite materials are used to make structural parts with various kinds of shapes. Specially, rectangular composite tubes are used to make a few of composite bicycle frames, but there has been a few of research on this issue. Rectangular composite tubes are designed to have appropriate radius of curvature and endure bending and torsional loads. In this research, nine kinds of rectangular composite tubes having aspect ratios 1:1, 1:1.5, 1:2 and radius of curvatures R5, R10, R15 were fabricated. The carbon fiber reinforced composite material was used to make tubes having same cross sectional areas. The stacking sequence of tubes is $[0/90/{\pm}45]s$. Experimental evaluation was accomplished to apply bending and torsional load to the tubes. Experimental results show that bending and torsional characteristics depend on radius of curvature and aspect ratio of rectangular composite tubes.

Effect of Fluorination of Carbon Nanotubes on Physico-chemical and EMI Shielding Properties of Polymer Composites (고분자 복합재의 물리화학적 및 전자파차폐 특성에 미치는 탄소나노튜브의 불소화 영향)

  • Lee, Si-Eun;Kim, Doyoung;Lee, Man Young;Lee, Min-Kyung;Jeong, Euigyung;Lee, Young-Seak
    • Polymer(Korea)
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    • v.39 no.1
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    • pp.114-121
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    • 2015
  • Mutli-walled carbon nanotubes (MWCNTs) were surface-modified by a hydrofluoric acid solution to remove impurities and improve interfacial bonding and dispersion of nanotubes in an epoxy matrix. The crystallinity on the surface of treated MWCNTs was investigated by X-ray photoelectron spectroscopy and Raman spectroscopy. The mechanical properties were characterized by tensile test, and the enhancement of mechanical properties of the modified MWCNTs/epoxy composites was indicated by a 33% increase in tensile strength. The electromagnetic interference shielding effectiveness (EMI-SE) of modified MWCNTs/epoxy composites was improved with an increase in concentration of hydrofluoric solution, and EMI-SE showed the maximum increase with 25% HF. However, mechanical and EMI-SE properties didn't show further increase with over 50% HF concentration because the properties of MWCNTs were influenced by degradation of crystallinity and intrinsic properties of MWCNTs. The mechanical and electrical property enhancements of the polymer composites are attributed to the modification of MWCNTs which improve crystallinity of MWCNTs and dispersion in the epoxy resin.

Isogeometric Analysis of FG-CNTRC Plate in Bending based on Higher-order Shear Deformation Theory (탄소 나노튜브 보강 기능경사복합재 판의 등기하 거동 해석)

  • Jeon, Juntai
    • Journal of the Society of Disaster Information
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    • v.17 no.4
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    • pp.839-847
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    • 2021
  • Purpose: This study investigates mechanical behavior of functionally graded (FG) carbon nanotube-reinforced composite (CNTRC) plate in flexure. Isogeometric analysis (IGA) method coupled with shear deformable theory of higher-order (HSDT) to analyze the nonlinear bending response is presented. Method: Shear deformable plate theory into which a polynomial shear shape function and the von Karman type geometric nonlinearity are incorporated is used to derive the nonlinear equations of equilibrium for FG-CNTRC plate in bending. The modified Newton-Raphson iteration is adopted to solve the system equations. Result: The dispersion pattern of carbon nanotubes, plate geometric parameter and boundary condition have significant effects on the nonlinear flexural behavior of FG-CNTRC plate. Conclusion: The proposed IGA method coupled with the HSDT can successfully predict the flexural behavior of FG-CNTRC plate.

Electromechanical Behaviors and Application of Carbon Nanotube Composite Actuators Consisting of Bundles and Mats (다발/매트로 구성된 탄소나노튜브 복합재 엑츄에이터의 거동특성 및 응용연구)

  • Kim, Cheol;Liu, Xinyun
    • Composites Research
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    • v.18 no.5
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    • pp.34-39
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    • 2005
  • The relationship between strain and applied potential was derived for composite actuators consisting of single-wall carbon nanotubes (SWNTs) and conductive polymers (CPs). During deriving the relationship, an electrochemical ionic approach is utilized to formulate the electromechanical actuation of the composite film actuator. This relationship can give us a direct understanding of the actuation of a nanoactuator. The results show that the well-aligned SWNTs composite actuator can give good actuation responses and high actuating forces available. The actuation is found to be affected by both SWNTs and CPs components and the actuation of SWNTs component has two kinds of influences on that of the CPs component: reinforcement at the positive voltage and abatement at the negative voltage. Optimizations of SWNTs-CPs composite actuator may be achieved by using well-aligned nanotubes as well as choosing suitable electrolyte and input voltage range.

Interfacial Characterization of Mineralized Carbon Nanotubes (광물화된 탄소나노튜브 첨가재의 계면 특성화)

  • Park, Chanwook;Jung, Jiwon;Yun, Gunjin
    • Composites Research
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    • v.31 no.5
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    • pp.282-287
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    • 2018
  • In this paper, we explore interfacial properties of the mineralized CNTs when they are employed as reinforcing fillers in a polymer nanocomposite using molecular dynamics (MD) simulations. Recently, several studies on mineralizing carbon nanotubes (CNTs) with an aid of nitrogen doping to CNTs have been reported. However, there is a lack of studies on the reinforcing effects of the mineralized CNTs when it is employed as a filler of nanocomposites. Silica ($SiO_2$) is used as a mineral material and poly (methyl metacrylate) (PMMA) is used as a polymer matrix. Pull-out simulations are conducted to obtain the interfacial energy and the interfacial shear stress. It was found that the silica mineralized CNTs have higher interfacial interaction with the polymer matrix. In the future, by examining various thermomechanical properties of the mineralized-CNT-filler/polymer nanocomposites, we will search for potential applications of the novel reinforcing filler.

Mechanical and Thermal Properties of Epoxy Composites Reinforced Fluorinated Illite and Carbon Nanotube (불소화 일라이트 및 탄소나노튜브 강화 에폭시 복합재의 기계적 및 열적 특성)

  • Lee, Kyeong Min;Lee, Si-Eun;Kim, Min Il;Kim, Hyeong Gi;Lee, Young-Seak
    • Applied Chemistry for Engineering
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    • v.27 no.3
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    • pp.285-290
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    • 2016
  • To improve properties of epoxy composites, surfaces of the illite and carbon nanotube (CNT) were treated by fluorine gas. The fluorinated illite and CNT were then characterized by X-ray photoelectron microscopy (XPS) and the mechanical and thermal properties of their composites were evaluated. The tensile and impact strengths and thermal stability of the composites increased upto about 59%, 18% and 124%, respectively compared to those of the neat epoxy. Improvements of mechanical and thermal properties in the composites were attributed that the fluorination of illite and carbon nanotube helps to enhance the dispersion in epoxy resin and interfacial interaction between them.

An Evaluation on Bending Behaviors of Conical Composite Tubes for Bicycle Frames (자전거 프레임용 원추형 복합재 튜브의 굽힘 거동 분석)

  • Hwang, Sang-Kyun;Lee, Jung-Woo;Hwang, Hui-Yun
    • Composites Research
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    • v.29 no.6
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    • pp.358-362
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    • 2016
  • Mechanical properties of static and dynamic behavior became important since the use of conical composite tubes in large structures such as aerospace, planes, and submarines as well as leisure goods such as bicycle frames, fishing rods, and golf shafts. In the past, the mechanical property prediction model for static behavior was studied using vibration, bending, and buckling. But there is a need to study how fiber orientation error affects mechanical properties of conical composite structure because the model assumes constant fiber orientation angle. The purpose of this study is to derive an equation that can predict the static behavior of conical composite tube for bicycle frames by considering fiber orientation error with respect to various design parameters.

A Study on Tensile Properties of Multi-Welled Carbon Nanotube/Epoxy Composites (다중벽 탄소나노튜브/에폭시 복합재료의 인장 물성에 관한 연구)

  • Lee Sang-Eui;Lee Won-Jun;Kim Chun-Gon
    • Composites Research
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    • v.17 no.6
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    • pp.1-7
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    • 2004
  • The studies of particulate reinforced composites have been conducted for many years. The nanocomposites to be studied vigorously in recent years are one of them. We fabricated and studied multi-walled carbon nanotube(MWNT)/epoxy composites which may be useful as matrix for continuous fiber-reinforced composites. We investigated tensile properties of MWNT/epoxy composites as a function of MWNT concentration, which were prepared by the fabrication method established in this study. Tensile stiffness and strength increased 19% at 0.5 wt% and 12% at 0.2 wt%, respectively. We observed the reaggregation phenomenon of MWNTS during curing, which should be controlled to obtain higher tensile properties.