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Sample records for carbon-fiber composite molecular

  1. Carbon fiber composite molecular sieves

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, T.D.; Rogers, M.R.; Williams, A.M.

    1996-06-01

    The removal of CO{sub 2} is of significance in several energy applications. The combustion of fossil fuels, such as coal or natural gas, releases large volumes of CO{sub 2} to the environment. Several options exist to reduce CO{sub 2} emissions, including substitution of nuclear power for fossil fuels, increasing the efficiency of fossil plants and capturing the CO{sub 2} prior to emission to the environment. All of these techniques have the attractive feature of limiting the amount of CO{sub 2} emitted to the atmosphere, but each has economic, technical, or societal limitations. In the production of natural gas, the feed stream from the well frequently contains contaminants and diluents which must be removed before the gas can enter the pipeline distribution system. Notable amongst these diluent gasses is CO{sub 2}, which has no calorific value. Currently, the pipeline specification calls for <2 mol % CO{sub 2} in the gas. Gas separation is thus a relevant technology in the field of energy production. A novel separation system based on a parametric swing process has been developed that utilizes the unique combination of properties exhibited by our carbon fiber composite molecular sieve (CFCMS).

  2. Use of Carbon Fiber Composite Molecular Sieves for Air Separation

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Frederick S [ORNL; Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Burchell, Timothy D [ORNL

    2005-09-01

    A novel adsorbent material, 'carbon fiber composite molecular sieve' (CFCMS), has been developed by the Oak Ridge National Laboratory. Its features include high surface area, large pore volume, and a rigid, permeable carbon structure that exhibits significant electrical conductivity. The unique combination of high adsorptive capacity, permeability, good mechanical properties, and electrical conductivity represents an enabling technology for the development of novel gas separation and purification systems. In this context, it is proposed that a fast-cycle air separation process that exploits a kinetic separation of oxygen and nitrogen should be possible using a CFCMS material coupled with electrical swing adsorption (ESA). The adsorption of O{sub 2}, N{sub 2}, and CO{sub 2} on activated carbon fibers was investigated using static and dynamic techniques. Molecular sieving effects in the activated carbon fiber were highlighted by the adsorption of CO{sub 2}, a more sensitive probe molecule for the presence of microporosity in adsorbents. The kinetic studies revealed that O2 was more rapidly adsorbed on the carbon fiber than N{sub 2}, and with higher uptake under equilibrium conditions, providing the fiber contained a high proportion of very narrow micropores. The work indicated that CFCMS is capable of separating O{sub 2} and N{sub 2} from air on the basis of the different diffusion rates of the two molecules in the micropore network of the activated carbon fibers comprising the composite material. In response to recent enquires from several potential users of CFCMS materials, attention has been given to the development of a viable continuous process for the commercial production of CFCMS material. As part of this effort, work was implemented on characterizing the performance of lignin-based activated carbon fiber, a potentially lower cost fiber than the pitch-based fibers used for CFCMS production to date. Similarly, to address engineering issues

  3. Carbon-fiber composite molecular sieves for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F.; Kimber, G.; Fei, Y.Q. [Univ. of Kentucky Center for Applied Energy Research, Lexington, KY (United States)

    1995-08-01

    The progress of research in the development of novel, rigid, monolithic adsorbent carbon fiber composites is described. Carbon fiber composites are produced at ORNL and activated at the CAER using steam or CO{sub 2} under different conditions, with the aims of producing a uniform degree of activation through the material, and of closely controlling pore structure and adsorptive properties The principal focus of the work to date has been to produce materials with narrow porosity for use in gas separations.

  4. Carbon-fiber composite molecular sieves for gas separation

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F. [Univ. of Kentucky, Lexington, KY (United States)

    1996-08-01

    This report describes continuing work on the activation and characterization of formed carbon fiber composites. The composites are produced at the Oak Ridge National Laboratory (ORNL) and activated at the Center for Applied Energy Research (CAER) using steam, CO{sub 2}, or O{sub 2} at different conditions of temperature and time, and with different furnace configurations. The general aims of the project are to produce uniformly activated samples with controlled pore structures for specialist applications such as gas separation and water treatment. In previous work the authors reported that composites produced from isotropic pitch fibers weighing up to 25g can be uniformly activated through the appropriate choice of reaction conditions and furnace configurations. They have now succeeded in uniformly activating composites of dimensions up to 12 x 7 x 6 cm, or up to about 166 gram - a scale-up factor of about six. Part of the work has involved the installation of a new furnace that can accommodate larger composites. Efforts were made to achieve uniform activation in both steam and CO{sub 2}. The authors have also succeeded in producing materials with very uniform and narrow pore size distributions by using a novel method involving low temperature oxygen chemisorption in combination with heat treatment in N{sub 2} at high temperatures. Work has also started on the activation of PAN based carbon fibers and fiber composites with the aim of producing composites with wide pore structures for use as catalyst supports. So far activation of the PAN fiber composites supplied by ORNL has been difficult which is attributed to the low reactivity of the PAN fibers. As a result, studies are now being made of the activation of the PAN fibers to investigate the optimum carbonization and activation conditions for PAN based fibers.

  5. CARBON FIBER COMPOSITES IN HIGH VOLUME

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Charles David [ORNL; Das, Sujit [ORNL; Jeon, Dr. Saeil [Volvo Trucks North America

    2014-01-01

    Vehicle lightweighting represents one of several design approaches that automotive and heavy truck manufacturers are currently evaluating to improve fuel economy, lower emissions, and improve freight efficiency (tons-miles per gallon of fuel). With changes in fuel efficiency and environmental regulations in the area of transportation, the next decade will likely see considerable vehicle lightweighting throughout the ground transportation industry. Greater use of carbon fiber composites and light metals is a key component of that strategy. This paper examines the competition between candidate materials for lightweighting of heavy vehicles and passenger cars. A 53-component, 25 % mass reduction, body-in-white cost analysis is presented for each material class, highlighting the potential cost penalty for each kilogram of mass reduction and then comparing the various material options. Lastly, as the cost of carbon fiber is a major component of the elevated cost of carbon fiber composites, a brief look at the factors that influence that cost is presented.

  6. Carbon fiber content measurement in composite

    Science.gov (United States)

    Wang, Qiushi

    Carbon fiber reinforced polymers (CFRPs) have been widely used in various structural applications in industries such as aerospace and automotive because of their high specific stiffness and specific strength. Their mechanical properties are strongly influenced by the carbon fiber content in the composites. Measurement of the carbon fiber content in CFRPs is essential for product quality control and process optimization. In this work, a novel carbonization-in-nitrogen method (CIN) is developed to characterize the fiber content in carbon fiber reinforced thermoset and thermoplastic composites. In this method, a carbon fiber composite sample is carbonized in a nitrogen environment at elevated temperatures, alongside a neat resin sample. The carbon fibers are protected from oxidization while the resin (the neat resin and the resin matrix in the composite sample) is carbonized under the nitrogen environment. The residue of the carbonized neat resin sample is used to calibrate the resin carbonization rate and calculate the amount of the resin matrix in the composite sample. The new method has been validated on several thermoset and thermoplastic resin systems and found to yield an accurate measurement of fiber content in carbon fiber polymer composites. In order to further understand the thermal degradation behavior of the high temperature thermoplastic polymer during the carbonization process, the mechanism and the kinetic model of thermal degradation behavior of carbon fiber reinforced poly (phenylene sulfide) (CPPS) are studied using thermogravimetry analysis (TGA). The CPPS is subjected to TGA in an air and nitrogen atmosphere at heating rates from 5 to 40°C min--1. The TGA curves obtained in air are different from those in nitrogen. This demonstrates that weight loss occurs in a single stage in nitrogen but in two stages in air. To elucidate this difference, thermal decomposition kinetics is analyzed by applying the Kissinger, Flynn-Wall-Ozawa, Coat-Redfern and

  7. Carbonized asphaltene-based carbon-carbon fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Bohnert, George; Lula, James; Bowen, III, Daniel E.

    2016-12-27

    A method of making a carbon binder-reinforced carbon fiber composite is provided using carbonized asphaltenes as the carbon binder. Combinations of carbon fiber and asphaltenes are also provided, along with the resulting composites and articles of manufacture.

  8. Carbon Fiber Composite Monoliths as Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  9. Carbon Fiber Composite Monoliths for Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL; Gallego, Nidia C [ORNL; Pickel, Joseph M [ORNL; Blom, Douglas Allen [ORNL; Burchell, Timothy D [ORNL

    2006-01-01

    Carbon fiber composite monoliths are rigid bodies that can be activated to a large surface area, have tunable porosity, and proven performance in gas separation and storage. They are ideal as catalyst supports in applications where a rigid support, with open structure and easy fluid access is desired. We developed a procedure for depositing a dispersed nanoparticulate phase of molybdenum carbide (Mo2C) on carbon composite monoliths in the concentration range of 3 to 15 wt% Mo. The composition and morphology of this phase was characterized using X-ray diffraction and electron microscopy, and a mechanism was suggested for its formation. Molybdenum carbide is known for its catalytic properties that resemble those of platinum group metals, but at a lower cost. The materials obtained are expected to demonstrate catalytic activity in a series of hydrocarbon reactions involving hydrogen transfer. This project demonstrates the potential of carbon fiber composite monoliths as catalyst supports.

  10. Manufacturing of Nanocomposite Carbon Fibers and Composite Cylinders

    Science.gov (United States)

    Tan, Seng; Zhou, Jian-guo

    2013-01-01

    Pitch-based nanocomposite carbon fibers were prepared with various percentages of carbon nanofibers (CNFs), and the fibers were used for manufacturing composite structures. Experimental results show that these nanocomposite carbon fibers exhibit improved structural and electrical conductivity properties as compared to unreinforced carbon fibers. Composite panels fabricated from these nanocomposite carbon fibers and an epoxy system also show the same properties transformed from the fibers. Single-fiber testing per ASTM C1557 standard indicates that the nanocomposite carbon fiber has a tensile modulus of 110% higher, and a tensile strength 17.7% times higher, than the conventional carbon fiber manufactured from pitch. Also, the electrical resistance of the carbon fiber carbonized at 900 C was reduced from 4.8 to 2.2 ohm/cm. The manufacturing of the nanocomposite carbon fiber was based on an extrusion, non-solvent process. The precursor fibers were then carbonized and graphitized. The resultant fibers are continuous.

  11. Carbon Fiber Foam Composites and Methods for Making the Same

    Science.gov (United States)

    Leseman, Zayd Chad (Inventor); Atwater, Mark Andrew (Inventor); Phillips, Jonathan (Inventor)

    2014-01-01

    Exemplary embodiments provide methods and apparatus of forming fibrous carbon foams (FCFs). In one embodiment, FCFs can be formed by flowing a fuel rich gas mixture over a catalytic material and components to be encapsulated in a mold to form composite carbon fibers, each composite carbon fiber having a carbon phase grown to encapsulate the component in situ. The composite carbon fibers can be intertwined with one another to form FCFs having a geometry according to the mold.

  12. Quasi-Carbon Fibers and the Composites

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    @@The aim of this report is to study the properties of quasi-carbon fibers (QCF) prepared from the PAN fiber precursor by pyrolysis at a temperature between 400℃ and 1200℃. The resistivity of QCF with different heat-treated temperature (HTT) was investigated by a Hall-35 testing system,and the flexural properties of the result composites (QCFC) are also discussed. In addition, the scanning electronic microscope (SEM) was utilized to observe the surface morphology of QCF and the fracture section of QCFC obtained from flexural testing.

  13. The dynamic response of carbon fiber-filled polymer composites

    OpenAIRE

    Patterson B.; Orler E.B.; Furmanski J.; Rigg P.A.; Scharff R.J.; Stahl D.B.; Sheffield S.A.; Gustavsen R.L.; Dattelbaum D.M.; Coe J.D.

    2012-01-01

    The dynamic (shock) responses of two carbon fiber-filled polymer composites have been quantified using gas gun-driven plate impact experimentation. The first composite is a filament-wound, highly unidirectional carbon fiber-filled epoxy with a high degree of porosity. The second composite is a chopped carbon fiber- and graphite-filled phenolic resin with little-to-no porosity. Hugoniot data are presented for the carbon fiber-epoxy (CE) composite to 18.6 GPa in the through-thickness direction,...

  14. Carbon fiber resin matrix interphase: effect of carbon fiber surface treatment on composite performance

    Energy Technology Data Exchange (ETDEWEB)

    Lehmann, S.; Megerdigian, C.; Papalia, R.

    1985-04-01

    Carbon fibers are supplied by various manufacturers with a predetermined level of surface treatment and matrix compatible sizings. Surface treatment of the carbon fiber increases the active oxygen content, the polarity and the total free surface energy of the fiber surface. This study is directed toward determining the effect of varying carbon fiber surface treatment on the composite performance of thermoset matrix resins. The effect of varying fiber surface treatment on performance of a promising proprietary sizing is also presented. 6 references, 11 figures.

  15. RADIATION EFFECTS ON EPOXY CARBON FIBER COMPOSITE

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, E

    2008-05-30

    Carbon fiber-reinforced bisphenol-A epoxy matrix composite was evaluated for gamma radiation resistance. The composite was exposed to total gamma doses of 50, 100, and 200 Mrad. Irradiated and baseline samples were tested for tensile strength, hardness and evaluated using FTIR (Fourier transform infrared) spectroscopy and DSC (differential scanning calorimetry) for structural changes. Scanning electron microscopy was used to evaluate microstructural behavior. Mechanical testing of the composite bars revealed no apparent change in modulus, strain to failure, or fracture strength after exposures. However, testing of only the epoxy matrix revealed changes in hardness, thermal properties, and FTIR results with increasing gamma irradiation. The results suggest the epoxy within the composite can be affected by exposure to gamma irradiation.

  16. Carbon Fiber Reinforced, Zero CME Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Technical Abstract: This project proposes to develop moisture insensitive, high performance, carbon fiber laminates for future missions. Current space-qualified...

  17. Carbon fiber reinforced thermoplastic composites for future automotive applications

    Science.gov (United States)

    Friedrich, K.

    2016-05-01

    After a brief introduction to polymer composite properties and markets, the state of the art activities in the field of manufacturing of advanced composites for automotive applications are elucidated. These include (a) long fiber reinforced thermoplastics (LFT) for secondary automotive components, and (b) continuous carbon fiber reinforced thermosetting composites for car body applications. It is followed by future possibilities of carbon fiber reinforced thermoplastic composites for e.g. (i) crash elements, (ii) racing car seats, and (iii) production and recycling of automotive fenders.

  18. Puncture-Healing Thermoplastic Resin Carbon-Fiber-Reinforced Composites

    Science.gov (United States)

    Gordon, Keith L. (Inventor); Siochi, Emilie J. (Inventor); Grimsley, Brian W. (Inventor); Cano, Roberto J. (Inventor); Czabaj, Michael W. (Inventor)

    2015-01-01

    A composite comprising a combination of a self-healing polymer matrix and a carbon fiber reinforcement is described. In one embodiment, the matrix is a polybutadiene graft copolymer matrix, such as polybutadiene graft copolymer comprising poly(butadiene)-graft-poly(methyl acrylate-co-acrylonitrile). A method of fabricating the composite is also described, comprising the steps of manufacturing a pre-impregnated unidirectional carbon fiber preform by wetting a plurality of carbon fibers with a solution, the solution comprising a self-healing polymer and a solvent, and curing the preform. A method of repairing a structure made from the composite of the invention is described. A novel prepreg material used to manufacture the composite of the invention is described.

  19. Electron microscopy investigation of interface between carbon fiber and ultra high molecular weight polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Stepashkin, A.A.; Chukov, D.I., E-mail: dil_chukov@yahoo.com; Gorshenkov, M.V.; Tcherdyntsev, V.V.; Kaloshkin, S.D.

    2014-02-15

    Highlights: • Effect of the carbon fibers surface treatments on the adhesive interactions in UHMWPE composites was studied. • Air oxidation of carbon filler ensures most significant increase in adhesion interaction in UHMWPE based composites. • Nanosized UHMWPE fibers with 20–40 nm in diameter and with 6–10 μm in length, was observed on the surface of carbon fibers. -- Abstract: Scanning electron microscopy was used to investigate the surface of initial and modified high-strength and high-modulus carbon fibers as well as interfaces in the ultra high molecular weight polyethylene, filled with above-mentioned fibers. Effect of the fibers surface modifying method on the adhesive interactions in composites was studied. It was observed that interaction of matrix with a modified surface of fibers results in a formation of bonds with strength higher than the yield strength of the polymer. It results in a formation of long nanosized polymer wires at tensile fracture of composites.

  20. Mechanical properties of carbon fiber composites for environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, R.; Grulke, E. [Univ. of Kentucky, Lexington, KY (United States)

    1996-10-01

    Activated carbon fiber composites show great promise as fixed-bed catalytic reactors for use in environmental applications such as flue gas clean-up and ground water decontamination. A novel manufacturing process produces low density composites from chopped carbon fibers and binders. These composites have high permeability, can be activated to have high surface area, and have many potential environmental applications. This paper reports the mechanical and flow properties of these low density composites. Three point flexural strength tests were used to measure composite yield strength and flexural moduli. Composites containing over 10 pph binder had an adequate yield strength of about 200 psi at activations up to 40% weight loss. The composites were anisotropic, having along-fiber to cross-fiber yield strength ratios between 1.2 and 2.0. The friction factor for flow through the composites can be correlated using the fiber Reynolds number, and is affected by the composite bulk density.

  1. Mechanical properties of carbon fiber composites for environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, R.; Grulke, E.; Kimber, G. [Univ. of Kentucky, Lexington, KY (United States)

    1996-12-31

    Activated carbon fiber composites show great promise as fixed-bed catalytic reactors for use in environmental applications such as flue gas clean-up and ground water decontamination. A novel manufacturing process produces low density composites from chopped carbon fibers and binders. These composites have high permeability, can be activated to have high surface area, and have many potential environmental applications. This paper reports the mechanical and flow properties of these low density composites. Three point flexural strength tests were used to measure composite yield strength and flexural moduli. Composites containing over 10 pph binder had an adequate yield strength of about 200 psi at activations up to 40% weight loss. The composites were anisotropic, having along-fiber to cross-fiber yield strength ratios between 1.2 and 2.0. The pressure drop of air through the composites correlated with the gas velocity, and showed a dependence on sample density.

  2. Interlaminar fracture in carbon fiber/thermoplastic composites

    Science.gov (United States)

    Hinkley, J. A.; Bascom, W. D.; Allred, R. E.

    1990-01-01

    The surfaces of commercial carbon fibers are generally chemically cleaned or oxidized and then coated with an oligomeric sizing to optimize their adhesion to epoxy matrix resins. Evidence from fractography, from embedded fiber testing and from fracture energies suggests that these standard treatments are relatively ineffective for thermoplastic matrices. This evidence is reviewed and model thermoplastic composites (polyphenylene oxide/high strain carbon fibers) are used to demonstrate how differences in adhesion can lead to a twofold change in interlaminar fracture toughness. The potential for improved adhesion via plasma modification of fiber surfaces is discussed. Finally, a surprising case of fiber-catalyzed resin degradation is described.

  3. Aligning carbon fibers in micro-extruded composite ink

    Science.gov (United States)

    Mahajan, Chaitanya G.

    Direct write processes include a wide range of additive manufacturing techniques with the ability to fabricate structures directly onto planar and non-planar surfaces. Most additive manufacturing techniques use unreinforced polymers to produce parts. By adding carbon fiber as a reinforcing material, properties such as mechanical strength, electrical conductivity, and thermal conductivity can be enhanced. Carbon fibers can be long and continuous, or short and discontinuous. The strength of carbon fiber composite parts is greatly increased when the fibers are preferentially aligned. This research focuses on increasing the strength of additively manufactured parts reinforced using discontinuous carbon fibers that have been aligned during the micro extrusion process. A design of experiments (DOE) approach was used to identify significant process parameters affecting fiber alignment. Factors such as the length of carbon fibers, nozzle diameter, fiber loading fraction, air pressure, translational speed and standoff distance were considered. A two dimensional Fast Fourier Transform (2D FFT) was used to quantify the degree of fiber alignment in the extruded composite inks. ImageJ software supported by an oval profile plugin was used with micrographs of printed samples to obtain the carbon fiber alignment values. The optimal value for the factors was derived by identifying the significant main and interaction effects. Based on the results of the DOE, tensile test samples were printed with fibers aligned parallel and perpendicular to the tensile axis. A standard test method for tensile properties of plastic revealed that the extruded parts with fibers aligned along the tensile axis were better in tensile strength and modulus.

  4. The dynamic response of carbon fiber-filled polymer composites

    Directory of Open Access Journals (Sweden)

    Patterson B.

    2012-08-01

    Full Text Available The dynamic (shock responses of two carbon fiber-filled polymer composites have been quantified using gas gun-driven plate impact experimentation. The first composite is a filament-wound, highly unidirectional carbon fiber-filled epoxy with a high degree of porosity. The second composite is a chopped carbon fiber- and graphite-filled phenolic resin with little-to-no porosity. Hugoniot data are presented for the carbon fiber-epoxy (CE composite to 18.6 GPa in the through-thickness direction, in which the shock propagates normal to the fibers. The data are best represented by a linear Rankine-Hugoniot fit: Us = 2.87 + 1.17 ×up(ρ0 = 1.536g/cm3. The shock wave structures were found to be highly heterogeneous, both due to the anisotropic nature of the fiber-epoxy microstructure, and the high degree of void volume. Plate impact experiments were also performed on a carbon fiber-filled phenolic (CP composite to much higher shock input pressures, exceeding the reactants-to-products transition common to polymers. The CP was found to be stiffer than the filament-wound CE in the unreacted Hugoniot regime, and transformed to products near the shock-driven reaction threshold on the principal Hugoniot previously shown for the phenolic binder itself. [19] On-going research is focused on interrogating the direction-dependent dyanamic response and dynamic failure strength (spall for the CE composite in the TT and 0∘ (fiber directions.

  5. Fabrication of polytetrafluoroethylene/carbon fiber composites using radiation crosslinking

    Science.gov (United States)

    Oshima, Akihiro; Udagawa, Akira; Tanaka, Shigeru

    2001-07-01

    A fabrication method for fiber-reinforced plastic (FRP) composites based on carbon fibers and polytetrafluoroethylene (PTFE) which was crosslinked by electron beam (EB) irradiation under specific conditions was studied. Though the fabricated composite showed high mechanical properties compared with a ready-made PTFE composite (non-crosslinked PTFE with 5˜20 wt% filler), mechanical properties of laminated panels were a bit poor compared with those of usual FRP. It was found that the toughness of the PTFE matrix is poor in the composite. On the other hand, the one-ply sheet of carbon fibers and crosslinked PTFE composite showed good mechanical properties for sheet-shape materials. The wettability of the obtained crosslinked PTFE composite is hardly changed by crosslinking and reinforcement.

  6. Fabrication of polytetrafluoroethylene/carbon fiber composites using radiation crosslinking

    Energy Technology Data Exchange (ETDEWEB)

    Oshima, Akihiro E-mail: aks@taka.jaeri.go.jp; Udagawa, Akira; Tanaka, Shigeru

    2001-07-01

    A fabrication method for fiber-reinforced plastic (FRP) composites based on carbon fibers and polytetrafluoroethylene (PTFE) which was crosslinked by electron beam (EB) irradiation under specific conditions was studied. Though the fabricated composite showed high mechanical properties compared with a ready-made PTFE composite (non-crosslinked PTFE with 5{approx}20 wt% filler), mechanical properties of laminated panels were a bit poor compared with those of usual FRP. It was found that the toughness of the PTFE matrix is poor in the composite. On the other hand, the one-ply sheet of carbon fibers and crosslinked PTFE composite showed good mechanical properties for sheet-shape materials. The wettability of the obtained crosslinked PTFE composite is hardly changed by crosslinking and reinforcement.

  7. Hybrid Composites Based on Carbon Fiber/Carbon Nanofilament Reinforcement

    Directory of Open Access Journals (Sweden)

    Mehran Tehrani

    2014-05-01

    Full Text Available Carbon nanofilament and nanotubes (CNTs have shown promise for enhancing the mechanical properties of fiber-reinforced composites (FRPs and imparting multi-functionalities to them. While direct mixing of carbon nanofilaments with the polymer matrix in FRPs has several drawbacks, a high volume of uniform nanofilaments can be directly grown on fiber surfaces prior to composite fabrication. This study demonstrates the ability to create carbon nanofilaments on the surface of carbon fibers employing a synthesis method, graphitic structures by design (GSD, in which carbon structures are grown from fuel mixtures using nickel particles as the catalyst. The synthesis technique is proven feasible to grow nanofilament structures—from ethylene mixtures at 550 °C—on commercial polyacrylonitrile (PAN-based carbon fibers. Raman spectroscopy and electron microscopy were employed to characterize the surface-grown carbon species. For comparison purposes, a catalytic chemical vapor deposition (CCVD technique was also utilized to grow multiwall CNTs (MWCNTs on carbon fiber yarns. The mechanical characterization showed that composites using the GSD-grown carbon nanofilaments outperform those using the CCVD-grown CNTs in terms of stiffness and tensile strength. The results suggest that further optimization of the GSD growth time, patterning and thermal shield coating of the carbon fibers is required to fully materialize the potential benefits of the GSD technique.

  8. Fracture morphology of carbon fiber reinforced plastic composite laminates

    OpenAIRE

    Vinod Srinivasa; Vinay Shivakumar; Vinay Nayaka; Sunil Jagadeeshaiaih; Murali Seethram; Raghavendra Shenoy; Abdelhakim Nafidi

    2010-01-01

    Carbon fiber reinforced plastic (CFRP) composites have been extensively used in fabrication of primary structures for aerospace, automobile and other engineering applications. With continuous and widespread use of these composites in several advanced technology, the frequency of failures is likely to increase. Therefore, to establish the reasons for failures, the fracture modes should be understood thoroughly and unambiguously. In this paper, CFRP composite have been tested in tension, compre...

  9. SURFACE MORPHOLOGY OF CARBON FIBER POLYMER COMPOSITES AFTER LASER STRUCTURING

    Energy Technology Data Exchange (ETDEWEB)

    Sabau, Adrian S [ORNL; Chen, Jian [ORNL; Jones, Jonaaron F. [University of Tennessee (UT); Alexandra, Hackett [University of Tennessee (UT); Jellison Jr, Gerald Earle [ORNL; Daniel, Claus [ORNL; Warren, Charles David [ORNL; Rehkopf, Jackie D. [Plasan Carbon Composites

    2015-01-01

    The increasing use of Carbon Fiber Polymer Composite (CFPC) as a lightweight material in automotive and aerospace industries requires the control of surface morphology. In this study, the composites surface was prepared by ablating the resin in the top fiber layer of the composite using an Nd:YAG laser. The CFPC specimens with T700S carbon fiber and Prepreg - T83 resin (epoxy) were supplied by Plasan Carbon Composites, Inc. as 4 ply thick, 0/90o plaques. The effect of laser fluence, scanning speed, and wavelength was investigated to remove resin without an excessive damage of the fibers. In addition, resin ablation due to the power variation created by a laser interference technique is presented. Optical property measurements, optical micrographs, 3D imaging, and high-resolution optical profiler images were used to study the effect of the laser processing on the surface morphology.

  10. Activation and micropore structure of carbon-fiber composites

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F.; Kimber, G. [Univ. of Kentucky, Lexington, KY (United States). Center for Applied Energy Research

    1997-12-01

    Rigid, high surface area activated carbon fiber composites have been produced with high permeabilities for environmental applications in gas and water purification. The project involves a collaboration between the Oak Ridge National Laboratory (ORNL) and the Center for Applied Energy Research (CAER), University of Kentucky. The main focus of recent work has been to find a satisfactory means to uniformly activate large samples of carbon fiber composites to produce controlled pore structures. Processes have been developed using activation in steam and CO{sub 2}, and a less conventional method involving oxygen chemisorption and subsequent heat treatment. Another objective has been to explore applications for the activated composites in environmental applications related to fossil energy production.

  11. Carbon fiber composite molecular sieves

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, T.D.; Rogers, M.R. [Oak Ridge National Lab., TN (United States)

    1997-12-01

    Monolithic adsorbents based on isotropic pitch fibers have been developed jointly by ORNL and the University of Kentucky, Center for Applied Energy Research. The monoliths are attractive for gas separation and storage applications because of their unique combination of physical properties and microporous structure. Currently at ORNL the monoliths are produced in billets that are 10 cm in diameter and 25 cm in length. The monolithic adsorbent material is being considered for guard bed applications on a natural gas (NG) powered device. In order for the material to be successful in this application, one must attain a uniform activation to modest micropore volumes throughout the large monoliths currently being produced. Here the authors report the results of a study directed toward attaining uniform activation in these billets.

  12. Smart Behavior of Carbon Fiber Reinforced Cement-based Composite

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The electrical characteristics of cement-based material can be remarkably improved by the addition of short carbon fibers.Carbon fiber reinforced cement composite (CFRC) is an intrinsically smart material that can sense not only the stress andstrain, but also the temperature. In this paper, variations of electrical resistivity with external applied load, and relationof thermoelectric force and temperature were investigated. Test results indicated that the electrical signal is related to theincrease in the material volume resistivity during crack generation or propagation and the decrease in the resistivity duringcrack closure. Moreover, it was found that the fiber addition increased the linearity and reversibility of the Seebeck effect inthe cement-based materials. The change of electrical characteristics reflects large amount of information of inner damage andtemperature differential of composite, which can be used for stress-strain or thermal self-monitoring by embedding it in theconcrete structures.

  13. Mechanical Properties of Graphene Nanoplatelet/Carbon Fiber/Epoxy Hybrid Composites: Multiscale Modeling and Experiments

    Science.gov (United States)

    Hadden, C. M.; Klimek-McDonald, D. R.; Pineda, E. J.; King, J. A.; Reichanadter, A. M.; Miskioglu, I.; Gowtham, S.; Odegard, G. M.

    2015-01-01

    Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using multiscale modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical multiscale modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the multiscale modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite, while the effect on the axial properties is shown to be insignificant.

  14. Mechanical Properties of Graphene Nanoplatelet Carbon Fiber Epoxy Hybrid Composites: Multiscale Modeling and Experiments

    Science.gov (United States)

    Hadden, Cameron M.; Klimek-McDonald, Danielle R.; Pineda, Evan J.; King, Julie A.; Reichanadter, Alex M.; Miskioglu, Ibrahim; Gowtham, S.; Odegard, Gregory M.

    2015-01-01

    Because of the relatively high specific mechanical properties of carbon fiber/epoxy composite materials, they are often used as structural components in aerospace applications. Graphene nanoplatelets (GNPs) can be added to the epoxy matrix to improve the overall mechanical properties of the composite. The resulting GNP/carbon fiber/epoxy hybrid composites have been studied using multiscale modeling to determine the influence of GNP volume fraction, epoxy crosslink density, and GNP dispersion on the mechanical performance. The hierarchical multiscale modeling approach developed herein includes Molecular Dynamics (MD) and micromechanical modeling, and it is validated with experimental testing of the same hybrid composite material system. The results indicate that the multiscale modeling approach is accurate and provides physical insight into the composite mechanical behavior. Also, the results quantify the substantial impact of GNP volume fraction and dispersion on the transverse mechanical properties of the hybrid composite, while the effect on the axial properties is shown to be insignificant.

  15. The development of high precision carbon fiber composite mirror

    Science.gov (United States)

    Xu, Liang; Ding, Jiao-teng; Wang, Yong-jie; Xie, Yong-jie; Ma, Zhen; Fan, Xue-wu

    2016-10-01

    Due to low density, high stiffness, low thermal expansion coefficient, duplicate molding, etc., carbon fiber reinforced polymer (CFRP) is one of the potential materials of the optical mirror. The process developed for Φ300mm high precision CFRP mirror described in this paper. A placement tool used to improve laying accuracy up to ± 0.1°.A special reinforced cell structure designed to increase rigidity and thermal stability. Optical replication process adopted for surface modification of the carbon fiber composite mirror blank. Finally, surface accuracy RMS of Φ300mm CFRP mirror is 0.22μm, surface roughness Ra is about 2nm, and the thermal stability can achieve 13nm /°C from the test result. The research content is of some reference value in the infrared as well as visible light applications.

  16. Hybrid Matrices Layer of Carbon Fiber Composites

    Directory of Open Access Journals (Sweden)

    Dr. B. Balu Naik

    2013-04-01

    Full Text Available Polymeric composites have gone through a level of maturity beyond the laboratory stage with the development of all composite aircraft structures. Yet the basic understanding of the material used in its primary structure has not been extensively investigated. Although this may be attributed in part to the proprietary nature of the system, we believe that it is because of lack of specific tools required for its analysis.Specifically, micromechanical models always assume an evenly distributed homogeneous matrix while lamination theory assumes constant stress through the laminate thickness. Specifically, this work focuses on the development of model systems that can be studied without concerns of proprietary and/or export control requirements. Consequently, the amount of toughness improvement must be balanced between interlaminar and intralaminar fracture toughness. Finally, this work has demonstrated that even though the multilayer structured laminates provide Mode II interlaminar fracture toughness improvements, their mechanical testing behavior is extremely different than conventional composite structures.

  17. Damage-tolerant composite materials produced by stitching carbon fibers

    Science.gov (United States)

    Dow, Marvin B.; Smith, Donald L.

    1989-01-01

    NASA-Langley has undertaken the investigation of composite damage-tolerance enhancement and fabrication economies-maximization via reinforcement-stitching, in combination with resin transfer molding. Attention is given to results obtained by an experimental evaluation of composites tailored for damage tolerance by stitching layers of dry carbon-fiber fabric with closely-spaced threads, in order to furnish through-the-thickness reinforcement. Various stitching patterns and thread materials have been evaluated, using flat-plate specimens; blade-stiffened structural elements have been fabricated and tested. The results presented indicate that stitched laminates furnish damage tolerance performance comparable to that of more expensive, toughened-matrix composites.

  18. Process Optimization of Bismaleimide (BMI) Resin Infused Carbon Fiber Composite

    Science.gov (United States)

    Ehrlich, Joshua W.; Tate, LaNetra C.; Cox, Sarah B.; Taylor, Brian J.; Wright, M. Clara; Faughnan, Patrick D.; Batterson, Lawrence M.; Caraccio, Anne J.; Sampson, Jeffery W.

    2013-01-01

    Engineers today are presented with the opportunity to design and build the next generation of space vehicles out of the lightest, strongest, and most durable materials available. Composites offer excellent structural characteristics and outstanding reliability in many forms that will be utilized in future aerospace applications including the Commercial Crew and Cargo Program and the Orion space capsule. NASA's Composites for Exploration (CoEx) project researches the various methods of manufacturing composite materials of different fiber characteristics while using proven infusion methods of different resin compositions. Development and testing on these different material combinations will provide engineers the opportunity to produce optimal material compounds for multidisciplinary applications. Through the CoEx project, engineers pursue the opportunity to research and develop repair patch procedures for damaged spacecraft. Working in conjunction with Raptor Resins Inc., NASA engineers are utilizing high flow liquid infusion molding practices to manufacture high-temperature composite parts comprised of intermediate modulus 7 (IM7) carbon fiber material. IM7 is a continuous, high-tensile strength composite with outstanding structural qualities such as high shear strength, tensile strength and modulus as well as excellent corrosion, creep, and fatigue resistance. IM7 carbon fiber, combined with existing thermoset and thermoplastic resin systems, can provide improvements in material strength reinforcement and deformation-resistant properties for high-temperature applications. Void analysis of the different layups of the IM7 material discovered the largest total void composition within the [ +45 , 90 , 90 , -45 ] composite panel. Tensile and compressional testing proved the highest mechanical strength was found in the [0 4] layup. This paper further investigates the infusion procedure of a low-cost/high-performance BMI resin into an IM7 carbon fiber material and the

  19. Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Composites

    Science.gov (United States)

    Kang, Jin Ho; Cano, Roberto J.; Ratcliffe, James G.; Luong, Hoa; Grimsley, Brian W.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strengthand stiffness-to-weight ratio, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Despite several attempts to solve these issues with the addition of carbon nanotubes (CNT) into polymer matrices, and/or by interleaving CNT sheets between conventional carbon fiber (CF) composite layers, there are still interfacial problems that exist between CNTs (or CF) and the resin. In this study, hybrid CNT/CF polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing (double cantilever beam and end-notched flexure test). Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated. Interleaving CNT sheets significantly improved the in-plane (axial and perpendicular direction of CF alignment) thermal conductivity of the hybrid composite laminates by 50 - 400%.

  20. Interfacial Properties Modification of Carbon Fiber/ Polyarylacetylene Composites

    Institute of Scientific and Technical Information of China (English)

    FU Hong-jun; MA Chong-qi; KUANG Nai-hang; LUAN Shi-lin

    2007-01-01

    This work was dedicated to performing surface oxidation and coating treatments on carbon fibers (CF) and investigating the changes of fiber surface properties after these treatments, including surface composition, relative volume of functional groups, and surface topography with X-ray photoelectron spectroscopy (XPS) and atom force microscopy (AFM) technology. The results show that,after oxidation treatments, interfacial properties between CF and non-polar polyarylacetylene (PAA) resin are remarkably modified by removing weak surface layers and increasing fiber surface roughness. Coating treatment by high char phenolic resin solution after oxidation makes interface of CF/PAA composites to be upgraded and the interfacial properties further bettered.

  1. Effects of Graphene Oxide Modified Sizing Agents on Interfacial Properties of Carbon Fibers/Epoxy Composites.

    Science.gov (United States)

    Zhang, Qingbo; Jiang, Dawei; Liu, Li; Huang, Yudong; Long, Jun; Wu, Guangshun; Wu, Zijian; Umar, Ahmad; Guo, Jiang; Zhang, Xi; Guo, Zhanhu

    2015-12-01

    A kind of graphene oxide (GO) modified sizing agent was used to improve the interfacial properties of carbon fibers/epoxy composites. The surface topography of carbon fibers was investigated by scanning electron microscopy (SEM). The surface compositions of carbon fibers were determined by X-ray photoelectron spectroscopy (XPS) and the interfacial properties of composites were studied by interlaminar shear strength (ILSS). The results show that the existence of GO increases the content of reactive functional groups on carbon fiber surface. Thus it enhances the interfacial properties of carbon fibers/epoxy composites. When GO loading in sizing agents is 1 wt%, the ILSS value of composite reaches to 96.2 MPa, which is increased by 27.2% while comparing with unsized carbon fiber composites. Furthermore, the ILSS of composites after aging is also increased significantly with GO modified sizing agents.

  2. Surface modification of carbon fibers and its effect on the fiber–matrix interaction of UHMWPE based composites

    Energy Technology Data Exchange (ETDEWEB)

    Chukov, D.I., E-mail: dil_chukov@yahoo.com; Stepashkin, A.A.; Gorshenkov, M.V.; Tcherdyntsev, V.V.; Kaloshkin, S.D.

    2014-02-15

    Highlights: • Both chemical and thermal treatments of UKN 5000 carbon fibers allow one to obtain well-developed surface. • The changes of structure and properties of VMN-4 fibers after both thermal and chemical oxidation are insignificant due to more perfect initial structure of these fibers. • The oxidative treatment of carbon fibers allows one to improve the interfacial interaction in the UHMWPE-based composites. • The oxidative treatment of the fibers allows one to a triple increase of Young’s modulus of the modified fibers reinforced UHMWPE composites. -- Abstract: The PAN-based carbon fibers (CF) were subjected to thermal and chemical oxidation under various conditions. The variation in the surface morphology of carbon fibers after surface treatment was analyzed by scanning electron microscopy (SEM). It was found that the tensile strength of carbon fibers changed after surface modification. The interaction between the fibers and the matrix OF ultra-high molecular weight polyethylene (UHMWPE) was characterized by the Young modulus of produced composites. It was shown that the Young modulus of composites reinforced with modified carbon fibers was significantly higher than that of composites reinforced with non-modified fibers.

  3. RADIATION EFFECTS ON EPOXY/CARBON FIBER COMPOSITE

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, E; Eric Skidmore, E

    2008-12-12

    The Department of Energy Savannah River Site vitrifies nuclear waste incident to defense programs through its Defense Waste Processing Facility (DWPF). The piping in the DWPF seal pot jumper configuration must withstand the stresses during an unlikely but potential deflagration event, and maintain its safety function for a 20-year service life. Carbon fiber-reinforced epoxy composites (CFR) were proposed for protection and reinforcement of piping during such an event. The proposed CFR materials have been ASME-approved (Section XI, Code Case N-589-1) for post-construction maintenance and is DOT-compliant per 49CFR 192 and 195. The proposed carbon fiber/epoxy composite reinforcement system was originally developed for pipeline rehabilitation and post-construction maintenance in petrochemical, refineries, DOT applications and other industries. The effects of ionizing radiation on polymers and organic materials have been studied for many years. The majority of available data are based on traditional exposures to gamma irradiation at high dose rates ({approx}10,000 Gy/hr) allowing high total dose within reasonable test periods and general comparison of different materials exposed at such conditions. However, studies in recent years have shown that degradation of many polymers are sensitive to dose rate, with more severe degradation often observed at similar or even lower total doses when exposed to lower dose rates. This behavior has been primarily attributed to diffusion-limited oxidation which is minimized during very high dose rate exposures. Most test standards for accelerated aging and nuclear qualification of components acknowledge these limitations. The results of testing to determine the radiation resistance and microstructural effects of gamma irradiation exposure on a bisphenol-A based epoxy matrix composite reinforced with carbon fibers are presented. This work provides a foundation for a more extensive evaluation of dose rate effects on advanced epoxy

  4. Carbon fiber composite characterization in adverse thermal environments.

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Vasquez, Sylvia; Brown, Alexander L.; Hubbard, Joshua A.; Ramirez, Ciro J.; Dodd, Amanda B.

    2011-05-01

    The behavior of carbon fiber aircraft composites was studied in adverse thermal environments. The effects of resin composition and fiber orientation were measured in two test configurations: 102 by 127 millimeter (mm) test coupons were irradiated at approximately 22.5 kW/m{sup 2} to measure thermal response, and 102 by 254 mm test coupons were irradiated at approximately 30.7 kW/m{sup 2} to characterize piloted flame spread in the vertically upward direction. Carbon-fiber composite materials with epoxy and bismaleimide resins, and uni-directional and woven fiber orientations, were tested. Bismaleimide samples produced less smoke, and were more resistant to flame spread, as expected for high temperature thermoset resins with characteristically lower heat release rates. All materials lost approximately 20-25% of their mass regardless of resin type, fiber orientation, or test configuration. Woven fiber composites displayed localized smoke jetting whereas uni-directional composites developed cracks parallel to the fibers from which smoke and flames emanated. Swelling and delamination were observed with volumetric expansion on the order of 100% to 200%. The purpose of this work was to provide validation data for SNL's foundational thermal and combustion modeling capabilities.

  5. FIBER ORIENTATION IN INJECTION MOLDED LONG CARBON FIBER THERMOPLASTIC COMPOSITES

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jin; Nguyen, Ba Nghiep; Mathur, Raj N.; Sharma, Bhisham; Sangid, Michael D.; Costa, Franco; Jin, Xiaoshi; Tucker III, Charles L.; Fifield, Leonard S.

    2015-03-23

    A set of edge-gated and center-gated plaques were injection molded with long carbon fiber-reinforced thermoplastic composites, and the fiber orientation was measured at different locations of the plaques. Autodesk Simulation Moldflow Insight (ASMI) software was used to simulate the injection molding of these plaques and to predict the fiber orientation, using the anisotropic rotary diffusion and the reduced strain closure models. The phenomenological parameters of the orientation models were carefully identified by fitting to the measured orientation data. The fiber orientation predictions show very good agreement with the experimental data.

  6. Fracture morphology of carbon fiber reinforced plastic composite laminates

    Directory of Open Access Journals (Sweden)

    Vinod Srinivasa

    2010-09-01

    Full Text Available Carbon fiber reinforced plastic (CFRP composites have been extensively used in fabrication of primary structures for aerospace, automobile and other engineering applications. With continuous and widespread use of these composites in several advanced technology, the frequency of failures is likely to increase. Therefore, to establish the reasons for failures, the fracture modes should be understood thoroughly and unambiguously. In this paper, CFRP composite have been tested in tension, compression and flexural loadings; and microscopic study with the aid of Scanning Electron Microscope (SEM has been performed on failed (fractured composite surfaces to identify the principle features of failure. Efforts have been made in correlating the fracture surface characteristics to the failure mode. The micro-mechanics analysis of failure serves as a useful guide in selecting constituent materials and designing composites from the failure behavior point of view. Also, the local failure initiation results obtained here has been reliably extended to global failure prediction.

  7. Global Carbon Fiber Composites Supply Chain Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Sujit Das, Josh Warren, Devin West, Susan M. Schexnayder

    2016-05-01

    This analysis identifies key opportunities in the carbon fiber supply chain where resources and investments can help advance the clean energy economy. The report focuses on four application areas — wind energy, aerospace, automotive, and pressure vessels — that top the list of industries using carbon fiber and carbon fiber reinforced polymers. For each of the four application areas, the report addresses the supply and demand trends within that sector, supply chain, and costs of carbon fiber and components.

  8. RC T beams strengthened to shear with carbon fiber composites

    Directory of Open Access Journals (Sweden)

    L. A. Spagnolo JR

    Full Text Available This paper presents the experimental data of the behavior of reinforced concrete beams strengthened to shear with carbon fiber composites. The tests were composed of eight T beams, b w=15 cm, h=40 cm, flange width 40 cm, flange height 8 cm, and length 300 cm, divided into two series with the same longitudinal steel reinforcement and a reference beam without strengthening in each series. The beams had two types of arrangement of internal steel stirrups. The test variables were the internal and external geometric ratio of the transverse reinforcement and the mechanical ratio of carbon fiber composites stirrups. All the beams were loaded at two points. The strengthened beams were submitted to a preloading and the strengthening was applied to the cracked beam. All the beams were designed in order to guarantee shear failure, and the ultimate load of the strengthened beams was 36% to 54% greater than the reference beams. The Cracking Sliding Model applied to the strengthened beams was evaluated and showed good agreement with the experimental results.

  9. 21 CFR 878.3500 - Polytetrafluoroethylene with carbon fibers composite implant material.

    Science.gov (United States)

    2010-04-01

    ... composite implant material. 878.3500 Section 878.3500 Food and Drugs FOOD AND DRUG ADMINISTRATION... Prosthetic Devices § 878.3500 Polytetrafluoroethylene with carbon fibers composite implant material. (a) Identification. A polytetrafluoroethylene with carbon fibers composite implant material is a porous...

  10. Hierarchical Carbon Fibers with ZnO Nanowires for Volatile Sensing in Composite Curing (Postprint)

    Science.gov (United States)

    2014-07-01

    AFRL-RX-WP-JA-2014-0171 HIERARCHICAL CARBON FIBERS WITH ZnO NANOWIRES FOR VOLATILE SENSING IN COMPOSITE CURING (POSTPRINT) Gregory...REPORT TYPE Interim 3. DATES COVERED (From – To) 16 April 2012 – 02 June 2014 4. TITLE AND SUBTITLE HIERARCHICAL CARBON FIBERS WITH ZnO NANOWIRES...needed to demonstrate the use of Zinc Oxide ( ZnO ) nanowire coated carbon fibers as a volatile sensor. ZnO nanowires are demonstrated to function as

  11. Rapid Fabrication of Carbide Matrix/Carbon Fiber Composites

    Science.gov (United States)

    Williams, Brian E.; Bernander, Robert E.

    2007-01-01

    Composites of zirconium carbide matrix material reinforced with carbon fibers can be fabricated relatively rapidly in a process that includes a melt infiltration step. Heretofore, these and other ceramic matrix composites have been made in a chemical vapor infiltration (CVI) process that takes months. The finished products of the CVI process are highly porous and cannot withstand temperatures above 3,000 F (approx.1,600 C). In contrast, the melt-infiltration-based process takes only a few days, and the composite products are more nearly fully dense and have withstood temperatures as high as 4,350 F (approx.2,400 C) in a highly oxidizing thrust chamber environment. Moreover, because the melt- infiltration-based process takes much less time, the finished products are expected to cost much less. Fabrication begins with the preparation of a carbon fiber preform that, typically, is of the size and shape of a part to be fabricated. By use of low-temperature ultraviolet-enhanced chemical vapor deposition, the carbon fibers in the preform are coated with one or more interfacial material(s), which could include oxides. The interfacial material helps to protect the fibers against chemical attack during the remainder of the fabrication process and against oxidation during subsequent use; it also enables slippage between the fibers and the matrix material, thereby helping to deflect cracks and distribute loads. Once the fibers have been coated with the interfacial material, the fiber preform is further infiltrated with a controlled amount of additional carbon, which serves as a reactant for the formation of the carbide matrix material. The next step is melt infiltration. The preform is exposed to molten zirconium, which wicks into the preform, drawn by capillary action. The molten metal fills most of the interstices of the preform and reacts with the added carbon to form the zirconium carbide matrix material. The zirconium does not react with the underlying fibers because they

  12. Tensile Properties of Polyimide Composites Incorporating Carbon Nanotubes-Grafted and Polyimide-Coated Carbon Fibers

    Science.gov (United States)

    Naito, Kimiyoshi

    2014-09-01

    The tensile properties and fracture behavior of polyimide composite bundles incorporating carbon nanotubes-grafted (CNT-grafted) and polyimide-coated (PI-coated) high-tensile-strength polyacrylonitrile (PAN)-based (T1000GB), and high-modulus pitch-based (K13D) carbon fibers were investigated. The CNT were grown on the surface of the carbon fibers by chemical vapor deposition. The pyromellitic dianhydride/4,4'-oxydianiline PI nanolayer coating was deposited on the surface of the carbon fiber by high-temperature vapor deposition polymerization. The results clearly demonstrate that CNT grafting and PI coating were effective for improving the Weibull modulus of T1000GB PAN-based and K13D pitch-based carbon fiber bundle composites. In addition, the average tensile strength of the PI-coated T1000GB carbon fiber bundle composites was also higher than that of the as-received carbon fiber bundle composites, while the average tensile strength of the CNT-grafted T1000GB, K13D, and the PI-coated K13D carbon fiber bundle composites was similar to that of the as-received carbon fiber bundle composites.

  13. Mechanical properties of carbon fiber composites for applications in space

    Science.gov (United States)

    Hana, P.; Inneman, A.; Daniel, V.; Sieger, L.; Petru, M.

    2015-01-01

    This article describes method of measurement mechanical properties of carbon fiber composites in space. New material structures are specifically designed for use on space satellites. Composite structures will be exposed to cosmic radiation in Earth orbit on board of a '2U CubeSat' satellite. Piezoelectric ceramic sensors are used for detection mechanical vibrations of composite test strip. A great deal of attention is paid to signal processing using 8-bit microcontroler. Fast Fourier Transformation is used. Fundamental harmonic frequencies and damping from on-board measurements will serve as the input data for terrestrial data processing. The other step of elaboration data is creation of the physical model for evaluating mechanical properties of Carbon composite - Piezoelectric ceramic system. Evaluation of anisotropic mechanical properties of piezoelectric ceramics is an interesting secondary outcome of the investigation. Extreme changes in temperature and the effect of cosmic rays will affect the mechanical properties and durability of the material used for the external construction of satellites. Comparative terrestrial measurements will be performed.

  14. Effect of electropolymer sizing of carbon fiber on mechanical properties of phenolic resin composites

    Institute of Scientific and Technical Information of China (English)

    LI Jin; FAN Qun; CHEN Zhen-hua; HUANG Kai-bing; CHENG Ying-liang

    2006-01-01

    Carbon fiber/phenolic resin composites were reinforced by the carbon fiber sized with the polymer films of phenol,m-phenylenediamine or acrylic acid,which was electropolymerized by cyclic voltammetry or chronopotentiometry. The contact angles of the sized carbon fibers with deionized water and diiodomethane were measured by the wicking method based on the modified Washburn equation,to show the effects of the different electropolymer film on the surface free energy of the carbon fiber after sizing by the electropolymerization. Compared with the unsized carbon fiber,which has 85.6°of contact angle of water,52.2° of contact angle of diiodomethane,and 33.1 mJ/m2 of surface free energy with 29.3 mJ/m2 of dispersive components (γL) and 3.8 mJ/m2 of polar components (γsp),respectively. It is found that the electropolymer sized carbon fiber tends to reduce the surface energy due to the decrease of dispersive γL with the increase of the polymer film on the surface of the carbon fiber that plays an important role in improving the mechanical properties of carbon/phenolic resin composites. Compared with the phenolic resin composites reinforced by the unsized carbon fiber,the impact,flexural and interlaminar shear strength of the phenolic resin composites were improved by 44 %,68% and 87% when reinforced with the carbon fiber sized by the electropolymer of m-phenylenediamine,66%,100%,and 112% by the electropolymer of phenol,and 20%,80 %,100% by the electropolymer of acrylic acid. The results indicate the skills of electropolymerization may provide a feasible method for the sizing of carbon fiber in a composite system,so as to improve the interfacial performance between the reinforce materials and the matrix and to increase the mechanical properties of the composites.

  15. Effect of anodic surface treatment on PAN-based carbon fiber and its relationship to the fracture toughness of the carbon fiber-reinforced polymer composites

    DEFF Research Database (Denmark)

    Sarraf, Hamid; Skarpova, Ludmila

    2008-01-01

    The effect of anodic surface treatment on the polyacrylonitrile (PAN)-based carbon fibers surface properties and the mechanical behavior of the resulting carbon fiber-polymer composites has been studied in terms of the contact angle measurements of fibers and the fracture toughness of composites...... in the fiber surface nature and the mechanical interfacial properties between the carbon fiber and epoxy resin matrix of the resulting composites, i.e., the fracture toughness. We suggest that good wetting plays an important role in improving the degree of adhesion at interfaces between fibers and matrices...

  16. Thermal conductivity, electrical conductivity and specific heat of copper-carbon fiber composite

    Science.gov (United States)

    Kuniya, Keiichi; Arakawa, Hideo; Kanai, Tsuneyuki; Chiba, Akio

    1988-01-01

    A new material of copper/carbon fiber composite is developed which retains the properties of copper, i.e., its excellent electrical and thermal conductivity, and the property of carbon, i.e., a small thermal expansion coefficient. These properties of the composite are adjustable within a certain range by changing the volume and/or the orientation of the carbon fibers. The effects of carbon fiber volume and arrangement changes on the thermal and electrical conductivity, and specific heat of the composite are studied. Results obtained are as follows: the thermal and electrical conductivity of the composite decrease as the volume of the carbon fiber increases, and were influenced by the fiber orientation. The results are predictable from a careful application of the rule of mixtures for composites. The specific heat of the composite was dependent, not on fiber orientation, but on fiber volume. In the thermal fatigue tests, no degradation in the electrical conductivity of this composite was observed.

  17. Global Carbon Fiber Composites. Supply Chain Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sujit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Warren, Joshua A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); West, Devin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schexnayder, Susan M. [Univ. of Tennessee, Knoxville, TN (United States)

    2016-05-01

    The objective of this study is to identify key opportunities in the carbon fiber (CF) supply chain where resources and investments can help advance the clean energy economy. The report focuses on four application areas—wind energy, aerospace, automotive, and pressure vessels—that top the list of industries using CF and carbon fiber reinforced polymers (CFRP) and are particularly relevant to the mission of U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (DOE EERE). For each of the four application areas, the report addresses the supply and demand trends within that sector, supply chain, and costs of carbon fiber and components.

  18. Piezoresistivity in Carbon Fiber Reinforced Cement Based Composites

    Institute of Scientific and Technical Information of China (English)

    Bing CHEN; Keru WU; Wu YAO

    2004-01-01

    The resu lts of some i nteresti ng investigation on the piezoresistivity of ca rbon fi ber reinforced cement based com posites (CFRC) are presented with the prospect of developing a new nondestructive testing method to assess the integrity of the composite. The addition of short carbon fibers to cement-based mortar or concrete improves the structural performance and at the same time significantly decreases the bulk electrical resistivity. This makes CFRC responsive to the smart behavior by measuring the resistance change with uniaxial pressure. The piezoresistivity of CFRC under different stress was studied, at the same time the damage occurring inner specimens was detected by acoustic emission as well. Test results show that there exists a marking pressure dependence of the conductivity in CFRC, in which the so-called negative pressure coefficient of resistive (NPCR) and positive pressure coefficient of resistive (PPCR) are observed under low and high pressure. Under constant pressures, time-dependent resistivity is an outstanding characteristic for the composites, which is defined as resistance creep. The breakdown and rebuild-up process of conductive network under pressure may be responsible for the pressure dependence of resistivity.

  19. Global Carbon Fiber Composites Supply Chain Competitiveness Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Das, Sujit [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Warren, Josh [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); West, Devin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Schexnayder, Susan M. [Univ. of Tennessee, Knoxville, TN (United States)

    2016-05-01

    This study identifies key opportunities in the carbon fiber supply chain where the United States Department of Energy's Office of Energy Efficiency and Renewable Energy resources and investments can help the United States achieve or maintain a competitive advantage. The report focuses on four application areas--wind energy, aerospace, automotive, and pressure vessels--that top the list of industries using carbon fiber and carbon fiber reinforced polymers and are also particularly relevant to EERE's mission. For each of the four application areas, the report addresses the supply and demand trends within that sector, supply chain, and costs of carbon fiber and components, all contributing to a competitiveness assessment that addresses the United States' role in future industry growth. This report was prepared by researchers at Oak Ridge National Laboratory and the University of Tennessee for the Clean Energy Manufacturing Analysis Center.

  20. Mechanical properties of carbon fiber/cellulose composite papers modified by hot-melting fibers

    OpenAIRE

    Yunzhou Shi; Biao Wang

    2014-01-01

    Carbon fiber (CF)/cellulose (CLS) composite papers were prepared by papermaking techniques and hot-melting fibers were used for modification. The mechanical properties of the obtained composite papers with different CF, CLS and hot-melting fiber ratios were studied and further discussed. It is observed that, for both CF/CLS composite papers and those modified by hot-melting fibers, the normal stress firstly increases and then declines with the addition of carbon fibers. The results also show ...

  1. Influence of carbon nanotubes coatings onto carbon fiber by oxidative treatments combined with electrophoretic deposition on interfacial properties of carbon fiber composite

    Science.gov (United States)

    Deng, Chao; Jiang, Jianjun; Liu, Fa; Fang, Liangchao; Wang, Junbiao; Li, Dejia; Wu, Jianjun

    2015-12-01

    To improve the interfacial performance of carbon fiber (CF) and epoxy resin, carbon nanotubes (CNTs) coatings were utilized to achieve this purpose through coating onto CF by the treatment with hydrogen peroxide and concentrated nitric acid combined with electrophoretic deposition (EPD) process. The influence of electrophoretically deposited CNTs coatings on the surface properties of CFs were investigated by Fourier transform infrared spectrometer, atomic force microscopy, scanning electron microscopy and dynamic contact angle analysis. The results indicated that the deposition of carbon nanotubes introduced some polar groups to carbon fiber surfaces, enhanced surface roughness and changed surface morphologies of carbon fibers. Surface wettability of carbon fibers may be significantly improved by increasing surface free energy of the fibers due to the deposition of CNTs. The thickness and density of the coatings increases with the introduction of pretreatment of the CF during the EPD process. Short beam shear test was performed to examine the effect of carbon fiber functionalization on mechanical properties of the carbon fiber/epoxy resin composites. The interfacial adhesion of CNTs/CF reinforced epoxy composites showed obvious enhancement of interlaminar shear strength by 60.2% and scanning electron microscope photographs showed that the failure mode of composites was changed after the carbon fibers were coated with CNTs.

  2. UV-cured adhesives for carbon fiber composite applications

    Science.gov (United States)

    Lu, Hsiao-Chun

    Carbon fiber composite materials are increasingly used in automobile, marine, and aerospace industries due to their unique properties, including high strength, high stiffness and low weight. However, due to their brittle characteristic, these structures are prone to physical damage, such as a bird strike or impact damage. Once the structure is damaged, it is important to have fast and reliable temporary repair until the permanent repair or replacement can take place. In this dissertation, UV-based adhesives were used to provide a bonding strength for temporary repair. Adhesively bonded patch repair is an efficient and effective method for temporary repair. In this study, precured patches (hard patches) and dry fabric patches with laminating resins (soft patches) were performed. UV-based epoxy adhesives were applied to both patch repair systems. For precured patch repair, the bonding strengths were investigated under different surface treatments for bonding area and different adhesives thicknesses. The shear stresses of different UV exposure times and curing times were tested. Besides, the large patch repair was investigated as well. For soft patch repair, the hand wet lay-up was applied due to high viscosity of UV resins. A modified single lap shear testing (ASTM D5868) was applied to determine the shear stress. The large patches used fiber glass instead of carbon fiber to prove the possibility of repair with UV epoxy resin by hand wet lay-up process. The hand lay-up procedure was applied and assisted by vacuum pressure to eliminate the air bubbles and consolidate the patches. To enhance the bonding strength and effective soft patch repair, vacuum assisted resin transferring molding (VaRTM) is the better option. However, only low viscosity resins can be operated by VaRTM. Hence, new UV-based adhesives were formulated. The new UV-based adhesives included photoinitiator (PI), epoxy and different solvents. Solvents were used to compound the photoinitiator into epoxy

  3. Optimization of interfacial properties of carbon fiber/epoxy composites via a modified polyacrylate emulsion sizing

    Science.gov (United States)

    Yuan, Xiaomin; Zhu, Bo; Cai, Xun; Liu, Jianjun; Qiao, Kun; Yu, Junwei

    2017-04-01

    The adhesion behavior of epoxy resin to carbon fibers has always been a challenge, on account of the inertness of carbon fibers and the lack of reactive functional groups. In this work, a modified polyacrylate sizing agent was prepared to modify the interface between the carbon fiber and the epoxy matrix. The surface characteristics of carbon fibers were investigated to determine chemical composition, morphology, wettability, interfacial phase analysis and interfacial adhesion. Sized carbon fibers featured improved wettability and a slightly decreased surface roughness due to the coverage of a smooth sizing layer, compared with the unsized ones. Moreover, the content of surface activated carbon atoms increased from 12.65% to 24.70% and the interlaminar shear strength (ILSS) of carbon fiber/epoxy composites raised by 14.2%, indicating a significant improvement of chemical activity and mechanical property. SEM images of the fractured surface of composites further proved that a gradient interfacial structure with increased thicknesses was formed due to the transition role of the sizing. Based on these results, a sizing mechanism consisting of chemical interaction bonding and physical force absorption was proposed, which provides an efficient and feasible method to solve the poor adhesion between carbon fiber and epoxy matrix.

  4. Effect of surface modification on carbon fiber and its reinforced phenolic matrix composite

    Science.gov (United States)

    Yuan, Hua; Wang, Chengguo; Zhang, Shan; Lin, Xue

    2012-10-01

    In this work, polyacrylonitrile (PAN)-based carbon fiber were chemically modified with H2SO4, KClO3 and silane coupling agent (γ-aminopropyltriethoxysilane, APS), and carbon fiber reinforced phenolic matrix composites were prepared. The structural and surface characteristics of the carbon fiber were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), laser Raman scattering (LRS) and Fourier transform infrared spectroscopy (FTIR). Single fiber mechanical properties, specific surface area, composite impact properties and interfacial shear strength (ILSS) were researched to indicate the effects of surface modification on fibers and the interaction between modified fiber surface and phenolic matrix. The results showed that carbon fiber surface modification by oxidation and APS can strengthen fiber surface chemical activity and enlarge the fiber surface area as well as its roughness. When carbon fiber (CF) is oxidized treatment, the oxygen content as well as the O/C ratio will be obviously increased. Oxygen functional groups increase with oxidation time increasing. Carbon fiber treated with APS will make Csbnd Osbnd R content increase and Osbnd Cdbnd O content decrease due to surface reaction. Proper treatment of carbon fiber with acid and silane coupling agent prove an effective way to increase the interfacial adhesion and improve the mechanical and outdoor performance of the resulting fiber/resin composites.

  5. Process Optimization of Bismaleimide (BMI) Resin Infused Carbon Fiber Composite

    Science.gov (United States)

    Ehrlich, Joshua W.; Tate, LaNetra C.; Cox, Sarah B.; Taylor, Brian J.; Wright, M. Clara; Caraccio, Anne J.; Sampson, Jeffery W.

    2013-01-01

    Bismaleimide (BMI) resins are an attractive new addition to world-wide composite applications. This type of thermosetting polyimide provides several unique characteristics such as excellent physical property retention at elevated temperatures and in wet environments, constant electrical properties over a vast array of temperature settings, and nonflammability properties as well. This makes BMI a popular choice in advance composites and electronics applications [I]. Bismaleimide-2 (BMI-2) resin was used to infuse intermediate modulus 7 (IM7) based carbon fiber. Two panel configurations consisting of 4 plies with [+45deg, 90deg]2 and [0deg]4 orientations were fabricated. For tensile testing, a [90deg]4 configuration was tested by rotating the [0deg]4 configirration to lie orthogonal with the load direction of the test fixture. Curing of the BMI-2/IM7 system utilized an optimal infusion process which focused on the integration of the manufacturer-recommended ramp rates,. hold times, and cure temperatures. Completion of the cure cycle for the BMI-2/IM7 composite yielded a product with multiple surface voids determined through visual and metallographic observation. Although the curing cycle was the same for the three panellayups, the surface voids that remained within the material post-cure were different in abundance, shape, and size. For tensile testing, the [0deg]4 layup had a 19.9% and 21.7% greater average tensile strain performance compared to the [90deg]4 and [+45deg, 90deg, 90deg,-45degg] layups, respectively, at failure. For tensile stress performance, the [0deg]4 layup had a 5.8% and 34.0% greater average performance% than the [90deg]4 and [+45deg, 90deg, 90deg,-45deg] layups.

  6. Repairable Woven Carbon Fiber Composites with Full Recyclability Enabled by Malleable Polyimine Networks.

    Science.gov (United States)

    Taynton, Philip; Ni, Huagang; Zhu, Chengpu; Yu, Kai; Loob, Samuel; Jin, Yinghua; Qi, H Jerry; Zhang, Wei

    2016-04-20

    Carbon-fiber reinforced composites are prepared using catalyst-free malleable polyimine networks as binders. An energy neutral closed-loop recycling process has been developed, enabling recovery of 100% of the imine components and carbon fibers in their original form. Polyimine films made using >21% recycled content exhibit no loss of mechanical performance, therefore indicating all of the thermoset composite material can be recycled and reused for the same purpose.

  7. Surface Characteristics of Rare Earth Treated Carbon Fibers and Interfacial Properties of Composites

    Institute of Scientific and Technical Information of China (English)

    Xu Zhiwei; Huang Yudong; Song Yuanjun; Zhang Chunhua; Liu Li

    2007-01-01

    Effect of rare earth treatment on surface physicochemical properties of carbon fibers and interfacial properties of carbon fiber/epoxy composites was investigated, and the interfacial adhesion mechanism of treated carbon fiber/epoxy composite was analyzed. It was found that rare earth treatment led to an increase of fiber surface roughness, improvement of oxygen-containing groups, and introduction of rare earth element on the carbon fiber surface. As a result, coordination linkages between fibers and rare earth, and between rare earth and resin matrix were formed separately, thereby the interlaminar shear strength (ILSS) of composites increased, which indicated the improvement of the interfacial adhesion between fibers and matrix resin resulting from the increase of carboxyl and carbonyl.

  8. Shockwave response of two carbon fiber-polymer composites to 50 GPa

    Science.gov (United States)

    Dattelbaum, Dana M.; Coe, Joshua D.; Rigg, Paulo A.; Scharff, R. Jason; Gammel, J. Tinka

    2014-11-01

    Shock compression of two molded, carbon fiber-filled polymer composites was performed in gas gun-driven plate impact experiments at impact velocities up to ≈5 km/s. Hugoniot states for both composites were obtained from chopped carbon fibers, bound by either phenolic or cyanate ester polymeric resins. Their dynamic responses were similar, although the 10 wt. % difference of carbon fill produced measureable divergence in shock compressibility. The chopped carbon fibers in the polymer matrix led to moderately anisotropic shocks, particularly when compared with the more commonly encountered filament-wound carbon fiber-epoxy composites. A discontinuity, or cusp, was observed in the principal Hugoniot of both materials near 25 GPa. We attribute the accompanying volume collapse to shock-driven chemical decomposition above this condition. Inert and reacted products equations of state were used to capture the response of the two materials below and above the cusp.

  9. Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite.

    Science.gov (United States)

    Petersen, Richard C

    2014-12-01

    The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC) solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo properties, electrical

  10. Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2014-12-01

    Full Text Available The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo

  11. Circuit models for Salisbury screens made from unidirectional carbon fiber composite sandwich structures

    Science.gov (United States)

    Riley, Elliot J.; Lenzing, Erik H.; Narayanan, Ram M.

    2016-05-01

    Carbon fiber composite materials have many useful structural material properties. The electromagnetic perfor- mance of these materials is of great interest for future applications. The work presented in this paper deals with the construction of Salisbury screen microwave absorbers made from unidirectional carbon fiber composite sand- wich structures. Specifically, absorbers centered at 7.25 GHz and 12.56 GHz are investigated. Circuit models are created to match the measured performance of the carbon fiber Salisbury screens using a genetic algorithm to extract lumped element circuit values. The screens presented in this paper utilize unidirectional carbon fiber sheets in place of the resistive sheet utilized in the classic Salisbury screen. The theory, models, prototypes, and measurements of these absorbers are discussed.

  12. Hansen solubility parameters for a carbon fiber/epoxy composite

    DEFF Research Database (Denmark)

    Launay, Helene; Hansen, Charles M.; Almdal, Kristoffer

    2007-01-01

    In this study, the physical affinity between an epoxy matrix and oxidized, unsized carbon fibers has been evaluated using Hansen solubility (cohesion) parameters (HSP). A strong physical compatibility has been shown, since their respective HSP are close. The use of a glassy carbon substrate...

  13. Rheological behavior of composites based on carbon fibers recycled from aircraft waste

    OpenAIRE

    Marcaníková, Lucie; Hausnerová, Berenika; KITANO, Takeshi

    2009-01-01

    Rheological investigation of composite materials prepared from the recycled aircraft waste materials based on thermoset (epoxy/resin) matrix and long carbon fibers (CF) is presented with the aim of their utilization in consumer industry applications. The carbon fibers recovered via thermal process of pyrolysis were cut into about 150 pm length and melt mixed with thermoplastic matrices based on polypropylene (PP) and polyamide 6 (PA) and various modifiers - ethylene-ethyl acrylate-maleic anhy...

  14. Interfacial enhancement of carbon fiber composites by generation 1–3 dendritic hexamethylenetetramine functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Lichun; Meng, Linghui [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Fan, Dapeng [College of Material and Chemical Engineering, Heilongjiang Institute of Technology (China); He, Jinmei; Yu, Jiali; Qi, Meiwei; Chen, Zhongwu [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Huang, Yudong, E-mail: ydhuang.hit1@yahoo.com.cn [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

    2014-03-01

    Highlights: • A new chemical grafting method for carbon fibers was proposed. • The oxidation system adopts K{sub 2}S{sub 2}O{sub 8} and AgNO{sub 3}. • The interfacial shear strength (IFSS) of carbon fiber increased by 61%, and the interfacial adhesion increased with dendritic generation number. • The tensile strength of carbon fiber does not decrease distinctly. • The treatment conditions are mild and convenient. - Abstract: PAN-based carbon fibers (CF) were functionalized with generation (n) 1–3 dendritic hexamethylenetetramine (HMTA) (denoted as CF-G{sub n}-HMTA, n = 1, 2 and 3) in an attempt to improve the interfacial properties between carbon fibers and epoxy matrix. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), dynamic contact angle analysis (DCA), interfacial shear strength (IFSS) and single fiber tensile testing were carried out to investigate the functionalization process of carbon fibers and the interfacial properties of the composites. Experimental results showed that generation (n) 1–3 dendritic hexamethylenetetramine was grafted uniformly on the fiber surface through the chemical reaction, and then it increased significantly the fiber surface polarity and roughness. The surface energy and IFSS of carbon fibers increased obviously after the graft CF-G{sub 3}-HMTA, by 147.6% and 81%, respectively. Generation (n) 1–3 dendritic hexamethylenetetramine enhanced effectively the interfacial adhesion of the composites by improving resin wettability, increasing chemical bonding and mechanical interlocking, and the interfacial adhesion increased with dendritic generation number. Moreover, the grafting of generation (n) 1–3 dendritic hexamethylenetetramine on the carbon fiber surface improved the fiber tensile strength, which is beneficial to the in-plane properties of the resulting composites.

  15. Characterization of carbon fibers and fiber-matrix adhesion in composites

    Science.gov (United States)

    Wightman, J. P.; Devilbiss, T. A.

    1985-01-01

    The effect of fiber/matrix interactions on the mechanical properties of thermoplastic carbon fiber composites was determined. The experimental approach was a multi-faceted one involving the following areas: characterization of the surface of carbon fibers using X-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS) and scanning transmission electron microcopy (STEM); determination of the functional groups on carbon fiber surfaces using an elemental tagging scheme - derivatization; determination of the polar and dispersion contribution to the surface energy of carbon fibers by measuring wetting forces in a series of liquids having known polar and dispersion components; and study of the interaction of thermoplastic polymers with carbon surfaces by solution adsorption, STEM and fiber critical length.

  16. Electromagnetic Interference Shielding Properties of Electroless Nickel-coated Carbon Fiber Paper Reinforced Epoxy Composites

    Institute of Scientific and Technical Information of China (English)

    CHEN Wei; WANG Jun; WANG Tao; WANG Junpeng; XU Renxin; YANG Xiaoli

    2014-01-01

    Carbon fibers (CFs) were coated with a nickel-phosphorus (Ni-P) film using an electroless plating process. The morphology, elemental composition and phases in the coating layer of the CFs were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD), respectively. Wet paper-making method was used to prepare nickle coated carbon fiber paper (NCFP). Vacuum assisted infusion molding process (VAIMP) was employed to manufacture the NCFP reinforced epoxy composites, and carbon fiber paper (CFP) reinforced epoxy composites were also produced as a comparison. Electromagnetic interference (EMI) shielding properties of the composites were measured in the 3.22-4.9 GHz frequency range using waveguide method. Both NCFP and CFP reinforced epoxy composites of 0.5 mm thickness exhibited high EMI shielding effectiveness (SE) at 8wt%fiber content, 35 dB and 30 dB, respectively, and reflection was the dominant shielding mechanism.

  17. RTA-treated carbon fiber/copper core/shell hybrid for thermally conductive composites.

    Science.gov (United States)

    Yu, Seunggun; Park, Bo-In; Park, Cheolmin; Hong, Soon Man; Han, Tae Hee; Koo, Chong Min

    2014-05-28

    In this paper, we demonstrate a facile route to produce epoxy/carbon fiber composites providing continuous heat conduction pathway of Cu with a high degree of crystal perfection via electroplating, followed by rapid thermal annealing (RTA) treatment and compression molding. Copper shells on carbon fibers were coated through electroplating method and post-treated via RTA technique to reduce the degree of imperfection in the Cu crystal. The epoxy/Cu-plated carbon fiber composites with Cu shell of 12.0 vol % prepared via simple compression molding, revealed 18 times larger thermal conductivity (47.2 W m(-1) K(-1)) in parallel direction and 6 times larger thermal conductivity (3.9 W m(-1) K(-1)) in perpendicular direction than epoxy/carbon fiber composite. Our novel composites with RTA-treated carbon fiber/Cu core/shell hybrid showed heat conduction behavior of an excellent polymeric composite thermal conductor with continuous heat conduction pathway, comparable to theoretical values obtained from Hatta and Taya model.

  18. Determination of Water Diffusion Coefficients and Dynamics in Adhesive/ Carbon Fiber Reinforced Epoxy Resin Composite Joints

    Institute of Scientific and Technical Information of China (English)

    WANG Chao; WANG Zhi; WANG Jing; SU Tao

    2007-01-01

    To determinate the water diffusion coefficients and dynamics in adhesive/carbon fiber reinforced epoxy resin composite joints, energy dispersive X-ray spectroscopy analysis(EDX) is used to establish the content change of oxygen in the adhesive in adhesive/carbon fiber reinforced epoxy resin composite joints. As water is made up of oxygen and hydrogen, the water diffusion coefficients and dynamics in adhesive/carbon fiber reinforced epoxy resin composite joints can be obtained from the change in the content of oxygen in the adhesive during humidity aging, via EDX analysis. The authors have calculated the water diffusion coefficients and dynamics in the adhesive/carbon fiber reinforced epoxy resin composite joints with the aid of both energy dispersive X-ray spectroscopy and elemental analysis. The determined results with EDX analysis are almost the same as those determined with elemental analysis and the results also show that the durability of the adhesive/carbon fiber reinforced epoxy resin composite joints subjected to silane coupling agent treatment is better than those subjected to sand paper burnishing treatment and chemical oxidation treatment.

  19. RADAR ABSORPTION PROPERTY AND MECHANISM OF CARBON FIBER AND CARBON FIBER COMPOSITES%炭纤维及其复合材料的吸波性能和吸波机理

    Institute of Scientific and Technical Information of China (English)

    赵东林; 沈曾民; 迟伟东

    2001-01-01

    炭纤维和炭纤维复合材料在隐身技术中已经得到了广泛应用。通过分析连续炭纤维、短切炭纤维、螺旋形炭纤维、异形截面炭纤维、掺杂改性炭纤维及其复合材料的微波电磁特性和吸波性能,探讨了以上几种炭纤维的吸波机理,其中螺旋形炭纤维和异形截面炭纤维是最有发展前景的两种吸波炭纤维。%Carbon fiber and carbon fiber composites are widely used in stealth technology. Microwave permittivities and permeabilities and radar absorption properties of continuous carbon fiber, shot carbon fibers, coiled carbon fibers, non-circular carbon fibers, modified carbon fibers and carbon fiber composites were discussed. The radar absorption mechanisms of these carbon fibers and carbon fiber composites were analyzed. The coiled carbon fibers and non-circular carbon fibers are two kinds of the most promising candidates for radar absorbing material.

  20. Research on the melt impregnation of continuous carbon fiber reinforced nylon 66 composites

    Science.gov (United States)

    Jia, M. Y.; Li, C. X.; Xue, P.; Chen, K.; Chen, T. H.

    2016-07-01

    Impregnation mold of continuous carbon fiber reinforced thermoplastic composites was designed and built in the article. Based on the theory of fluid mechanics and Darcy's law, a model of the melt impregnation was also established. The influences of fiber bundle width and impregnation pins’ diameter on the impregnation degree were studied by numerical simulation. Continuous carbon fiber reinforced nylon 66 composites were prepared. The effects of coated angle and impregnation mold temperature on the mechanical properties of the composites were also described.The agreement between the experimental data and prediction by the model was found to be satisfactory.

  1. EXPERIMENTAL STUDY ON PEK-C MODIFIED EPOXIES AND THE CARBON FIBER COMPOSITES FOR AEROSPACE APPLICATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The morphological structure of various epoxies toughened with a special amorphous thermoplastic PEK-C and their carbon fiber composites were studied by using SEM. For both cases, phase separation and inversion took place to form fine epoxy-rich globules dispersing in the PEK-C matrix, in which the epoxy-rich phase had the absolutely higher volume fraction. The phase structure and the interfacial properties were also studied by means of FTIR, DSC, and DMTA as well. An accompanying mechanical determination revealed that an improved toughness was achieved both in the blend casts and in the carbon fiber composites. A composite structural model was hence suggested.

  2. Surface and sub-surface degradation of unidirectional carbon fiber reinforced epoxy composites under dry and wet reciprocating sliding

    OpenAIRE

    Dhieb, H.; Buijnsters, J.G.; Eddoumy, F.; Vázquez, Luis; Celis, J. P.

    2013-01-01

    The role of water on the sub-surface degradation of unidirectional carbon fiber reinforced epoxy composite is examined. The correlation between the debonding of carbon fibers at the fiber-epoxy interface, and the wear behavior of the carbon fiber composite are discussed based on an in-depth analysis of the worn surfaces. We demonstrate that a reciprocating sliding performed along an anti-parallel direction to the fiber orientation under dry conditions results in a large degradation by debondi...

  3. Interfacial enhancement of carbon fiber composites by generation 1-3 dendritic hexamethylenetetramine functionalization

    Science.gov (United States)

    Ma, Lichun; Meng, Linghui; Fan, Dapeng; He, Jinmei; Yu, Jiali; Qi, Meiwei; Chen, Zhongwu; Huang, Yudong

    2014-03-01

    PAN-based carbon fibers (CF) were functionalized with generation (n) 1-3 dendritic hexamethylenetetramine (HMTA) (denoted as CF-Gn-HMTA, n = 1, 2 and 3) in an attempt to improve the interfacial properties between carbon fibers and epoxy matrix. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), dynamic contact angle analysis (DCA), interfacial shear strength (IFSS) and single fiber tensile testing were carried out to investigate the functionalization process of carbon fibers and the interfacial properties of the composites. Experimental results showed that generation (n) 1-3 dendritic hexamethylenetetramine was grafted uniformly on the fiber surface through the chemical reaction, and then it increased significantly the fiber surface polarity and roughness. The surface energy and IFSS of carbon fibers increased obviously after the graft CF-G3-HMTA, by 147.6% and 81%, respectively. Generation (n) 1-3 dendritic hexamethylenetetramine enhanced effectively the interfacial adhesion of the composites by improving resin wettability, increasing chemical bonding and mechanical interlocking, and the interfacial adhesion increased with dendritic generation number. Moreover, the grafting of generation (n) 1-3 dendritic hexamethylenetetramine on the carbon fiber surface improved the fiber tensile strength, which is beneficial to the in-plane properties of the resulting composites.

  4. Numerical and Experimental Investigations on Deep Drawing of G1151 Carbon Fiber Woven Composites

    Science.gov (United States)

    Gherissi, A.; Abbassi, F.; Ammar, A.; Zghal, A.

    2016-06-01

    This study proposes to simulate the deep drawing on carbon woven composites in order to reduce the manufacturing cost and waste of composite material during the stamping process, The multi-scale anisotropic approach of woven composite was used to develop a finite element model for simulating the orientation of fibers accurately and predicting the deformation of composite during mechanical tests and forming process. The proposed experimental investigation for bias test and hemispherical deep drawing process is investigated in the G1151 Interlock. The mechanical properties of carbon fiber have great influence on the deformation of carbon fiber composites. In this study, shear angle-displacement curves and shear load-shear angle curves were obtained from a bias extension test. Deep drawing experiments and simulation were conducted, and the shear load-displacement curves under different forming depths and shear angle-displacement curves were obtained. The results showed that the compression and shear between fibers bundles were the main deformation mechanism of carbon fiber woven composite, as well as the maximum shear angle for the composites with G1151 woven fiber was 58°. In addition, during the drawing process, it has been found that the forming depth has a significant influence on the drawing force. It increases rapidly with the increasing of forming depth. In this approach the suitable forming depth deep drawing of the sheet carbon fiber woven composite was approximately 45 mm.

  5. Curing agent for polyepoxides and epoxy resins and composites cured therewith. [preventing carbon fiber release

    Science.gov (United States)

    Serafini, T. T.; Delvigs, P.; Vannucci, R. D. (Inventor)

    1981-01-01

    A curing for a polyepoxide is described which contains a divalent aryl radical such as phenylene a tetravalent aryl radical such as a tetravalent benzene radical. An epoxide is cured by admixture with the curing agent. The cured epoxy product retains the usual properties of cured epoxides and, in addition, has a higher char residue after burning, on the order of 45% by weight. The higher char residue is of value in preventing release to the atmosphere of carbon fibers from carbon fiber-epoxy resin composites in the event of burning of the composite.

  6. Development of Carbon Fiber Reinforced Stellite Alloy Based Composites for Tribocorrosion Applications

    Science.gov (United States)

    Khoddamzadeh, Alireza

    This thesis reports the design and development of two classes of new composite materials, which are low-carbon Stellite alloy matrices, reinforced with either chopped plain carbon fiber or chopped nickel-coated carbon fiber. The focus of this research is on obviating the problems related to the presence of carbides in Stellite alloys by substituting carbides as the main strengthening agent in Stellite alloys with the aforementioned carbon fibers. Stellite 25 was selected as the matrix because of its very low carbon content (0.1 wt%) and thereby relatively carbide free microstructure. The nickel coating was intended to eliminate any chance of carbide formation due to the possible reaction between carbon fibers and the matrix alloying additions. The composite specimens were fabricated using the designed hot isostatic pressing and sintering cycles. The fabricated specimens were microstructurally analyzed in order to identify the main phases present in the specimens and also to determine the possible carbide formation from the carbon fibers. The material characterization of the specimens was achieved through density, hardness, microhardness, corrosion, wear, friction, and thermal conductivity tests. These novel materials exhibit superior properties compared to existing Stellite alloys and are expected to spawn a new generation of materials used for high temperature, severe corrosion, and wear resistant applications in various industries.

  7. Preparation and characterization of boron nitride/carbon fiber composite with high specific surface area

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Yan; Fan, Mingwen [Wuhan Univ. (China). Key Laboratory for Oral Biomedical Engineering; Yuan, Songdong; Xiong, Kun; Hu, Kunpeng; Luo, Yi [Hubei Univ. of Technology, Wuhan (China). School of Chemistry and Chemical Engineering; Li, Dong [Hubei Univ. of Technology, Wuhan (China). School of Chemistry and Chemical Engineering; Oxford Univ. (United Kingdom). Chemistry Research Lab.

    2014-06-15

    Boron nitride can be used as a good catalyst carrier because of its high thermal conductivity and chemical stability. However, a high specific surface area of boron nitride is still desirable. In this work, a carbon fiber composite coated with boron nitride villous nano-film was prepared, and was also characterized by means of scanning electron microscopy, high resolution transmission electron microscopy, Fourier transform infrared spectroscopy, and Brunauer-Emmett-Teller analysis. The results indicated that the carbon fibers were covered by uniform villous boron nitride films whose thickness was about 150 - 200 nm. The specific surface area of the boron nitride/carbon fiber composite material was 96 m{sup 2} g{sup -1}, which was markedly improved compared with conventional boron nitride materials. (orig.)

  8. Friction Behaviour of Polymeric Composite Materials Mixed with Carbon Fibers Having Different Orientations Layout

    Science.gov (United States)

    Caliman, R.

    2016-06-01

    This paper presents a study of the friction properties of polymeric composite materials reinforced with unidirectional carbon fibers having different stratified structure. So, the composites are complex and versatile materials but their behaviour in practice is not fully studied. For instance, these polymeric composite materials mixed with carbon fibers after being investigated in terms of wear, did not elucidate the effect of fiber orientation on wear properties. Is therefore necessary to investigate the effect of carbon fibers orientation on the friction-wear properties of the reinforced composite materials tested to abrasive and adhesive friction. Research work has been done with unidirectional composite materials having overlap 18 successive layers made from a polymeric resine and 60% of carbon fibers. The stratified structure was obtained by compressing multiple pre-impregnated strips, positioned manually. During this experimental work, three types of test samples were investigated: parallel, normal and anti-parallel, taking in consideration the carbon fibre orientation with respect to the sliding direction. The friction coefficient is computed function to the friction load and loading value. Also, the specific wear rate was calculated according to: the mass loss, density, the normal contact surface, the sliding distance and load rating.

  9. Toughness and Hot/Wet Properties of a Novel Modified BMI/Carbon Fiber Composite

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The toughness and hot/wet properties of a novel modified bismaleimide (BMI) 5428/carbon fiber composite was investigated. Results indicate that the prepared BMI/T700 composite owns high toughness, excellent hot/wet properties and mechanical properties. The compression strength after impact (CAl) of 5428/T700 composite is 260 MPa, and the results of hot/wet test show that the long-term service temperature of 5428/T700 composite can maintain at 170°C.

  10. Size Classification of Chopped Carbon Fibers in the Composite Materials Manufacturing

    Directory of Open Access Journals (Sweden)

    А.S. Dovbysh

    2010-01-01

    Full Text Available Information synthesis of the learning decision support system for automation of the chopped carbon fibers size control used for the matrix filling within the manufacturing of composite materials based on polytetrafluoroethylene is considered. To improve the reliability of recognition learning algorithm with the optimization of the precision control is proposed.

  11. Size Classification of Chopped Carbon Fibers in the Composite Materials Manufacturing

    OpenAIRE

    А.S. Dovbysh; А.F. Budnik; N.І. Andriienko

    2010-01-01

    Information synthesis of the learning decision support system for automation of the chopped carbon fibers size control used for the matrix filling within the manufacturing of composite materials based on polytetrafluoroethylene is considered. To improve the reliability of recognition learning algorithm with the optimization of the precision control is proposed.

  12. Bisphenyl-Polymer/Carbon-Fiber-Reinforced Composite Compared to Titanium Alloy Bone Implant

    Directory of Open Access Journals (Sweden)

    Richard C. Petersen

    2011-01-01

    Full Text Available Aerospace/aeronautical thermoset bisphenyl-polymer/carbon-fiber-reinforced composites are considered as new advanced materials to replace metal bone implants. In addition to well-recognized nonpolar chemistry with related bisphenol-polymer estrogenic factors, carbon-fiber-reinforced composites can offer densities and electrical conductivity/resistivity properties close to bone with strengths much higher than metals on a per-weight basis. In vivo bone-marrow tests with Sprague-Dawley rats revealed far-reaching significant osseoconductivity increases from bisphenyl-polymer/carbon-fiber composites when compared to state-of-the-art titanium-6-4 alloy controls. Midtibial percent bone area measured from the implant surface increased when comparing the titanium alloy to the polymer composite from 10.5% to 41.6% at 0.8 mm, P<10−4, and 19.3% to 77.7% at 0.1 mm, P<10−8. Carbon-fiber fragments planned to occur in the test designs, instead of producing an inflammation, stimulated bone formation and increased bone integration to the implant. In addition, low-thermal polymer processing allows incorporation of minerals and pharmaceuticals for future major tissue-engineering potential.

  13. Anodization of carbon fibers on interfacial mechanical properties of epoxy matrix composites.

    Science.gov (United States)

    Park, Soo-Jin; Chang, Yong-Hwan; Kim, Yeong-Cheol; Rhee, Kyong-Yop

    2010-01-01

    The influence of anodic oxidation on the mechanical interfacial properties of carbon-fiber-reinforced epoxy resin composites was investigated. The surface properties of the anodized carbon fibers were studied through the measurement of contact angles and through SEM, XPS, and FT-IR analyses. The mechanical interfacial properties of the composites were studied through measurements of interlaminar shear strength (ILSS), critical stress intensity factor (K(IC)), and critical strain energy release rate (G(IC)). It was shown that the surface functional groups containing oxygen on the anodized carbon fibers exert great effects on the surface energetics of fibers and the mechanical interfacial properties, e.g., ILSS, of the resulting composites. Contact angle measurements based on the wicking rate of a test liquid showed that anodic oxidation lead to an increase in the surface free energy of the carbon fibers, mainly in its specific (or polar) component. In terms of surface energetics, it was found that wetting played an important role in increasing the degree of adhesion at interfaces between the fibers and the resin matrices of the composites.

  14. Effects of carbon fiber surface characteristics on interfacial bonding of epoxy resin composite subjected to hygrothermal treatments

    Science.gov (United States)

    Li, Min; Liu, Hongxin; Gu, Yizhuo; Li, Yanxia; Zhang, Zuoguang

    2014-01-01

    The changes of interfacial bonding of three types of carbon fibers/epoxy resin composite as well as their corresponding desized carbon fiber composites subjecting to hygrothermal conditions were investigated by means of single fiber fragmentation test. The interfacial fracture energy was obtained to evaluate the interfacial bonding before and after boiling water aging. The surface characteristics of the studied carbon fiber were characterized using X-ray photoelectron spectroscopy. The effects of activated carbon atoms and silicon element at carbon fiber surface on the interfacial hygrothermal resistance were further discussed. The results show that the three carbon fiber composites with the same resin matrix possess different hygrothermal resistances of interface and the interfacial fracture energy after water aging can not recovery to the level of raw dry sample (irreversible changes) for the carbon fiber composites containing silicon. Furthermore, the activated carbon atoms have little impact on the interfacial hygrothermal resistance. The irreversible variations of interfacial bonding and the differences among different carbon fiber composites are attributed to the silicon element on the carbon fiber bodies, which might result in hydrolyzation in boiling water treatment and degrade interfacial hygrothermal resistance.

  15. Carbon fiber/carbon nanotube reinforced hierarchical composites: Effect of CNT distribution on shearing strength

    DEFF Research Database (Denmark)

    Zhou, H. W.; Mishnaevsky, Leon; Yi, H. Y.;

    2016-01-01

    The strength and fracture behavior of carbon fiber reinforced polymer composites with carbon nanotube (CNT) secondary reinforcement are investigated experimentally and numerically. Short Beam Shearing tests have been carried out, with SEM observations of the damage evolution in the composites. 3D...... multiscale computational (FE) models of the carbon/polymer composite with varied CNT distributions have been developed and employed to study the effect of the secondary CNT reinforcement, its distribution and content on the strength and fracture behavior of the composites. It is shown that adding secondary...... CNT nanoreinforcement into the matrix and/or the sizing of carbon fiber/reinforced composites ensures strong increase of the composite strength. The effect of secondary CNTs reinforcement is strongest when some small addition of CNTs in the polymer matrix is complemented by the fiber sizing with high...

  16. The effect of exfoliated graphite on carbon fiber reinforced composites for cryogenic applications

    Science.gov (United States)

    McLaughlin, Adam Michael

    It is desirable to lighten cryogenic fuel tanks through the use of composites for the development of a reusable single stage launch vehicle. Conventional composites fall victim to microcracking due to the cyclic loading and temperature change experienced during launch and re-entry conditions. Also, the strength of a composite is generally limited by the properties of the matrix. The introduction of the nanoplatelet, exfoliated graphite or graphene, to the matrix shows promise of increasing both the microcracking resistivity and the mechanical characteristics. Several carbon fiber composite plates were manufactured with varying concentrations of graphene and tested under both room and cryogenic conditions to characterize graphene's effect on the composite. Results from tensile and fracture testing indicate that the ideal concentration of graphene in our carbon fiber reinforced polymer composites for cryogenic applications is 0.08% mass graphene.

  17. Interlaminar damage of carbon fiber reinforced polymer composite laminate under continuous wave laser irradiation

    Science.gov (United States)

    Liu, Yan-Chi; Wu, Chen-Wu; Huang, Yi-Hui; Song, Hong-Wei; Huang, Chen-Guang

    2017-01-01

    The interlaminar damages were investigated on the carbon fiber reinforced polymer (CFRP) composite laminate under laser irradiation. Firstly, the laminated T700/BA9916 composites were exposed to continuous wave laser irradiation. Then, the interface cracking patterns of such composite laminates were examined by optical microscopy and scanning electron microscopy. Finally, the Finite Element Analysis (FEA) was performed to compute the interface stress of the laminates under laser irradiation. And the effects of the laser parameters on the interlaminar damage were discussed.

  18. Macroscopic Crosslinked Neat Carbon Nanotube Materials and CNT/Carbon Fiber Hybrid Composites: Supermolecular Structure and New Failure Mode Study

    Science.gov (United States)

    2015-10-01

    bubbles in carbon fiber layers were not able to be expelled, resulting in a high void content. In contrast to the CF layers, SEM examination indicated... Reinforcement on the Processing and the Mechanical Behaviour of Carbon Fiber/epoxy Composites. Carbon 2009, 47 (12), 2914–2923. (135) Kharisov, B. I...50  4.4 Permeability  Results

  19. STUDY OF DEPENDENCE OF POLYETHYLENE AND CARBON FIBERS COMPOSITES PROPERNIES ON SURFACE CHARACTERISTICS OF FIBER AND TYPE OF SAMPLES

    Directory of Open Access Journals (Sweden)

    Petukhova E. S.

    2015-06-01

    Full Text Available PE2NT11 and chopped carbon fibers and PE2NT11 and modified carbon fibers composites were investigated. It was shown that the mechanical properties depend on the surface characteristics of fibers. It was found that laboratory and tube samples have some difference in mechanical properties that connected with specific distribution of fibers in samples

  20. STUDY OF DEPENDENCE OF POLYETHYLENE AND CARBON FIBERS COMPOSITES PROPERNIES ON SURFACE CHARACTERISTICS OF FIBER AND TYPE OF SAMPLES

    OpenAIRE

    Petukhova E. S.

    2015-01-01

    PE2NT11 and chopped carbon fibers and PE2NT11 and modified carbon fibers composites were investigated. It was shown that the mechanical properties depend on the surface characteristics of fibers. It was found that laboratory and tube samples have some difference in mechanical properties that connected with specific distribution of fibers in samples

  1. Aging life evaluation of a new carbon fiber composite core wire

    Science.gov (United States)

    Cao, Jiangming; Wang, Zhihua; Zhang, Yongbo; Fu, Huimin

    2017-01-01

    The carbon fiber composite core wire is the key component for new overhead transmission lines in the power industry. As the primary load-bearing member, the composite mandrel will produce long-term creep because of the tensile during operation. Therefore, designers need to understand the long-term deformation behaviour of the composite mandrel to assess its durability. To this end, an accelerated creep test on the composite core rod under different temperatures and stresses has been conducted in the current study. According to the time- temperature- stress superposition principle, the shift factors are calculated, and the creep under normal working condition is predicted. Results show that the carbon fiber composite core wire can satisfy the design requirements under normal working condition.

  2. Properties of glass/carbon fiber reinforced epoxy hybrid polymer composites

    Science.gov (United States)

    Patel, R. H.; Sevkani, V. R.; Patel, B. R.; Patel, V. B.

    2016-05-01

    Composite Materials are well known for their tailor-made properties. For the fabrication of composites different types of reinforcements are used for different applications. Sometimes for a particular application, one type of reinforcement may not fulfill the requirements. Therefore, more than one type of reinforcements may be used. Thus, the idea of hybrid composites arises. Hybrid composites are made by joining two or more different reinforcements with suitable matrix system. It helps to improve the properties of composite materials. In the present work glass/carbon fiber reinforcement have been used with a matrix triglycidyl ether of tris(m-hydroxy phenyl) phosphate epoxy resin using amine curing agent. Different physical and mechanical properties of the glass, carbon and glass/carbon fiber reinforced polymeric systems have been found out.

  3. Effect of Rare Earths on Tribological Properties of Carbon Fibers Reinforced PTFE Composites

    Institute of Scientific and Technical Information of China (English)

    Shangguan Qianqian; Cheng Xianhua

    2007-01-01

    Carbon fibers (CF) were surface treated with air-oxidation and rare earths (RE), respectively. The effect of RE surface treatment on tensile strength and tribological properties of CF reinforced polytetrafluoroethylene (PTFE) composites was investigated. Experimental results revealed that RE was superior to air oxidation in improving the tensile strength, elongation, and the tensile modulus of CF reinforced PTFE (CF/PTFE) composite. Compared to the untreated and air-oxidated CF/PTFE composite, the RE treated composite had the lowest friction coefficient and specific wear rate under a given applied load and reciprocating sliding frequency. The RE treatment effectively improved the interfacial adhesion between CF and PTFE. With strong interfacial coupling, the carbon fibers carried most of the load, and direct contact and adhesion between PTFE and the counterpart were reduced, accordingly the friction and wear properties of the composite were improved.

  4. Surface Characterization of Carbon Fiber Polymer Composites and Aluminum Alloys After Laser Interference Structuring

    Science.gov (United States)

    Sabau, Adrian S.; Greer, Clayton M.; Chen, Jian; Warren, Charles D.; Daniel, Claus

    2016-07-01

    The increasing use of carbon fiber-reinforced polymer matrix composites (CFPC) and aluminum alloys as lightweight materials in the automotive and aerospace industries demands enhanced surface preparation and control of surface morphology prior to joining. In this study, surfaces of both composite and aluminum were prepared for joining using an Nd:YAG laser in a two-beam interference setup, enabling the (1) structuring of the AL 5182 surface, (2) removal of the resin layer on top of carbon fibers, and (3) structuring of the carbon fibers. CFPC specimens of T700S carbon fiber, Prepreg—T83 epoxy, 5 ply thick, 0°/90° plaques were used. The effects of laser fluence, scanning speed, and number of shots-per-spot were investigated on the removal rate of the resin without an excessive damage of the fibers. Optical micrographs, 3D imaging, and scanning electron microscope imaging were used to study the effect of the laser processing on the surface morphology. It was found that an effective resin ablation and a low density of broken fibers for CFPC specimens was attained using laser fluences of 1-2 J/cm2 and number of 2-4 pulses per spot. A relatively large area of periodic line structures due to energy interference were formed on the aluminum surface at laser fluences of 12 J/cm2 and number of 4-6 pulses per spot.

  5. Interfacial Microstructure and Enhanced Mechanical Properties of Carbon Fiber Composites Caused by Growing Generation 1-4 Dendritic Poly(amidoamine) on a Fiber Surface.

    Science.gov (United States)

    Gao, Bo; Zhang, Ruliang; Gao, Fucheng; He, Maoshuai; Wang, Chengguo; Liu, Lei; Zhao, Lifen; Cui, Hongzhi

    2016-08-23

    In an attempt to improve the mechanical properties of carbon fiber composites, propagation of poly(amidoamine) (PAMAM) dendrimers by in situ polymerization on a carbon fiber surface was performed. During polymerization processes, PAMAM was grafted on carbon fiber by repeated Michael addition and amidation reactions. The changes in surface microstructure and the chemical composition of carbon fibers before and after modification were investigated by atomic force microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy. All the results indicated that PAMAM was successfully grown on the carbon fiber surface. Such propagation could significantly increase the surface roughness and introduce sufficient polar groups onto the carbon fiber surface, enhancing the surface wettability of carbon fiber. The fractured surface of carbon fiber-reinforced composites showed a great enhancement of interfacial adhesion. Compared with those of desized fiber composites, the interlaminar shear strength and interfacial shear strength of PAMAM/fiber-reinforced composites showed increases of 55.49 and 110.94%, respectively.

  6. MECHANICAL AND THERMO–MECHANICAL PROPERTIES OF BI-DIRECTIONAL AND SHORT CARBON FIBER REINFORCED EPOXY COMPOSITES

    Directory of Open Access Journals (Sweden)

    G. AGARWAL

    2014-10-01

    Full Text Available This paper based on bidirectional and short carbon fiber reinforced epoxy composites reports the effect of fiber loading on physical, mechanical and thermo-mechanical properties respectively. The five different fiber loading, i.e., 10wt. %, 20wt. %, 30wt. %, 40wt. % and 50wt. % were taken for evaluating the above said properties. The physical and mechanical properties, i.e., hardness, tensile strength, flexural strength, inter-laminar shear strength and impact strength are determined to represent the behaviour of composite structures with that of fiber loading. Thermo-mechanical properties of the material are measured with the help of Dynamic Mechanical Analyser to measure the damping capacity of the material that is used to reduce the vibrations. The effect of storage modulus, loss modulus and tan delta with temperature are determined. Finally, Cole–Cole analysis is performed on both bidirectional and short carbon fiber reinforced epoxy composites to distinguish the material properties of either homogeneous or heterogeneous materials. The results show that with the increase in fiber loading the mechanical properties of bidirectional carbon fiber reinforced epoxy composites increases as compared to short carbon fiber reinforced epoxy composites except in case of hardness, short carbon fiber reinforced composites shows better results. Similarly, as far as Loss modulus, storage modulus is concerned bidirectional carbon fiber shows better damping behaviour than short carbon fiber reinforced composites.

  7. Rate dependent response and failure of a ductile epoxy and carbon fiber reinforced epoxy composite

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Eric N [Los Alamos National Laboratory; Rae, Philip J [Los Alamos National Laboratory; Dattelbaum, Dana M [Los Alamos National Laboratory; Stahl, David B [Los Alamos National Laboratory

    2010-01-01

    An extensive characterization suite has been performed on the response and failure of a ductile epoxy 55A and uniaxial carbon fiber reinforced epoxy composite of IM7 fibers in 55A resin from the quasistatic to shock regime. The quasistatic and intermediate strain rate response, including elastic modulus, yield and failure have are characterized by quasistatic, SHPB, and DMA measurements as a function of fiber orientation and temperature. The high strain rate shock effect of fiber orientation in the composite and response of the pure resin are presented for plate impact experiments. It has previously been shown that at lower impact velocities the shock velocity is strongly dependent on fiber orientation but at higher impact velocity the in-plane and through thickness Hugoniots converge. The current results are compared with previous studies of the shock response of carbon fiber composites with more conventional brittle epoxy matrices. The spall response of the composite is measured and compared with quasistatic fracture toughness measurements.

  8. Multiscale carbon nanotube-carbon fiber reinforcement for advanced epoxy composites.

    Science.gov (United States)

    Bekyarova, E; Thostenson, E T; Yu, A; Kim, H; Gao, J; Tang, J; Hahn, H T; Chou, T-W; Itkis, M E; Haddon, R C

    2007-03-27

    We report an approach to the development of advanced structural composites based on engineered multiscale carbon nanotube-carbon fiber reinforcement. Electrophoresis was utilized for the selective deposition of multi- and single-walled carbon nanotubes (CNTs) on woven carbon fabric. The CNT-coated carbon fabric panels were subsequently infiltrated with epoxy resin using vacuum-assisted resin transfer molding (VARTM) to fabricate multiscale hybrid composites in which the nanotubes were completely integrated into the fiber bundles and reinforced the matrix-rich regions. The carbon nanotube/carbon fabric/epoxy composites showed approximately 30% enhancement of the interlaminar shear strength as compared to that of carbon fiber/epoxy composites without carbon nanotubes and demonstrate significantly improved out-of-plane electrical conductivity.

  9. Oxidation Kinetics and Strength Degradation of Carbon Fibers in a Cracked Ceramic Matrix Composite

    Science.gov (United States)

    Halbig, Michael C.

    2003-01-01

    Experimental results and oxidation modeling will be presented to discuss carbon fiber susceptibility to oxidation, the oxidation kinetics regimes and composite strength degradation and failure due to oxidation. Thermogravimetric Analysis (TGA) was used to study the oxidation rates of carbon fiber and of a pyro-carbon interphase. The analysis was used to separately obtain activation energies for the carbon constituents within a C/SiC composite. TGA was also conducted on C/SiC composite material to study carbon oxidation and crack closure as a function of temperature. In order to more closely match applications conditions C/SiC tensile coupons were also tested under stressed oxidation conditions. The stressed oxidation tests show that C/SiC is much more susceptible to oxidation when the material is under an applied load where the cracks are open and allow for oxygen ingress. The results help correlate carbon oxidation with composite strength reduction and failure.

  10. Studying Impact Damage on Carbon-Fiber Reinforced Aircraft Composite Panels with Sonicir

    Science.gov (United States)

    Han, Xiaoyan; Zhao, Xinyue; Zhang, Ding; He, Qi; Song, Yuyang; Lubowicki, Anthony; Newaz, Golam.; Favro, Lawrence D.; Thomas, Robert L.

    2011-06-01

    Composites are becoming more important materials in commercial aircraft structures such as the fuselage and wings with the new B787 Dreamliner from Boeing which has the target to utilize 50% by weight of composite materials. Carbon-fiber reinforced composites are the material of choice in aircraft structures. This is due to their light weight and high strength (high strength-to-weight ratio), high specific stiffness, tailorability of properties, design flexibility etc. Especially, by reducing the aircraft's body weight by using such lighter structures, the cost of fuel can be greatly reduced with the high jet fuel price for commercial airlines. However, these composites are prone to impact damage and the damage may occur without any observable sign on the surface, yet resulting in delaminations and disbonds that may occur well within the layers. We are studying the impact problem with carbon-fiber reinforced composite panels and developing SonicIR for this application as a fast and wide-area NDE technology. In this paper, we present our results in studying composite structures including carbon-fiber reinforced composite materials, and preliminary quantitative studies on delamination type defect depth identification in the panels.

  11. PREDICTION OF MODE Ⅰ CRACK PROPAGATION DIRECTION IN CARBON-FIBER REINFORCED COMPOSITE PLATE

    Institute of Scientific and Technical Information of China (English)

    张少琴; 杨维阳

    2004-01-01

    A newly developed Z fracture criterion for the composite materials was introduced,the new concepts of in-plane average strain,in-plane dilatational strain energy density factor and reciprocal characteristic function were presented.Many experimental results show that the Z fracture criterion can be well used to predict the crack propagating direction for mode Ⅰ crack in carbon-fiber reinforced composite laminates.

  12. Durability-Based Design Properties of Reference Crossply Carbon-Fiber Composite

    Energy Technology Data Exchange (ETDEWEB)

    Corum, J.M.

    2001-04-16

    This report provides recommended durability-based design properties and criteria for a crossply carbon-fiber composite for possible automotive structural applications. Although the composite utilized aerospace-grade carbon-fiber reinforcement, it was made by a rapid-molding process suitable for high-volume automotive use. The material is the first in a planned progression of candidate composites to be characterized as part of an Oak Ridge National Laboratory project entitled Durability of Carbon-Fiber Composites. The overall goal of the project, which is sponsored by the U.S. Department of Energy's Office of Advanced Automotive Technologies and is closely coordinated with the Advanced Composites Consortium, is to develop durability-driven design data and criteria to assure the long-term integrity of carbon-fiber-based composite systems for automotive structural applications. The composite addressed in this report is a ({+-}45{degree})3S crossply consisting of continuous Thornel T300 fibers in a Baydur 420 IMR urethane matrix. This composite is highly anisotropic with two dominant fiber orientations--0/90{degree} and {+-}45{degree}. Properties and models were developed for both orientations. This document is in two parts. Part 1 provides design data and correlations, while Part 2 provides the underlying experimental data and models. The durability issues addressed include the effects of short-time, cyclic, and sustained loadings; temperature; fluid environments; and low-energy impacts (e.g., tool drops and kickups of roadway debris) on deformation, strength, and stiffness. Guidance for design analysis, time-independent and time-dependent allowable stresses, rules for cyclic loadings, and damage-tolerance design guidance are provided.

  13. Analysis and optimization of temperature distribution in carbon fiber reinforced composite materials during microwave curing process

    OpenAIRE

    2014-01-01

    Vacuum assisted microwave curing technologies and modified optical sensing systems have been employed to investigate the influence of ply orientation and thickness on through-thickness temperature distribution of carbon fiber reinforced composite laminates. Two different types of epoxy systems have been studied. The results demonstrated that the ply orientation did not affect the temperature distribution of composite materials. However, the thickness was an important influencing factor. Nearl...

  14. 3D-Printing of Meso-structurally Ordered Carbon Fiber/Polymer Composites with Unprecedented Orthotropic Physical Properties

    Science.gov (United States)

    Lewicki, James P.; Rodriguez, Jennifer N.; Zhu, Cheng; Worsley, Marcus A.; Wu, Amanda S.; Kanarska, Yuliya; Horn, John D.; Duoss, Eric B.; Ortega, Jason M.; Elmer, William; Hensleigh, Ryan; Fellini, Ryan A.; King, Michael J.

    2017-01-01

    Here we report the first example of a class of additively manufactured carbon fiber reinforced composite (AMCFRC) materials which have been achieved through the use of a latent thermal cured aromatic thermoset resin system, through an adaptation of direct ink writing (DIW) 3D-printing technology. We have developed a means of printing high performance thermoset carbon fiber composites, which allow the fiber component of a resin and carbon fiber fluid to be aligned in three dimensions via controlled micro-extrusion and subsequently cured into complex geometries. Characterization of our composite systems clearly show that we achieved a high order of fiber alignment within the composite microstructure, which in turn allows these materials to outperform equivalently filled randomly oriented carbon fiber and polymer composites. Furthermore, our AM carbon fiber composite systems exhibit highly orthotropic mechanical and electrical responses as a direct result of the alignment of carbon fiber bundles in the microscale which we predict will ultimately lead to the design of truly tailorable carbon fiber/polymer hybrid materials having locally programmable complex electrical, thermal and mechanical response. PMID:28262669

  15. 3D-Printing of Meso-structurally Ordered Carbon Fiber/Polymer Composites with Unprecedented Orthotropic Physical Properties

    Science.gov (United States)

    Lewicki, James P.; Rodriguez, Jennifer N.; Zhu, Cheng; Worsley, Marcus A.; Wu, Amanda S.; Kanarska, Yuliya; Horn, John D.; Duoss, Eric B.; Ortega, Jason M.; Elmer, William; Hensleigh, Ryan; Fellini, Ryan A.; King, Michael J.

    2017-03-01

    Here we report the first example of a class of additively manufactured carbon fiber reinforced composite (AMCFRC) materials which have been achieved through the use of a latent thermal cured aromatic thermoset resin system, through an adaptation of direct ink writing (DIW) 3D-printing technology. We have developed a means of printing high performance thermoset carbon fiber composites, which allow the fiber component of a resin and carbon fiber fluid to be aligned in three dimensions via controlled micro-extrusion and subsequently cured into complex geometries. Characterization of our composite systems clearly show that we achieved a high order of fiber alignment within the composite microstructure, which in turn allows these materials to outperform equivalently filled randomly oriented carbon fiber and polymer composites. Furthermore, our AM carbon fiber composite systems exhibit highly orthotropic mechanical and electrical responses as a direct result of the alignment of carbon fiber bundles in the microscale which we predict will ultimately lead to the design of truly tailorable carbon fiber/polymer hybrid materials having locally programmable complex electrical, thermal and mechanical response.

  16. Hybrid Carbon Fibers/Carbon Nanotubes Structures for Next Generation Polymeric Composites

    Directory of Open Access Journals (Sweden)

    M. Al-Haik

    2010-01-01

    Full Text Available Pitch-based carbon fibers are commonly used to produce polymeric carbon fiber structural composites. Several investigations have reported different methods for dispersing and subsequently aligning carbon nanotubes (CNTs as a filler to reinforce polymer matrix. The significant difficulty in dispersing CNTs suggested the controlled-growth of CNTs on surfaces where they are needed. Here we compare between two techniques for depositing the catalyst iron used toward growing CNTs on pitch-based carbon fiber surfaces. Electrochemical deposition of iron using pulse voltametry is compared to DC magnetron iron sputtering. Carbon nanostructures growth was performed using a thermal CVD system. Characterization for comparison between both techniques was compared via SEM, TEM, and Raman spectroscopy analysis. It is shown that while both techniques were successful to grow CNTs on the carbon fiber surfaces, iron sputtering technique was capable of producing more uniform distribution of iron catalyst and thus multiwall carbon nanotubes (MWCNTs compared to MWCNTs grown using the electrochemical deposition of iron.

  17. Carbon Fiber Reinforced Glass Matrix Composites for Space Based Applications.

    Science.gov (United States)

    1987-08-31

    composite plates were prepared using standard i, c-pressing procedures. The plates were cut into tensile specimens which were then subsequently notched...reinforced HMU composites were prepared using the matrix compositions and hot-pressing parameters shown in Table VI-1. The compositions are identical...shown in Figure VI-6. Traces of a- cristobalite are present in all three composites, with a noticeably larger amount present in the Nb20 5 composite. All

  18. Multifunctional structural supercapacitor composites based on carbon aerogel modified high performance carbon fiber fabric.

    Science.gov (United States)

    Qian, Hui; Kucernak, Anthony R; Greenhalgh, Emile S; Bismarck, Alexander; Shaffer, Milo S P

    2013-07-10

    A novel multifunctional material has been designed to provide excellent mechanical properties while possessing a high electrochemical surface area suitable for electrochemical energy storage: structural carbon fiber fabrics are embedded in a continuous network of carbon aerogel (CAG) to form a coherent but porous monolith. The CAG-modification process was found to be scalable and to be compatible with a range of carbon fiber fabrics with different surface properties. The incorporation of CAG significantly increased the surface area of carbon fiber fabrics, and hence the electrochemical performance, by around 100-fold, resulting in a CAG-normalized specific electrode capacitance of around 62 F g(-1), determined by cyclic voltammetry in an aqueous electrolyte. Using an ionic liquid (IL) electrolyte, the estimated energy density increased from 0.003 to 1 Wh kg(-1), after introducing the CAG into the carbon fiber fabric. 'Proof-of-concept' multifunctional structural supercapacitor devices were fabricated using an IL-modified solid-state polymer electrolyte as a multifunctional matrix to provide both ionic transport and physical support for the primary fibers. Two CAG-impregnated carbon fabrics were sandwiched around an insulating separator to form a functioning structural electrochemical double layer capacitor composite. The CAG-modification not only improved the electrochemical surface area, but also reinforced the polymer matrix surrounding the primary fibers, leading to dramatic improvements in the matrix-dominated composite properties. Increases in in-plane shear strength and modulus, of up to 4.5-fold, were observed, demonstrating that CAG-modified structural carbon fiber fabrics have promise in both pure structural and multifunctional energy storage applications.

  19. The effect of bromination of carbon fibers on the coefficient of thermal expansion of graphite fiber-epoxy composites

    Science.gov (United States)

    Jaworske, D. A.; Maciag, C.

    1987-01-01

    To examine the effect of bromination of carbon fibers on the coefficient of thermal expansion (CTE) of carbon fiber epoxy composites, several pristine and brominated carbon fiber-epoxy composite samples were subjected to thermomechanical analysis. The CTE's of these samples were measured in the uniaxial and transverse directions. The CTE was dominated by the fibers in the uniaxial direction, while it was dominated by the matrix in the transverse directions. Bromination had no effect on the CTE of any of the composites. In addition, the CTE of fiber tow was measured in the absence of a polymer matrix, using an extension probe. The results from this technique were inconclusive.

  20. Effect of rare earths surface treatment on tribological properties of carbon fibers reinforced PTFE composite under oil-lubricated condition

    Institute of Scientific and Technical Information of China (English)

    SHANGGUAN Qianqian; CHENG Xianhua

    2008-01-01

    The effect of rare earths (RE) surface treatment of carbon fibers (CF) on tribological properties of CF reinforced polytetrafluoroethylene (PTFE) composites under oil-lubricated condition was investigated. Experimental results revealed that RE treated CF reinforced PTFE (CF/PTFE) composite had the lowest friction coefficient and wear under various applied loads and sliding speeds compared with untreated and air-oxidated composites. X-ray photoelectron spectroscopy (XPS) study of carbon fiber surface showed that, after RE treatment, oxygen concentration increased obviously, and the amount of oxygen-containing groups on CF surfaces were largely increased. The increase in the amount of oxygen-containing groups enhanced interfacial adhesion between CF and PTFE matrix. With strong interfacial adhesion of the composite, stress could be effectively transmitted to carbon fibers;carbon fibers were strongly bonded with PTFE matrix, and large scale rubbing-off of PTFE be prevented, therefore, tribological properties of the composite was improved.

  1. Effect of Sizing on the Interfacial Shear Strength of Carbon Fiber/Epoxy Resin Monofilament Composite

    Institute of Scientific and Technical Information of China (English)

    YANG Yusong; ZHAO Yan; LI Ye; DONG Qi; CHEN Da

    2014-01-01

    The single fiber fragmentation test (SFFT) was used to measure the interfacial shear strength (IFSS) of sized and unsized CF800/epoxy resin monofilament composite in order to evaluate the effect of sizing respectively. Besides, the interfacial reinforcing mechanism was explored by analyzing the surface morphology of the carbon fibers, the wettability between the carbon fibers and the epoxy resin, and the chemical characteristics of the fiber surface. Moreover, the effect of sizing on heat and humidity resistance of interface was investigated by aging test. The results show that sizing improves IFSS of CF800/epoxy resin monofilament composite by 59% through increasing the functional groups containing oxygen and through enhancing wettability, while after sizing the heat and humidity resistance of interface is decreased.

  2. ENGINEERED INTERFACE CHEMISTRY TO IMPROVE THE MECHANICAL PROPERTIES OF CARBON FIBER COMPOSITES CURED BY ELECTRON BEAM

    Energy Technology Data Exchange (ETDEWEB)

    Vautard, Frederic [ORNL; Grappe, Hippolyte A. [Oak Ridge Institute for Science and Education (ORISE); Ozcan, Soydan [ORNL

    2014-01-01

    A reactive sizing was designed to achieve high levels of interfacial adhesion and mechanical properties with a carbon fiber-acrylate system cured by electron beam (EB). The sizing was made of a partially cured epoxy sizing with a high density of pendant functional groups (acrylate functionality) able to generate a covalent bonding with the matrix. The interlaminar shear strength was clearly improved from 61 MPa to 81 MPa (+ 33 %) without any post-processing, reaching a similar value to the one obtained with the same system cured by a thermal treatment. Observation of the fracture profiles clearly highlighted a change in the fracture mechanism from a purely adhesive failure to a cohesive failure. Such improvements of the mechanical properties of carbon fiber composites cured by EB, without any post-cure, have not been reported previously to the best of our knowledge. This constitutes a breakthrough for the industrial development of composites EB curing.

  3. Effect of Gamma and electron beam irradiation on PAN-carbon fiber composite

    Energy Technology Data Exchange (ETDEWEB)

    Jafari, R.; Kasaei, H.; Hajihashemi, M.; Daneshvari, V.; Emamalizadeh, M.; Kasaei, M.H., E-mail: rvzreza@gmail.com [Materials Research School, Nuclear Science and Technology Research Institute, Isfahan, I. R. (Iran, Islamic Republic of)

    2016-11-01

    The aim of this study was to evaluate the effects of irradiation on structural, mechanical and thermal properties of PAN- carbon fiber composite. The overall applied doses were 250, 500, 750, and 1000 kGy. Irradiated and non-irradiated samples were characterized by Scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. Tensile strength test was conducted in order to measure mechanical properties. Scanning electron microscopy was used to evaluate microstructural behavior. Thermal behavior of the samples was studied by thermogravimetric analysis and differential scanning calorimetry. The results showed that by increasing gamma and electron doses the thermal behavior of the composite indicated higher decomposition degree as a function of the temperature. Electron irradiated carbon fiber surfaces are relatively smoothed than that virgin fibers. Bulges after gamma treatment were decreased and surface was unrough. (author)

  4. Extracting Information from Conventional AE Features for Fatigue Onset Damage Detection in Carbon Fiber Composites

    DEFF Research Database (Denmark)

    Unnthorsson, Runar; Pontoppidan, Niels Henrik Bohl; Jonsson, Magnus Thor

    2005-01-01

    We have analyzed simple data fusion and preprocessing methods on Acoustic Emission measurements of prosthetic feet made of carbon fiber reinforced composites. This paper presents the initial research steps; aiming at reducing the time spent on the fatigue test. With a simple single feature probab...... approaches can readily be investigated using the improved features, possibly improving the performance using multiple feature classifiers, e.g., Voting systems; Support Vector Machines and Gaussian Mixtures....

  5. Electrical conductivity improvement of aeronautical carbon fiber reinforced polyepoxy composites by insertion of carbon nanotubes

    OpenAIRE

    Lonjon, Antoine; Demont, Philippe; Dantras, Eric; Lacabanne, Colette

    2012-01-01

    International audience; An increase and homogenization of electrical conductivity is essential in epoxy carbon fiber laminar aeronautical composites. Dynamic conductivity measurements have shown a very poor transversal conductivity. Double wall carbon nanotubes have been introduced into the epoxy matrix to increase the electrical conductivity. The conductivity and the degree of dispersion of carbon nanotubes in epoxy matrix were evaluated. The epoxy matrix was filled with 0.4 wt.% of CNTs to ...

  6. Theoretical Estimation of Thermal Effects in Drilling of Woven Carbon Fiber Composite

    OpenAIRE

    José Díaz-Álvarez; Alvaro Olmedo; Carlos Santiuste; María Henar Miguélez

    2014-01-01

    Carbon Fiber Reinforced Polymer (CFRPs) composites are extensively used in structural applications due to their attractive properties. Although the components are usually made near net shape, machining processes are needed to achieve dimensional tolerance and assembly requirements. Drilling is a common operation required for further mechanical joining of the components. CFRPs are vulnerable to processing induced damage; mainly delamination, fiber pull-out, and thermal degradation, drilling in...

  7. A novel surface modification of carbon fiber for high-performance thermoplastic polyurethane composites

    Science.gov (United States)

    Zhang, Yuanyuan; Zhang, Yizhen; Liu, Yuan; Wang, Xinling; Yang, Bin

    2016-09-01

    Properties of carbon fiber (CF) reinforced composites depend largely on the interfacial bonding strength between fiber and the matrix. In the present work, CF was grafted by 4,4‧-diphenylmethane diisocyanate (MDI) molecules after electrochemical oxidation treatment. The existence of functional groups introduced to the fiber surface and the changes of surface roughness were confirmed by FTIR, AFM, XPS, SEM and Raman spectroscopy. To evaluate the possible applications of this surface modification of carbon fiber, we examined the mechanical properties as well as the friction and wear performance of pristine CF and MDI-CF reinforced thermoplastic polyurethane (TPU) composites with 5-30 wt.% fiber contents, and found that the mechanical properties of TPU composites were all significantly improved. It is remarkable that when fiber content was 30 wt.%, the tensile strength of TPU/MDI-CF was increased by 99.3%, which was greater than TPU/CF (53.2%), and the friction loss of TPU/MDI-CF was decreased by 49.09%. The results of DMA and SEM analysis indicated the positive effects of MDI modification on the interfacial bonding between fibers and matrix. We believed that this simple and effective method could be used to the development of surface modified carbon fiber for high-performance TPU.

  8. Guangzhou Chemical Industry%Modification of Carbon Fiber/BMI Composites by Using Functionalized Graphene Oxide

    Institute of Scientific and Technical Information of China (English)

    朱婷婷; 岳远志; 王雪; 辛姝颖; 李伟

    2016-01-01

    The graphene oxide ( GO) was functionalized by the silane couplingagentγ-methacryloxypropyltrimethox-ysilane (KH570). The effect of silane functionalized GO on the interfacial properties of the carbon fiber/BMI composites was investigated. The results indicated that the KH570 molecules were successfully grafted onto the GO surfaces. The interfacial adhesive properties of carbon fiber/BMI composites were improved. The maximum increment of the interlaminar shear strength of the carbon fiber/BMI composite was 26. 6% when the content of KH570-GO was 0. 1%.%选用γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH570)对氧化石墨烯(GO)进行表面功能化修饰,考察了硅烷功能化氧化石墨烯( KH570-GO)对碳纤维/双马来酰亚胺( BMI)复合材料层间剪切强度的影响。实验结果表明, KH570硅烷分子成功地接枝到GO表面,碳纤维/BMI复合材料的界面黏结性能得到改善,当KH570-GO含量的为0.1wt%时,复合材料的层间剪切强度提高了26.6%。

  9. Compression Molding of Chemical/Thermal Resistant Composite Materials Using Wastes of Glass Fiber Reinforced PTFE and Carbon Fiber

    OpenAIRE

    Kimura, Teruo

    2013-01-01

    This report proposed the compression molding method of chemical/thermal resistant composite materials reinforced by the carbon fiber extracted from CFRP waste and the waste of glass fiber coated by PTFE. The FEP resin was used for the matrix material. The contents of carbon fiber and FEP resin were varied in the experiments, and the machanical properties of composite materials were discussed in detail. As a result, the bending strength and modulus increased with increasing the content of carb...

  10. A novel carbon fiber based porous carbon monolith

    Energy Technology Data Exchange (ETDEWEB)

    Burchell, T.D.; Klett, J.W.; Weaver, C.E.

    1995-06-01

    A novel porous carbon material based on carbon fibers has been developed. The material, when activated, develops a significant micro- or mesopore volume dependent upon the carbon fiber type utilized (isotropic pitch or polyacrylonitrile). The materials will find applications in the field of fluid separations or as a catalyst support. Here, the manufacture and characterization of our porous carbon monoliths are described. A novel adsorbent carbon composite material has been developed comprising carbon fibers and a binder. The material, called carbon fiber composite molecular sieve (CFCMS), was developed through a joint research program between Oak Ridge National Laboratory (ORNL) and the University of Kentucky, Center for Applied Energy Research (UKCAER).

  11. NDT and SHM of Carbon Fiber Composites using Linear Drive MWM-Arrays

    Science.gov (United States)

    Washabaugh, Andrew; Martin, Christopher; Lyons, Robert; Grundy, David; Goldfine, Neil; Russell, Richard; Wincheski, Russell

    2012-01-01

    Carbon fiber composites are used in a wide range of structural applications due to their excellent specific strength and stiffness. However, the anisotropic mechanical and electrical properties associated with the fibers within each composite layer present challenges, and opportunities, for Nondestructive Testing (NDT) methods used to characterize and assess the structure condition. This includes composite condition after manufacture (such as fiber orientation and density, porosity, delamination, and bond strength) and during usage (such as damage from impact, fiber breakage, thermal exposure or applied stress). Ultrasonic and thermographic methods can address some of these challenges, but eddy current methods provide an alternative method for composite structures that contain a conducting material, such as carbon fibers or a metallic liner. This presentation reviews recent advances in the development of eddy current sensors and arrays for carbon fiber composite NDT and Structural Health Monitoring (SHM) applications. The focus is on eddy current sensor constructs with linear drive windings, such as MWM -Arrays, that induce currents primarily within the linear fibers of the composite. By combining this type of sensor construct with micromechanical models that relate composite constituent properties to measurable sensor responses, insight is obtained into the volumetric distribution of electrical properties within the composite and the associated manufacturing, damage, or strain conditions. With knowledge of the fiber layup, this MWM-Array technology is able to detect damage and strain/stress as a function of depth and fiber orientation. This work has been funded by NASA, NA V AIR and the Army for applications ranging from composite overwrapped pressure vessels (COPVs) to aircraft structures and rotorcraft blades. This presentation will specifically present background on the MWM-Array technology, results from the micromechanical modeling effort, and results from

  12. Poly(borosiloxanes as precursors for carbon fiber ceramic matrix composites

    Directory of Open Access Journals (Sweden)

    Renato Luiz Siqueira

    2007-06-01

    Full Text Available Ceramic matrix composites (CMCs, constituted of a silicon boron oxycarbide (SiBCO matrix and unidirectional carbon fiber rods as a reinforcement phase, were prepared by pyrolysis of carbon fiber rods wrapped in polysiloxane (PS or poly(borosiloxane (PBS matrices. The preparation of the polymeric precursors involved hydrolysis/condensation reactions of alkoxysilanes in the presence and absence of boric acid, with B/Si atomic ratios of 0.2 and 0.5. Infrared spectra of PBS showed evidence of Si-O-B bonds at 880 cm-1, due to the incorporation of the crosslinker trigonal units of BO3 in the polymeric network. X ray diffraction analyses exhibited an amorphous character of the resulting polymer-derived ceramics obtained by pyrolysis up to 1000 °C under inert atmosphere. The C/SiBCO composites showed better thermal stability than the C/SiOC materials. In addition, good adhesion between the carbon fiber and the ceramic phase was observed by SEM microscopy

  13. Shear Properties of Carbon Fiber/Phenolic Resin Composites Heat Treated at High Temperatures

    Directory of Open Access Journals (Sweden)

    Homero Paula Silva

    2016-07-01

    Full Text Available Carbon fiber/phenolic resin composites have long been used as ablative materials in rocketry. Ablation is a complex multiscale problem where radiative and convective heating leads to the pyrolysis of phenolic resin matrix, resulting in the formation of a porous insulation char as thermal protection. This study investigates the shear properties evolution during the heat treatment of a carbon fiber/phenolic resin nozzle extension entrance (exit cone which is part of an integrated nozzle of launching and sounding vehicles, developed at the Instituto de Aeronáutica e Espaço (SP, Brazil. Specimens of the material (carbon fiber/phenolic resin composite were subjected to heat treatment at 500, 1,000, 1,500 and 2,000°C, and measurements of shear strength and shear modulus were performed using the Iosipescu mode. Experimental data were compared with the results obtained theoretically. Also, morphological analysis was accomplished by optical microscopy and the observation of fractured surfaces, by scanning electron microscopy. Significant morphological changes in the microstructure after heat treatments were observed. The lowest value for shear strength obtained experimentally was 4.05 MPa, which is greater than the ultimate value obtained analytically (2.35 MPa, fulfilling its structural function during the propulsion time.

  14. Piezoresistivity of Carbon Fiber Graphite Cement-based Composites with CCCW

    Institute of Scientific and Technical Information of China (English)

    FAN Xiaoming; FANG Dong; SUN Mingqing; LI Zhuoqiu

    2011-01-01

    The electrical conductivity and piezoresistivity of carbon fiber graphite cement-matrix composites(CFGCC) with carbon fiber content(l% by the weight of cement), graphite powder contents (0%-50% by the weight of cement) and CCCW(cementitious capillary crystalline waterproofing materials, 4% by the weight of cement) were studied. The experimental results showed that the relationship between the resistivity of CFGCC and the concentration of graphite powders had typical features of percolation phenomena. The percolation threshold was about 20%. A clear piezoresistive effect was observed in CFGCC with 1 wt% of carbon fibers, 20wt% or 30wt% of graphite powders under uniaxial compressive tests, indicating that this type of smart composites was a promising candidate for strain sensing. The measured gage factor (defined as the fractional change in resistance per unit strain) of CFGCC with graphite content of 20wt% and 30wt% were 37 and 22, respectively. With the addition of CCCW, the mechanical properties of CFGCC were improved, which benefited CFGCC piezoresistivity of stability.

  15. Boron-doped MnO{sub 2}/carbon fiber composite electrode for supercapacitor

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Hong Zhong, E-mail: hzchi@hdu.edu.cn [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Zhu, Hongjie [College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou 310018 (China); Gao, Linhui [Center of Materials Engineering, Zhejiang Sci-Tech University, Hangzhou 310018 (China)

    2015-10-05

    Highlights: • Interstitial ion in MnO{sub 2} lattice. • Porous film composed by interlocking worm-like nanostructure. • Boron-doped birnessite-type MnO{sub 2}/carbon fiber composite electrode. • Enhanced capacitive properties through nonmetal element doping. - Abstract: The boron-doped MnO{sub 2}/carbon fiber composite electrode has been prepared via in situ redox reaction between potassium permanganate and carbon fibers in the presence of boric acid. The addition of boron as dopant results in the increase of growth-rate of MnO{sub 2} crystal and the formation of worm-like nanostructure. Based on the analysis of binding energy, element boron incorporates into the MnO{sub 2} lattice through interstitial mode. The doped electrode with porous framework is beneficial to pseudocapacitive reaction and surface charge storage, leading to higher specific capacitance and superior rate capability. After experienced 1000 cycles, the boron-doped MnO{sub 2} still retain a higher specific capacitance by about 80% of its initial value. The fall in capacitance is blamed to be the combination of the formation of soluble Mn{sup 2+} and the absence of active site on the outer surface.

  16. Formation of interfacial network structure via photo-crosslinking in carbon fiber/epoxy composites

    Directory of Open Access Journals (Sweden)

    S. H. Deng

    2014-07-01

    Full Text Available A series of diblock copolymers (poly(n-butylacrylate-co-poly(2-hydroxyethyl acrylate-b-poly(glycidyl methacrylate ((PnBA-co-PHEA-b-PGMA, containing a random copolymer block PnBA-co-PHEA, were successfully synthesized by atom transfer radical polymerization (ATRP. After being chemically grafted onto carbon fibers, the photosensitive methacrylic groups were introduced into the random copolymer, giving a series of copolymers (poly(n-butylacrylate-co-poly(2-methacryloyloxyethyl acrylate-b-poly(glycidyl methacrylate((PnBA-co-PMEA-b-PGMA. Dynamic mechanical analysis indicated that the random copolymer block after ultraviolet (UV irradiation was a lightly crosslinked polymer and acted as an elastomer, forming a photo-crosslinked network structure at the interface of carbon fiber/epoxy composites. Microbond test showed that such an interfacial network structure greatly improved the cohesive strength and effectively controlled the deformation ability of the flexible interlayer. Furthermore, three kinds of interfacial network structures, i physical crosslinking by H-bonds, ii chemical crosslinking by photopolymerization, and iii interpenetrating crosslinked network by photopolymerization and epoxy curing reaction were received in carbon fiber/epoxy composite, depending on the various preparation processes.

  17. Modal analysis of additive manufactured carbon fiber reinforced polymer composite framework: Experiment and modeling

    Science.gov (United States)

    Dryginin, N. V.; Krasnoveikin, V. A.; Filippov, A. V.; Tarasov, S. Yu.; Rubtsov, V. E.

    2016-11-01

    Additive manufacturing by 3D printing is the most advanced and promising trend for making the multicomponent composites. Polymer-based carbon fiber reinforced composites demonstrate high mechanical properties combined with low weight characteristics of the component. This paper shows the results of 3D modeling and experimental modal analysis on a polymer composite framework obtained using additive manufacturing. By the example of three oscillation modes it was shown the agreement between the results of modeling and experimental modal analysis with the use of laser Doppler vibrometry.

  18. Preparation and characterization of silicon nitride (Si−N)-coated carbon fibers and their effects on thermal properties in composites

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyeon-Hye [R& D Division, Korea Institute of Carbon Convergence Technology, Jeonju 561-844 (Korea, Republic of); Nano& Advanced Materials Engineering, Jeonju University, Jeonju 560-759 (Korea, Republic of); Han, Woong [R& D Division, Korea Institute of Carbon Convergence Technology, Jeonju 561-844 (Korea, Republic of); Lee, Hae-seong [Nano& Advanced Materials Engineering, Jeonju University, Jeonju 560-759 (Korea, Republic of); Min, Byung-Gak [Department of Polymer Science & Engineering, Korea National University of Transportation, Chungju 380-702 (Korea, Republic of); Kim, Byung-Joo, E-mail: ap2-kbj@hanmail.net [R& D Division, Korea Institute of Carbon Convergence Technology, Jeonju 561-844 (Korea, Republic of)

    2015-10-15

    Graphical abstract: We report preparation and characterization of silicon nitride (Si−N)-coated carbon fibers and their effects on thermal properties in composites. Thermally composites showed enhanced thermal conductivity increasing from up to 59% by the thermal network. - Highlights: • A new method of Si−N coating on carbon fibers was reported. • Silane layer were successfully converted to Si−N layer on carbon fiber surface. • Si−N formation was confirmed by FT-IR, XPS, and EDX. • Thermal conductivity of Si−N coated CF composites were enhanced to 0.59 W/mK. - Abstract: This study investigates the effect of silicon nitride (Si−N)-coated carbon fibers on the thermal conductivity of carbon-fiber-reinforced epoxy composite. The surface properties of the Si−N-coated carbon fibers (SiNCFs) were observe using Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive spectroscopy, and X-ray photoelectron spectroscopy, and the thermal stability was analyzed using thermogravimetric analysis. SiNCFs were fabricated through the wet thermal treatment of carbon fibers (Step 1: silane finishing of the carbon fibers; Step 2: high-temperature thermal treatment in a N{sub 2}/NH{sub 3} environment). As a result, the Si−N belt was exhibited by SEM. The average thickness of the belt were 450–500 nm. The composition of Si−N was the mixture of Si−N, Si−O, and C−Si−N as confirmed by XPS. Thermal residue of the SiNCFs in air was enhanced from 3% to 50%. Thermal conductivity of the composites increased from 0.35 to 0.59 W/mK after Si−N coating on carbon surfaces.

  19. Electrical resistance stability of high content carbon fiber reinforced cement composite

    Institute of Scientific and Technical Information of China (English)

    YANG Zai-fu; TANG Zu-quan; LI Zhuo-qiu; QIAN Jue-shi

    2005-01-01

    The influences of curing time, the content of free evaporable water in cement paste, environmental temperature, and alternative heating and cooling on the electrical resistance of high content carbon fiber reinforced cement (CFRC) paste are studied by experiments with specimens of Portland cement 42.5 with 10 mm PAN-based carbon fiber and methylcellulose. Experimental results indicate that the electrical resistance of CFRC increases relatively by 24% within a hydration time of 90 d and almost keeps constant after 14 d, changes hardly with the mass loss of free evaporable water in the concrete dried at 50℃C, increases relatively by 4% when ambient temperature decreases from 15℃ to-20℃, and decreases relatively by 13% with temperature increasing by 88℃. It is suggested that the electric resistance of the CFRC is stable, which is testified by the stable power output obtained by electrifying the CFRC slab with a given voltage. This implies that such kind of high content carbon fiber reinforced cement composite is potentially a desirable electrothermal material for airfield runways and road surfaces deicing.

  20. Durability-Based Design Criteria for a Quasi-Isotropic Carbon-Fiber Automotive Composite

    Energy Technology Data Exchange (ETDEWEB)

    Corum, J.M.

    2002-04-17

    This report provides recommended durability-based design properties and criteria for a quasi-isotropic carbon-fiber composite for possible automotive structural applications. The composite, which was made by a rapid molding process suitable for high-volume automotive applications, consisted of continuous Thornel T300 fibers (6K tow) in a Baydur 420 IMR urethane matrix. The reinforcement was in the form of four {+-}45{sup o} stitch-bonded mats in the following layup: [0/90{sup o}/{+-}45{sup o}]{sub S}. This material is the second in a progression of three candidate thermoset composites to be characterized and modeled as part of an Oak Ridge National Laboratory project entitled Durability of Carbon-Fiber Composites. The overall goal of the project, which is sponsored by the U.S. Department of Energy's Office of Advanced Automotive Technologies and is closely coordinated with the industry Automotive Composites Consortium, is to develop durability-driven design data and criteria to assure the long-term integrity of carbon-fiber-based composite systems for large automotive structural components. This document is in two parts. Part I provides the design criteria, and Part 2 provides the underlying experimental data and models. The durability issues addressed include the effects on deformation, strength, and stiffness of cyclic and sustained loads, operating temperature, automotive fluid environments, and low-energy impacts (e.g., tool drops and kickups of roadway debris). Guidance is provided for design analysis, time-dependent allowable stresses, rules for cyclic loadings, and damage tolerance design guidance, including the effects of holes. Chapter 6 provides a brief summary of the design criteria.

  1. Properties of Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Matrix Composites

    Science.gov (United States)

    Cano, Roberto J.; Kang, Jin Ho; Grimsley, Brian W.; Ratcliffe, James G.; Siochi, Emilie J.

    2016-01-01

    For aircraft primary structures, carbon fiber reinforced polymer (CFRP) composites possess many advantages over conventional aluminum alloys due to their light weight, higher strength- and stiffness-to-weight ratios, and low life-cycle maintenance costs. However, the relatively low electrical and thermal conductivities of CFRP composites fail to provide structural safety in certain operational conditions such as lightning strikes. Carbon nanotubes (CNT) offer the potential to enhance the multi-functionality of composites with improved thermal and electrical conductivity. In this study, hybrid CNT/carbon fiber (CF) polymer composites were fabricated by interleaving layers of CNT sheets with Hexcel® IM7/8852 prepreg. Resin concentrations from 1 wt% to 50 wt% were used to infuse the CNT sheets prior to composite fabrication. The interlaminar properties of the resulting hybrid composites were characterized by mode I and II fracture toughness testing. Fractographical analysis was performed to study the effect of resin concentration. In addition, multi-directional physical properties like thermal conductivity of the orthotropic hybrid polymer composite were evaluated.

  2. Modified carbon fibers to improve composite properties. [sizing fibers for reduced electrical conductivity and adhesion during combustion

    Science.gov (United States)

    Shepler, R. E.

    1979-01-01

    Thin coatings, 5 to 10 wt. percent, were applied to PAN-based carbon fibers. These coatings were intended to make the carbon fibers less electrically conductive or to cause fibers to stick together when a carbon fiber/epoxy composite burned. The effectiveness of the coatings in these regards was evaluated in burn tests with a test rig designed to simulate burning, impact and wind conditions which might release carbon fibers. The effect of the coatings on fiber and composite properties and handling was also investigated. Attempts at sizing carbon fibers with silicon dioxide, silicon carbide and boron nitride meet with varying degrees of success; however, none of these materials provided an electrically nonconductive coating. Coatings intended to stick carbon fibers together after a composite burned were sodium silicate, silica gel, ethyl silicate, boric acid and ammonium borate. Of these, only the sodium silicate and silica gel provided any sticking together of fibers. The amount of sticking was insufficient to achieve the desired objectives.

  3. Evaluation of Tribological Performance of PTFE Composite Filled with Rare Earths Treated Carbon Fibers under Water-Lubricated Condition

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Carbon fibers (CFs) were surface treated with air-oxidation, rare earths (RE) after air-oxidation, and rare earths, respectively. Erichsen test was conducted to study the interfacial adhesion of PTFE composites filled with carbon fibers treated with different treatment methods. Tribological properties of the PTFE composites, sliding against GCrl5 steel under water-lubricated condition, were investigated on a reciprocating ball-on-disk UMT-2MT tribometer. The worn surfaces of the composites were examined using scanning electron microscopy. Experimental results reveal that RE treatment is superior to air oxidation in promoting tribological properties of CF reinforced PTFE (CF/PTFE) composite. The friction and wear properties of PTFE composite filled with RE treated CF are the best of the PTFE composites. RE treatment is more effective than air oxidation to improve the tribological properties of CF/PTFE composite owing to the effective improvement of interfacial adhesion between carbon fibers and PTFE matrix.

  4. Thermal Protection of Carbon Fiber-Reinforced Composites by Ceramic Particles

    Directory of Open Access Journals (Sweden)

    Baljinder Kandola

    2016-06-01

    Full Text Available The thermal barrier efficiency of two types of ceramic particle, glass flakes and aluminum titanate, dispersed on the surface of carbon-fiber epoxy composites, has been evaluated using a cone calorimeter at 35 and 50 kW/m2, in addition to temperature gradients through the samples’ thicknesses, measured by inserting thermocouples on the exposed and back surfaces during the cone tests. Two techniques of dispersing ceramic particles on the surface have been employed, one where particles were dispersed on semi-cured laminate and the other where their dispersion in a phenolic resin was applied on the laminate surface, using the same method as used previously for glass fiber composites. The morphology and durability of the coatings to water absorption, peeling, impact and flexural tension were also studied and compared with those previously reported for glass-fiber epoxy composites. With both methods, uniform coatings could be achieved, which were durable to peeling or water absorption with a minimal adverse effect on the mechanical properties of composites. While all these properties were comparable to those previously observed for glass fiber composites, the ceramic particles have seen to be more effective on this less flammable, carbon fiber composite substrate.

  5. Application of Carbon Fiber Paper in Integrated Wooden Electric Heating Composite

    Directory of Open Access Journals (Sweden)

    Quanping Yuan

    2014-07-01

    Full Text Available To endow wooden material with an electric heating function, carbon fiber paper, as an electric heating membrane, was laminated with wood veneer to prepare wooden electric heating composites. The electric heating performance of the membrane under different power densities and resistance stabilities, as well as the influencing mechanism of the process on both the resistance and bonding performance of the composite, were studied. The surface temperature of the membrane and composite increased by more than 20 °C in 30 s and 10 min, respectively, after electricity was applied. Furthermore, the samples had a surface temperature unevenness of 4 and 2 °C, respectively. Many potential contact points between carbon fibers fulfilled their connections, reducing the drop rate of resistance (DRR after hot-pressing to the range of 30% to 43%. The hot-press pressure and glue spread had a high degree of relevancy (coefficient of determination R2=0.960 and R2=0.997 with the DRR of the composite, respectively. The composite exhibited a negative temperature coefficient effect (NTC, and the DRR after heating for 15 h was 4.4%, but tended to ultimately stabilize. The composite, which exhibited good time-temperature effects and had a linear relationship with a high value of the coefficient of determination (R2=0.983 between power density and equilibrium temperature, displays solid potential for use in preparing integrated wooden electric heating products.

  6. Surface and interface properties of carbon fiber composites under cyclical aging

    Science.gov (United States)

    Lv, Xinying; Wang, Rongguo; Liu, Wenbo; Jiang, Long

    2011-10-01

    Carbon fiber-reinforced BMI composites have been subjected to combination accelerated aging comprising a hygrothermal process, a thermal-oxidative process, and a freezing process in order to simulate their responses under complicated service environments. This cyclical condition, including the freezing process, has not been investigated by other researchers so far. The effects of this combination accelerated aging on the mechanical properties have been characterized by FTIR, SEM/EDXA, XRD, and moisture-uptake determination. The results indicated that combination accelerated aging had great effects on the mechanical properties of the composite, the network structure of the BMI matrix, and the moisture uptake by the composite. After a third cycle of accelerated aging, moisture reached the center layer of the composite and as a result led to an obvious decrease in ILSS due to deterioration of the carbon fiber-BMI interface. Sufficient moisture absorption on the composite surface made the network structure of the BMI matrix more open, which facilitated stress relaxation and the creation of micro-cracks, with a consequent obvious decrease in flexural strength. With increasing number of combined-action accelerated aging cycles, ever more moisture was absorbed during each hygrothermal process due to the plasticizing effect of water, and micro-cracks propagated as a result of internal stresses caused by the hygrothermal process, the thermal-oxidative process, and the freezing process of each cycle. XRD analysis indicated that moisture penetrated through the amorphous region of the BMI matrix.

  7. Activated carbon fibers/poly(lactic-co-glycolic) acid composite scaffolds: Preparation and characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yanni [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Han, Hao [College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Bayer Material Science China Co., Ltd, Shanghai 200120 (China); Quan, Haiyu; Zang, Yongju; Wang, Ning; Ren, Guizhi [College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Xing, Melcolm [Department of Mechanical Engineering, Faculty of Engineering and Department of Biochemistry and Genetics, Faculty of Medicine P.I., Manitoba Institute of Child Health, University of Manitoba, Winnipeg, Manitoba (Canada); Wu, Qilin, E-mail: wql@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China)

    2014-10-01

    The present work is a first trial to introduce activated carbon fibers (ACF) with high adsorption capacity into poly(lactic-co-glycolic) acid (PLGA), resulting in a novel kind of scaffolds for tissue engineering applications. ACF, prepared via high-temperature processing of carbon fibers, are considered to possess bioactivity and biocompatibility. The ACF/PLGA composite scaffolds are prepared by solvent casting/particulate leaching method. Increments in both pore quantity and quality over the surface of ACF as well as a robust combination between ACF and PLGA matrix are observed via scanning electron microscopy (SEM). The high adsorption capacity of ACF is confirmed by methylene blue solution absorbency test. The surfaces of ACF are affiliated with many hydrophilic groups and characterized by Fourier transform infrared spectroscopy. Furthermore, the SEM images show that cells possess a favorable spreading morphology on the ACF/PLGA scaffolds. Besides, vivo experiments are also carried out to evaluate the histocompatibility of the composite scaffolds. The results show that ACF have the potential to become one of the most promising materials in biological fields. - Highlights: • ACF with strong adsorption capacity and porous structure for enhanced surface area • The incorporation of ACF promoting the porosity of composite scaffolds • The composite scaffolds having no side effect on cell adhesion and proliferation • The composite scaffolds presenting good biocompatibility in vivo.

  8. Environmental effects on the hybrid glass fiber/carbon fiber composites

    Science.gov (United States)

    Tsai, Yun-I.

    2009-12-01

    Fiber reinforced polymer composites (FRPCs) have been widely used to replace conventional metals due to the high specific strength, fatigue resistance, and light weight. In the power distribution industry, an advanced composites rod has been developed to replace conventional steel cable as the load-bearing core of overhead conductors. Such conductors, called aluminum conductor composite core (ACCC) significantly increases the transmitting efficiency of existing power grid system without extensive rebuilding expenses, while meeting future demand for electricity. In general, the service life of such overhead conductors is required to be at least 30 years. Therefore, the long-term endurance of the composite core in various environments must be well-understood. Accelerated aging by hygrothermal exposure was conducted to determine the effect of moisture on the glass fiber (GF)/carbon fiber (CF) hybrid composites. The influence of water immersion and humid air exposure on mechanical properties is investigated. Results indicated that immersion in water is the most severe environment for such hybrid GF/CF composites, and results in greater saturation and degradation of properties. When immersed directly in water, the hybrid GF/CF composites exhibit a moisture uptake behavior that is more complex than composite materials reinforced with only one type of fiber. The unusual diffusion behavior is attributed to a higher packing density of fibers at the annular GF/CF interface, which acts as a temporary moisture barrier. Moisture uptake leads to the mechanical and thermal degradation of such hybrid GF/CF composites. Findings presented here indicate that the degradation is a function of exposure temperature, time, and moisture uptake level. Results also indicate that such hybrid GF/CF composites recover short beam shear (SBS) strength and glass transition temperature (Tg) values comparable to pre-aged samples after removal of the absorbed moisture. In the hygrothermal environment

  9. Effect of epoxy resin properties on the mechanical properties of carbon fiber/epoxy resin composites

    Energy Technology Data Exchange (ETDEWEB)

    He, Hong-Wei; Gao, Feng [Taiyuan Univ. of Technology (China). College of Materials Science and Engineering; Taiyuan Univ. of Technology (China). Key Laboratory of Interface Science and Engineering in Advanced Materials; Li, Kai-Xi [Chinese Academy of Sciences, Taiyuan, Shanxi (China). Key Laboratory of Carbon Materials

    2013-09-15

    Three kinds of epoxy resins, i.e. tetraglycidyl diaminodiphenyl methane (AG80), difunctional diglycidyl ether of bisphenol-A (E51) and novolac type epoxy resin (F46) were selected as matrices for carbon fiber/epoxy composites. The objective of this work is to study the mechanical properties of fiber/epoxy composites by using these three kinds of epoxy resins with different physical and chemical performance. The results show that the composites fabricated with AG80 present the best stiffness and the composites prepared with E5 1have the best toughness. The stiffness and toughness of the composites prepared with F46 are middle values located between those for AG80/epoxy and E51/epoxy composites. Thus, the mixed epoxy resin is a promising approach for industrial production. (orig.)

  10. Hybrid carbon fiber/carbon nanotube composites for structural damping applications.

    Science.gov (United States)

    Tehrani, M; Safdari, M; Boroujeni, A Y; Razavi, Z; Case, S W; Dahmen, K; Garmestani, H; Al-Haik, M S

    2013-04-19

    Carbon nanotubes (CNTs) were grown on the surface of carbon fibers utilizing a relatively low temperature synthesis technique; graphitic structures by design (GSD). To probe the effects of the synthesis protocols on the mechanical properties, other samples with surface grown CNTs were prepared using catalytic chemical vapor deposition (CCVD). The woven graphite fabrics were thermally shielded with a thin film of SiO2 and CNTs were grown on top of this film. Raman spectroscopy and electron microscopy revealed the grown species to be multi-walled carbon nanotubes (MWCNTs). The damping performance of the hybrid CNT-carbon fiber-reinforced epoxy composite was examined using dynamic mechanical analysis (DMA). Mechanical testing confirmed that the degradations in the strength and stiffness as a result of the GSD process are far less than those encountered through using the CCVD technique and yet are negligible compared to the reference samples. The DMA results indicated that, despite the minimal degradation in the storage modulus, the loss tangent (damping) for the hybrid composites utilizing GSD-grown MWCNTs improved by 56% compared to the reference samples (based on raw carbon fibers with no surface treatment or surface grown carbon nanotubes) over the frequency range 1-60 Hz. These results indicated that the energy dissipation in the GSD-grown MWCNTs composite can be primarily attributed to the frictional sliding at the nanotube/epoxy interface and to a lesser extent to the stiff thermal shielding SiO2 film on the fiber/matrix interface.

  11. Mechanical properties of carbon fiber/cellulose composite papers modified by hot-melting fibers

    Institute of Scientific and Technical Information of China (English)

    Yunzhou Shi; Biao Wang

    2014-01-01

    Carbon fiber (CF)/cellulose (CLS) composite papers were prepared by papermaking techniques and hot-melting fibers were used for modi-fication. The mechanical properties of the obtained composite papers with different CF, CLS and hot-melting fiber ratios were studied and further discussed. It is observed that, for both CF/CLS composite papers and those modified by hot-melting fibers, the normal stress firstly increases and then declines with the addition of carbon fibers. The results also show that with the addition of hot-melting fibers, the modified papers exhibit enhanced mechanical performance compared to CF/CLS composite papers. Through SEM characterization, it is confirmed that the improvement of mechanical properties attributes to the reinforcement of adhesive binding at the fiber overlap nodes. Also, through four-probe method, the resistivity and the electrical performance of the modified and unmodified papers were characterized and the result shows that the hot-melting fiber modification brings no harm to the electrical properties.

  12. Aspects regarding wearing behaviour in case of aluminium composite materials reinforced with carbon fibers

    Science.gov (United States)

    Caliman, R.

    2016-08-01

    This paper presents a study regarding wear comportment of sintered composite materials obtained by mixture of aluminium with short carbon fibers. The necessity to satisfying more and more the specific functions during design of high performance structures leads to perform multi-materials such as reinforced composite parts. The wear tests were made on three different orientations of fibers on a standard machine of tribology, pin disk type. Counter-disk was made of cast iron with a superficial hardness of 92 HB. The wear rate and friction coefficient decreased exponentially with time of friction and reached a stationary value. This behaviour was attributed to the development of a lubricating film on the friction surface. To conduct this work was performed measurements on samples from the Al matrix composites and carbon fiber 43%, wear mechanism was investigated by scanning electron microscopy. In addition to fiber orientation, the tribological behaviour of metal matrix composites reinforced with fiber is influenced by the interfacial reaction of fiber-matrix. The characteristics and the dimensions of the interface depend on the cycle of temperature and time at which the material has been subjected during the manufacturing process and thereafter.

  13. Mechanical properties of carbon fiber/cellulose composite papers modified by hot-melting fibers

    Directory of Open Access Journals (Sweden)

    Yunzhou Shi

    2014-02-01

    Full Text Available Carbon fiber (CF/cellulose (CLS composite papers were prepared by papermaking techniques and hot-melting fibers were used for modification. The mechanical properties of the obtained composite papers with different CF, CLS and hot-melting fiber ratios were studied and further discussed. It is observed that, for both CF/CLS composite papers and those modified by hot-melting fibers, the normal stress firstly increases and then declines with the addition of carbon fibers. The results also show that with the addition of hot-melting fibers, the modified papers exhibit enhanced mechanical performance compared to CF/CLS composite papers. Through SEM characterization, it is confirmed that the improvement of mechanical properties attributes to the reinforcement of adhesive binding at the fiber overlap nodes. Also, through four-probe method, the resistivity and the electrical performance of the modified and unmodified papers were characterized and the result shows that the hot-melting fiber modification brings no harm to the electrical properties.

  14. The Reinforcing Effect of Carbon Fibers and PA6 on the Mechanical Properties of a PU Composites

    Science.gov (United States)

    Peng, Yongxin; Chi, Yilin; Dong, Weimin; Sun, Dongming; Mi, Weijian

    2013-07-01

    Ternary blend composites composed of two immiscible organic phases, polyurethane (PU) and polyamide-6 (PA6), and carbon fibers (CFs) as an inorganic filler are studied in terms of mechanical properties and morphology of the composites. The effects of different filler component ratios on its tensile, flexural, and impact strengths are investigated. Using the scanning electron microscopy (SEM), it is found that the addition of carbon fibers and PA6 is beneficial for raising the mechanical strength by increasing the dispersed interface phase. The optimum impact properties of CF/PA6/PU composites were obtained when the PA6 content in the 15 vol.% CF/PU composite was 6 vol.%.

  15. An integrated computational materials engineering method for woven carbon fiber composites preforming process

    Science.gov (United States)

    Zhang, Weizhao; Ren, Huaqing; Wang, Zequn; Liu, Wing K.; Chen, Wei; Zeng, Danielle; Su, Xuming; Cao, Jian

    2016-10-01

    An integrated computational materials engineering method is proposed in this paper for analyzing the design and preforming process of woven carbon fiber composites. The goal is to reduce the cost and time needed for the mass production of structural composites. It integrates the simulation methods from the micro-scale to the macro-scale to capture the behavior of the composite material in the preforming process. In this way, the time consuming and high cost physical experiments and prototypes in the development of the manufacturing process can be circumvented. This method contains three parts: the micro-scale representative volume element (RVE) simulation to characterize the material; the metamodeling algorithm to generate the constitutive equations; and the macro-scale preforming simulation to predict the behavior of the composite material during forming. The results show the potential of this approach as a guidance to the design of composite materials and its manufacturing process.

  16. Carbon fiber polymer-matrix structural composites for electrical-resistance-based sensing

    Science.gov (United States)

    Wang, Daojun

    This dissertation has advanced the science and technology of electrical-resistance-based sensing of strain/stress and damage using continuous carbon fiber epoxy-matrix composites, which are widely used for aircraft structures. In particular, it has extended the technology of self-sensing of carbon fiber polymer-matrix composites from uniaxial longitudinal loading and flexural loading to uniaxial through-thickness loading and has extended the technology from structural composite self-sensing to the use of the composite (specifically a one-lamina composite) as an attached sensor. Through-thickness compression is encountered in the joining of composite components by fastening. Uniaxial through-thickness compression results in strain-induced reversible decreases in the through-thickness and longitudinal volume resistivities, due to increase in the fiber-fiber contact in the through-thickness direction, and minor-damage-induced irreversible changes in these resistivities. The Poisson effect plays a minor role. The effects in the longitudinal resistivity are small compared to those in the through-thickness direction, but longitudinal resistance measurement is more amenable to practical implementation in structures than through-thickness resistance measurement. The irreversible effects are associated with an increase in the through-thickness resistivity and a decrease in the longitudinal resistivity. The through-thickness gage factor is up to 5.1 and decreases with increasing compressive strain above 0.2%. The reversible fractional change in through-thickness resistivity per through-thickness strain is up to 4.0 and decreases with increasing compressive strain. The irreversible fractional change in through-thickness resistivity per unit through-thickness strain is around -1.1 and is independent of the strain. The sensing is feasible by measuring the resistance away from the stressed region, though the effectiveness is less than that at the stressed region. A one

  17. A Modeling Technique and Representation of Failure in the Analysis of Triaxial Braided Carbon Fiber Composites

    Science.gov (United States)

    Littell, Justin D.; Binienda, Wieslaw K.; Goldberg, Robert K.; Roberts, Gary D.

    2008-01-01

    Quasi-static tests have been performed on triaxially braided carbon fiber composite materials with large unit cell sizes. The effects of different fibers and matrix materials on the failure mode were investigated. Simulations of the tests have been performed using the transient dynamic finite element code, LS-DYNA. However, the wide range of failure modes observed for the triaxial braided carbon fiber composites during tests could not be simulated using composite material models currently available within LS-DYNA. A macroscopic approach has been developed that provides better simulation of the material response in these materials. This approach uses full-field optical measurement techniques to measure local failures during quasi-static testing. Information from these experiments is then used along with the current material models available in LS-DYNA to simulate the influence of the braided architecture on the failure process. This method uses two-dimensional shell elements with integration points through the thickness of the elements to represent the different layers of braid along with a new analytical method for the import of material stiffness and failure data directly. The present method is being used to examine the effect of material properties on the failure process. The experimental approaches used to obtain the required data will be described, and preliminary results of the numerical analysis will be presented.

  18. Mechanical properties of neat polymer matrix materials and their unidirectional carbon fiber-reinforced composites

    Science.gov (United States)

    Zimmerman, Richard S.; Adams, Donald F.

    1988-01-01

    The mechanical properties of two neat resin systems for use in carbon fiber epoxy composites were characterized. This included tensile and shear stiffness and strengths, coefficients of thermal and moisture expansion, and fracture toughness. Tests were conducted on specimens in the dry and moisture-saturated states, at temperatures of 23, 82 and 121 C. The neat resins tested were American Cyanamid 1806 and Union Carbide ERX-4901B(MPDA). Results were compared to previously tested neat resins. Four unidirectional carbon fiber reinforced composites were mechanically characterized. Axial and transverse tension and in-plane shear strengths and stiffness were measured, as well as transverse coefficients of thermal and moisture expansion. Tests were conducted on dry specimens only at 23 and 100 C. The materials tested were AS4/3502, AS6/5245-C, T300/BP907, and C6000/1806 unidirectional composites. Scanning electron microscopic examination of fracture surfaces was performed to permit the correlation of observed failure modes with the environmental test conditions.

  19. Ablation Property of Ceramics/Carbon Fibers/Resin Novel Super-hybrid Composite

    Institute of Scientific and Technical Information of China (English)

    Jun QIU; Xiaoming CAO; Chong TIAN; Jinsong ZHANG

    2005-01-01

    A novel super-hybrid composite (NSHC) is prepared with three-dimension reticulated SiC ceramic (3DRC), high performance carbon fibers and modified phenolic resin (BPR) in this paper. Ablation performance of super-hybrid composite is studied. The results show that the NSHC has less linear ablation rate compared with pure BPR and CF/BPR composite, for example, its linear ablation rate is 50% of CF/BPR at the same fiber content. Mass ablation rate of the NSHC is slightly lower than that of pure BPR and CF/BPR composite because of their difference in the density. Scanning electron microscopic analysis indicates that 3DRC can increase anti-erosion capacity of materials because its special reticulated structure can control the deformation of materials and strengthen the stability of integral structure.

  20. Mechanical properties and failure mechanisms of carbon fiber reinforced epoxy laminated composites

    Energy Technology Data Exchange (ETDEWEB)

    Thissell, W.R.; Zurek, A.K.; Addessio, F.

    1995-09-01

    The mechanical behavior of quasi-isotropic and unidirectional epoxy-matrix carbon-fiber laminated composites subjected compressive loading at strain rates of 10{sup {minus}3} and 2000 s{sup {minus}1} are described. Failure in the studied composites was dominated by delamination which proceeded by brittle fracture of the epoxy-matrix. The matrix-fiber bonding in these composites is very strong and prevented the occurrence of significant fiber-pullout. The mode I delamination strain energy release rate of the unidirectional composites was determined using the double cantilever beam and hole in plate compression method. The DCB method indicated a significant R curve effect attributed to fiber bridging while the presently available hole in plate analytical methods show questionable validity for highly anisotropic materials.

  1. Mechanical properties, microscopy, and failure mechanisms of carbon fiber reinforced epoxy laminated composites

    Energy Technology Data Exchange (ETDEWEB)

    Thissell, W.R.; Zurek, A.K.; Addessio, F.

    1995-12-31

    The mechanical behavior of quasi-isotropic and unidirectional epoxy- matrix carbon-fiber laminated composites subjected to compressive loading at strain rates of 10{sup {minus}3} and 2000 s{sup {minus}1} are described. Failure in the studied composites was dominated by delamination which proceeded by brittle fracture of the epoxy matrix. The matrix-fiber bonding in these composites is very strong and prevented the occurrence of significant fiber-pullout. The mode I delamination strain energy release rate of the unidirectional composites was determined using the double cantilever beam and hole in plate compression methods. The DCB method indicated a significant R curve effect attributed to fiber bridging while the presently available hole in plate analytical methods show questionable validity for highly anisotropic materials.

  2. Basic failure mechanisms in advanced composites. [composed of epoxy resins reinforced with carbon fibers

    Science.gov (United States)

    Mazzio, V. F.; Mehan, R. L.; Mullin, J. V.

    1973-01-01

    The fundamental failure mechanisms which result from the interaction of thermal cycling and mechanical loading of carbon-epoxy composites were studied. This work was confined to epoxy resin uniderictionally reinforced with HTS carbon fibers, and consists of first identifying local fiber, matrix and interface failure mechanisms using the model composite specimen containing a small number of fibers so that optical techniques can be used for characterization. After the local fracture process has been established for both mechanical loading and thermal cycling, engineering composite properties and gross fracture modes are then examined to determine how the local events contribute to real composite performance. Flexural strength in high fiber content specimens shows an increase in strength with increased thermal cycling. Similar behavior is noted for 25 v/o material up to 200 cycles; however, there is a drastic reduction after 200 cycles indicating a major loss of integrity probably through the accumulation of local cleavage cracks in the tensile region.

  3. X-ray-cured carbon-fiber composites for vehicle use

    Science.gov (United States)

    Herer, Arnold; Galloway, Richard A.; Cleland, Marshall R.; Berejka, Anthony J.; Montoney, Daniel; Dispenza, Dan; Driscoll, Mark

    2009-07-01

    Carbon-fiber-reinforced composites were cured in molds using X-rays derived from a high-energy, high-current electron beam. X-rays could penetrate the mold walls as well as the fiber reinforcements and polymerize a matrix system. Matrix materials made from modified epoxy-acrylates were tailored to suitably low viscosity so that fiber wetting and adhesion could be attained. Techniques similar to vacuum-assisted resin transfer molding (VARTM) and conventional vacuum bagging of wet lay-ups were used. Inexpensive reinforced polyester molds were used to fabricate vehicle fenders. Moderately low-dose X-ray exposure was sufficient to attain functional properties, such as resistance to heat distortion at temperatures as high as 180 °C. The matrix system contained an impact additive which imparted toughness to the cured articles. "Class A" high gloss surfaces were achieved. Thermo-analytical techniques were used on small-sized samples of X-ray-cured matrix materials to facilitate selection of a system for use in making prototypes of vehicle components. X-rays-penetrated metal pieces that were placed within layers of carbon-fiber twill, which were cured and bonded into a structure that could be mechanically attached without concern over fracturing the composite. X-ray curing is a low temperature process that eliminates residual internal stresses which are imparted by conventional thermo-chemical curing processes.

  4. X-ray-cured carbon-fiber composites for vehicle use

    Energy Technology Data Exchange (ETDEWEB)

    Herer, Arnold; Galloway, Richard A.; Cleland, Marshall R. [IBA Industrial, Inc., Edgewood, NY (United States); Berejka, Anthony J. [Ionicorp, Huntington, NY (United States)], E-mail: berejka@msn.com; Montoney, Daniel [Strathmore Products, Syracuse, NY (United States); Dispenza, Dan [Nordan Composite Technologies, Patchogue, NY (United States); Driscoll, Mark [State University of New York, SUNY-ESF, Syracuse, NY (United States)

    2009-07-15

    Carbon-fiber-reinforced composites were cured in molds using X-rays derived from a high-energy, high-current electron beam. X-rays could penetrate the mold walls as well as the fiber reinforcements and polymerize a matrix system. Matrix materials made from modified epoxy-acrylates were tailored to suitably low viscosity so that fiber wetting and adhesion could be attained. Techniques similar to vacuum-assisted resin transfer molding (VARTM) and conventional vacuum bagging of wet lay-ups were used. Inexpensive reinforced polyester molds were used to fabricate vehicle fenders. Moderately low-dose X-ray exposure was sufficient to attain functional properties, such as resistance to heat distortion at temperatures as high as 180 {sup o}C. The matrix system contained an impact additive which imparted toughness to the cured articles. 'Class A' high gloss surfaces were achieved. Thermo-analytical techniques were used on small-sized samples of X-ray-cured matrix materials to facilitate selection of a system for use in making prototypes of vehicle components. X-rays-penetrated metal pieces that were placed within layers of carbon-fiber twill, which were cured and bonded into a structure that could be mechanically attached without concern over fracturing the composite. X-ray curing is a low temperature process that eliminates residual internal stresses which are imparted by conventional thermo-chemical curing processes.

  5. Activated carbon fibers/poly(lactic-co-glycolic) acid composite scaffolds: preparation and characterizations.

    Science.gov (United States)

    Shi, Yanni; Han, Hao; Quan, Haiyu; Zang, Yongju; Wang, Ning; Ren, Guizhi; Xing, Melcolm; Wu, Qilin

    2014-10-01

    The present work is a first trial to introduce activated carbon fibers (ACF) with high adsorption capacity into poly(lactic-co-glycolic) acid (PLGA), resulting in a novel kind of scaffolds for tissue engineering applications. ACF, prepared via high-temperature processing of carbon fibers, are considered to possess bioactivity and biocompatibility. The ACF/PLGA composite scaffolds are prepared by solvent casting/particulate leaching method. Increments in both pore quantity and quality over the surface of ACF as well as a robust combination between ACF and PLGA matrix are observed via scanning electron microscopy (SEM). The high adsorption capacity of ACF is confirmed by methylene blue solution absorbency test. The surfaces of ACF are affiliated with many hydrophilic groups and characterized by Fourier transform infrared spectroscopy. Furthermore, the SEM images show that cells possess a favorable spreading morphology on the ACF/PLGA scaffolds. Besides, vivo experiments are also carried out to evaluate the histocompatibility of the composite scaffolds. The results show that ACF have the potential to become one of the most promising materials in biological fields.

  6. [Research on treatment of high salt wastewater by the graphite and activated carbon fiber composite electrodes].

    Science.gov (United States)

    Zhou, Gui-Zhong; Wang, Zhao-Feng; Wang, Xuan; Li, Wen-Qian; Li, Shao-Xiang

    2014-05-01

    High salinity wastewater is one of the difficulties in the field of wastewater treatment. As a new desalination technology, electrosorption technology has many advantages. This paper studied a new type of carbon-based electrodes, the graphite and activated carbon fiber composite electrodes. And the influencing factors of electrosorption and its desalination effect were investigated. The electrosorption device had optimal desalination effect when the voltage was 1. 6 V, the retention time was 60 min and the plate spacing was 1 cm. The graphite and activated carbon fiber composite electrodes were used to treat the black liquor of refined cotton and sodium copper chlorophyll wastewater to investigate its desalination effect. When the electrodes were used to treat the black liquor of refined cotton after acid treatment, the removal rate of conductivity and COD reached 58. 8% and 75. 6% respectively when 8 pairs of electrodes were used. And when the electrode was used to treat the sodium copper chlorophyll wastewater, the removal rate of conductivity and COD reached higher than 50. 0% and 13. 5% respectively when 6-8 pairs of electrodes were used.

  7. Design and analysis of automotive carbon fiber composite bumper beam based on finite element analysis

    Directory of Open Access Journals (Sweden)

    Tie Wang

    2015-06-01

    Full Text Available In this article, the most important part of the automotive front bumper system, namely, the bumper beam, is studied by changing the material and thickness to improve the crashworthiness performance in low-velocity impact. According to the low-speed standard of automotives stated in E.C.E. United Nations Agreement, Regulation no. 42, the low-velocity impact simulation based on finite element analysis is carried out. Lightweight is the main purpose of this article. First, the bumper beam analysis is accomplished for carbon fiber composite and steel material to analyze their deformation, weight, impact force, energy absorption, and the acceleration of the impactor. As a consequence, the bumper beam made by carbon fiber composite achieves better impact behavior. Second, on the purpose of lightweight, the bumper beams of different thickness including 5.4, 6, 6.6, and 7.2 mm are investigated. The results show that the 5.4 mm bumper beam is the best selection without sacrificing the impact performance. Third, according to the stress distribution, the thickness distribution of the bumper beam is changed to get better lightweight results. It is indicated that the weight of the improved bumper beam is further reduced and the impact performance is not weakened.

  8. Thermo-physical Properties of Continuous Carbon Fiber Reinforced Copper Matrix Composites

    Institute of Scientific and Technical Information of China (English)

    曹金华; 黄俊波; 陈先有

    2007-01-01

    Continuous carbon fiber reinforced copper matrix composites with 70%(volume fraction)of carbon fibers prepared by squeeze casting technique have been used for investigation of the coefficient of thermal expansion(CTE)and thermal conductivity.Thermo-physical properties have been measured in both, longitudinal and transversal directions to the fiber orientation.The results showed that Cf/Cu composites may be a suitable candidate for heat sinks because of its good thermo-physical properties e.g.the low CTE(4.18×10-6/K)in longitudinal orientation and(14.98×10-6/K)in transversal orientation at the range of 20-50℃,a good thermal conductivity(87.2 W/m·K)in longitudinal orientation and(58.2 W/m·K)in transversal orientation.Measured CTE and thermal conductivity values are compared with those predicted by several well-known models.Eshelby model gave better results for prediction of the CTE and thermal conductivity of the unidirectional composites.

  9. Investigations on damage resistance of carbon fiber composite panels toughened using veils

    Institute of Scientific and Technical Information of China (English)

    Zhu Lingang

    2013-01-01

    This research focused on how to improve damage resistance of carbon fiber laminates.It was carried out at Cranfield University Composites Centre,Milton Keynes,UK as an MSc by research thesis project.A series of low-cost composite laminates,with or without novel veils provided by Tenax,was manufactured using current aircraft carbon fiber preforms via vacuum infusion (Ⅵ) molding in this research.All the investigations on damage resistance of these panels were carried out according to the British Standard (BS ISO 18353:2009).Initial damage was induced using a falling weight apparatus mounting a 16mm hemispherical tip.C-scan and Micrograph were employed to reveal damage characteristics.Finally,both compression after impact (CAI) and plain compression strength were experimented.The behaviors of these panels,including damage size,damage construction,residual compression strength,and compression strength reduction,were utilized to investigate how and to what extent the veils affected the damage resistance.The results show that using veils is an efficient method of improving the damage resistance of the laminates studied.Maximum 32% increase in residual compression strength is achieved via veils accompanying with 7% increase in cost.

  10. Influence of Terahertz Waves on Unidirectional Carbon Fibers in CFRP Composite Materials

    Directory of Open Access Journals (Sweden)

    Kwang-Hee IM

    2014-12-01

    Full Text Available Terahertz time domain spectroscopy (THz TDS system based on the reflective and through-transmission modes was utilized. Influence of terahertz waves (T-ray on the fiber surface layups in the CFRP solid composites was studied. It was found that the value of electrical conductivity in the carbon fibers varies by the layup directions of carbon fibers based on E-field (Electrical field. T-ray optimized scanning data could be obtained at the 90° angle normal to the E-field direction. GFRP (Glass-fiber reinforced plastics composite laminates were scanned with two saw cuts using a T-ray THz TDS system and the terahertz optimized scanning images were obtained at the angles normal to the E-field direction on the nonconducting materials. Also, by use of 2-dimensional spatial Fourier transform, interface C-scan images were transformed into quantitative angular distribution plots in order to show the fiber orientation information therein and to make the orientation of the ply predictable. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6440

  11. Effect of particle size and distribution of the sizing agent on the carbon fibers surface and interfacial shear strength (IFSS) of its composites

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R.L. [Open Project of State Key Laboratory Breeding Base for Mining Disaster Prevention and Control, Shandong University of Science and Technology (China); School of Materials Science and Engineering, Shandong University of Science and Technology, 266590 Qingdao (China); Liu, Y. [School of Materials Science and Engineering, Shandong University of Science and Technology, 266590 Qingdao (China); Huang, Y.D., E-mail: rlzhit@126.com [School of Chemical Engineering and Technology, State Key laboratory of Urban Water Resource and Environment Department of Applied Chemistry, Harbin Institute of Technology, 150001 Harbin (China); Liu, L. [School of Chemical Engineering and Technology, State Key laboratory of Urban Water Resource and Environment Department of Applied Chemistry, Harbin Institute of Technology, 150001 Harbin (China)

    2013-12-15

    Effect of particle size and distribution of the sizing agent on the performance of carbon fiber and carbon fiber composites has been investigated. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to characterize carbon fiber surface topographies. At the same time, the single fiber strength and Weibull distribution were also studied in order to investigate the effect of coatings on the fibers. The interfacial shear strength and hygrothermal aging of the carbon fiber/epoxy resin composites were also measured. The results indicated that the particle size and distribution is important for improving the surface of carbon fibers and its composites performance. Different particle size and distribution of sizing agent has different contribution to the wetting performance of carbon fibers. The fibers sized with P-2 had higher value of IFSS and better hygrothermal aging resistant properties.

  12. Improved thermoplastic composite by alignment of vapor-grown carbon fiber

    Science.gov (United States)

    Kuriger, Rex Jerrald

    2000-10-01

    Vapor grown carbon fiber (VGCF) is a new and inexpensive carbon fiber produced by vapor deposition of hydrocarbons on metal catalysts. Unlike continuous conventional PAN or pitch-derived carbon fibers, VGCF is discontinuous with diameters of about 200 nanometers and lengths ranging from 10 to 200 micrometers. The microscopic size and random entanglement of the fibers create several problems when processing VGCF composites. It is particularly difficult to disperse the entangled fibers in the matrix and orient them along a preferred axis to provide directional reinforcement. This work introduces a technique to produce an improved polymeric composite by alignment of vapor grown carbon nano-fibers in a polypropylene matrix. A twin-screw extruder was used to shear mix and disperse the fibers in the polymer matrix. The composite mixtures were extruded through a converging-annular die that generates flow-induced fiber alignment along the extrusion direction. The effect that the various extrusion conditions have on the bulk properties of the extrudate was investigated. It was found that the extrusion process is strongly dependent on the fiber content of the composite. The extrusion pressure increased and the flow rate decreased with fiber volume fraction. The tensile strength and modulus for the composite samples varied with extrusion temperature and screw speed, and the void content increased with fiber volume fraction. It was shown that fiber alignment could be improved by increasing the residence time in the die channel and was verified using x-ray diffraction. The mechanical properties of the aligned samples increased with fiber content. Also, the tensile strength improved with greater fiber orientation; however, more fiber alignment had little affect on the modulus. To better predict the strength of these partially aligned fiber composites, an experimental and theoretical approach was introduced. The experimental data correspond reasonably well when compared with the

  13. Peapod-like composite with nickel phosphide nanoparticles encapsulated in carbon fibers as enhanced anode for li-ion batteries.

    Science.gov (United States)

    Zhang, Huijuan; Feng, Yangyang; Zhang, Yan; Fang, Ling; Li, Wenxiang; Liu, Qing; Wu, Kai; Wang, Yu

    2014-07-01

    Herein, we introduce a peapod-like composite with Ni12 P5 nanoparticles encapsulated in carbon fibers as the enhanced anode in Li-ion batteries for the first time. In the synthesis, NiNH4 PO4 ⋅H2 O nanorods act as precursors and sacrificial templates, and glucose molecules serve as the green carbon source. With the aid of hydrogen bonding between the precursor and carbon source, a polymer layer is hydrothermally formed and then rationally converted into carbon fibers upon inert calcination at elevated temperatures. Meanwhile, NiNH4 PO4 ⋅H2 O nanorods simultaneously turn into Ni12 P5 nanoparticles encapsulated in carbon fibers by undergoing a decomposition and reduction process induced by high temperature and the carbon fibers. The obtained composite performs excellently as a Li-ion batteries anode relative to pure-phase materials. Specific capacity can reach 600 m Ah g(-1) over 200 cycles, which is much higher than that of isolated graphitized carbon or phosphides, and reasonably believed to originate from the synergistic effect based on the combination of Ni12 P5 nanoparticles and carbon fibers. Due to the benignity, sustainability, low cost, and abundance of raw materials of the peapod-like composite, numerous potential applications, in fields such as optoelectronics, electronics, specific catalysis, gas sensing, and biotechnology can be envisaged.

  14. SILICA SURFACED CARBON FIBERS.

    Science.gov (United States)

    carbon fibers . Several economical and simple processes were developed for obtaining research quantities of silica surfaced carbon filaments. Vat dipping processes were utilized to deposit an oxide such as silica onto the surface and into the micropores of available carbon or graphite base fibers. High performance composite materials were prepared with the surface treated carbon fibers and various resin matrices. The ablative characteristics of these composites were very promising and exhibited fewer limitations than either silica or...treated

  15. Graphite Sheet Coating for Improved Thermal Oxidative Stability of Carbon Fiber Reinforced/PMR-15 Composites

    Science.gov (United States)

    Campbell, Sandi; Papadopoulos, Demetrios; Heimann, Paula; Inghram, Linda; McCorkle, Linda

    2005-01-01

    Expanded graphite was compressed into graphite sheets and used as a coating for carbon fiber reinforced PMR-15 composites. BET analysis of the graphite indicated an increase in graphite pore size on compression, however the material was proven to be an effective barrier to oxygen when prepegged with PMR-15 resin. Oxygen permeability of the PMR-15/graphite was an order of magnitude lower than the compressed graphite sheet. By providing a barrier to oxygen permeation, the rate of oxidative degradation of PMR-15 was decreased. As a result, the composite thermo-oxidative stability increased by up to 25%. The addition of a graphite sheet as a top ply on the composites yielded little change in the material's flexural strength or interlaminar shear strength.

  16. Nondestructive Evaluation of Carbon Fiber Reinforced Polymer Composites Using Reflective Terahertz Imaging

    Directory of Open Access Journals (Sweden)

    Jin Zhang

    2016-06-01

    Full Text Available Terahertz (THz time-domain spectroscopy (TDS imaging is considered a nondestructive evaluation method for composite materials used for examining various defects of carbon fiber reinforced polymer (CFRP composites and fire-retardant coatings in the reflective imaging modality. We demonstrate that hidden defects simulated by Teflon artificial inserts are imaged clearly in the perpendicular polarization mode. The THz TDS technique is also used to measure the thickness of thin fire-retardant coatings on CFRP composites with a typical accuracy of about 10 micrometers. In addition, coating debonding is successfully imaged based on the time-delay difference of the time-domain waveforms between closely adhered and debonded sample locations.

  17. Effect of Water Absorption on the Impact Properties of Carbon Fiber/ Epoxy Composites

    Institute of Scientific and Technical Information of China (English)

    LU Xiao-jun; ZHANG Qi

    2006-01-01

    In this paper, the effects of test temperatures and time on the impact damage behavior of unidirectional carbon fiber reinforced epoxy resin composites, immersed in pure water, on a pendulum impact tester, was studied. The results show that immersion in liquids has a significant effect on the impact resistance of the unidirectional composite material. It is obvious that after immersion, the mass of the material increases. The fracture initiation forces as well as the fracture initiation energy decrease as the immersion time lengthens. Moreover, the higher the temperature and the longer the time are, the more the crack propagation energy and the ductility index will be. Immersion makes the fracture mode change from the dominant fiber fracture into dominant delamination. All in all, immersion decreases the impact resistance of the composites and causes the fracture mode to change.

  18. Isothermal and hygrothermal agings of hybrid glass fiber/carbon fiber composite

    Science.gov (United States)

    Barjasteh, Ehsan

    anhydride/epoxy network used in composite-reinforced conductor cables was investigated to determine the extent of thermal oxidative (surface effect) and non-oxidative (bulk effect) degradation. Thermal oxidation tests were performed in air-circulating and vacuum ovens at 180°C and 200ºC (the maximum emergency temperature for ACCC conductors). The extent of oxidation during aging was determined by monitoring the thickness of the oxidized layer. Results showed that the oxidized layer thickness did not increase monotonically as a function of exposure time, and even decreased for a limited period of time. A phenomenological reaction-diffusion model was implemented to predict the thickness of oxidized layer, and the calculated results were compared with measurements for aging times up to 10,000 hours. The accuracy of the reaction-diffusion-based thickness values for the isothermally aged epoxy specimen was affected by the permeability properties of the oxidized material, and to a lesser extent by the degree of oxidation. The diffusivity varied because of changes in the density of the oxidized layer, the macro-void content, crack formation, and the molecular structures. To investigate the effects on diffusivity, the morphology of the oxidized layer and the void content was monitored over time. In addition, the density of the oxidized specimens was calculated by direct measurements of volume and weight during exposure. An empirically based volume-loss model was developed to predict the changes in volume of the specimen as a function of aging times and hence to predict the effects on the oxidized layer thickness. Volume-loss measurements provide an indication of material degradation by demonstrating a direct measurement of shrinkage rates and insight into crack initiation, as opposed to typical weight-loss measurements that provide no insight into material failure. Thermal oxidation of a unidirectional carbon-fiber/glass-fiber hybrid composite was also investigated in this study

  19. Synergetic Effects of Mechanical Properties on Graphene Nanoplatelet and Multiwalled Carbon Nanotube Hybrids Reinforced Epoxy/Carbon Fiber Composites

    OpenAIRE

    Pin-Ning Wang; Tsung-Han Hsieh; Chin-Lung Chiang; Ming-Yuan Shen

    2015-01-01

    Graphene nanoplatelets (GNPs) and carbon nanotubes (CNTs) are novel nanofillers possessing attractive characteristics, including robust compatibility with most polymers, high absolute strength, and cost effectiveness. In this study, an outstanding synergetic effect on the grapheme nanoplatelets (GNPs) and multiwalled carbon nanotubes (CNTs) hybrids were used to reinforce epoxy composite and epoxy/carbon fiber composite laminates to enhance their mechanical properties. The mechanical propertie...

  20. Material characterization of several resin systems for high temperature carbon fiber reinforced composites

    Science.gov (United States)

    Yoon, Sung Ho; Oh, Jin Oh; Choi, Dong Hyun; Lee, Sang Woo

    2012-04-01

    Material characterization of several resin systems for high temperature carbon fiber reinforced composites was performed through a series of the tensile test, the dynamic mechanical analysis (DMA) test, and the strand test. The modified tensile specimens and the DMA specimens were used to evaluate the tensile and thermal analysis properties of resin systems. The strand specimens were used to evaluate the tensile properties and load transfer efficiencies of the specimens. Four types of resin systems were considered. One was a conventional resin system currently used for filament wound structures and other three were high temperature resin systems. According to the tensile and DMA test results, the tensile modulus decreases slightly and the tensile strength decreases rapidly until the temperature reaches glass transition temperature. The tensile modulus and tensile strength are almost negligible above glass transition temperature. The tensile modulus obtained from the tensile test is consistent with that from the DMA test at different temperatures. From the strand test results, considering, the load transfer efficiency is found to be around 87 to 90 % of the tensile strength of T800H-12K carbon fibers for all resin systems except the specimen with the Type 2. Finally we found that the Type 4 is the best candidate for high temperature resin system applicable to filament wound structures in the view of the glass transition temperature as well as the tensile properties.

  1. Mechanism of Functional Responses to Loading of Carbon Fiber Reinforced Cement-based Composites

    Institute of Scientific and Technical Information of China (English)

    JIANG Cuixiang; LI Zhuoqiu; SONG Xianhui; LU Yong

    2008-01-01

    Single fiber pull-out testing was conducted to study the origin of the functional responses to loading of carbon fiber reinforced cement-based composites.The variation of electrical resistance with the bonding force on the fiber-matrix interface was measured.Single fiber electromechanical testing was also conducted by measuring the electrical resistance under static tension.Comparison of the results shows that the resistance increasing during single fiber pull-out is mainly due to the changes at the interface.The conduction mechanism of the composite can be explained by the tunneling model.The interfacial stress causes the deformation of interfacial structure and the interfacial debonding.which have influences on the tunneling effect and result in the change of resistance.

  2. Nanoparticle Filtration in a RTM Processed Epoxy/Carbon Fiber Composite

    Science.gov (United States)

    Miller, Sandi G.; Micham, Logan; Copa, Christine C.; Criss, James M., Jr.; Mintz, Eric A.

    2011-01-01

    Several epoxy matrix composite panels were fabricated by resin transfer molding (RTM) E862/W resin onto a triaxially braided carbon fiber pre-form. Nanoparticles including carbon nanofiber, synthetic clay, and functionalized graphite were dispersed in the E862 matrix, and the extent of particle filtration during processing was characterized. Nanoparticle dispersion in the resin flashing on both the inlet and outlet edges of the panel was compared by TEM. Variation in physical properties such as Tg and moisture absorption throughout the panel were also characterized. All nanoparticle filled panels showed a decrease in Tg along the resin flow path across the panel, indicating nanoparticle filtration, however there was little change in moisture absorption. This works illustrates the need to obtain good nano-particle dispersion in the matrix resin to prevent particle agglomeration and hence particle filtration in the resultant polymer matrix composites (PMC).

  3. Enhancement of the total focusing method imaging for immersion testing of anisotropic carbon fiber composite structures

    Science.gov (United States)

    Aschy, Ameni; Terrien, Nicolas; Robert, Sébastien; Bentahar, Mourad

    2017-02-01

    The use of composite structures has importantly increased because of their reduced weight, assembly simplification and excellent specific strength and stiffness. The multiple possibilities of their manufacturing allow today to integrate within a single structure multiple functions: design, mechanical strength, multi-material…These structures, by their geometric and structural complexity (anisotropy, attenuation and scattering noise), do not always allow the application of conventional ultrasound real-time methods. In this communication, the problem related to anisotropy is treated in a first part with an analysis of the influence of materials properties on the conventional array imaging methods. In the second part, anisotropy is taken into account in the Total Focusing Method (TFM) to improve the image quality in carbon fiber composite plates.

  4. Wear and transfer characteristics of carbon fiber reinforced polymer composites under water lubrication

    Institute of Scientific and Technical Information of China (English)

    JIA Jun-hong; CHEN Jian-min; ZHOU Hui-di; CHEN Lei

    2004-01-01

    The tribological characteristics of carbon fiber reinforced polymer composites under distilled-water-lubricated-sliding and dry-sliding against stainless steel were comparatively investigated. Scanning electron microscopy (SEM) was utilized to examine composite microstructures and modes of failure. The typical chemical states of elements of the transfer film on the stainless steel were examined with X-ray photoelectron spectroscopy (XPS). Wear testing and SEM analysis show that all the composites hold the lowered friction coefficient and show much better wear resistance under water lubricated sliding against stainless steel than those under dry sliding. The wear of composites is characterized by plastic deformation, scuffing, micro cracking, and spalling under both dry-sliding and water lubricated conditions. Plastic deformation, scuffing, micro cracking, and spalling, however, are significantly abated under water-lubricated condition. XPS analysis conforms that none of the materials produces transfer films on the stainless steel counterface with the type familiar from dry sliding, and the transfer of composites onto the counterpart ring surface is significantly hindered while the oxidation of the stainless steel is speeded under water lubrication. The composites hinder transfer onto the steel surface and the boundary lubricating action of water accounts for the much smaller wear rate under water lubrication compared with that under dry sliding. The easier transfer of the composite onto the counterpart steel surface accounts for the larger wear rate of the polymer composite under dry sliding.

  5. Applications research in ultrasonic testing of carbon fiber composite based on an optical fiber F-p sensor

    Science.gov (United States)

    Shan, Ning

    2016-10-01

    Carbon fiber composite is widely applied to the field of aerospace engineering because of its excellent performance. But it will be able to form more defects in the process of manufacturing inevitably on account of unique manufacturing process. Meanwhile it has sophisticated structure and services in the bad environment long time. The existence of defects will be able to cause the sharp decline in component's performance when the defect accumulates to a certain degree. So the reliability and safety test demand of carbon fiber composite is higher and higher. Ultrasonic testing technology is the important means used for characteristics of component inspection of composite materials. Ultrasonic information detection uses acoustic transducer generally. It need coupling agent and is higher demand for the surface of sample. It has narrow frequency band and low test precision. The extrinsic type optical fiber F-P interference cavity structure is designed to this problem. Its optical interference model is studied. The initial length of F-P cavity is designed. The realtime online detection system of carbon fiber composite is established based on optical fiber F-P Ultrasound sensing technology. Finally, the testing experiment study is conducted. The results show that the system can realize real-time online detection of carbon fiber composite's defect effectively. It operates simply and realizes easily. It has low cost and is easy to practical engineering.

  6. Increasing the Tensile Property of Unidirectional Carbon/Carbon Composites by Grafting Carbon Nanotubes onto Carbon Fibers by Electrophoretic Deposition

    Institute of Scientific and Technical Information of China (English)

    Qiang Song; Kezhi Li; Hejun Li; Qiangang Fu

    2013-01-01

    Although in-situ growing carbon nanotubes (CNTs) on carbon fibers could greatly increase the matrix-dominated mechanical properties of carbon/carbon composites (C/Cs),it always decreased the tensile strength of carbon fibers.In this work,CNTs were introduced into unidirectional carbon fiber (CF) preforms by electrophoretic deposition (EPD) and they were used to reinforce C/Cs.Effects of the content of CNTs introduced by EPD on tensile property of unidirectional C/Cs were investigated.Results demonstrated that EPD could be used as a simple and efficient method to fabricate carbon nanotube reinforced C/Cs (CNT-C/Cs) with excellent tensile strength,which pays a meaningful way to maximize the global performance of CNT-C/Cs.

  7. Spectroscopic study of terahertz reflection and transmission properties of carbon-fiber-reinforced plastic composites

    Science.gov (United States)

    Zhang, Jin; Shi, Changcheng; Ma, Yuting; Han, Xiaohui; Li, Wei; Chang, Tianying; Wei, Dongshan; Du, Chunlei; Cui, Hong-Liang

    2015-05-01

    Carbon-fiber-reinforced plastic (CFRP) composites are widely used in aerospace and concrete structure reinforcement due to their high strength and light weight. Terahertz (THz) time-domain spectroscopy is an attractive tool for defect inspection in CFRP composites. In order to improve THz nondestructive testing of CFRP composites, we have carried out systematic investigations of THz reflection and transmission properties of CFRP. Unidirectional CFRP composites with different thicknesses are measured with polarization directions 0 deg to 90 deg with respect to the fiber direction, in both reflection and transmission modes. As shown in the experiments, CFRP composites are electrically conducting and therefore exhibit a high THz reflectivity. In addition, CFRP composites have polarization-dependent reflectivity and transmissivity for THz radiation. The reflected THz power in the case of parallel polarization is nearly 1.8 times higher than for perpendicular polarization. At the same time, in the transmission of THz wave, a CFRP acts as a Fabry-Pérot cavity resulting from multiple internal reflections from the CFRP-air interfaces. Moreover, from the measured data, we extract the refractive index and absorption coefficient of CFRP composites in the THz frequency range.

  8. Effect of the surface roughness on interfacial properties of carbon fibers reinforced epoxy resin composites

    Energy Technology Data Exchange (ETDEWEB)

    Song Wei [College of Chemistry, Chemical Engineering and Materials Science, Department of Materials Science and Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Gu Aijuan, E-mail: ajgu@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Department of Materials Science and Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Liang Guozheng, E-mail: lgzheng@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science, Department of Materials Science and Engineering, Soochow University, Suzhou, Jiangsu 215123 (China); Yuan Li [College of Chemistry, Chemical Engineering and Materials Science, Department of Materials Science and Engineering, Soochow University, Suzhou, Jiangsu 215123 (China)

    2011-02-15

    The effect of the surface roughness on interfacial properties of carbon fibers (CFs) reinforced epoxy (EP) resin composite is studied. Aqueous ammonia was applied to modify the surfaces of CFs. The morphologies and chemical compositions of original CFs and treated CFs (a-CFs) were characterized by Atomic Force Microscopy (AFM), and X-ray Photoelectron Spectroscopy (XPS). Compared with the smooth surface of original CF, the surface of a-CF has bigger roughness; moreover, the roughness increases with the increase of the treating time. On the other hand, no obvious change in chemical composition takes place, indicating that the treating mechanism of CFs by aqueous ammonia is to physically change the morphologies rather than chemical compositions. In order to investigate the effect of surface roughness on the interfacial properties of CF/EP composites, the wettability and Interfacial Shear Strength (IFSS) were measured. Results show that with the increase of the roughness, the wettabilities of CFs against both water and ethylene glycol improves; in addition, the IFSS value of composites also increases. These attractive phenomena prove that the surface roughness of CFs can effectively overcome the poor interfacial adhesions between CFs and organic matrix, and thus make it possible to fabricate advanced composites based on CFs.

  9. Electrical impedance spectroscopy for measuring the impedance response of carbon-fiber-reinforced polymer composite laminates

    KAUST Repository

    Almuhammadi, Khaled

    2017-02-16

    Techniques that monitor the change in the electrical properties of materials are promising for both non-destructive testing and structural health monitoring of carbon-fiber-reinforced polymers (CFRPs). However, achieving reliable monitoring using these techniques requires an in-depth understanding of the impedance response of these materials when subjected to an alternating electrical excitation, information that is only partially available in the literature. In this work, we investigate the electrical impedance spectroscopy response at various frequencies of laminates chosen to be representative of classical layups employed in composite structures. We clarify the relationship between the frequency of the electrical current, the conductivity of the surface ply and the probing depth for different CFRP configurations for more efficient electrical signal-based inspections. We also investigate the effect of the amplitude of the input signal.

  10. Segmenting delaminations in carbon fiber reinforced polymer composite CT using convolutional neural networks

    Science.gov (United States)

    Sammons, Daniel; Winfree, William P.; Burke, Eric; Ji, Shuiwang

    2016-02-01

    Nondestructive evaluation (NDE) utilizes a variety of techniques to inspect various materials for defects without causing changes to the material. X-ray computed tomography (CT) produces large volumes of three dimensional image data. Using the task of identifying delaminations in carbon fiber reinforced polymer (CFRP) composite CT, this work shows that it is possible to automate the analysis of these large volumes of CT data using a machine learning model known as a convolutional neural network (CNN). Further, tests on simulated data sets show that with a robust set of experimental data, it may be possible to go beyond just identification and instead accurately characterize the size and shape of the delaminations with CNNs.

  11. Electrical Resistance and Microstructure of Latex Modified Carbon Fiber Reinforced Cement Composites

    Institute of Scientific and Technical Information of China (English)

    WEI Jian; CHENG Feng; YUAN Hudie

    2012-01-01

    The electrical resistance,flexural strength,and microstructure of carbon fiber reinforced cement composites (CFRC) were improved greatly by adding water-redispersible latex powder.The electrical resistance of CFRC was investigated by two-probe method.The input range of CFRC based strain sensors was therefore increased,whereas electrical resistance was increased and remained in the perfect range of CFRC sensors.The analysis of scanning electron microscopy indicated that elastic latex bridges and a latex layer existed among the interspaces of the adjacent cement hydration products which were responsible for the enhancement of the flexural strength and electrical resistance.The formation mechanism of the elastic latex bridges was also discussed in detail.The continuous moving of two opposite interfaces of the latex solution-air along the interspaces of the adjacent hydrated crystals or colloids was attributed to the formation of the elastic latex bridges.

  12. Low Temperature Mechanical Testing of Carbon-Fiber/Epoxy-Resin Composite Materials

    Science.gov (United States)

    Nettles, Alan T.; Biss, Emily J.

    1996-01-01

    The use of cryogenic fuels (liquid oxygen and liquid hydrogen) in current space transportation vehicles, in combination with the proposed use of composite materials in such applications, requires an understanding of how such materials behave at cryogenic temperatures. In this investigation, tensile intralaminar shear tests were performed at room, dry ice, and liquid nitrogen temperatures to evaluate the effect of temperature on the mechanical response of the IM7/8551-7 carbon-fiber/epoxy-resin system. Quasi-isotropic lay-ups were also tested to represent a more realistic lay-up. It was found that the matrix became both increasingly resistant to microcracking and stiffer with decreasing temperature. A marginal increase in matrix shear strength with decreasing temperature was also observed. Temperature did not appear to affect the integrity of the fiber-matrix bond.

  13. Processing of thermo-structural carbon-fiber reinforced carbon composites

    Directory of Open Access Journals (Sweden)

    Luiz Cláudio Pardini

    2009-06-01

    Full Text Available The present work describes the processes used to obtain thermostructural Carbon/Carbon composites. The processing of these materials begins with the definition of the architecture of the carbon fiber reinforcement, in the form of stacked plies or in the form of fabrics or multidirectional reinforcement. Incorporating fiber reinforcement into the carbon matrix, by filling the voids and interstices, leads to the densification of the material and a continuous increase in density. There are two principal processing routes for obtaining these materials: liquid phase processing and gas phase processing. In both cases, thermal processes lead to the formation of a carbon matrix with specific properties related to their precursor. These processes also differ in terms of yield. With liquid phase impregnation the yield is around 45 per cent, while gas phase processing yields around 15 per cent.

  14. Effect of TiO2 deposition on the mechanical properties of a carbon-fiber-reinforced bismaleimide composite

    Science.gov (United States)

    Di, Jang; Chunhua, Cao; Jie, Wu

    2013-07-01

    In order to improve the mechanical properties of carbon-fiber-reinforced bismaleimide (CF/BMI) composites, TiO2 was deposited on the carbon fibers. The short-beam shear and mechanical properties of the composites were investigated. Both raw and TiO2-coated CFs were utilized for their fabrication. The tensile strength of the composites, both with raw and TiO2-coated fibers, grew with increasing filler content. The tensile strength of the CF/BMI composites with treated fibers, at all mixing ratios, was found to be by 18% higher than that of the composites with untreated ones. The surface morphologies of fracture surfaces of the composites were recorded using the scanning electron microscopy (SEM) to gain information about the interfacial fiber-matrix adhesion in the composites.

  15. Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

    Directory of Open Access Journals (Sweden)

    John H. Cantrell

    2015-03-01

    Full Text Available The chemical treatment of carbon fibers used in carbon fiber-epoxy matrix composites greatly affects the fraction of hydrogen bonds (H-bonds formed at the fiber-matrix interface. The H-bonds are major contributors to the fiber-matrix interfacial shear strength and play a direct role in the interlaminar shear strength (ILSS of the composite. The H-bond contributions τ to the ILSS and magnitudes KN of the fiber-matrix interfacial stiffness moduli of seven carbon fiber-epoxy matrix composites, subjected to different fiber surface treatments, are calculated from the Morse potential for the interactions of hydroxyl and carboxyl acid groups formed on the carbon fiber surfaces with epoxy receptors. The τ calculations range from 7.7 MPa to 18.4 MPa in magnitude, depending on fiber treatment. The KN calculations fall in the range (2.01 – 4.67 ×1017 N m−3. The average ratio KN/|τ| is calculated to be (2.59 ± 0.043 × 1010 m−1 for the seven composites, suggesting a nearly linear connection between ILSS and H-bonding at the fiber-matrix interfaces. The linear connection indicates that τ may be assessable nondestructively from measurements of KN via a technique such as angle beam ultrasonic spectroscopy.

  16. Hydrogen bonds, interfacial stiffness moduli, and the interlaminar shear strength of carbon fiber-epoxy matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, John H., E-mail: john.h.cantrell@nasa.gov [Research Directorate, NASA Langley Research Center, Hampton, Virginia 23681 (United States)

    2015-03-15

    The chemical treatment of carbon fibers used in carbon fiber-epoxy matrix composites greatly affects the fraction of hydrogen bonds (H-bonds) formed at the fiber-matrix interface. The H-bonds are major contributors to the fiber-matrix interfacial shear strength and play a direct role in the interlaminar shear strength (ILSS) of the composite. The H-bond contributions τ to the ILSS and magnitudes K{sub N} of the fiber-matrix interfacial stiffness moduli of seven carbon fiber-epoxy matrix composites, subjected to different fiber surface treatments, are calculated from the Morse potential for the interactions of hydroxyl and carboxyl acid groups formed on the carbon fiber surfaces with epoxy receptors. The τ calculations range from 7.7 MPa to 18.4 MPa in magnitude, depending on fiber treatment. The K{sub N} calculations fall in the range (2.01 – 4.67) ×10{sup 17} N m{sup −3}. The average ratio K{sub N}/|τ| is calculated to be (2.59 ± 0.043) × 10{sup 10} m{sup −1} for the seven composites, suggesting a nearly linear connection between ILSS and H-bonding at the fiber-matrix interfaces. The linear connection indicates that τ may be assessable nondestructively from measurements of K{sub N} via a technique such as angle beam ultrasonic spectroscopy.

  17. Durability-Based Design Criteria for a Quasi-Isotropic Carbon-Fiber-Reinforced Thermoplastic Automotive Composite

    Energy Technology Data Exchange (ETDEWEB)

    Naus, Dan J [ORNL; Corum, James [ORNL; Klett, Lynn B [ORNL; Davenport, Mike [ORNL; Battiste, Rick [ORNL; Simpson, Jr., William A [ORNL

    2006-04-01

    This report provides recommended durability-based design properties and criteria for a quais-isotropic carbon-fiber thermoplastic composite for possible automotive structural applications. The composite consisted of a PolyPhenylene Sulfide (PPS) thermoplastic matrix (Fortron's PPS - Ticona 0214B1 powder) reinforced with 16 plies of carbon-fiber unidirectional tape, [0?/90?/+45?/-45?]2S. The carbon fiber was Hexcel AS-4C and was present in a fiber volume of 53% (60%, by weight). The overall goal of the project, which is sponsored by the U.S. Department of Energy's Office of Freedom Car and Vehicle Technologies and is closely coordinated with the Advanced Composites Consortium, is to develop durability-driven design data and criteria to assure the long-term integrity of carbon-fiber-based composite systems for automotive structural applications. This document is in two parts. Part 1 provides design data and correlations, while Part 2 provides the underlying experimental data and models. The durability issues addressed include the effects of short-time, cyclic, and sustained loadings; temperature; fluid environments; and low-energy impacts (e.g., tool drops and kickups of roadway debris) on deformation, strength, and stiffness. Guidance for design analysis, time-independent and time-dependent allowable stresses, rules for cyclic loadings, and damage-tolerance design guidance are provided.

  18. Activation and Micropore Structure Determination of Activated Carbon-Fiber Composites

    Energy Technology Data Exchange (ETDEWEB)

    Jagtoyen, M.; Derbyshire, F.

    1999-04-23

    Previous work focused on the production of carbon fiber composites and subsequently activating them to induce adsorbent properties. One problem related to this approach is the difficulty of uniformly activating large composites. In order to overcome this problem, composites have been made from pre-activated fibers. The loss of surface area upon forming the composites after activation of the fibers was investigated. The electrical resistivity and strength of these composites were compared to those made by activation after forming. It was found that the surface area is reduced by about 35% by forming the composite from pre-activated fibers. However, the properties of the activated sample are very uniform: the variation in surface area is less than {+-}0.5%. So, although the surface area is somewhat reduced, it is believed that making composites from pre-activated fibers could be useful in applications where the BET surface area is not required to be very high. The strength of the composites produced from pre-activated fibers is lower than for composites activated after forming when the carbon burnoff is below 45%. For higher burnoffs, the strength of composites made with pre-activated fibers is as good or better. In both cases, there is a dramatic decrease in strength when the fiber:binder ratio is reduced below 4:1. The electrical resistivity is slightly higher for composites made from pre-activated fibers than for composites that are activated after forming, other parameters being constant (P-200 fibers, similar carbon burnoffs). For both types of composite the resistivity was also found to increase with carbon burnoff. This is attributed to breakage of the fiber causing shorter conductive paths. The electrical resistivity also increases when the binder content is lowered, which suggests that there are fewer solid contact points between the fibers.

  19. Influence of Interleaved Films on the Mechanical Properties of Carbon Fiber Fabric/Polypropylene Thermoplastic Composites

    Directory of Open Access Journals (Sweden)

    Jong Won Kim

    2016-05-01

    Full Text Available A laminated composite was produced using a thermoplastic prepreg by inserting an interleaved film with the same type of matrix as the prepreg during the lay-up process to improve the low interlaminar properties, which is a known weakness of laminated composites. Carbon fiber fabric (CFF and polypropylene (PP were used to manufacture the thermoplastic prepregs. Eight prepregs were used to produce the laminated composites. Interleaved films with different thicknesses were inserted into each prepreg. The physical properties of the composite, such as thickness, density, fiber volume fraction (Vf, and void content (Vc, were examined. The tensile strength, flexural strength, interlaminar shear strength (ILSS, impact property, and scanning electron microscopy (SEM were used to characterize the mechanical properties. Compared to the composite without any inserted interleaved film, as the thickness of the inserted interleaved resin film was increased, Vc decreased by 51.45%. At the same time, however, the tensile strength decreased by 8.75%. Flexural strength increased by 3.79% and flexural modulus decreased by 15.02%. Interlaminar shear strength increased by 11.05% and impact strength increased by 15.38%. Fracture toughness of the laminated composite was improved due to insertion of interleaved film.

  20. Polypropylene/Graphene and Polypropylene/Carbon Fiber Conductive Composites: Mechanical, Crystallization and Electromagnetic Properties

    Directory of Open Access Journals (Sweden)

    Chien-Lin Huang

    2015-11-01

    Full Text Available This study aims to examine the properties of composites that different carbon materials with different measurements can reinforce. Using a melt compounding method, this study combines polypropylene (PP and graphene nano-sheets (GNs or carbon fiber (CF to make PP/GNs and PP/CF conductive composites, respectively. The DSC results and optical microscopic observation show that both GNs and CF enable PP to crystalize at a high temperature. The tensile modulus of PP/GNs and PP/CF conductive composites remarkably increases as a result of the increasing content of conductive fillers. The tensile strength of the PP/GNs conductive composites is inversely proportional to the loading level of GNs. Containing 20 wt% of GNs, the PP/GNs conductive composites have an optimal conductivity of 0.36 S/m and an optimal EMI SE of 13 dB. PP/CF conductive composites have an optimal conductivity of 10−6 S/m when composed of no less than 3 wt% of CF, and an optimal EMI SE of 25 dB when composed of 20 wt% of CF.

  1. Advanced Carbon Fiber Nears Broad Automotive Use

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    General Motors and Teijin Limited, a leader in the carbon fiber and composites industry, will co-develop advanced carbon fiber composite technologies for potential high-volume use globally in GM cars, trucks and crossovers.

  2. Effect of chemical vapor infiltration treatment on the wave-absorbing performance of carbon fiber/cement composites

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Short carbon fibers were treated at high temperatures around 1100℃ through chemical vapor infiltration technology.A thinner layer ofpyrocarbon was deposited on the fiber surface.The dispersion of carbon fibers in a cement matrix and the mechanical properties of carbon fiber/cement composites were investigated by scanning electron microscopy (SEM) and other tests.The reflectivity of electromagnetic waves by the composites was measured in the frequency range of 8.0-18 GHz for different carbon fiber contents of 0.2wt%,0.4wt%,0.6wt% ,and 1.0wt%.The results show that the reflectivity tends to increase with the increase of fiber content above 0.4wt%.The minimum reflectivity is -19.3 dB and the composites exhibit wave-absorbing performances.After pyrocarbon is deposited on the fiber,all the reflectivity data are far greater.They are all above -10 dB and display mainly wave-reflecting performances.

  3. Preparation of PAN/phenolic-based carbon/carbon composites with flexible towpreg carbon fiber

    Energy Technology Data Exchange (ETDEWEB)

    Li Wei [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)], E-mail: liwei5168@hnu.cn; Chen Zhenhua; Li Jin; Chen Xianhong; Xuan Hao; Wang Xiaoyi [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China)

    2008-06-25

    Carbon/carbon composites made with flexible towpreg carbon fiber as reinforcement and phenolic resins as matrix precursor were impregnated with pitch during re-carbonization process. The structural characteristics of the composites were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), three-point bending tests, Archimedes' method and water adsorption. Results showed that the density of the carbon/carbon composites increases from 1.45 to 1.54 g/cm{sup 3} with the cycles of pitch impregnated and re-carbonization. Open porosity measurement indicated that the increase of porosity resulted from the decomposition of phenolic resin matrix, and the open porosity of the composite gradually decreased after the impregnation and re-carbonization process. These composites also exhibited an improvement in flexural strength with increasing number of densification cycles. From SEM morphological observation, it was concluded that few cracks appeared in the surfaces and a few smaller pores with a diameter <1 {mu}m could be observed.

  4. Composite material based on an ablative phenolic resin and carbon fibers

    Directory of Open Access Journals (Sweden)

    DIMKO DIMESKI

    2009-04-01

    Full Text Available In this study, a technological procedure for the production of a molding compound based on short carbon fibers and an ablative phenol–formaldehyde resin for high temperature application was optimized. The starting raw materials were characterized and molding compounds with different fiber/matrix ratios and different fiber lengths were obtained. From the different laboratory samples, molded parts were made by thermocompression. The basic mechanical and thermal properties of the composites were determined. From the obtained results, the optimal fiber/matrix ratio was determined for a production of molding compound for high temperature application. The molding process of the composite material was optimized and all the parameters for good mechanical properties and high thermal stability of the composite were obtained. Optimization of the composite molding process was performed by the application of a numerical method for a planned experiment, i.e., a full three-factorial experimental design with variance of all three parameters (fiber length, temperature and time of the press cycle on two levels. The obtained mechanical properties (flexural strength: 247 MPa, modulus: 27.6 GPa, impact resistance: 110 (for test moldings 10 mm´10 mm and 91 kJ/m2 (for test moldings 15 mm´15 mm justified the application of this composite material in the automotive, leisure, military and other industries where high temperature resistance and high mechanical strength is required.

  5. [Research on the extracorporeal cytocompatibility of a composite of HA, carbon fiber and polyetheretherket-one].

    Science.gov (United States)

    Liu, Xueyong; Deng, Chunbo; Liu, Jiquan; Li, Jianjun; Sui, Guoxin

    2011-12-01

    The present research was to study the biocompatibility of a composite of hydroxyapatite (HA), carbon fiber (CF) and polyetheretherket-one (PEEK) by co-culturing with the osteoblasts in vitro. Cell relative growth (RGR) was used as a quantitative assessment for cytotoxicity of the biomaterials by CCK-8. The proliferation index of the co-cultured cells and ALP activity was measured to study the effect of PEEK-HA-CF composites. Morphological properties of the osteoblast cells in vitro were observed by scanning electro-microscopy (SEM). The PEEK-HA-CF materials have no cytotoxicity to osteoblasts. The proliferation index of PEEK-HA-CF was higher than that of Ti alloy group, but these was no significant difference compared to that of control group. The ALP activity was the highest on PEEK-HA-CF composites surface after 7 days. The osteoblast cells co-cultured with the PEEK-HA-CF composite were adhered well to the biomaterial as observed under the SEM. The results suggested that the PEEK-HA-CF composites had good biocompatibility in vitro and might be a novel orthopedic implanted material.

  6. Erosion of carbon fiber composites under high-fluence heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Andrianova, Natalya N.; Borisov, Anatoly M. [Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation); Mashkova, Eugenia S., E-mail: es_mashkova@mail.r [Institute of Nuclear Physics, Moscow State University, 119991 Moscow (Russian Federation); Virgiliev, Yury S. [NIIgraphite, 111141 Moscow (Russian Federation)

    2011-05-01

    The ion-induced erosion, determining by sputtering yield Y and surface evolution including structure and morphology changes of the modified surface layers, of two commercial carbon fiber composites (CFC) with different reinforcement - KUP-VM (1D) and Desna 4 (4D) have been studied under 30 keV Ar{sup +} high fluence ({phi}t {approx} 10{sup 18}-10{sup 20} ion/cm{sup 2}) irradiation in the temperature range from room temperature to 400 {sup o}C. Ion-induced erosion results in the changes of carbon fiber structure which depend on temperature and ion fluence. Monitoring of ion-induced structural changes using the temperature dependence of ion-induced electron emission yield has shown that for Desna 4 and KUP-VM at dynamic annealing temperature T{sub a} {approx} 170 {sup o}S the transition takes place from disordering at T < T{sub a} to recrystallization at T > T{sub a}. The annealing temperature T{sub a} is close to the one for polycrystalline graphites. Microscopy analysis has shown that at temperatures T < T{sub a} the etching of the fibers results in a formation of trough-like longitudinal cavities and hillocks. Irradiation at temperatures T > T{sub a} leads to a crimped structure with the ribs perpendicular to fiber axis. After further sputtering of the crimps the fiber morphology is transformed to an isotropic globular structure. As a result the sputtering yield decreases for Desna 4 more than twice. This value is almost equal to that for KUP-VM, Desna 4, polycrystalline graphites and glassy carbons at room temperature.

  7. Effects of surface treating methods of high-strength carbon fibers on interfacial properties of epoxy resin matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Quansheng; Gu, Yizhuo, E-mail: benniegu@buaa.edu.cn; Li, Min; Wang, Shaokai; Zhang, Zuoguang

    2016-08-30

    Highlights: • Effects of surface treating on T700 grade high strength carbon fiber were discussed. • The fiber surface roughness, surface energy and chemical properties are analyzed. • The surface treating significantly affect the properties of carbon fiber. • The composite with electrolysis and sizing-fiber has the highest mechanical properties. - Abstract: This paper aims to study the effects of surface treating methods, including electrolysis of anodic oxidation, sizing and heat treatment at 200 °C, on physical and chemical properties of T700 grade high-strength carbon fiber GQ4522. The fiber surface roughness, surface energy and chemical properties were analyzed for different treated carbon fibers, using atom force microscopy, contact angle, Fourier transformed infrared and X-ray photoelectron spectroscopy, respectively. The results show that the adopted surface treating methods significantly affect surface roughness, surface energy and active chemical groups of the studied carbon fibers. Electrolysis and sizing can increase the roughness, surface energy and chemical groups on surface, while heat treatment leads to decreases in surface energy and chemical groups due to chemical reaction of sizing. Then, unidirectional epoxy 5228 matrix composite laminates were prepared using different treated GQ4522 fibers, and interlaminar shear strength and flexural property were measured. It is revealed that the composite using electrolysis and sizing-fiber has the strongest interfacial bonding strength, indicating the important roles of the two treating processes on interfacial adhesion. Moreover, the composite using heat-treating fiber has lower mechanical properties, which is attributed to the decrease of chemical bonding between fiber surface and matrix after high temperature treatment of fiber.

  8. Properties Variation of Carbon Fiber Reinforced Composite for Marine Current Turbine in Seawater

    Directory of Open Access Journals (Sweden)

    Li Jing

    2016-01-01

    Full Text Available Turbine blade which are generally made of composite is a core device among components of tidal current power generator that converts the flow of tidal current into a turning force. Recent years, damages of composite turbine blades have been reported due to reasons like seawater degradation, lake of strength, manufacture etc. In this paper, water absorption, tensile, bending, longitudinal transverse shearing properties of carbon fiber reinforced plastic (CRP composite which would be applied to fabricate the marine current turbine blade has been investigated. Furthermore, the variations of properties with seawater immersion period were studied. The results indicated that the water absorption increased almost linearly at the beginning of immersion and then became stable. Tensile strength of specimen tended to decrease firstly and then recovered slightly. However, the longitudinal transverse shearing strength showed reverse variation trend comparing to tensile strength. And the bending property of specimens was depressed significantly. The properties variations in seawater shall be referenced to design and fabrication of composite marine current turbine blade.

  9. Three-Phase Carbon Fiber Amine Functionalized Carbon Nanotubes Epoxy Composite: Processing, Characterisation, and Multiscale Modeling

    Directory of Open Access Journals (Sweden)

    Kamal Sharma

    2014-01-01

    Full Text Available The present paper discusses the key issues of carbon nanotube (CNT dispersion and effect of functionalisation on the mechanical properties of multiscale carbon epoxy composites. In this study, CNTs were added in epoxy matrix and further reinforced with carbon fibres. Predetermined amounts of optimally amine functionalised CNTs were dispersed in epoxy matrix, and unidirectional carbon fiber laminates were produced. The effect of the presence of CNTs (1.0 wt% in the resin was reflected by pronounced increase in Young’s modulus, inter-laminar shear strength, and flexural modulus by 51.46%, 39.62%, and 38.04%, respectively. However, 1.5 wt% CNT loading in epoxy resin decreased the overall properties of the three-phase composites. A combination of Halpin-Tsai equations and micromechanics modeling approach was also used to evaluate the mechanical properties of multiscale composites and the differences between the predicted and experimental values are reported. These multiscale composites are likely to be used for potential missile and aerospace structural applications.

  10. Adhesive force measurement between HOPG and zinc oxide as an indicator for interfacial bonding of carbon fiber composites.

    Science.gov (United States)

    Patterson, Brendan A; Galan, Ulises; Sodano, Henry A

    2015-07-22

    Vertically aligned zinc oxide (ZnO) nanowires have recently been utilized as an interphase to increase the interfacial strength of carbon fiber composites. It was shown that the interaction between the carbon fiber and the ZnO nanowires was a critical parameter in adhesion; however, fiber based testing techniques are dominated by local defects and cannot be used to effectively study the bonding interaction directly. Here, the strength of the interface between ZnO and graphitic carbon is directly measured with atomic force microscopy (AFM) using oxygen plasma treated highly oriented pyrolytic graphite (HOPG) and an AFM tip coated with ZnO nanoparticles. X-ray photoelectron spectroscopy analysis is used to compare the surface chemistry of HOPG and carbon fiber and to quantify the presence of various oxygen functional groups. An indirect measurement of the interfacial strength is then performed through single fiber fragmentation testing (SFF) on functionalized carbon fibers coated with ZnO nanowires to validate the AFM measurements. The SFF and AFM methods showed the same correlation, demonstrating the capacity of the AFM method to study the interfacial properties in composite materials. Additionally, the chemical interactions between oxygen functional groups and the ionic structure of ZnO suggest that intermolecular forces at the interface are responsible for the strong interface.

  11. Interlaminar improvement of carbon fiber/epoxy composites via depositing mixture of carbon nanotubes and sizing agent

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Cuiqin [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Wang, Julin, E-mail: julinwang@126.com [Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029 (China); Zhang, Tao [Beijing Institute of Ancient Architecture, Beijing 100050 (China)

    2014-12-01

    Graphical abstract: - Highlights: • COOH-CNTs can react with sizing agent, and the optimum reaction ratio was 1:20. • Carbon fibers were dipped into the mixture bath of CNTs and sizing agent. • SEM results indicate that fibers surfaces were coated with CNTs and sizing agent. • ILSS was increased by 67.01% for the composites after the mixture coating process. • Single fibers tensile strength was maintained after the deposited process. - Abstract: The effects of deposition to carbon fibers surfaces with mixture of functionalized multi-walled carbon fibers (MWCNTs) and sizing agent were investigated. Relationships between CNTs and sizing agent were studied with Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS) and Ubbelohde viscometer. The results revealed that CNTs could react with sizing agent at 120 °C, and optimal reaction occurs when mass ratio was about 1:20. Then, carbon fibers were immersed in mixed aqueous suspension of CNTs and sizing agent with the above ratio dispersed by ultrasonication. According to scanning electron microscope (SEM) observations, fibers surfaces were coated with CNTs and sizing agent. The static contact angle tests indicated wetting performance between fibers and epoxy resin were improved after deposited procedures. Interlaminar shear strength was increased by 67.01% for fibers/epoxy resin composites after mixture deposited process. Moreover, the tensile strength of single fibers after depositing showed a slightly increase compared with that of fibers without depositing layer.

  12. Interfacial toughening and consequent improvement in fracture toughness of carbon fiber reinforced epoxy resin composites: induced by diblock copolymers

    Directory of Open Access Journals (Sweden)

    X. D. Zhou

    2013-11-01

    Full Text Available Carbon fibers chemically grafted with hydroxyl-terminated diblock copolymer poly (n-butylacrylate-b-poly (glycidyl methacrylate (OH-PnBA-b-PGMA, were used as the reinforcement for epoxy composites. The multi-filament composite specimens were prepared and measured by dynamic mechanical analysis (DMA, to study the interfacial toughness of carbon fiber reinforced epoxy composites with the diblock copolymers. The loss modulus and loss factor peaks of β-relaxation indicated that composites with diblock copolymers could dissipate more energy at small strain and possess better interfacial toughness, whereas composites without the ductile block PnBA having the worse interfacial toughness. The glass transition temperature and the apparent activation energy calculated from the glass transition showed that the strong interfacial adhesion existed in the composites with diblock copolymers, corresponding with the value of interfacial shear strength. Therefore, a strengthening and toughening interfacial structure in carbon fiber/epoxy composites was achieved by introducing the diblock copolymer OH-PnBA-b-PGMA. The resulting impact toughness, characterized with an Izod impact tester, was better than that of composite without the ductile block PnBA.

  13. In situ formation of nanometer-scale TiO2/SiC functional compositional film on carbon fiber

    Institute of Scientific and Technical Information of China (English)

    ZHOU Chunhua; YIN Yansheng; ZHANG Shuxiang; LIU Wei

    2005-01-01

    In the toluene solution of the precursor Polycarbosilane (PCS) containing low- molecular-mass additive Ti(OC4H9)4, TiO2/SiC nanometer-scale functional compositional film with the surface TiO2 layer on CF was formed in situ by means of polymer-derived precursors. The effects of Ti (OC4H9)4 concentrations and the maturating time were studied on the densification and TiO2 particle size of surface layer. The compositions of film were TiO2 and SiC crystal by XRD. According to the results of ESCA analysis, Ti(OC4H9)4 compound oozed gradiently from the pre-ceramic PCS to the surface layer after maturating time of 100 h. In the conditions of 45wt% Ti (OC4H9)4 and 100 h maturation, the nanometer-scale TiO2 particles on continuous surface layer were formed by SEM photographs. The nanometer-scale TiO2/SiC functional compositional film can modify the resistance to oxidation of carbon fiber.

  14. Manipulating microstructures and electrical properties of carbon fiber/reduced graphene oxide/nickel composite textiles with electrochemical deposition techniques

    Science.gov (United States)

    Cheng, Wei-Liang; Zhao, Quan-Liang; Shi, Fei

    2017-04-01

    Since graphene and their composites play significant roles in the catalysts, energy storage, electronics and other fields, where electron transport is highly critical, here, we introduce reduced graphene oxide (RGO) interfaces in the carbon fiber (CF) networks for preparing a novel lightweight carbon fiber/reduced graphene oxide/nickel (CF-RGO-Ni) composite textile. Upon the charaterizations on the microscopic morphologies, electrical and magnetic properties, and density, the presence of RGO nanosheets and nickel nanoparticles would substantially influence the related physical properties in the resulting composite textiles. Furthermore, the key parameters, including RGO loading, deposition time, current density and annealing temperature of carbon matrices, have been studied to understand their effects on the electrochemical deposition of nickel nanoparticles. Implication of the results suggests that the RGO interface is a unique medium for essentially promoting the electrochemical deposition kinetics and active sites for growing nickel nanoparticles, which indicates a universal approach for preparing advanced lightweight composites with the presence of graphene naonstructures.

  15. Design and Manufacturing of a Composite Lattice Structure Reinforced by Continuous Carbon Fibers

    Institute of Scientific and Technical Information of China (English)

    FAN Hualin; YANG Wei; WANG Bin; YAN Yong; FU Qiang; FANG Daining; ZHUANG Zhuo

    2006-01-01

    New techniques have been developed to make materials with a periodic three-dimensional lattice structure. The high stiffness per unit weight and multifunction of such lattice structures make them attractive for use in aeronautic and astronautic structures. In this paper, epoxy-soaked continuous carbon fibres were first introduced to make lattice composite structures, which maximize the specific load carrying capacity. A micromechanical analysis of several designs, each corresponding to a different manufacturing route, was carried out, in order to find the optimized lattice structure with maximum specific stiffness. An intertwining method was chosen and developed as the best route to make lattice composite materials reinforced by carbon fibers. A sandwich-weaved sample with a three-dimensional intertwined lattice structure core was found to be best. The manufacturing of such a composite lattice material was outlined. In addition to a high shear strength of the core and the integral manufacturing method, the lattice sandwich structure is expected to possess better mechanical capability.

  16. Novel carbon fiber composite for hip replacement with improved in vitro and in vivo osseointegration.

    Science.gov (United States)

    Dimitrievska, S; Whitfield, J; Hacking, S A; Bureau, M N

    2009-10-01

    A novel composite femoral stem has been developed to match cortical stiffness and achieve fixation by osseointegration with the primary goal to reduce cortical bone loss associated with stress shielding. The femoral stem consists of three distinct material layers: the first is a long carbon fiber (CF) in a polyamide 12 (PA12) polymer matrix (PA12/CF); the second is a PA12/HA (hydroxyapatite) interface; and the third is a plasma-sprayed coating of HA. In vitro studies with MG63 cells indicated that the HA surface supported improved proliferation and differentiation of osteoblast-like cells as determined by alkaline phosphatase activity and osteocalcin production when compared with Ti-6Al-4V (Ti64). In vivo studies comparing the composite and Ti64 rods in the rabbit femur demonstrated significantly higher bone apposition to the composite than Ti64 rods. The results of this study indicate that the invasion of surrounding bone cells and thus osteointegration together with its bone-matching mechanical properties make the PA12/CF/HA stem a promising hip replacement candidate.

  17. Mechanical properties of several neat polymer matrix materials and unidirectional carbon fiber-reinforced composites

    Science.gov (United States)

    Coguill, Scott L.; Adams, Donald F.

    1989-01-01

    The mechanical and physical properties of three neat matrix materials, i.e., PEEK (polyetheretherketone) thermoplastic, Hexcel F155 rubber-toughened epoxy and Hercules 8551-7 rubber-toughened epoxy, were experimentally determined. Twelve unidirectional carbon fiber composites, incorporating matrix materials characterized in this or earlier studies (with one exception; the PISO(sub 2)-TPI matrix itself was not characterized), were also tested. These composite systems included AS4/2220-1, AS4/2220-3, T500/R914, IM6/HX1504, T300/4901A (MDA), T700/4901A (MDA), T300/4901B (MPDA), T700/4901B (MPDA), APC2 (AS4/PEEK, ICI), APC2 (AS4/PEEK, Langley Research Center), AS4/8551-7, and AS4/PISO(sub 2)-TPI. For the neat matrix materials, the tensile, shear, fracture toughness, coefficient of thermal expansion, and coefficient of moisture expansion properties were measured as a function of both temperature and moisture content. For the unidirectional composites, axial and transverse tensile, longitudinal shear, coefficient of thermal expansion, and coefficient of moisture expansion properties were determined, at room temperature and 100 C.

  18. Friction behaviour of aluminium composites mixed with carbon fibers with different orientations

    Science.gov (United States)

    Caliman, R.

    2016-08-01

    The primary goal of this study work it was to distinguish a mixture of materials with enhanced friction and wearing behaviour. The composite materials may be differentiated from alloys; which can contain two more components but are formed naturally through different processes such as casting. The load applied on the specimen during the tests, is playing a very important role regarding friction coefficient and also the wearing speed. Sintered composites are gaining importance because the reinforcement serves to reduce the coefficient of thermal expansion and increase the strength and modulus. The friction tests are carried out, at the room temperature in dry condition, on a pin-on-disc machine. The exponentially decreasing areas form graphs, represented to the curves coefficient of friction, are attributed to the formation of lubricant transfer film and initial polishing surface samples. The influence of the orientation of the carbon fibers on the friction properties in the sintered polymer composites may be studied by the use of both mechanical wear tests by microscopy and through the use of phenomenological models.

  19. Theoretical Estimation of Thermal Effects in Drilling of Woven Carbon Fiber Composite

    Directory of Open Access Journals (Sweden)

    José Díaz-Álvarez

    2014-06-01

    Full Text Available Carbon Fiber Reinforced Polymer (CFRPs composites are extensively used in structural applications due to their attractive properties. Although the components are usually made near net shape, machining processes are needed to achieve dimensional tolerance and assembly requirements. Drilling is a common operation required for further mechanical joining of the components. CFRPs are vulnerable to processing induced damage; mainly delamination, fiber pull-out, and thermal degradation, drilling induced defects being one of the main causes of component rejection during manufacturing processes. Despite the importance of analyzing thermal phenomena involved in the machining of composites, only few authors have focused their attention on this problem, most of them using an experimental approach. The temperature at the workpiece could affect surface quality of the component and its measurement during processing is difficult. The estimation of the amount of heat generated during drilling is important; however, numerical modeling of drilling processes involves a high computational cost. This paper presents a combined approach to thermal analysis of composite drilling, using both an analytical estimation of heat generated during drilling and numerical modeling for heat propagation. Promising results for indirect detection of risk of thermal damage, through the measurement of thrust force and cutting torque, are obtained.

  20. Modeling of Failure for Analysis of Triaxial Braided Carbon Fiber Composites

    Science.gov (United States)

    Goldberg, Robert K.; Littell, Justin D.; Binienda, Wieslaw K.

    2010-01-01

    In the development of advanced aircraft-engine fan cases and containment systems, composite materials are beginning to be used due to their low weight and high strength. The design of these structures must include the capability of withstanding impact loads from a released fan blade. Relatively complex triaxially braided fiber architectures have been found to yield the best performance for the fan cases. To properly work with and design these structures, robust analytical tools are required that can be used in the design process. A new analytical approach models triaxially braided carbon fiber composite materials within the environment of a transient dynamic finite-element code, specifically the commercially available transient dynamic finite-element code LS-DYNA. The geometry of the braided composites is approximated by a series of parallel laminated composites. The composite is modeled by using shell finite elements. The material property data are computed by examining test data from static tests on braided composites, where optical strain measurement techniques are used to examine the local strain variations within the material. These local strain data from the braided composite tests are used along with a judicious application of composite micromechanics- based methods to compute the stiffness properties of an equivalent unidirectional laminated composite required for the shell elements. The local strain data from the braided composite tests are also applied to back out strength and failure properties of the equivalent unidirectional composite. The properties utilized are geared towards the application of a continuum damage mechanics-based composite constitutive model available within LS-DYNA. The developed model can be applied to conduct impact simulations of structures composed of triaxially braided composites. The advantage of this technology is that it facilitates the analysis of the deformation and damage response of a triaxially braided polymer matrix

  1. Optimization of interfacial microstructure and mechanical properties of carbon fiber/epoxy composites via carbon nanotube sizing

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Hongwei; Sui, Xianhang; Zhao, Zhongbo; Xu, Zhiwei; Chen, Lei, E-mail: chenlei@tjpu.edu.cn; Deng, Hui; Liu, Ya; Qian, Xiaoming, E-mail: qianxiaoming@tjpu.edu.cn

    2015-08-30

    Highlights: • Multiple sizing treatments were used to modify the surface of carbon fiber with carbon nanotubes. • The distribution state of carbon nanotubes in interface had a great effect on the performance of carbon fiber composites. • Interfacial microstructure changes brought by sizing treatment were detected by energy dispersive X-ray spectroscopy and atomic force microscope. • Gradient interphase composed of carbon nanotubes and epoxy was favorable to improve the mechanical properties of carbon composites. - Abstract: Repetitious sizing treatment was used to modify the carbon fiber (CF) surface with carbon nanotubes (CNTs) for improving interfacial properties of CF/epoxy composites. Interlaminar shear and flexural results showed that mechanical properties of composites were significantly depended on the dispersion state and contents of CNTs in interfacial regions. Increases of 13.45% in interlaminar shear strength and 20.31% in flexural strength were achieved in quintuple sized-CF/epoxy composites, whereas excessive CNTs led to decrease of interfacial performance due to defects induced by agglomerated CNTs. Energy dispersive X-ray spectroscopy and force modulation atomic force microscope were used to detect the structure of interfacial phase and results indicated that gradient interfacial structure with various thicknesses was formed due to CNT incorporation. This means that such a simple and efficient method to improve interfacial performance of composites via regulating the fiber–matrix interphase structure was developed and showed great commercial application potential.

  2. Electroadsorption Desalination with Carbon Nanotube/PAN-Based Carbon Fiber Felt Composites as Electrodes

    Directory of Open Access Journals (Sweden)

    Yang Liu

    2014-01-01

    Full Text Available The chemical vapor deposition method is used to prepare CNT (carbon nanotube/PCF (PAN-based carbon fiber felt composite electrodes in this paper, with the surface morphology of CNT/PCF composites and electroadsorption desalination performance being studied. Results show such electrode materials with three-dimensional network nanostructures having a larger specific surface area and narrower micropore distribution, with a huge number of reactive groups covering the surface. Compared with PCF electrodes, CNT/PCF can allow for a higher adsorption and desorption rate but lower energy consumption; meanwhile, under the condition of the same voltage change, the CNT/PCF electrodes are provided with a better desalination effect. The study also found that the higher the original concentration of the solution, the greater the adsorption capacity and the lower the adsorption rate. At the same time, the higher the solution’s pH, the better the desalting; the smaller the ions’ radius, the greater the amount of adsorption.

  3. Characterization, test and interpretative simulations of one-dimensional Carbon Fiber Composite prototype for SPIDER experiment

    Energy Technology Data Exchange (ETDEWEB)

    De Muri, M., E-mail: michela.demuri@igi.cnr.it [Consorzio RFX – Associazione Euratom-Enea sulla Fusione, corso Stati Uniti 4, I-35127 Padova (Italy); Dipartimento di Ingegneria Elettrica, Padova University, Padova (Italy); Cervaro, V.; Dal Bello, S.; Dalla Palma, M.; Fasolo, D.; Franchin, L.; Pasqualotto, R.; Pomaro, N.; Rizzolo, A.; Tollin, M.; Serianni, G. [Consorzio RFX – Associazione Euratom-Enea sulla Fusione, corso Stati Uniti 4, I-35127 Padova (Italy)

    2013-10-15

    Highlights: • Prototype ITER neutral beam injector to study the beam source behavior requires beam characterization. • Among several types of diagnostic, a calorimeter made of fiber carbon composite (CFC) tiles will be used. • The CFC thermal behaviour is study by laser beam and will be characterize in particel beam. • Experiments and simulations results are discussed. • Designs for tests in particle beams are presented. -- Abstract: For ITER operations, additional heating systems are required. One of these systems is the neutral beam injector (NBI). The SPIDER experiment, a small-scale NBI, is going to be built with the aim to optimize the beam source. For this reason it is provided with several diagnostics, among which the Short-Time Retractable Instrumented Kalorimeter Experiment (STRIKE). In this contribution, a characterization of the Carbon Fiber Composite (CFC) tiles, which are the main component of the diagnostic, is presented. Such analyses include tests with a power laser, exposure to particle beams and thermal stress tests. The results are discussed, which will drive the definition of the acceptance tests of the final supply of CFC tiles.

  4. Durability of carbon fiber reinforced shape memory polymer composites in space

    Science.gov (United States)

    Jang, Joon Hyeok; Hong, Seok Bin; Ahn, Yong San; Kim, Jin-Gyun; Nam, Yong-Youn; Lee, Geun Ho; Yu, Woong-Ryeol

    2016-04-01

    Shape memory polymer (SMP) is one of smart polymers which exhibit shape memory effect upon external stimuli. Recently, shape memory polymer composites (SMPCs) have been considered for space structure instead of shape memory alloys due to their deformability, lightweight and large recovery ratio, requiring characterization of their mechanical properties against harsh space environment and further prediction of the durability of SMPCs in space. As such, the durability of carbon fiber reinforced shape memory polymer composites (CF-SMPCs) was investigated using accelerated testing method based on short-term testing of CF-SMPCs in harsh condition. CF-SMPCs were prepared using woven carbon fabrics and a thermoset SMP via vacuum assisted resin transfer molding process. Bending tests with constant strain rate of CF-SMPCs were conducted using universal tensile machine (UTM) and Storage modulus test were conducted using dynamic mechanical thermal analysis (DMTA). Using the results, a master curve based on time-temperature superposition principle was then constructed, through which the mechanical properties of CF-SMPCs at harsh temperature were predicted. CF-SMPCs would be exposed to simulated space environments under ultra-violet radiations at various temperatures. The mechanical properties including flexural and tensile strength and shape memory properties of SMPCs would be measured using UTM before and after such exposures for comparison. Finally, the durability of SMPCs in space would be assessed by developing a degradation model of SMPC.

  5. Extinction characterization of soot produced by laser ablating carbon fiber composite materials in air flow

    Science.gov (United States)

    Liu, Weiping; Ma, Zhiliang; Zhang, Zhenrong; Zhou, Menglian; Wei, Chenghua

    2015-05-01

    In order to research the dynamic process of energy coupling between an incident laser and a carbon fiber/epoxy resin composite material, an extinction characterization analysis of soot, which is produced by laser ablating and located in an air flow that is tangential to the surface of the composite material, is carried out. By the theory analyses, a relationship of mass extinction coefficient and extinction cross section of the soot is derived. It is obtained that the mass extinction coefficients of soot aggregates are the same as those of the primary particles when they contain only a few primary particles. This conclusion is significant when the soot is located in an air flow field, where the generations of the big soot aggregates are suppressed. A verification experiment is designed. The experiment employs Laser Induced Incandescence technology and laser extinction method for the soot synchronization diagnosis. It can derive a temporal curve of the mass extinction coefficient from the soot concentration and laser transmittance. The experiment results show that the mass extinction coefficient becomes smaller when the air flow velocity is higher. The reason is due to the decrease of the scatter effects of the soot particles. The experiment results agree with the theory analysis conclusion.

  6. Experimental Results in Support of Simulating Progressive Crush in Carbon-Fiber Textile Composites

    Energy Technology Data Exchange (ETDEWEB)

    DeTeresa, S J; Allison, L M; Cunningham, B J; Freeman, DC; Saculla, M D; Sanchez, R J; Winchester, S W

    2001-04-02

    This report summarizes the findings of an experimental program conducted to support the modeling of the crush behavior of triaxial braid carbon fiber composites. The matrix material as well as braided panels and tubes were characterized in order to determine material properties, to assess failure modes, and to provide a test bed for new analytical and numerical tools developed specifically for braided composites. The matrix material selected by the ACC was an epoxy vinyl ester (Ashland Hetron 922). Tensile tests were used to compare two formulations-one used by the ACC and one recommended by the resin supplier. The latter was a faster reacting system and gelled in one-third the time of the ACC formulation. Both formulations had an average elongation at failure that was only half of the resin supplier's reported value. Only one specimen of each type came close to the reported elongation value and it was shown that failure invariably initiated at both surface and internal defects. Overall, the tensile properties of the two formulations were nearly identical, but those of the ACC system were more consistent. The properties of the ACC matrix formulation were measured in tension, shear, and compression and the average properties obtained in these tests are summarized.

  7. Comparative Characterization of Multiscale Carbon Fiber Composite with Long and Short MWCNTs at Higher Weight Fractions

    Directory of Open Access Journals (Sweden)

    Michael Zimmer

    2012-01-01

    Full Text Available There are documented advantages to using carbon nanotubes (CNTs in composites for various property enhancements. However, to date, only limited studies have been conducted on using of longer CNTs over 1 mm in length. This study used long multiwalled carbon nanotubes (LMWCNTs and their longer extended networks to test multiple properties in thermal conductivity, electrical conductivity, mechanical strength, and modulus and then compared these properties to those of shorter multi-walled carbon nanotubes (SMWCNTs. For carbon fiber-reinforced composites, the longer graphite paths from LMWCNTs in the matrix were expected to improve all properties. The longer networks were expected to allow for more undisturbed phonon transportation to improve thermal conductivity. This in turn relates to improved electrical conductivity and better mechanical properties. However, results have shown that the LMWCNTs do not improve or decrease thermal conductivity, whereas the shorter MWCNTs provide mixed results. LMWCNTs did show improvements in electrical, mechanical, and physical properties, but compared to shorter MWCNTs, the results in other certain properties varied. This perplexing outcome resides in the functioning of the networks made by both the LMWCNTs and shorter MWCNTs.

  8. Design aid for shear strengthening of reinforced concrete T-joints using carbon fiber reinforced plastic composites

    Science.gov (United States)

    Gergely, Ioan

    The research presented in the present work focuses on the shear strengthening of beam column joints using carbon fiber composites, a material considered in seismic retrofit in recent years more than any other new material. These composites, or fiber reinforced polymers, offer huge advantages over structural steel reinforced concrete or timber. A few of these advantages are the superior resistance to corrosion, high stiffness to weight and strength to weight ratios, and the ability to control the material's behavior by selecting the orientation of the fibers. The design and field application research on reinforced concrete cap beam-column joints includes analytical investigations using pushover analysis; design of carbon fiber layout, experimental tests and field applications. Several beam column joints have been tested recently with design variables as the type of composite system, fiber orientation and the width of carbon fiber sheets. The surface preparation has been found to be critical for the bond between concrete and composite material, which is the most important factor in joint shear strengthening. The final goal of this thesis is to develop design aids for retrofitting reinforced concrete beam column joints. Two bridge bents were tested on the Interstate-15 corridor. One bent was tested in the as-is condition. Carbon fiber reinforced plastic composite sheets were used to externally reinforce the second bridge bent. By applying the composite, the displacement ductility has been doubled, and the bent overall lateral load capacity has been increased as well. The finite element model (using DRAIN-2DX) was calibrated to model the actual stiffness of the supports. The results were similar to the experimental findings.

  9. Crystallization behaviors of carbon fiber reinforced BN-Si{sub 3}N{sub 4} matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Li, Bin; Zhang, Chang-Rui; Wang, Si-Qing; Cao, Feng [State Key Laboratory of Advanced Ceramic Fibers and Composites, College of Aerospace and Materials Engineering, National University of Defense Technology, Changsha 410073 (China)

    2007-07-15

    The crystallization behaviors of a new carbon fiber reinforced composite with a hybrid matrix comprising BN and Si{sub 3}N{sub 4} prepared by precursor infiltration and pyrolysis were investigated by Fourier transform infrared spectroscopy, X-ray diffraction and scanning electron microscopy. The results show that the as-received composite is almost amorphous, and its main composition is BN and Si{sub 3}N{sub 4}. When heat treated at 1600 C, the composite is crystallized and shows a much better crystal form. When heat treated at 2100 C, Si{sub 3}N{sub 4} in the matrix is decomposed, and BN exhibits a relatively complete crystallization. The existence of B{sub 4}C and SiC is detected, which indicates the interfacial chemical reactions between nitride matrices and carbon fibers. The surface morphology of carbon fibers in the composite changed significantly when heated from 1600 to 2100 C, which also proved the occurrence of interfacial chemical reactions. (copyright 2007 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Curing kinetics and thermomechanical properties of latent epoxy/carbon fiber composites

    Science.gov (United States)

    Dalle Vacche, S.; Michaud, V.; Demierre, M.; Bourban, P.-E.; Månson, J.-A. E.

    2016-07-01

    In this work, resins based on diglycidyl ether of bisphenol A (DGEBA) epoxy and a latent hardener, dicyandiamide (DICY), as well as carbon fiber (CF) composites based on them, were prepared with three commercial accelerators: a methylene bis (phenyl dimethyl urea), a cycloaliphatic substituted urea, and a modified polyamine. The curing kinetics of the three DGEBA/DICY/accelerator systems were investigated by chemorheology and differential scanning calorimetry (DSC), in isothermal and over temperature change conditions. Differences in the reaction onset temperature, and in the glass transition temperature (Tg) were highlighted. For curing of thick resin samples, a slow curing cycle at the lowest possible temperature was used, followed by high temperature (160 - 180 °C) post-curing. Indeed, fast curing at higher temperatures caused the formation of hot spots and led to local burning of the samples. The obtained thermomechanical properties, assessed by ultimate tensile testing and dynamic mechanical analysis (DMA) in single cantilever configuration, were all in the expected range for epoxy resins, with tensile moduli close to 3 GPa and Tg > 140 °C. The longterm stability of these resins at room temperature was verified by DSC. Composite samples were prepared by hand lay-up by manually impregnating four layers of 5-harness satin CF textile, and curing in vacuum bag. Impregnation quality and void content were assessed by optical microscopy. The flexural properties of the post-cured composites were assessed by three-point bending test at room temperature and showed no relevant differences, all composites having bending moduli of 45 - 50 GPa. Finally, composites cured with a faster high temperature curing cycle (20 min at 140 °C) were prepared with the DGEBA/DICY/ methylene bis (phenyl dimethyl urea) system, obtaining similar properties as with the slower curing cycle, showing that the prepreg system allowed more flexibility in terms of curing cycle than the bulk resin

  11. Damage Tolerance Enhancement of Carbon Fiber Reinforced Polymer Composites by Nanoreinforcement of Matrix

    Science.gov (United States)

    Fenner, Joel Stewart

    Nanocomposites are a relatively new class of materials which incorporate exotic, engineered nanoparticles to achieve superior material properties. Because of their extremely small size and well-ordered structure, many nanoparticles possess properties that exceed those offered by a wide range of other known materials, making them attractive candidates for novel materials engineering development. Their small size is also an impediment to their practical use, as they typically cannot be employed by themselves to realize those properties in large structures. Furthermore, nanoparticles typically possess strong self-affinity, rendering them difficult to disperse uniformly into a composite. However, contemporary research has shown that, if well-dispersed, nanoparticles have great capacity to improve the mechanical properties of composites, especially damage tolerance, in the form of fracture toughness, fatigue life, and impact damage mitigation. This research focuses on the development, manufacturing, and testing of hybrid micro/nanocomposites comprised of woven carbon fibers with a carbon nanotube reinforced epoxy matrix. Material processing consisted of dispersant-and-sonication based methods to disperse nanotubes into the matrix, and a vacuum-assisted wet lay-up process to prepare the hybrid composite laminates. Various damage tolerance properties of the hybrid composite were examined, including static strength, fracture toughness, fatigue life, fatigue crack growth rate, and impact damage behavior, and compared with similarly-processed reference material produced without nanoreinforcement. Significant improvements were obtained in interlaminar shear strength (15%), Mode-I fracture toughness (180%), shear fatigue life (order of magnitude), Mode-I fatigue crack growth rate (factor of 2), and effective impact damage toughness (40%). Observations by optical microscopy, scanning electron microscopy, and ultrasonic imaging showed significant differences in failure behavior

  12. Carbon Fiber Biocompatibility for Implants

    Directory of Open Access Journals (Sweden)

    Richard Petersen

    2016-01-01

    Full Text Available Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-reinforced composite stimulated osseointegration inside the tibia bone marrow measured as percent bone area (PBA to a great extent when compared to the titanium-6-4 alloy at statistically significant levels. PBA increased significantly with the carbon-fiber composite over the titanium-6-4 alloy for distances from the implant surfaces of 0.1 mm at 77.7% vs. 19.3% (p < 10−8 and 0.8 mm at 41.6% vs. 19.5% (p < 10−4, respectively. The review focuses on carbon fiber properties that increased PBA for enhanced implant osseointegration. Carbon fibers acting as polymer coated electrically conducting micro-biocircuits appear to provide a biocompatible semi-antioxidant property to remove damaging electron free radicals from the surrounding implant surface. Further, carbon fibers by removing excess electrons produced from the cellular mitochondrial electron transport chain during periods of hypoxia perhaps stimulate bone cell recruitment by free-radical chemotactic influences. In addition, well-studied bioorganic cell actin carbon fiber growth would appear to interface in close contact with the carbon-fiber-reinforced composite implant. Resulting subsequent actin carbon fiber/implant carbon fiber contacts then could help in discharging the electron biological overloads through electrochemical gradients to lower negative charges and lower concentration.

  13. Processing and Damage Tolerance of Continuous Carbon Fiber Composites Containing Puncture Self-Healing Thermoplastic Matrix

    Science.gov (United States)

    Grimsley, Brian W.; Gordon, Keith L.; Czabaj, Michael W.; Cano, Roberto J.; Siochi, Emilie J.

    2012-01-01

    Research at NASA Langley Research Center (NASA LaRC) has identified several commercially available thermoplastic polymers that self-heal after ballistic impact and through-penetration. One of these resins, polybutadiene graft copolymer (PB(sub g)), was processed with unsized IM7 carbon fibers to fabricate reinforced composite material for further evaluation. Temperature dependent characteristics, such as the degradation point, glass transition (T(sub g)), and viscosity of the PBg polymer were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic parallel plate rheology. The PBg resin was processed into approximately equal to 22.0 cm wide unidirectional prepreg tape in the NASA LaRC Advanced Composites Processing Research Laboratory. Data from polymer thermal characterization guided the determination of a processing cycle used to fabricate quasi-isotropic 32-ply laminate panels in various dimensions up to 30.5cm x 30.5cm in a vacuum press. The consolidation quality of these panels was analyzed by optical microscopy and acid digestion. The process cycle was further optimized based on these results and quasi-isotropic, [45/0/-45/90]4S, 15.24cm x 15.24cm laminate panels were fabricated for mechanical property characterization. The compression strength after impact (CAI) of the IM7/pBG composites was measured both before and after an elevated temperature and pressure healing cycle. The results of the processing development effort of this composite material as well as the results of the mechanical property characterization are presented in this paper.

  14. Application of vibrational spectroscopy in the in vitro studies of carbon fiber-polylactic acid composite degradation.

    Science.gov (United States)

    Blazewicz, Marta; Gajewska, Maria Chomyszyn; Paluszkiewicz, Czeslawa

    1999-05-01

    Vibrational spectroscopy was used for assessment of new material for stomatology, for guided tissue regeneration (GTR) techniqe.Implants applied in the healing of periodontal defects using GTR technique have to meet stringent requirements concerning their chemical as well physical properties.At present the implants prepared from two layers membranes differing in porosity in their outer and inner layers are studied clinically. Composite plates prepared by us consist of three layers: polylactic acid film, carbon fibres coated with polylactic acid and carbon fabric.Vibrational spectroscopic studies of the material; polylactic acid- carbon fiber have made it possible to analyse chemical reactions occurring between the polymer and carbon surface. Analysis of the IR spectra of samples treated in Ringer solution allowed to describe the phenomena resulting from the composite degradation. It was shown that material biostability is related to the presence of carbon fibers.

  15. 美国HEXEL公司的碳纤维及其复合材料%CARBON FIBERS AND COMPOSITE MATERIALS IN HEXEL CORPORATION,USA

    Institute of Scientific and Technical Information of China (English)

    赵稼祥

    2001-01-01

    简要介绍美国第45届材料与加工工程促进学会年会与展览会概况及美国HEXEL公司碳纤维及其复合材料的现况与发展。%At the 45th SAMPE Conference and Exhibition there Were 8 famous carbon fibers corporations and incorporation’s in the world exhibited their carbon fibers & composites products. In this paper,present status & development of carbon fibers & composite materials in HEXEL Corporation,USA were briefly presented.

  16. Flexural Properties of E Glass and TR50S Carbon Fiber Reinforced Epoxy Hybrid Composites

    Science.gov (United States)

    Dong, Chensong; Sudarisman; Davies, Ian J.

    2013-01-01

    A study on the flexural properties of E glass and TR50S carbon fiber reinforced hybrid composites is presented in this paper. Specimens were made by the hand lay-up process in an intra-ply configuration with varying degrees of glass fibers added to the surface of a carbon laminate. These specimens were then tested in the three-point bend configuration in accordance with ASTM D790-07 at three span-to-depth ratios: 16, 32, and 64. The failure modes were examined under an optical microscope. The flexural behavior was also simulated by finite element analysis, and the flexural modulus, flexural strength, and strain to failure were calculated. It is shown that although span-to-depth ratio shows an influence on the stress-strain relationship, it has no effect on the failure mode. The majority of specimens failed by either in-plane or out-of-plane local buckling followed by kinking and splitting at the compressive GFRP side and matrix cracking combined with fiber breakage at the CFRP tensile face. It is shown that positive hybrid effects exist for the flexural strengths of most of the hybrid configurations. The hybrid effect is noted to be more obvious when the hybrid ratio is small, which may be attributed to the relative position of the GFRP layer(s) with respect to the neutral plane. In contrast to this, flexural modulus seems to obey the rule of mixtures equation.

  17. Evolution of the composition and structure of PAN carbon fiber during preoxidation

    Institute of Scientific and Technical Information of China (English)

    LI; Xiaojia; LUO; Qianhua; ZHU; Yijun; WANG; Haizhou

    2001-01-01

    Using scanning electronic microscope, X-ray diffraction analysis, PYR-GCMS and IR etc., we studied the evolving process of the composition and structure of PAN carbon fiber during preoxidation. In the initial stage of preoxidation, PAN filament tows disappear and become semi-thaw. At first, reactions happen between the copolymers and esters disappear. The molecules annularly crosslink and the index of cyclation slowly increases. It is easy to fix the structure and form defects during the initial and the medium stages, which are most reactive. More traction is advised in these stages to minimize the structural deficiencies. In the medium stage of preoxidation, the fiber was reshaped into new sheet stacks and gradually changed to sheet sectors, and this structure tends to be stable in the final stage. Induced by acid and ester copolymer, PAN fiber forms a very stable cycle structure in the final stage. Besides, monomer, dimmer and trimer obviously decrease. In the final stage of the preoxidation, there exists only the fragment of -CN, and it also disappears at last. The index of cyclation rises with the process of preoxidation and the structural shape stabilizes.

  18. Effect of moisture absorption on damping and dynamic stiffness of carbon fiber/epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Zai, Behzad Ahmed; Park, M. K.; Mehboob, Hassan; Ali, Rashid [Myongji University, Yongin (Korea, Republic of); Choi, H. S. [Korean Air Daejeon (Korea, Republic of)

    2009-11-15

    In this paper, the damping and dynamic stiffness of UHN125C carbon fiber/epoxy composite beam was experimentally measured. The effect of fiber orientation angle and stacking sequences on damping, resonance frequency, and dynamic stiffness was discussed with a focus on the effect of moisture absorption. Dried specimens were immersed in distilled water for a certain period to absorb water for 8, 16, and 24 d, respectively, and the moisture content absorbed in the specimen was measured. Furthermore, using the impact hammer technique, the measurements of dynamic responses were conducted on a cantilever beam specimen with one end clamped by bolts and metal plates. The damping properties in terms of loss factor were approximated by half-power bandwidth technique. The dynamic stiffness was evaluated using resonance frequency as a function of moisture content. The damping increased with the increase of moisture content: however, the dynamic stiffness reduced with the reduction of resonance frequency. The results of the dynamic stiffness were aided by measuring the dynamic strain using DBU-120A strain-indicating software. The increment in the dynamic strain strengthened the results obtained for dynamic stiffness

  19. MECHANICAL AND THERMO–MECHANICAL PROPERTIES OF BI-DIRECTIONAL AND SHORT CARBON FIBER REINFORCED EPOXY COMPOSITES

    OpenAIRE

    Agarwal, G; A. Patnaik; Sharma, R. K.

    2014-01-01

    This paper based on bidirectional and short carbon fiber reinforced epoxy composites reports the effect of fiber loading on physical, mechanical and thermo-mechanical properties respectively. The five different fiber loading, i.e., 10wt. %, 20wt. %, 30wt. %, 40wt. % and 50wt. % were taken for evaluating the above said properties. The physical and mechanical properties, i.e., hardness, tensile strength, flexural strength, inter-laminar shear strength and impact strength are determined to re...

  20. Aspects regarding the tribological evaluation of sintered composites obtained from mixture of copper with carbon fibers

    Science.gov (United States)

    Caliman, R.

    2015-11-01

    This paper presents a study of the tribological properties of sintered composite materials made from combination of copper with short carbon fibers. Sintered composite materials are more effective if refer to specific properties per unit volume compared to conventional isotropic materials. Potential advantages of copper - carbon composite materials are: high resistance to breakage and high value ratios strength/density; resistance to high temperatures; low density and high resistance to wear; low or high friction coefficient. The sintered composite materials used in this research work are obtained combining different percentages of copper with short carbon fibres with iron and lead in order to investigate the variation of the friction behaviour. Varying the percentage of copper from 92,2% to 97,6% and the percentage of short carbon fibres from 7,8% to 2,4%, five different composite materials are obtained and tested. Friction tests are carried out, at room temperature, in dry conditions, on a pin-on-disc machine. The friction coefficient was measured using abrasive discs made from steel 4340 having the average hardness of 40 HRC, and sliding velocity of 0,6 m/sec. The main objective of this research work it was to identify a combination of materials with improved friction behaviour. The experimental results revealed that the force applied on the specimen during the tests, is playing a very important role regarding friction coefficient and also the wearing speed. Graphite particles are conveyed consistently inside the net, enhancing scraped spot safety and voltage drop over normal composite material. The static tests demonstrated that this new kind of sintered composite material has preferable electrical execution over previous brush material in the same conditions, and the element tests demonstrated that the temperature climb is not enormous when the brush with this new composite material is exchanged on with huge current and the surface scraped spot is littler amid

  1. Carbon fiber based composites stress analysis. Experimental and computer comparative studies

    Science.gov (United States)

    Sobek, M.; Baier, A.; Buchacz, A.; Grabowski, Ł.; Majzner, M.

    2015-11-01

    Composite materials used nowadays for the production of composites are the result of advanced research. This allows assuming that they are among the most elaborate tech products of our century. That fact is evidenced by the widespread use of them in the most demanding industries like aerospace and space industry. But the heterogeneous materials and their advantages have been known to mankind in ancient times and they have been used by nature for millions of years. Among the fibers used in the industry most commonly used are nylon, polyester, polypropylene, boron, metal, glass, carbon and aramid. Thanks to their physical properties last three fiber types deserve special attention. High strength to weight ratio allow the use of many industrial solutions. Composites based on carbon and glass fibers are widely used in the automotive. Aramid fibers ideal for the fashion industry where the fabric made from the fibers used to produce the protective clothing. In the paper presented issues of stress analysis of composite materials have been presented. The components of composite materials and principles of composition have been discussed. Particular attention was paid to the epoxy resins and the fabrics made from carbon fibers. The article also includes basic information about strain measurements performed on with a resistance strain gauge method. For the purpose of the laboratory tests a series of carbon - epoxy composite samples were made. For this purpose plain carbon textile was used with a weight of 200 g/mm2 and epoxy resin LG730. During laboratory strain tests described in the paper Tenmex's delta type strain gauge rosettes were used. They were arranged in specific locations on the surface of the samples. Data acquisition preceded using HBM measurement equipment, which included measuring amplifier and measuring head. Data acquisition was performed using the Easy Catman. In order to verify the results of laboratory tests numerical studies were carried out in a

  2. EXPERIMENTAL STUDY ON PEK-C MODIFIEDEPOXIES AND THE CARBON FIBER COMPOSITES FOR AEROSPACE APPLICATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Epoxy (EP) resins have been widely used as traditional materials in aerospace applications due to their relatively high stiffness and strength, good thermal stability, excellent adhesion, and good processabilities, particularly because that they have been toughened by incorporating rubber particles and thermoplastic (TP) component into the resins to form multi-component systems[1~5]. Compared with rubber modifiers, thermoplastics can improve the epoxy toughness without sacrificing the thermal stabilities of epoxy resins[6,7]. Thermoplastics modifiers used for this purpose have usually a high glass transition temperature, good thermal stability, and a low propensity to moisture. The toughening structure and thus the mechanical properties of these thermoset/thermoplastic binary systems are generally governed by a complicated spinodal decomposition process induced by crosslinking reaction during curing process of epoxies, and the following growth mechanism of the dispersed particles[8]. Most investigations reported were conducted on model systems with thermoplastics such as PEI[9,10], PES[11], and PSF[12~14]  as modifier. In most cases, factors affecting the processabilities like tackiness and drapabilities of these binary resins impregnated prepregs have rarely been considered into account.  The present paper reports a new thermoplastic modifier polyetherketone-C (PEK-C) of Chinese development[15]. Different epoxies were modified with the thermoplastic to study the structure development under the aerospace practice relevant processing conditions. The PEK-C modified binary system was then used as matrix resin for carbon fiber composites. The structures and properties were studied by using microscopic, thermo-analytic, FTIR-spectral, and mechanical methods. Based on these results, a composite model was finally suggested to explain the toughening mechanism.

  3. Design and Analysis for the Carbon Fiber Composite Support Structure for Layer 0 of the D0 Silicon Micro Tracker

    Energy Technology Data Exchange (ETDEWEB)

    Daly, C.H.; Tuttle, Mark E.; Kuykendall, William; /Washington U., Seattle

    2009-01-01

    The support structures for the new Layer 0 (Figures 1, 2, 3) of the Run 2b silicon tracker in D0 were designed and fabricated at the University of Washington. These structures were required to have minimum mass, yet be very rigid so as to meet the high precision requirements placed on the position of the silicon detector chips. They also have to provide for cooling to remove the heat generated by the sensors and signal processing electronics and to keep the sensors at the desired operating temperature (below -5 C). All of these requirements were best met by carbon fiber/epoxy composite technology. State of the art carbon fiber materials have extremely high Young's moduli and high thermal conductivity. Appropriate fiber lay-ups and fabrication methods have been developed and used successfully to produce both various prototype structures and the structures used in the production Layer 0. The geometry of these structures was determined mainly by the geometry of the sensors themselves. The structures incorporated a complete cooling system consisting of extruded PEEK coolant tubes and distribution manifolds made from carbon fiber composites. In order to determine the mechanical and thermal performance of the structures, detailed FEA analyses of L0 have been carried out and are described.

  4. A Tow-Level Progressive Damage for Simulating Carbon-Fiber Textile Composites: Interim Report

    Energy Technology Data Exchange (ETDEWEB)

    Zywicz, E.

    2000-07-01

    A numerical approach to model the elasto-plastic and tensile damage response of tri-axially braided carbon-fiber polymeric-matrix composites is developed. It is micromechanically based and consists of a simplified unit cell geometry, a plane-stress tow-level constitutive relationship, a one-dimensional undulation constitutive law, and a non-traditional shell element integration rule. The braided composite lamina is idealized as periodic in the plane, and a simplified three-layer representative volume (RV) is assembled from axial and braider tows and pure resin regions. The constituents in each layer are homogenized with an iso-strain assumption in the fiber-direction and an iso-stress condition in the other directions. In the upper and lower layers, the fiber-direction strain is additively decomposed into an undulation and a tow portion. A finite-deformation tow model predicts the plane-stress tow response and is coupled to the undulation constitutive relationship. The overall braid model is implemented in DYNA3D and works with traditional shell elements. The finite-deformation tow constitutive relationship is derived from the fiber elasticity and the isotropic elasto-plastic power-law hardening matrix response using a thermodynamic framework and simple homogenization assumptions. The model replicates tensile damage evolution, in a smeared sense, parallel and perpendicular to the fiber axis and is regularized to yield mesh independent results. The tow-level model demonstrates reasonable agreement, prior to damage, with detailed three-dimensional FE (finite element) elasto-plastic simulations of aligned, periodically arranged, uni-directional composites. The 3-layer braid model response is compared with predictions obtained from detailed micromechanical simulations of the braid's unit cell in uni-axial extension, shear, and flexure for three braid angles. The elastic properties show good agreement as does the non-linear response for loadings dominated by the

  5. Acoustic characterization of void distributions across carbon-fiber composite layers

    Science.gov (United States)

    Tayong, Rostand B.; Smith, Robert A.; Pinfield, Valerie J.

    2016-02-01

    Carbon Fiber Reinforced Polymer (CFRP) composites are often used as aircraft structural components, mostly due to their superior mechanical properties. In order to improve the efficiency of these structures, it is important to detect and characterize any defects occurring during the manufacturing process, removing the need to mitigate the risk of defects through increased thicknesses of structure. Such defects include porosity, which is well-known to reduce the mechanical performance of composite structures, particularly the inter-laminar shear strength. Previous work by the authors has considered the determination of porosity distributions in a fiber-metal laminate structure [1]. This paper investigates the use of wave-propagation modeling to invert the ultrasonic response and characterize the void distribution within the plies of a CFRP structure. Finite Element (FE) simulations are used to simulate the ultrasonic response of a porous composite laminate to a typical transducer signal. This simulated response is then applied as input data to an inversion method to calculate the distribution of porosity across the layers. The inversion method is a multi-dimensional optimization utilizing an analytical model based on a normal-incidence plane-wave recursive method and appropriate mixture rules to estimate the acoustical properties of the structure, including the effects of plies and porosity. The effect of porosity is defined through an effective wave-number obtained from a scattering model description. Although a single-scattering approach is applied in this initial study, the limitations of the method in terms of the considered porous layer, percentage porosity and void radius are discussed in relation to single- and multiple-scattering methods. A comparison between the properties of the modeled structure and the void distribution obtained from the inversion is discussed. This work supports the general study of the use of ultrasound methods with inversion to

  6. Oxidation of Carbon Fibers in a Cracked Ceramic Matrix Composite Modeled as a Function of Temperature

    Science.gov (United States)

    Halbig, Michael C.; Cawley, James D.; Eckel, Andrew J.

    2003-01-01

    The oxidation model simulates the oxidation of the reinforcing carbon fibers within a ceramic matrix composite material containing as-fabricated microcracks. The physics-based oxidation model uses theoretically and experimentally determined variables as input for the model. The model simulates the ingress of oxygen through microcracks into a two-dimensional plane within the composite material. Model input includes temperature, oxygen concentration, the reaction rate constant, the diffusion coefficient, and the crack opening width as a function of the mechanical and thermal loads. The model is run in an iterative process for a two-dimensional grid system in which oxygen diffuses through the porous and cracked regions of the material and reacts with carbon in short time steps. The model allows the local oxygen concentrations and carbon volumes from the edge to the interior of the composite to be determined over time. Oxidation damage predicted by the model was compared with that observed from microstructural analysis of experimentally tested composite material to validate the model for two temperatures of interest. When the model is run for low-temperature conditions, the kinetics are reaction controlled. Carbon and oxygen reactions occur relatively slowly. Therefore, oxygen can bypass the carbon near the outer edge and diffuse into the interior so that it saturates the entire composite at relatively high concentrations. The kinetics are limited by the reaction rate between carbon and oxygen. This results in an interior that has high local concentrations of oxygen and a similar amount of consumed carbon throughout the cross section. When the model is run for high-temperature conditions, the kinetics are diffusion controlled. Carbon and oxygen reactions occur very quickly. The carbon consumes oxygen as soon as it is supplied. The kinetics are limited by the relatively slow rate at which oxygen is supplied in comparison to the relatively fast rate at which carbon and

  7. A New Fiber Preform with Nanocarbon Binder for Manufacturing Carbon Fiber Reinforced Composite by Liquid Molding Process.

    Science.gov (United States)

    Seong, Dong Gi; Ha, Jong Rok; Lee, Jea Uk; Lee, Wonoh; Kim, Byung Sun

    2015-11-01

    Carbon fiber reinforced composite has been a good candidate of lightweight structural component in the automotive industry. As fast production speed is essential to apply the composite materials for the mass production area such as automotive components, the high speed liquid composite molding processes have been developed. Fast resin injection through the fiber preform by high pressure is required to improve the production speed, but it often results in undesirable deformations of the fiber preform which causes defectives in size and properties of the final composite products. In order to prevent the undesirable deformation and improve the stability of preform shape, polymer type binder materials are used. More stable fiber preform can be obtained by increasing the amount of binder material, but it disturbs the resin impregnation through the fiber preform. In this study, carbon nanomaterials such as graphene oxide were embedded on the surface of carbon fiber by electrophoretic deposition method in order to improve the shape stability of fiber preform and interfacial bonding between polymer and the reinforcing fiber. Effects of the modified reinforcing fiber were investigated in two respects. One is to increase the binding energy between fiber tows, and the other is to increase the interfacial bonding between polymer matrix and fiber surface. The effects were analyzed by measuring the binding force of fiber preform and interlaminar shear strength of the composite. This study also investigated the high speed liquid molding process of the composite materials composed of polymer matrix and the carbon fiber preforms embedded by carbon nanomaterials. Process parameter such as permeability of fiber preform was measured to investigate the effect of nanoscale surface modification on the macroscale processing condition for composite manufacturing.

  8. High RF power test of a lower hybrid module mock-up in carbon fiber composite

    Energy Technology Data Exchange (ETDEWEB)

    Goniche, M.; Bibet, P.; Brossaud, J.; Cano, V.; Froissard, P.; Kazarian, F.; Rey, G. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Maebara, S.; Kiyono, K.; Seki, M.; Suganuma, K.; Ikeda, Y.; Imai, T. [Japan Atomic Energy Research Inst., Tokyo (Japan). Dept. of Fusion Facility

    1999-02-01

    A mock-up module of a Lower Hybrid Current Drive antenna module of a Carbon Fiber Composite (CFC) was fabricated for the development of heat resistive front facing the plasma. This module is made from CFC plates and rods which are copper coated to reduce the RF losses. The withstand-voltage, the RF properties and outgassing rates for long pulses and high RF power were tested at the Lower Hybrid test bed facility of Cadarache. After the short pulse conditioning, long pulses with a power density ranging between 50 and 150 MW/m{sup 2} were performed with no breakdowns. During these tests, the module temperaturewas increasing from 100-200 deg. C to 400-500 deg. C. It was also checked that high power density, up to 150 MW/m{sup 2}, could be transmitted when the waveguides are filled with H{sub 2} at a pressure of 5 x 10{sup -2} Pa. No significant change in the reflection coefficient is measured after the long pulse operation. During a long pulse, the power reflection increases during the pulse typically from 0.8% to 1.3%. It is concluded that the outgassing rate of Cu-plated CFC is about 6 times larger than of Dispersion Strengthened Copper (DSC) module at the module temperature of 300 deg. C. No significant increase of the global outgassing of the CFC module was measured after hydrogen pre-filling. After the test, visual inspection revealed that peeling of the copper coating occurred at one end of the module only on a very small area (0.2 cm{sup 2}). It is assessed that a CFC module is an attractive candidate for the hardening of the tip of the LHCD antenna. (authors)

  9. Recycling high-performance carbon fiber reinforced polymer composites using sub-critical and supercritical water

    Science.gov (United States)

    Knight, Chase C.

    Carbon fiber reinforced plastics (CFRP) are composite materials that consist of carbon fibers embedded in a polymer matrix, a combination that yields materials with properties exceeding the individual properties of each component. CFRP have several advantages over metals: they offer superior strength to weight ratios and superior resistance to corrosion and chemical attack. These advantages, along with continuing improvement in manufacturing processes, have resulted in rapid growth in the number of CFRP products and applications especially in the aerospace/aviation, wind energy, automotive, and sporting goods industries. Due to theses well-documented benefits and advancements in manufacturing capabilities, CFRP will continue to replace traditional materials of construction throughout several industries. However, some of the same properties that make CFRP outstanding materials also pose a major problem once these materials reach the end of service life. They become difficult to recycle. With composite consumption in North America growing by almost 5 times the rate of the US GDP in 2012, this lack of recyclability is a growing concern. As consumption increases, more waste will inevitably be generated. Current composite recycling technologies include mechanical recycling, thermal processing, and chemical processing. The major challenge of CFRP recycling is the ability to recover materials of high-value and preserve their properties. To this end, the most suitable technology is chemical processing, where the polymer matrix can be broken down and removed from the fiber, with limited damage to the fibers. This can be achieved using high concentration acids, but such a process is undesirable due to the toxicity of such materials. A viable alternative to acid is water in the sub-critical and supercritical region. Under these conditions, the behavior of this abundant and most environmentally friendly solvent resembles that of an organic compound, facilitating the breakdown

  10. Carbon-fiber tips for scanning probe microscopes and molecular electronics experiments

    NARCIS (Netherlands)

    Rubio-Bollinger, G.; Castellanos-Gomez, A.; Bilan, S.; Zotti, L.A.; Arroyo, C.R.; Agraït, N.; Cuevas, J.

    2012-01-01

    We fabricate and characterize carbon-fiber tips for their use in combined scanning tunneling and force microscopy based on piezoelectric quartz tuning fork force sensors. An electrochemical fabrication procedure to etch the tips is used to yield reproducible sub-100-nm apex. We also study electron t

  11. An electrical-heating and self-sensing shape memory polymer composite incorporated with carbon fiber felt

    Science.gov (United States)

    Gong, Xiaobo; Liu, Liwu; Liu, Yanju; Leng, Jinsong

    2016-03-01

    Shape memory polymers (SMPs) have the ability to adjust their stiffness, lock a temporary shape, and recover the permanent shape upon imposing an appropriate stimulus. They have found their way into the field of morphing structures. The electrically Joule resistive heating of the conductive composite can be a desirable stimulus to activate the shape memory effect of SMPs without external heating equipment. Electro-induced SMP composites incorporated with carbon fiber felt (CFF) were explored in this work. The CFF is an excellent conductive filler which can easily spread throughout the composite. It has a huge advantage in terms of low cost, simple manufacturing process, and uniform and tunable temperature distribution while heating. A continuous and compact conductive network made of carbon fibers and the overlap joints among them was observed from the microscopy images, and this network contributes to the high conductive properties of the CFF/SMP composites. The CFF/SMP composites can be electrical-heated rapidly and uniformly, and its’ shape recovery effect can be actuated by the electrical resistance Joule heating of the CFF without an external heater. The CFF/SMP composite get higher modulus and higher strength than the pure SMP without losing any strain recovery property. The high dependence of temperature and strain on the electrical resistance also make the composite a good self-sensing material. In general, the CFF/SMP composite shows great prospects as a potential material for the future morphing structures.

  12. Interlaminar improvement of carbon fiber/epoxy composites via depositing mixture of carbon nanotubes and sizing agent

    Science.gov (United States)

    Fang, Cuiqin; Wang, Julin; Zhang, Tao

    2014-12-01

    The effects of deposition to carbon fibers surfaces with mixture of functionalized multi-walled carbon fibers (MWCNTs) and sizing agent were investigated. Relationships between CNTs and sizing agent were studied with Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS) and Ubbelohde viscometer. The results revealed that CNTs could react with sizing agent at 120 °C, and optimal reaction occurs when mass ratio was about 1:20. Then, carbon fibers were immersed in mixed aqueous suspension of CNTs and sizing agent with the above ratio dispersed by ultrasonication. According to scanning electron microscope (SEM) observations, fibers surfaces were coated with CNTs and sizing agent. The static contact angle tests indicated wetting performance between fibers and epoxy resin were improved after deposited procedures. Interlaminar shear strength was increased by 67.01% for fibers/epoxy resin composites after mixture deposited process. Moreover, the tensile strength of single fibers after depositing showed a slightly increase compared with that of fibers without depositing layer.

  13. Study the Effect of Carbon Fiber Volume Fraction and their Orientations on the Thermal Conductivity of the Polymer Composite Materials.

    Directory of Open Access Journals (Sweden)

    Mohammed Sellab Hamza

    2008-01-01

    Full Text Available The effect of fiber volume fraction of the carbon fiber on the thermal conductivity of the polymer composite material was studied. Different percentages of carbon fibers were used (5%, 10%, 15%, 20%, and 25%. Specimens were made in two groups for unsaturated polyester as a matrix and carbon fibers, first group has parallel arrangement of fibers and the second group has perpendicular arrangement of fibers on the thermal flow, Lee's disk method was used for testing the specimens. This study showed that the values of the of thermal conductivity of the specimens when the fibers arranged in parallel direction was higher than that when the fibers arranged in the perpendicular direction The results indicated that the thermal conductivity increases with the increasing the fiber volume fraction. Minimum value was (0.64 W/m.?C for parallel arrangement and (0.1715 W/m.?C for perpendicular arrangement at (Vf = 5% .Maximum value for parallel and perpendicular were (2.65 W/m. ?C and (0.215 W/m.?C at (Vf = 25% respectively.

  14. Self-healable interfaces based on thermo-reversible Diels-Alder reactions in carbon fiber reinforced composites.

    Science.gov (United States)

    Zhang, W; Duchet, J; Gérard, J F

    2014-09-15

    Thermo-reversible Diels-Alder (DA) bonds formed between maleimide and furan groups have been used to generate an interphase between carbon fiber surface and an epoxy matrix leading to the ability of interfacial self-healing in carbon:epoxy composite materials. The maleimide groups were grafted on an untreated T700 carbon fiber from a three step surface treatment: (i) nitric acid oxidization, (ii) tetraethylenepentamine amination, and (iii) bismaleimide grafting. The furan groups were introduced in the reactive epoxy system from furfuryl glycidyl ether. The interface between untreated carbon fiber and epoxy matrix was considered as a reference. The interfacial shear strength (IFSS) was evaluated by single fiber micro-debonding test. The debonding force was shown to have a linear dependence with embedded length. The highest healing efficiency calculated from the debonding force was found to be about 82% more compared to the value for the reference interface. All the interphases designed with reversible DA bonds have a repeatable self-healing ability. As after the fourth healing, they can recover a relatively high healing efficiency (58% for the interphase formed by T700-BMI which is oxidized for 60 min during the first treatment step).

  15. The Smart Behavior of Cement-based Composite Containing Carbon Fibers under Three-point-bending Load

    Institute of Scientific and Technical Information of China (English)

    CHEN Bing; WU Keru; YAO Wu

    2005-01-01

    The influences of the fiber volume fraction on the electrical conductivity and the fraction change of electrical resistance under three-point- bending test were discussed. It is found that the relationship between the electrical conductivity of composites and the fiber volume fraction can be explained by the percolation theory and the change of electrical resistance of specimens reflects to the process of loading. The sensitivity and the response of the change of electrical resistance to the load for specimens with different fiber volume fractions are quite different,which provide an important guide for the manufacture of conductive and intrinsically smart carbon fiber composite.

  16. Preparation and performance of ZnO nanowires modified carbon fibers reinforced NiFe{sub 2}O{sub 4} ceramic matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Lei, E-mail: jwlzl77@163.com; Jiao, Wanli

    2013-12-25

    Highlights: •Unlike existing chemical modification, the liquid growth remains fiber’s strength. •ZnO nanowires array are grown on carbon fibers with controllable morphology. •ZnO nanowires array modified carbon fibers can reinforce the strength of ceramic matrix composite. •This research will provide a means to produce multifunctional composites. -- Abstract: The surface of carbon fibers was modified by ZnO nanowires using the liquid growth method. NiFe{sub 2}O{sub 4} ceramic matrix composites reinforced by the modified carbon fibers were prepared by a high-temperature solid-state reaction method at 1300 °C for 5 h in N{sub 2} atmosphere. The influences of modified carbon fibers on the mechanical performances of NiFe{sub 2}O{sub 4} composites were investigated. The crystal structure of modified carbon fibers and the morphology of modified carbon fibers surface and the NiFe{sub 2}O{sub 4} composites fracture cross-section were observed by meaning of X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The results showed that hexagonal wurtzite ZnO nanowires array grew from the surface of carbon fibers vertically, with nanowires diameters ranging from 170 nm to 380 nm and lengths up to 2.8 μm. Unlike existing chemical modification and high temperature oxidation method, the liquid growth allowed morphology control and maintained the single fiber tensile strength substantially unchanged under certain growth procedures. Compared to pure NiFe{sub 2}O{sub 4} ceramic and bare carbon fibers reinforced NiFe{sub 2}O{sub 4} composite, the bending strength of NiFe{sub 2}O{sub 4} composite reinforced with ZnO nanowires surface modified carbon fibers was shown to increase by up to 70% and 45%, respectively. The development of an interphase offering control over the morphology will provide a means to produce multifunctional composites.

  17. Preferential distribution and oxidation inhibiting/catalytic effects of boron in carbon fiber reinforced carbon (CFRC) composites

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Y.J.; Joo, H.J.; Radovic, L.R. [Penn State University, University Park, PA (United States). Dept. of Energy & Geoenvironmental Engineering, Fuel Science Program

    2003-07-01

    Two different batches of CFRC composites were prepared in the absence/presence of boron with the expectation of increasing oxidation stability and improving the processing compatibility of CFRC composites in commercial applications. The composites were examined to reveal the nature of substitutional B in oxidation, crystallinity and distribution preference in the composites. Substitutional B acts both a catalyst and an inhibitor in carbon oxidation, depending on the content and the extent of carbon burn-off reaction. Crystallinity increases with the incorporation of B. Boron prefers to be distributed in the less ordered structure; non-graphitizable PAN-based carbon fibers have higher B contents than graphitizable coal-tar pitch, but processing conditions can change this preference. The incorporation of B in CFRC composites seems to be beneficial for improving the potential ability of the composites in applications by increasing crystallinity and oxidation stability.

  18. Tensile strength and its scatter of unidirectional carbon fiber reinforced composites

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, H.; Oya, N.; Yamashita, K.; Maekawa, Z.I. [Kyoto Inst. of Technology (Japan)

    1995-12-31

    0 (along the fiber direction) and 90 degree (transverse to the fiber direction) tension tests of Carbon Fiber Reinforced Plastics (CFRP) using a great number of specimens were conducted. Tensile properties and their scatter were evaluated by means of the data base. Materials used in this study were seven kinds of carbon fibers and three kinds of epoxy resins. Reinforcing fiber and matrix resin properties strongly affected on 0 and 90 degree properties of CFRP respectively. In 0 degree tension tests, fracture mode of specimen vaned in each material, and a relationship between the scatter of strength and the fracture mode existed. From the results of 9 degree tension tests, some differences of interfacial properties between each laminate were` also detected. According to some considerations on fracture mechanism in 0 degree tension test, it was deduced that the fracture mode depended on the balance of fiber, matrix and interface properties.

  19. Study on the laser irradiation effects on carbon fiber reinforced resin composite subjected to tangential gas flow loading

    Science.gov (United States)

    Chen, Minsun; Jiang, Houman; Jiao, Luguang; Li, Junshen; Liu, Zejin

    2013-05-01

    The irradiation effects of 976nm continuous-wave laser on carbon fiber reinforced E-51 resin composite is studied experimentally, with a 0.4Ma tangential airflow or 0.4Ma tangential nitrogen gas flow on the target surface. In order to simulate the thermal response of fiber reinforced resin composite materials subjected to combined laser and tangential gas flow loading, a three-dimensional thermal response model of resin composite materials is developed. In the model, the thermal decomposition of resin is described by a multi-step model. The motion of the decomposition gas is assumed to be one-dimensional, for the case that the laser spot is significantly larger than the thickness of the sample. According the above assumption, the flow of the decomposition gas is considered in the three-dimensional model without introducing any mechanical quantities. The influences of the tangential gas flow, the outflow of the thermal decomposition gas and the ablation-including phase change ablation or oxidative ablation-of the surface material on the laser irradiation effects are included in the surface boundary conditions. The three-dimensional thermal response model is calculated numerically by use of the modified smooth particle hydrodynamics (MSPH) method which is coded with FORTRAN. The model is tested by experimentally measuring the temperature profiles during carbon fiber reinforced E-51 resin composite subjected to combined laser and tangential gas flow. The predicted temperature profiles are in good agreement with experimental temperatures obtained using thermocouples.

  20. Aligned Carbon Nanotube Reinforcement of Aerospace Carbon Fiber Composites: Substructural Strength Evaluation for Aerostructure Applications

    OpenAIRE

    Guzman de Villoria, Roberto; Ydrefors, L.; Hallander, P.; Ishiguro, Kyoko; Nordin, P.; Wardle, Brian L.

    2012-01-01

    Vertically aligned carbon nanotubes (VACNTs) are placed between all plies in an aerospace carbon fiber reinforced plastic laminate (unidirectional plies, [(0/90/±45)2]s) to reinforce the interlaminar region in the z-direction. Significant improvement in Mode I and II interlaminar toughness have been observed previously. In this work, several substructural in-plane strength tests relevant to aerostructures were undertaken: bolt/tension-bearing, open hole compression, and L-shape laminate be...

  1. Deformation behavior of FRP-metal composites locally reinforced with carbon fibers

    Science.gov (United States)

    Scholze, M.; Kolonko, A.; Lindner, T.; Lampke, T.; Helbig, F.

    2016-03-01

    This study investigates variations of hybrid laminates, consisting of one aluminum sheet and a unidirectional glass fiber (GF) reinforced polyamide 6 (PA6) basic structure with partial carbon fiber (CF) reinforcement. To create these heterogeneous FRP laminates, it is necessary to design and produce semi-finished textile-based products. Moreover, a warp knitting machine in conjunction with a warp thread offset unit was used to generate bionic inspired compounds. By the variation of stacking prior to the consolidation process of the hybrid laminate, an oriented CF reinforcement at the top and middle layer of the FRP is realized. In both cases the GFRP layer prevents contact between the aluminum and carbon fibers. In so doing, the high strength of carbon fibers can be transferred to the hybrid laminate in load directions with an active prevention of contact corrosion. The interface strength between thermoplastic and metal component was improved by a thermal spray coating on the aluminum sheet. Because of the high surface roughness and porosity, mechanical interlock was used to provide high interface strength without bonding agents between both components. The resulting mechanical properties of the hybrid laminates are evaluated by three point bending tests in different load directions. The effect of local fiber orientation and layer positioning on failure and deformation mechanism is additionally investigated by digital image correlation (DIC).

  2. Carbon Fiber Biocompatibility for Implants

    OpenAIRE

    Richard Petersen

    2016-01-01

    Carbon fibers have multiple potential advantages in developing high-strength biomaterials with a density close to bone for better stress transfer and electrical properties that enhance tissue formation. As a breakthrough example in biomaterials, a 1.5 mm diameter bisphenol-epoxy/carbon-fiber-reinforced composite rod was compared for two weeks in a rat tibia model with a similar 1.5 mm diameter titanium-6-4 alloy screw manufactured to retain bone implants. Results showed that carbon-fiber-rein...

  3. 碳纤维增强PE-UHMW/木粉复合材料的力学性能%Mechanical Properties on Carbon Fibers Reinforced PE-UHMW/Wood Flour Composites

    Institute of Scientific and Technical Information of China (English)

    游志培; 康美云; 李大纲; 邓巧云

    2014-01-01

    In order to improve the processing properties and mechanical properties of ultra high molecular weight polyethylene(PE-UHMW),the wood powder and carbon fibers were used as the filled materials. High filler content PE-UHMW/wood powder composites were prepared by mixed melt extrusion method. The effect of carbon fiber content on flexural properties, tensile properties and dynamic mechanical properties of the composites were investigated. The results show that the flexural strength and tensile strength of the composites are improved by adding carbon fibers. With the increasing of carbon fiber content,tensile strength and flexural strength of the composites are increased first and then decreased. When the mass fraction of carbon fiber is 3%,flexural strength of the composite reaches the maximum value(25.2 MPa),which is improved by 46.5%than that of composite without carbon fib ers. When the mass fraction of carbon fibers is 2%,the tensile strength of the composite reaches the maximum value(38.4 MPa),which is improved by 27.1%than that of the composite without carbon fibers. With the increase of the content of carbon fibers,storage modulus of the composite is improved significantly. Carbon fibers can increase loss factor peaks of the composites.%为了改善超高分子量聚乙烯(PE-UHMW)的加工性能,提高其力学性能,以木粉和碳纤维为填料,制备了高填充量碳纤维增强PE-UHMW/木粉复合材料。研究了碳纤维含量对PE-UHMW/木粉复合材料弯曲性能、拉伸性能及动态热机械性能的影响。研究结果表明,加入碳纤维可提高PE-UHMW/木粉复合材料的弯曲强度及拉伸强度。拉伸强度和弯曲强度都随着碳纤维的含量的增加呈现出先增加后减小的趋势。当碳纤维质量分数为3%时,弯曲强度达到最大值,为25.2 MPa,比未加碳纤维时提高了46.5%。当碳纤维质量分数为2%时,弯曲强度达到最大值,为38.4 MPa,比未加碳纤维时提高了27

  4. Investigating the energy harvesting capabilities of a hybrid ZnO nanowires/carbon fiber polymer composite beam.

    Science.gov (United States)

    Masghouni, N; Burton, J; Philen, M K; Al-Haik, M

    2015-03-06

    Hybrid piezoelectric composite structures that are able to convert mechanical energy into electricity have gained growing attention in the past few years. In this work, an energy harvesting composite beam is developed by growing piezoelectric zinc oxide nanowires on the surface of carbon fiber prior to forming structural composites. The piezoelectric behavior of the composite beam was demonstrated under different vibration sources such as water bath sonicator and permanent magnet vibration shaker. The beam was excited at its fundamental natural frequency (43.2 Hz) and the open circuit voltage and the short circuit current were measured to be 3.1 mV and 23 nA, respectively. Upon connecting an optimal resistor (1.2 kΩ) in series with the beam a maximum power output 2.5 nW was achieved.

  5. Optimization of interfacial microstructure and mechanical properties of carbon fiber/epoxy composites via carbon nanotube sizing

    Science.gov (United States)

    Yao, Hongwei; Sui, Xianhang; Zhao, Zhongbo; Xu, Zhiwei; Chen, Lei; Deng, Hui; Liu, Ya; Qian, Xiaoming

    2015-08-01

    Repetitious sizing treatment was used to modify the carbon fiber (CF) surface with carbon nanotubes (CNTs) for improving interfacial properties of CF/epoxy composites. Interlaminar shear and flexural results showed that mechanical properties of composites were significantly depended on the dispersion state and contents of CNTs in interfacial regions. Increases of 13.45% in interlaminar shear strength and 20.31% in flexural strength were achieved in quintuple sized-CF/epoxy composites, whereas excessive CNTs led to decrease of interfacial performance due to defects induced by agglomerated CNTs. Energy dispersive X-ray spectroscopy and force modulation atomic force microscope were used to detect the structure of interfacial phase and results indicated that gradient interfacial structure with various thicknesses was formed due to CNT incorporation. This means that such a simple and efficient method to improve interfacial performance of composites via regulating the fiber-matrix interphase structure was developed and showed great commercial application potential.

  6. Comparison of Fracture Characteristics of Openhole-Notch Carbon-Fiber-Reinforced Composites Subjected to Tensile and Compressive Loadings

    Science.gov (United States)

    Saeed, M.-U.; Chen, Z. F.; Chen, Z. H.; Li, B. B.

    2017-01-01

    Open-hole tension (OHT) and open-hole compression (OHC) tests were carried out on hot-pressed carbon-fiberreinforced composite samples with a singular open hole. The fracture surfaces of the OHT- and OHC-tested specimens were examined by using scanning electron microscopy (SEM). SEM micrographs showed significant features on the surface of carbon fiber, matrix, and especially in the fiber/matrix interface. Interpretation of these micrographs revealed the possible failure mechanism of composite samples with an open hole under tensile and compressive loadings. Furthermore, a comparative study of these micrographs also pointed to certain specific differences between the fracture characteristics of open-hole composite samples failed under tension and compression. This information is useful in the post-failure analysis of a composite structure.

  7. Computational modeling of the electromagnetic characteristics of carbon fiber-reinforced polymer composites with different weave structures

    Science.gov (United States)

    Hassan, A. M.; Douglas, J. F.; Garboczi, E. J.

    2014-02-01

    Carbon fiber reinforced polymer composites (CFRPC) are of great interest in the aerospace and automotive industries due to their exceptional mechanical properties. Carbon fibers are typically woven and inter-laced perpendicularly in warps and wefts to form a carbon fabric that can be embedded in a binding matrix. The warps and wefts can be interlaced in different patterns called weaving structures. The primary weaving structures are the plain, twill, and satin weaves, which give different mechanical composite properties. The goal of this work is to computationally investigate the dependence of CFRPC microwave and terahertz electromagnetic characteristics on weave structure. These bands are good candidates for the Nondestructive Evaluation (NDE) of CFRPC since their wavelengths are comparable to the main weave features. 3D full wave electromagnetic simulations of several different weave models have been performed using a finite element (FEM) simulator, which is able to accurately model the complex weave structure. The computational experiments demonstrate that the reflection of electromagnetic waves from CFRPC depend sensitively on weave structure. The reflection spectra calculated in this work can be used to identify the optimal frequencies for the NDE of each weave structure.

  8. Fracture Toughness of Carbon Fiber Composites Containing Various Fiber Sizings and a Puncture Self-Healing Thermoplastic Matrix

    Science.gov (United States)

    Cano, Roberto J.; Grimsley, Brian W.; Ratcliffe, James G.; Gordon, Keith L.; Smith, Joseph G.; Siochi, Emilie J.

    2015-01-01

    Ongoing efforts at NASA Langley Research Center (LaRC) have resulted in the identification of several commercially available thermoplastic resin systems which self-heal after ballistic impact and through penetration. One of these resins, polybutylene graft copolymer (PBg), was selected as a matrix for processing with unsized carbon fibers to fabricate reinforced composites for further evaluation. During process development, data from thermo-physical analyses was utilized to determine a processing cycle to fabricate laminate panels, which were analyzed by photo microscopy and acid digestion. The process cycle was further optimized based on these results to fabricate panels for mechanical property characterization. The results of the processing development effort of this composite material, as well as the results of the mechanical property characterization, indicated that bonding between the fiber and PBg was not adequate. Therefore, three sizings were investigated in this work to assess their potential to improve fiber/matrix bonding compared to previously tested unsized IM7 fiber. Unidirectional prepreg was made at NASA LaRC from three sized carbon fibers and utilized to fabricate test coupons that were tested in double cantilever beam configurations to determine GIc fracture toughness.

  9. Hybrid Carbon Fibers/Carbon Nanotubes Structures for Next Generation Polymeric Composites

    Science.gov (United States)

    2010-01-01

    carbon fiber surfaces. Electrochemical deposition of iron using pulse voltametry is compared to DC magnetron iron sputtering. Carbon nanostructures...04 5E − 04 6E − 04 Figure 2: Cyclic Voltammogramm 0f 0.05 M FeCl3. 6H2O/KOH (pH = 3), with scan rate 50 mV/s. 0 100 200 300 400 500 600 Time (s) C u...deposition the electrolyte-electrode interface was studies to set suitable parameters for the deposition experiment. Cyclic voltammetry was utilized to set

  10. Effect of Carbon Fiber Content on Mechanical Properties of Short Carbon Fiber Reinforced PE Composites%碳纤维含量对碳纤维增强PE复合材料力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    李力; 曹昌林

    2012-01-01

    以短切碳纤维为增强体,以聚乙烯树脂为基体,运用螺杆注射成型的方法制备碳纤维增强热塑性复合材料.研究了碳纤维含量对复合材料硬度、拉伸、疲劳等性能的影响.结果表明,随着碳纤维含量的增加,复合材料的维氏硬度呈S形增加,拉伸强度、弹性模量、条件疲劳极限值都有提高;当碳纤维含量为4.021%时,相对纯聚乙烯,硬度、拉伸强度、弹性模量、条件疲劳极限值分别增加了35.489%、18.421%、208.024%、213.240%%Taking chopped carbon fiber as reinforce element and the polyethylene resin as matrix, the carbon fiber reinforced thermoplastic composites were prepared by the way of screw injection molding method. The effects of carbon fiber content on mechanical properties were investigated by measuring the hardness, tensile and fatigue. The results show that: with the increase of carbon fiber content, the hardness increase tendency in S-shape. The tensile strength and elastic modulus and the fatigue cycle and the fatigue limit were increased by 35.489%, 18.421%, 208.024%, 213.240%, respectively.

  11. The influence of porosity on ultrasound attenuation in carbon fiber reinforced plastic composites using the laser-ultrasound spectroscopy

    Science.gov (United States)

    Karabutov, A. A.; Podymova, N. B.; Belyaev, I. O.

    2013-11-01

    Wideband acoustic spectroscopy with a laser ultrasound source for quantitative analysis of the effect of porosity on the attenuation coefficient of longitudinal acoustic waves in carbon fiber reinforced plastic (CFRP) composite materials was experimentally implemented. The samples under study had different bulk-porosity levels (up to 10%), which were determined using X-ray computer tomography. A resonance ultrasound attenuation peak associated with the one-dimensional periodicity of the layered composite structure was observed for all samples. The absolute value of the resonance-peak maximum and its width depend on the local concentration of microscopic isolated pores and extended delaminations in the sample structure. The obtained empirical relationships between these parameters of the frequency dependence of the ultrasound attenuation coefficient and the type of inhomogeneities and their volume concentration can be used for rapid evaluation of the structural quality of CFRP composites.

  12. Effect of temperature on the compressive behavior of carbon fiber composite pyramidal truss cores sandwich panels with reinforced frames

    Directory of Open Access Journals (Sweden)

    Xiaodong Li

    2016-03-01

    Full Text Available This paper focuses on the effect of temperature on the out-of-plane compressive properties and failure mechanism of carbon fiber/epoxy composite pyramidal truss cores sandwich panels (CF/CPTSP. CF/CPTSP with novel reinforced frames are manufactured by the water jet cutting and interlocking assembly method in this paper. The theoretical analysis is presented to predict the out-of-plane compressive stiffness and strength of CF/CPTSP at different ambient temperatures. The tests of composite sandwich panels are performed throughout the temperature range from −90∘C to 180∘C. Good agreement is found between theoretical predictions and experimental measurements. Experimental results indicate that the low temperature increases the compressive stiffness and strength of CF/CPTSP. However, the high temperature causes the degradation of the compressive stiffness and strength. Meanwhile, the effects of temperature on the failure mode of composite sandwich panels are also observed.

  13. Development of manufacturing process for large-diameter composite monofilaments by pyrolysis of resin-impregnated carbon-fiber bundles

    Science.gov (United States)

    Bradshaw, W. G.; Pinoli, P. C.; Vidoz, A. E.

    1972-01-01

    Large diameter, carbon-carbon composite, monofilaments were produced from the pyrolysis of organic precursor resins reinforced with high-strenght carbon fibers. The mechanical properties were measured before and after pyrolysis and the results were correlated with the properties of the constituents. The composite resulting from the combination of Thornel 75 and GW-173 resin precursor produced the highest tensile strength. The importance of matching strain-to-failure of fibers and matrix to obtain all the potential reinforcement of fibers is discussed. Methods are described to reduce, within the carbonaceous matrix, pyrolysis flaws which tend to reduce the composite strength. Preliminary studies are described which demonstrated the feasibility of fiber-matrix copyrolysis to alleviate matrix cracking and provide an improved matrix-fiber interfacial bonding.

  14. Cryogenic optical measurements of 12-segment-bonded carbon-fiber-reinforced silicon carbide composite mirror with support mechanism

    Science.gov (United States)

    Kaneda, Hidehiro; Nakagawa, Takao; Onaka, Takashi; Enya, Keigo; Makiuti, Sin'itirou; Takaki, Junji; Haruna, Masaki; Kume, Masami; Ozaki, Tsuyoshi

    2008-03-01

    A 720 mm diameter 12-segment-bonded carbon-fiber-reinforced silicon carbide (C/SiC) composite mirror has been fabricated and tested at cryogenic temperatures. Interferometric measurements show significant cryogenic deformation of the C/SiC composite mirror, which is well reproduced by a model analysis with measured properties of the bonded segments. It is concluded that the deformation is due mostly to variation in coefficients of thermal expansion among segments. In parallel, a 4-degree-of-freedom ball-bearing support mechanism has been developed for cryogenic applications. The C/SiC composite mirror was mounted on an aluminum base plate with the support mechanism and tested again. Cryogenic deformation of the mirror attributed to thermal contraction of the aluminum base plate via the support mechanism is highly reduced by the support, confirming that the newly developed support mechanism is promising for its future application to large-aperture cooled space telescopes.

  15. UV-Assisted 3D Printing of Glass and Carbon Fiber-Reinforced Dual-Cure Polymer Composites

    Directory of Open Access Journals (Sweden)

    Marta Invernizzi

    2016-07-01

    Full Text Available Glass (GFR and carbon fiber-reinforced (CFR dual-cure polymer composites fabricated by UV-assisted three-dimensional (UV-3D printing are presented. The resin material combines an acrylic-based photocurable resin with a low temperature (140 °C thermally-curable resin system based on bisphenol A diglycidyl ether as base component, an aliphatic anhydride (hexahydro-4-methylphthalic anhydride as hardener and (2,4,6,-tris(dimethylaminomethylphenol as catalyst. A thorough rheological characterization of these formulations allowed us to define their 3D printability window. UV-3D printed macrostructures were successfully demonstrated, giving a clear indication of their potential use in real-life structural applications. Differential scanning calorimetry and dynamic mechanical analysis highlighted the good thermal stability and mechanical properties of the printed parts. In addition, uniaxial tensile tests were used to assess the fiber reinforcing effect on the UV-3D printed objects. Finally, an initial study was conducted on the use of a sizing treatment on carbon fibers to improve the fiber/matrix interfacial adhesion, giving preliminary indications on the potential of this approach to improve the mechanical properties of the 3D printed CFR components.

  16. Polyhedral oligomeric silsesquioxanes/carbon nanotube/carbon fiber multiscale composite: Influence of a novel hierarchical reinforcement on the interfacial properties

    Science.gov (United States)

    Zhang, R. L.; Wang, C. G.; Liu, L.; Cui, H. Z.; Gao, B.

    2015-10-01

    A novel hierarchical reinforcing carbon fiber through co-grafting carbon nanotube (CNTs) and polyhedral oligomeric silsesquioxanes (POSS) was prepared in this paper. The structure and surface characteristics of the grafted carbon fiber were investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), thermogravimetry (TG) and scanning electron microscope (SEM), respectively. The surface energy and the functional groups of the carbon fiber surface were increased obviously after modification. The ILSS results showed that there was a remarkable improvement in the interfacial properties of the new hybrid CF-CNTs-POSS composites. The investigation can prove an effective way to increase the interfacial adhesion and improve the mechanical performance of the fiber/resin composites on the desired application.

  17. Characterization of unidirectional carbon fiber reinforced polyamide-6 thermoplastic composite under longitudinal compression loading at high strain rate

    Science.gov (United States)

    Ploeckl, Marina; Kuhn, Peter; Koerber, Hannes

    2015-09-01

    In the presented work, an experimental investigation has been performed to characterize the strain rate dependency of unidirectional carbon fiber reinforced polyamide-6 composite for longitudinal compression loading. An end-loaded compression specimen geometry, suitable for contactless optical strain measurement via digital image correlation and dynamic loading in a split-Hopkinson pressure bar, was developed. For the dynamic experiments at a constant strain rate of 100 s-1 a modified version of the Dynamic Compression Fixture, developed by Koerber and Camanho [Koerber and Camanho, Composites Part A, 42, 462-470, 2011] was used. The results were compared with quasi-static test results at a strain rate of 3 · 10-4 s-1 using the same specimen geometry. It was found that the longitudinal compressive strength increased by 61% compared to the strength value obtained from the quasi-static tests.

  18. Pyrolysis as a way to close a CFRC life cycle: Carbon fibers recovery and their use as feedstock for a new composite production

    Science.gov (United States)

    Giorgini, Loris; Benelli, Tiziana; Mazzocchetti, Laura; Leonardi, Chiara; Zattini, Giorgio; Minak, Giangiacomo; Dolcini, Enrico; Tosi, Cristian; Montanari, Ivan

    2014-05-01

    Pyrolysis is shown to be an efficient method for recycling carbon fiber composites in the form of both uncured prepregs scraps or as cured end-of-life objects. The pyrolytic process leads to different products in three physical states of matter. The gaseous fraction, called syngas, can be used as energy feedstock in the process itself. The oil fraction can be used as fuel or chemical feedstock. The solid residue contains substantially unharmed carbon fibers that can be isolated and recovered for the production of new composite materials, thus closing the life cycle of the composite in a "cradle to cradle" approach. All the pyrolysis outputs were thoroughly analyzed and characterized in terms of composition for oil and gas fraction and surface characteristics of the fibers. In particular, it is of paramount importance to correlate the aspect and properties of the fibers obtained with different composite feedstock and operational conditions, that can be significantly different, with the reinforcing performance in the newly produced Recycled Carbon Fibers Reinforced Polymers. Present results have been obtained on a pyrolysis pilot plant that offers the possibility of treating up to 70kg of materials, thus leading to a significant amount of products to be tested in the further composites production, focused mainly on chopped carbon fiber reinforcement.

  19. Experimental determinations of the eigenmodes for composite bars made with carbon and Kevlar-carbon fibers

    Science.gov (United States)

    Miriţoiu, C. M.; Stănescu, M. M.; Burada, C. O.; Bolcu, D.; Roşca, V.

    2015-11-01

    For modal identification, the single-point excitation method has been widely used in modal tests and it consists in applying a force in a given point and recording the vibratory structure response in all interest points, including the excitation point. There will be presented the experimental recordings for the studied bars (with Kevlar-carbon or carbon fibers), the frequency response function in Cartesian and polar coordinates. By using the frequency response functions we determine the eigenparameters for each bar. We present the final panel of the eigenmodes (with the damping factors, eigenfrequencies and critical damping) for each considered bar. Using the eigenfrequency of the first determined eigenmode, the bars stiffness has been determined. The presented bars can be used in practical engineering for: car or bus body parts, planes body parts, bullet-proof vests, reinforcements for sandwich beams, and so on.

  20. Plasma treatment of carbon fibers: Non-equilibrium dynamic adsorption and its effect on the mechanical properties of RTM fabricated composites

    Science.gov (United States)

    Ma, Keming; Wang, Baichen; Chen, Ping; Zhou, Xia

    2011-02-01

    The effect of oxygen plasma treatment on the non-equilibrium dynamic adsorption of the carbon fabric reinforcements in RTM process was studied. 5-Dimethylamino-1-naphthalene-sulfonylchloride (DNS-Cl) was attached to the curing agent to study the change of curing agent content in the epoxy resin matrix. Steady state fluorescence spectroscopy (FS) analysis was used to study this changes in the epoxy resin at the inlet and outlet of the RTM mould, and XPS was used to study the chemical changes on the carbon fiber surfaces introduced by plasma treatment. The interlaminar shear strength (ILSS) and flexural strength were also measured to study the effects of this non-equilibrium dynamic adsorption progress on the mechanical properties of the end products. FS analysis shows that the curing agent adsorbed onto the fiber surface preferentially for untreated carbon fiber, the curing agent content in the resin matrix maintain unchanged after plasma treatment for 3 min and 5 min, but after oxygen plasma treatment for 7 min, the epoxy resin adsorbed onto the fiber surface preferentially. XPS analysis indicated that the oxygen plasma treatment successfully increased some polar functional groups concentration on the carbon fiber surfaces, this changes on the carbon fiber surfaces can change the adsorption ability of carbon fiber to the resin and curing agent. The mechanical properties of the composites were correlated to this results.

  1. MODIFYING V-14 RUBBER WITH CARBON FIBERS

    Directory of Open Access Journals (Sweden)

    Shadrinov N. V.

    2016-01-01

    Full Text Available The influence of carbon fibers and modified carbon fibers on properties of industrially produced V-14 rubber is examined. The dependences of physical and mechanical properties, hardness, abrasion resistance and resistance in aggressive environment on few amount of filled fiber are established. Structural properties of reinforced elastomeric composites are studied by scanning electron microscopy. Elastomeric layer on the surface of modified carbon fiber, confirmed with high adhesion is identified

  2. Characterization and Effects of Fiber Pull-Outs in Hole Quality of Carbon Fiber Reinforced Plastics Composite

    Directory of Open Access Journals (Sweden)

    Sina Alizadeh Ashrafi

    2016-10-01

    Full Text Available Hole quality plays a crucial role in the production of close-tolerance holes utilized in aircraft assembly. Through drilling experiments of carbon fiber-reinforced plastic composites (CFRP, this study investigates the impact of varying drilling feed and speed conditions on fiber pull-out geometries and resulting hole quality parameters. For this study, hole quality parameters include hole size variance, hole roundness, and surface roughness. Fiber pull-out geometries are quantified by using scanning electron microscope (SEM images of the mechanically-sectioned CFRP-machined holes, to measure pull-out length and depth. Fiber pull-out geometries and the hole quality parameter results are dependent on the drilling feed and spindle speed condition, which determines the forces and undeformed chip thickness during the process. Fiber pull-out geometries influence surface roughness parameters from a surface profilometer, while their effect on other hole quality parameters obtained from a coordinate measuring machine is minimal.

  3. Mechanical analysis and reasonable design for Ti-Al alloy liner wound with carbon fiber resin composite high pressure vessel

    Institute of Scientific and Technical Information of China (English)

    Chuan-xiang ZHENG; Fan YANG; Ai-shi ZHU

    2009-01-01

    To consider the internal pressure loaded by both the cylindrical Ti-AI alloy liner and the carbon fiber resin composite (CFRC) wound layers, two models are built. The first one is a cylinder loaded with the internal pressure in the hoop direction only. In this model, the total hoop direction load is distributed over all layers under the internal pressure. The second one is a cylinder loaded with the internal pressure in the axial direction only. In this model, the total axial load is distributed over all cylinders under the internal pressure. Taking the boundary conditions of the continuous displacement between layers into account, a group of equations are built. From these equations, we get the solutions of stresses in both hoop direction and axial direction loaded by every layer under internal pressures. After the stresses are obtained, a reasonable design can be done. An example is given in the final section of this study.

  4. Mechanical analysis of carbon fiber reinforced shape memory polymer composite for self-deployable structure in space environment

    Science.gov (United States)

    Hong, Seok Bin; Ahn, Yong San; Jang, Joon Hyeok; Kim, Jin-Gyun; Goo, Nam Seo; Yu, Woong-Ryeol

    2016-04-01

    Shape memory polymer (SMP) is one of smart polymers which exhibit shape memory effect upon external stimuli. Reinforcements as carbon fiber had been used for making shape memory polymer composite (CF-SMPC). This study investigated a possibility of designing self-deployable structures in harsh space condition using CF-SMPCs and analyzed their shape memory behaviors with constitutive equation model.CF-SMPCs were prepared using woven carbon fabrics and a thermoset epoxy based SMP to obtain their basic mechanical properties including actuation in harsh environment. The mechanical and shape memory properties of SMP and CF-SMPCs were characterized using dynamic mechanical analysis (DMA) and universal tensile machine (UTM) with an environmental chamber. The mechanical properties such as flexural strength and tensile strength of SMP and CF-SMPC were measured with simple tensile/bending test and time dependent shape memory behavior was characterized with designed shape memory bending test. For mechanical analysis of CF-SMPCs, a 3D constitutive equation of SMP, which had been developed using multiplicative decomposition of the deformation gradient and shape memory strains, was used with material parameters determined from CF-SMPCs. Carbon fibers in composites reinforced tensile and flexural strength of SMP and acted as strong elastic springs in rheology based equation models. The actuation behavior of SMP matrix and CF-SMPCs was then simulated as 3D shape memory bending cases. Fiber bundle property was imbued with shell model for more precise analysis and it would be used for prediction of deploying behavior in self-deployable hinge structure.

  5. Carbon Fibers: Reexamination of the Critical Low-Temperature (200-300C) Stabilization of Polyacrylonitrile,

    Science.gov (United States)

    CARBON FIBERS , SYNTHESIS(CHEMISTRY)), (*ACRYLONITRILE POLYMERS, CARBON FIBERS ), SHEETS, CARBON, FILMS, OXIDATION, THERMAL ANALYSIS, CHEMICAL BONDS, INFRARED SPECTRA, MOLECULAR STRUCTURE, HEAT TREATMENT

  6. PP/碳纤维复合材料力学性能的研究%Research on Mechanical Properties of Carbon Fiber Reinforced PP Composites

    Institute of Scientific and Technical Information of China (English)

    冉红孟; 廖秋慧; 陶振刚; 连道君; 张忆顺; 吴慧君

    2015-01-01

    In consideration of the difficulty of producing and the ability of property improving,short carbon fiber and carbon fiber powder were selected as reinforced phase to compare the improving effect and producing difficulty of them,the influences of short carbon fiber/carbon fiber powder on the mechanical properties of these two composite materials were discussed by determining tensile property and impact toughness. The results show that with the content of carbon fiber increase,the impact toughness and the tensile property of these two composite materials increase first and then reduce,the reinforce effect of mechanical property are more obvious if short carbon fiber is chosen as the reinforced phase,on the contrary,when carbon fiber powder is chosen to be reinforced phase,a composite material with more stable property and easier producing adaptability is acquired,which is instructive to the actual injection production of carbon fiber products.%综合考虑碳纤维材料的加工适应性以及对基体力学性能改善的能力,分别选取了短切碳纤维和碳纤维粉末作为增强相,比较了它们对于PP的增强效果以及加工的难易,通过测定拉伸性能和冲击韧性考察了短切碳纤维的含量以及碳纤维粉末的含量对各自复合材料力学性能的影响。结果表明,随着碳纤维含量的增加,两种复合材料的冲击韧性以及拉伸性能都呈先增加后减小的趋势,短切碳纤维作为增强相对于基体树脂的力学性能增强效果更为显著,碳纤维粉末作为增强相的复合材料加工适应性强,性能更加稳定,该研究对碳纤维制品的实际注塑生产具有十分重要的意义。

  7. Transitions in Wear and Friction of Carbon Fiber Reinforced Copper Matrix Composite Sliding Against AISI-1045 Steel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The friction and wear properties of carbon fiber reinforced copper matrix composite in dry sliding against AISI-1045 steel was evaluated by a block-on-ring test machine. It was shown that the low frictional factor and wear rate of the composite block could be maintained when pressure or velocity was below a certain value. But when the pressure or velocity exceeded the critical value, the friction factor and wear rate tended to increase rapidly with pressure and sliding velocity. The morphologies, elemental compositions, and surface profile of worn composite surfaces at different wear stages were analyzed by means of scanning electron microscopy, energy dispersive spectrometry, and profile-meter. It was found that low values of friction and wear were due to a thin solid film forming on the surface of the composite block which includes carbon and copper at a mild wear stage. The film could impede adhesion and provide some degree of self-lubrication. When the film included more metal elements and were damaged, severe wear happened, and the wear rate increased sharply. As a result, a transition diagram in friction and wear was constructed, which provided pressure and velocity conditions of change from mild wear and low friction to severe wear and high friction for the wear-resisting design.

  8. Carbon fiber-reinforced cyanate ester/nano-ZrW2O8 composites with tailored thermal expansion.

    Science.gov (United States)

    Badrinarayanan, Prashanth; Rogalski, Mark K; Kessler, Michael R

    2012-02-01

    Fiber-reinforced composites are widely used in the design and fabrication of a variety of high performance aerospace components. The mismatch in coefficient of thermal expansion (CTE) between the high CTE polymer matrix and low CTE fiber reinforcements in such composite systems can lead to dimensional instability and deterioration of material lifetimes due to development of residual thermal stresses. The magnitude of thermally induced residual stresses in fiber-reinforced composite systems can be minimized by replacement of conventional polymer matrices with a low CTE, polymer nanocomposite matrix. Zirconium tungstate (ZrW(2)O(8)) is a unique ceramic material that exhibits isotropic negative thermal expansion and has excellent potential as a filler for development of low CTE polymer nanocomposites. In this paper, we report the fabrication and thermal characterization of novel, multiscale, macro-nano hybrid composite laminates comprising bisphenol E cyanate ester (BECy)/ZrW(2)O(8) nanocomposite matrices reinforced with unidirectional carbon fibers. The results reveal that incorporation of nanoparticles facilitates a reduction in CTE of the composite systems, which in turn results in a reduction in panel warpage and curvature after the cure because of mitigation of thermally induced residual stresses.

  9. Effects of electron irradiation in space environment on thermal and mechanical properties of carbon fiber/bismaleimide composite

    Science.gov (United States)

    Yu, Qi; Chen, Ping; Gao, Yu; Ma, Keming; Lu, Chun; Xiong, Xuhai

    2014-10-01

    The effects of electron irradiation in simulated space environment on thermal and mechanical properties of high performance carbon fiber/bismaleimide composites were investigated. The dynamic mechanical properties of the composites exposed to different fluences of electron irradiation were evaluated by Dynamic mechanical analysis (DMA). Thermogravimetric analysis was applied to investigate the changes in thermal stability of the resin matrix after exposure to electron irradiation. The changes in mechanical properties of the composites were evaluated by flexural strength and interlaminar shear strength (ILSS). The results indicated that electron irradiation in high vacuum had an impact on thermal and mechanical properties of CF/BMI composites, which depends on irradiation fluence. At lower irradiation fluences less than 5 × 1015 cm-2, the dynamic storage modulus, cross-linking degree, thermal stability and mechanical properties that were determined by a competing effect between chain scission and cross-linking process, decreased firstly and then increased. While at higher fluences beyond 5 × 1015 cm-2, the chain scission process was dominant and thus led to the degradation in thermal and mechanical properties of the composites.

  10. Effects of electron irradiation in space environment on thermal and mechanical properties of carbon fiber/bismaleimide composite

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Qi, E-mail: yuqi1027@126.com [Liaoning Key Laboratory of Advanced Polymer Matrix Composites and Faculty of Aerospace Engineering, Shenyang Aerospace University, Shenyang 110136 (China); Chen, Ping, E-mail: chenping_898@126.com [Liaoning Key Laboratory of Advanced Polymer Matrix Composites and Faculty of Aerospace Engineering, Shenyang Aerospace University, Shenyang 110136 (China); State Key Laboratory of Fine Chemicals and School of Chemical Engineering, Dalian University of Technology, Dalian 116024 (China); Gao, Yu; Ma, Keming; Lu, Chun; Xiong, Xuhai [Liaoning Key Laboratory of Advanced Polymer Matrix Composites and Faculty of Aerospace Engineering, Shenyang Aerospace University, Shenyang 110136 (China)

    2014-10-01

    Highlights: •Electron irradiation decreased the storage modulus finally. •T{sub g} decreased first and then increased and finally decreased. •The thermal stability was reduced and then improved and finally decreased. •The changing trend of flexural strength and ILSS are consistent. -- Abstract: The effects of electron irradiation in simulated space environment on thermal and mechanical properties of high performance carbon fiber/bismaleimide composites were investigated. The dynamic mechanical properties of the composites exposed to different fluences of electron irradiation were evaluated by Dynamic mechanical analysis (DMA). Thermogravimetric analysis was applied to investigate the changes in thermal stability of the resin matrix after exposure to electron irradiation. The changes in mechanical properties of the composites were evaluated by flexural strength and interlaminar shear strength (ILSS). The results indicated that electron irradiation in high vacuum had an impact on thermal and mechanical properties of CF/BMI composites, which depends on irradiation fluence. At lower irradiation fluences less than 5 × 10{sup 15} cm{sup −2}, the dynamic storage modulus, cross-linking degree, thermal stability and mechanical properties that were determined by a competing effect between chain scission and cross-linking process, decreased firstly and then increased. While at higher fluences beyond 5 × 10{sup 15} cm{sup −2}, the chain scission process was dominant and thus led to the degradation in thermal and mechanical properties of the composites.

  11. Research on 3D Braided Nickel Plated Carbon Fiber/epoxy Resin Composites and Their Electromagnetic Protection Properties

    Institute of Scientific and Technical Information of China (English)

    QU Zhaoming; WANG Qingguo; LEI Yisan; ZHANG Ruigang

    2013-01-01

    To develop electromagnetic protection composites with integrated structure-function properties,the three-dimension (3D) braided nickel plated carbon fiber/epoxy resin (Ni-CF3D/EP) composites were prepared based on 3D five-directional braiding,unitary nickel plating and mold compression shaping.The electromagnetic protection properties of Ni-CF3D/EP composites including shielding effectiveness (SE) and reflection loss against plane electromagnetic wave,shielding properties against electromagnetic pulse (EMP) were investigated.The test results show that the novel composites have good electromagnetic protection properties in a wide frequency range of 14 kHz~ 18 GHz with SE of 42 dB~95 dB,the absorption bandwidth of-5 dB in 2 GHz~ 18 GHz can reach 10 GHz and the pulse peak SE against EMP is 43.7 dB which can reduce the electromagnetic energy greatly.Meanwhile,the mechanic properties were also investigated and the results indicate that the Ni-CF3D/EP composites can replace metal materials for loading-bearing structural applications because of their excellent mechanic properties.

  12. Application of Polymeric Nanocomposites and Carbon Fiber Composites in the Production of Natural Gas Reservoirs

    Directory of Open Access Journals (Sweden)

    Gilberto João Pavani

    2015-01-01

    Full Text Available This research work is about the experimental analysis of the mechanical behavior of reservoirs for storage of compressed natural gas (CNG consisting of a nanopolymeric liner coated with carbon fiber preimpregnated with epoxy resin applied by filament winding (FW. It addresses technical solutions adopted to optimize the reservoir as reinforcement with fiber, the process of healing and thermal analysis, as well as the hydrostatic testing to verify its resistance to the pressure required for CNG storage. Different nanoclays were incorporated to the polymer aiming to increase the strength of the liner and to reduce the thickness of its wall and the final weight of the reservoir as well as decreasing gas permeability. The obtained results were the basis for proposing an adaptation of the equation traditionally used for the dimensioning of the wall thickness of metallic pressure vessels to determine the number of layers needed to endure any internal pressure to which the reservoir is subjected. They indicate that the used methodology enables the production of pressure vessels for the storage of CNG, according to the ISO 11439:2013 Standard.

  13. Flame Retardancy Effects of Graphene Nanoplatelet/Carbon Nanotube Hybrid Membranes on Carbon Fiber Reinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    Dongxian Zhuo

    2013-01-01

    Full Text Available Carbon nanotube/graphene nanoplatelet (MWCNT/GNP hybrid membranes with lower liquid permeability and better barrier effect compared to MWCNT membranes were successfully synthesized by vacuum filtering. Their morphologies, water permeability, and pore structures were characterized by a scanning electron microscope (SEM and nitrogen adsorption isotherms. Furthermore, MWCNT/GNP membranes were used to improve the flame retardancy of carbon fiber reinforced polymer (CFRP composites, and the influence of weight percentage of GNPs on the permeability and flame retardancy of MWCNT/GNP membranes was systematically investigated. Results show that incorporation of MWCNT/GNP membranes on CFRP composite plates can remarkably improve the flame retardancy of CFRP composites. Specifically, the incorporation of hierarchical MWCNT/GNP membrane with 7.5 wt% of GNP displays a 35% reduction in the peak heat release rate (PHRR for a CFRP composite plate with the epoxy as matrix and a 11% reduction in PHRR compared with the incorporation of MWCNT membrane only. A synergistic flame retarding mechanism is suggested to be attributed to these results, which includes controlling the pore size and penetrative network structure.

  14. Using maleic anhydride functionalized graphene oxide for improving the interfacial properties of carbon fiber/BMI composites

    Directory of Open Access Journals (Sweden)

    W. Li

    2016-11-01

    Full Text Available Maleic anhydride functionalized graphene oxide (MAH-GO was synthesized and then introduced into carbon fiber (CF reinforced bismaleimide (BMI composites, with the aim of improving the interfacial adhesion strength between CF and BMI resin. Various characterization techniques including Fourier transform infrared spectroscopy (FT-IR, X-ray photoelectron spectra (XPS and thermogravimetric analysis (TGA demonstrated that the maleic anhydride has been successfully grafted onto the GO surfaces. The study showed that the interlaminar shear strength (ILSS and flexural properties of CF/BMI composites were all improved by the incorporation of GO and MAH-GO, and the MAH-GO showed the substantially improved effect due to the strong interaction between the MAH-GO and the resin matrix. The maximum increment of the ILSS, flexural strength and flexural modulus of composites were 24.4, 28.7 and 49.7%, respectively. Scanning electron microscope (SEM photographs of the fracture surfaces revealed that the interfacial bonding between CF and resin matrix was significantly strengthened by the addition of MAH-GO. The results suggest that this feasible method may be an ideal substitute for the traditional method in the interfacial modification of composites.

  15. Improvement of carbon fiber surface properties using electron beam irradiation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Carbon fiber-reinforced advance composites have been used for struetural applications, mainly on account of their mechanical properties. The main factor for a good mechanical performance of carbon fiber-reinforced composite is the interfacial interaction between its components, which are carbon fiber and polymeric matrix. The aim of this study is to improve the surface properties of the carbon fiber using ionizing radiation from an electron beam to obtain better adhesion properties in the resultant composite. EB radiation was applied on the carbon fiber itself before preparing test specimens for the mechanical tests. Experimental results showed that EB irradiation improved the tensile strength of carbon fiber samples. The maximum value in tensile strength was reached using doses of about 250kGy. After breakage, the morphology aspect of the tensile specimens prepared with irradiated and non-irradiated carbon fibers were evaluated. SEM micrographs showed modifications on the carbon fiber surface.

  16. Interfacial Studies of Sized Carbon Fiber

    Science.gov (United States)

    Shahrul, S. N.; Hartini, M. N.; Hilmi, E. A.; Nizam, A.

    2010-03-01

    This study was performed to investigate the influence of sizing treatment on carbon fiber in respect of interfacial adhesion in composite materials, Epolam® 2025. Fortafil unsized carbon fiber was used to performed the experiment. The fiber was commercially surface treated and it was a polyacrylonitrile based carbon fiber with 3000 filament per strand. Epicure® 3370 was used as basic sizing chemical and dissolved in two types of solvent, ethanol and acetone for the comparison purpose. The single pull out test has been used to determine the influence of sizing on carbon fiber. The morphology of carbon fiber was observed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). The apparent interfacial strength IFSS values determined by pull out test for the Epicure® 3370/ethanol sized carbon fiber pointed to a good interfacial behaviour compared to the Epicure® 3370/acetone sized carbon fiber. The Epicure® 3370/ethanol sizing agent was found to be effective in promoting adhesion because of the chemical reactions between the sizing and Epolam® 2025 during the curing process. From this work, it showed that sized carbon fiber using Epicure® 3370 with addition of ethanol give higher mechanical properties of carbon fiber in terms of shear strength and also provided a good adhesion between fiber and matrix compared to the sizing chemical that contain acetone as a solvent.

  17. Modeling elastic and thermal properties of 2.5D carbon fiber and carbon/SiC hybrid matrix composites by homogenization method

    Directory of Open Access Journals (Sweden)

    Luiz Claudio Pardini

    2010-08-01

    Full Text Available Advanced carbon fiber hybrid carbon-ceramic matrix composites are realizing their potential in many thermostructural components for aerospace vehicles. This work presents ab-initio predictions of elastic constants and thermal properties for 2.5D carbon fiber reinforced carbon-silicon carbide hybrid matrix composites, by using the homogenization technique. The homogenization technique takes properties of individual components of the composites (fiber and matrix and characteristics of the geometrical architecture of the preform to perform calculations. Ab-initio modeling of mechanical and thermal properties is very attractive, especially during the material development stage, when larger samples may be prohibitively expensive or impossible to fabricate. Modeling is also useful when bigger samples would be prohibitively expensive or impractical. Thermostructural composites made of 2.5D preforms are easy to manufacture in relation to 3D preforms. Besides, 2.5D preforms are also resistant to thermo cycling and have high resistance to crack propagation in relation to ply stacked composites such as unidirectional (1D and bidirectional (2D structures. The calculations were performed by setting an overall carbon fiber volume fraction at 40, 45 and 50 for a 2D stacked composite, and volume fraction in Z-direction of 2, 4 and 6.

  18. 碳纤维复合材料起毛辊的结构与制备%Structure and Preparation of Carbon Fiber Composite Materials Fluff Rolls

    Institute of Scientific and Technical Information of China (English)

    徐艳; 张伟明

    2014-01-01

    一种碳纤维复合材料起毛辊的结构与制备,包括起毛辊的辊体和装在辊体两端的轴头。首先,在设计好的模具芯棒上缠绕碳纤维预浸布,做成碳纤维内衬管备用;然后将轴头的粘接段涂上粘合剂后插入碳纤维内衬管内进行胶接;最后以碳纤维内衬管作为芯棒,再缠绕碳纤维预浸布,同时将轴头的加强轴肩包裹在内,以固化粗加工-精加工-涂装,最后制成成品起毛辊。其质量轻、直线度好、抗疲劳、刚性好,不仅碳纤维和树脂结合更好,致密度更高,强度也大大超过了一步法,延长了起毛辊的寿命。而且碳纤维复合材料和金属轴头通过两次包覆粘接,增大了碳纤维管壁与金属轴头的接触面,粘接更牢,大大提高了碳纤维复合材料起毛辊的整体强度。%Structure and preparation of a carbon fiber composite material pile roller, including a roller body and the pile roller mounted at both ends of the roller shaft head body. First, in the design of a mold mandrel wound carbon fiber prepreg, made of carbon fiber liner spare; then coated with adhesive segment axis head is inserted within the adhesive lined carbon fiber tube glued; Finally, carbon fiber lined pipe as a mandrel, and then wound carbon fiber prepreg, while the head of the shaft, including strengthening the shoulder wrap to cure roughing - finishing - painting, finally finished products pile roller. Its light weight, good straightness, anti-fatigue, rigid, carbon fiber and resin bonded not only better, higher density, strength greatly exceeds the one-step, extend the life of fluff roll. And carbon fiber composite materials and metal shaft head covered by two bonding, increases the contact surface of the carbon fiber wall with metal shaft head, bonding more firmly, greatly improving the overall strength of the carbon fiber composite material fluff roll.

  19. Exploring molecular sieve capabilities of activated carbon fibers to reduce the impact of NOM preloading on trichloroethylene adsorption.

    Science.gov (United States)

    Karanfil, Tanju; Dastgheib, Seyed A; Mauldin, Dina

    2006-02-15

    Adsorption of trichloroethylene (TCE) by two activated carbon fibers (ACFs) and two granular activated carbons (GACs) preloaded with hydrophobic and transphilic fractions of natural organic matter (NOM) was examined. ACF10, the most microporous activated carbon used in this study, had over 90% of its pore volume in pores smaller than 10 A. It also had the highest volume in pores 5-8 A, which is the optimum pore size region for TCE adsorption, among the four activated carbons. Adsorption of NOM fractions by ACF10 was, in general, negligible. Therefore, ACF10, functioning as a molecular sieve during preloading, exhibited the least NOM uptake for each fraction, and subsequently the highest TCE adsorption. The other three sorbents had wider pore size distributions, including high volumes in pores larger than 10 A, where NOM molecules can adsorb. As a result, they showed a higher degree of uptake for all NOM fractions, and subsequently lower adsorption capacities for TCE, as compared to ACF10. The results obtained in this study showed that understanding the interplay between the optimum pore size region for the adsorption of target synthetic organic contaminant (SOC) and the pore size region for the adsorption of NOM molecules is important for controlling NOM-SOC competitions. Experiments with different NOM fractions indicated that the degree of NOM loading is important in terms of preloading effects; however the waythatthe carbon pores are filled and loaded by different NOM fractions can be different and may create an additional negative impact on TCE adsorption.

  20. The influence of sterilization processes on the micromechanical properties of carbon fiber-reinforced PEEK composites for bone implant applications.

    Science.gov (United States)

    Godara, A; Raabe, D; Green, S

    2007-03-01

    The effect of sterilization on the structural integrity of the thermoplastic matrix composite polyetheretherketone (PEEK) reinforced with carbon fibers (CF) is investigated by nanoindentation and nanoscratch tests. The use of the material as a medical implant grade requires a detailed understanding of the micromechanical properties which primarily define its in vivo behavior. Sterilization is a mandatory process for such materials used in medical applications like bone implants. The steam and gamma radiation sterilization processes employed in this study are at sufficient levels to affect the micromechanical properties of some polymer materials, particularly in the interphase region between the polymer matrix and the reinforcing fibers. Nanoindentation and nanoscratch tests are used in this work to reveal local gradients in the hardness and the elastic properties of the interphase regions. Both methods help to explore microscopic changes in the hardness, reduced stiffness and scratch resistance in the interphase region and in the bulk polymer matrix due to the different sterilization processes employed. The results reveal that neither steam nor gamma radiation sterilization entails significant changes of the reduced elastic modulus, hardness or coefficient of friction in the bulk polymer matrix. However, minor material changes of the PEEK matrix were observed in the interphase region. Of the two sterilization methods used, the steam treatment has a more significant influence on these small changes in this region and appears to increase slightly the thickness of the interphase zone.

  1. Digitally focused array ultrasonic testing technique for carbon fiber composite structures

    Science.gov (United States)

    Salchak, Y.; Zhvyrblya, V.; Sednev, D.; Lider, A.

    2016-06-01

    Composite fiber reinforced polymers are highly promising structures. At present, they are widely used in different areas such as aeronautics and nuclear industries. There is a great number of advantages of composite structures such as design flexibility, low cost per cubic inch, resistance to corrosion, lower material costs, lighter weight and improved productivity. However, composites degradation may be caused by different mechanisms such as overload, impact, overheating, creep and fatigue. Comparing to inspection of other materials some unique consideration is required for testing and analysis. Ultrasound testing is the most common method for inspection of composite structures. Digitally Focused Array Technology is considered as novel approach which enables fast and effective quantitative automatic testing. In this study new methodology of quality assurance of composite structure components based on DFA is performed.

  2. Compression failure mechanisms of single-ply, unidirectional, carbon-fiber composites

    Science.gov (United States)

    Ha, Jong-Bae; Nairn, John A.

    1992-01-01

    A single-ply composite compression test was used to study compression failure mechanisms as a function of fiber type, matrix type, and interfacial strength. Composites made with low- and intermediate-modulus fibers (Hercules AS4 and IM7) in either an epoxy (Hercules 3501-6) or a thermoplastic (ULTEM and LARC-TPI) matrix failed by kink banding and out-of-plane slip. The failures proceeded by rapid and catastrophic damage propagation across the specimen width. Composites made with high-modulus fibers (Hercules HMS4/3501-6) had a much lower compression strength. Their failures were characterized by kink banding and longitudinal splitting. The damage propagated slowly across the specimen width. Composites made with fibers treated to give low interfacial strength had low compression strength. These composites typically failed near the specimen ends and had long kink bands.

  3. Effect of the surface treatment of plain carbon fiber posts on the retention of the composite core: an in vitro evaluation.

    Science.gov (United States)

    Quintas, A F; Bottino, M A; Neisser, M P; de Araújo, M A

    2001-01-01

    This study aims to evaluate the role of surface treatments performed on plain carbon fiber posts, in relation to serrated carbon fiber posts, in the retention of the composite core. Fifty carbon fiber posts received surface treatments in order to verify their influence on the retention of the core material. An acrylic resin mold was developed in order to precisely fit the post, leaving a machined space to accommodate a self-curing composite resin. After the surface treatment, a primer was applied on the coronal portion of all posts, which were then dried. They were fitted to the mold and received a 3 mm composite core. All specimens were thermocycled and then stored in distilled water for a week. Tension test was performed at a speed of 0.5 mm/min until there was lack of adhesion or fracture of the core. The conclusions were: a) the values of retention related to aluminum oxide spray (group A), depth cutter diamond burs (group C) and posts with machined coronal portion (group D) were comparable to those of serrated posts (group E), although no statistically significant difference between these groups was found; b) the mean values of core retention in group B (medium grit diamond burs) were statistically lower than those of other groups.

  4. Validation of the numerical model of single-layer composites reinforced with carbon fiber and aramid

    Science.gov (United States)

    Sava, Mihaela; Hadǎr, Anton; Pǎrǎuşanu, Ioan; Petrescu, Horia-Alexandru; Baciu, Florin; Marinel, Stǎnescu Marius

    2016-06-01

    In this work we studied the experimental validation of the model and finite element analysis for a single layer of composite materials reinforced with carbon (denoted as C), aramid (K) and carbon-aramid (C-K) fibers. In the literature there are not many details about the differences that arise between transversal and longitudinal characteristics of composite materials reinforced with fabric, compared to those with unidirectional fibers. In order to achieve carbon and aramid composites we used twill fabric and for carbon-aramid plain fabric, as shown in Figure 1. In order to observe the static behavior of the considered specimens, numerical simulations were carried out in addition to the experimental determination of the characteristics of these materials. Layered composites are obviously the most widespread formula for getting advanced composite structures. It allows a unique variety of material and structural combinations leading to optimal design in a wide range of applications [1,2]. To design and verify the material composites it is necessary to know the basic mechanical constants of the materials. Almost all the layered composites consider that the every layer is an orthotropic material, so there are nine independent constants of material corresponding to the three principal directions: Young modulus E1, E2 and E3, shear modulus G12, G23 and G13, and major poison ratios ν12, ν23, ν13. Experimental determinations were performed using traction tests and strain gauges. For each of the three above mentioned materials, five samples were manufactured.

  5. Micromechanics model for predicting anisotropic electrical conductivity of carbon fiber composite materials

    Science.gov (United States)

    Haider, Mohammad Faisal; Haider, Md. Mushfique; Yasmeen, Farzana

    2016-07-01

    Heterogeneous materials, such as composites consist of clearly distinguishable constituents (or phases) that show different electrical properties. Multifunctional composites have anisotropic electrical properties that can be tailored for a particular application. The effective anisotropic electrical conductivity of composites is strongly affected by many parameters including volume fractions, distributions, and orientations of constituents. Given the electrical properties of the constituents, one important goal of micromechanics of materials consists of predicting electrical response of the heterogeneous material on the basis of the geometries and properties of the individual phases, a task known as homogenization. The benefit of homogenization is that the behavior of a heterogeneous material can be determined without resorting or testing it. Furthermore, continuum micromechanics can predict the full multi-axial properties and responses of inhomogeneous materials, which are anisotropic in nature. Effective electrical conductivity estimation is performed by using classical micromechanics techniques (composite cylinder assemblage method) that investigates the effect of the fiber/matrix electrical properties and their volume fractions on the micro scale composite response. The composite cylinder assemblage method (CCM) is an analytical theory that is based on the assumption that composites are in a state of periodic structure. The CCM was developed to extend capabilities variable fiber shape/array availability with same volume fraction, interphase analysis, etc. The CCM is a continuum-based micromechanics model that provides closed form expressions for upper level length scales such as macro-scale composite responses in terms of the properties, shapes, orientations and constituent distributions at lower length levels such as the micro-scale.

  6. Synthesis of higher molecular weight PAN and its copolymers for carbon fibers

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Higher molecular weight polyacrylonitrile (PAN) was obtained by the free-radical suspension copolymerization of itaconic acid (IA) and acrylonitrile (AN) which was carried out in DMSO/H2O using 2,2'-azodiisobutyronitrile (AIBN) as the initiator. The effects of polymerization parameters, such as IA monomer concentration and DMSO/H2O ratio, on the conversion of polymerization and number-average molecular weight are specially described. The copolymerization reaction rate and the number-average molecular weight of the resultant copolymers decrease with the result of high chain transfer constant of DMSO. For the copolymerization of AN and IA, with the inclusion of the good solvent DMSO, the solution degree of AN in DMSO/H2O is higher than that in water, as a result, the resulting copolymer pellets range from soft bulk to solid grain, as characterized by the use of SEM. Higher molecular weight P(AN-co-IA) copolymers have a lower initiation of exothermal reaction temperature and wider DSC exothermal peaks compared with PAN homopolymers, which corresponds with the results of an IR study.

  7. Surface modification of carbon fibers by a polyether sulfone emulsion sizing for increased interfacial adhesion with polyether sulfone

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Haojie [National Engineering Laboratory for Carbon Fiber Technology, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Shouchun, E-mail: zschun@sxicc.ac.cn [National Engineering Laboratory for Carbon Fiber Technology, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China); Lu, Chunxiang [National Engineering Laboratory for Carbon Fiber Technology, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan 030001 (China)

    2014-10-30

    Highlights: • A polyether sulfone emulsion (PES) sizing was prepared for the first time. • The sizing enhanced the surface activity and wettability of carbon fibers. • Compared to the original sizing, the PES emulsion sizing resulted in an 18.4% increase in the interlaminar shear strength of carbon fiber/PES composites. • Important influences of emulsifier on the fiber surface and composite interface were demonstrated. • The reinforcing mechanisms are the improved fiber surface wettability and interfacial compatibility in composites. - Abstract: Interests on carbon fiber-reinforced thermoplastic composites are growing rapidly, but the challenges with poor interfacial adhesion have slowed their adoption. In this work, a polyether sulfone (PES) emulsion sizing was prepared successfully for increased interfacial adhesion of carbon fiber/PES composites. To obtain a high-quality PES emulsion sizing, the key factor, emulsifier concentration, was studied by dynamic light scattering technique. The results demonstrated that the suitable weight ratio of PES to emulsifier was 8:3, and the resulting PES emulsion sizing had an average particle diameter of 117 nm and Zeta potential of −52.6 mV. After sizing, the surface oxygen-containing functional groups, free energy and wettability of carbon fibers increased significantly, which were advantageous to promote molecular-level contact between carbon fiber and PES. Finally, short beam shear tests were performed to evaluate the interfacial adhesion of carbon fiber/PES composites. The results indicated that PES emulsion sizing played a critical role for the enhanced interfacial adhesion in carbon fiber/PES composites, and a 26% increase of interlaminar shear strength was achieved, because of the improved fiber surface wettability and interfacial compatibility between carbon fiber and PES.

  8. Carbon Fiber with Ni-coating Reinforced Aluminum Matrix Composites%电镀镍碳纤维增强铝基复合材料

    Institute of Scientific and Technical Information of China (English)

    韩变华; 罗天骄; 梁春林; 姚广春; 刘宜汉

    2006-01-01

    提出一种碳纤维表面电镀镍的方法,通过正交实验优化了电镀镍配方及工艺条件,并研究了镀层的显微组织及镀液的成分、电流密度、电镀时间等工艺条件对沉镍速率和镀层质量的影响,并探讨了沉镍机理.用镀镍碳纤维制备铝基复合材料,观测碳纤维与铝的复合效果.%This paper introduces the process of electroplating with nickel on carbon fiber, and the technical conditions of nickel plating are obtained by orthogonal experiment. Microscopic structure of nickel coating and the effect of nickel plating rate and coating structure with the solution composition, current density and electroplating time are studied. The principle of nickel plating is also researched. The aluminum matrix composites is reinforced by carbon fiber with nickel coating, and the compound effect between aluminum and carbon fiber is observed.

  9. Imaging the interphase of carbon fiber composites using transmission electron microscopy:Preparations by focused ion beam, ion beam etching, and ultramicrotomy

    Institute of Scientific and Technical Information of China (English)

    Wu Qing; Li Min; Gu Yizhuo; Wang Shaokai; Zhang Zuoguang

    2015-01-01

    Three sample preparation techniques, focused ion beam (FIB), ion beam (IB) etching, and ultramicrotomy (UM) were used in comparison to analyze the interphase of carbon fiber/epoxy composites using transmission electron microscopy. An intact interphase with a relatively uniform thickness was obtained by FIB, and detailed chemical analysis of the interphase was investigated by electron energy loss spectroscopy. It shows that the interphase region is 200 nm wide with an increasing oxygen-to-carbon ratio from 10% to 19% and an almost constant nitrogen-to-carbon ratio of about 3%. However, gallium implantation of FIB tends to hinder fine structure analysis of the interphase. For IB etching, the interphase region is observed with transition morphology from amorphous resin to nano-crystalline carbon fiber, but the uneven sample thickness brings difficulty for quantitative chemical analysis. Moreover, UM tends to cause damage and/or deformation on the interphase. These results are meaningful for in-depth understanding on the interphase characteristic of carbon fiber composites.

  10. Novel Interphases: Synthesis, Molecular Orientation and Grafting of Liquid Crystal Polymers on Carbon Fibers

    Science.gov (United States)

    1990-01-01

    presumably due to the alkaline nature of the TBAF solution bringing about a base - catalyzed ester hydrolysis of the more susceptible biphenyl benzoate...polymer- based composites. A protection- polymerization-deprotection scheo.e was developed for the synthesis of these functionallzed polymers. Optical... Transesterification . 26 1.2.4.2 Grafting via Esterification in Solution ...... .. 41 1.3 Summary ....... .................... .. 43 1.4 Experimental

  11. Quantitative assessment on the orientation and distribution of carbon fibers in a conductive polymer composite using high-frequency ultrasound.

    Science.gov (United States)

    Lin, Yi-Hsun; Huang, Chih-Chung; Wang, Shyh-Hau

    2012-05-01

    Conductive polymer composites, typically fabricated from a mix of conductive fillers and a polymer substrate, are commonly applied as bipolar plates in a fuel cell stack. Electrical conductivity is a crucial property that greatly depends on the distribution and orientation of the fillers. In this study, a 50-MHz ultrasound imaging system and analysis techniques capable of nondestructively assessing the properties of carbon fibers (CFs) in conductive polymer composites were developed. Composite materials containing a mix of polycarbonate substrates and 0 to 0.3 wt% of CFs were prepared using an injection molding technique. Ultrasonic A-line signals and C-scan images were acquired from each composite sample in regions at a depth of 0.15 mm beneath the sample surface (region A) and those at a depth of 0.3 mm (region B). The integrated backscatter (IB) and the Nakagami statistical parameter were calculated to quantitatively assess the samples. The area ratio, defined as the percentage of areas composed of CF images normalized by that of the whole C-scan image, was applied to further quantify the orientation of CFs perpendicular to the sample surface. Corresponding to the increase in CF concentrations from 0.1 to 0.3 wt%, the average IB and Nakagami parameter (m) of the composite samples increased from -78.10 ± 2.20 (mean ± standard deviation) to -72.66 ± 1.40 dB and from 0.024 ± 0.012 to 0.048 ± 0.011, respectively. The corresponding area ratios were respectively estimated to be 0.78 ± 0.35%, 2.33 ± 0.66%, and 2.20 ± 0.60% in region A of the samples; those of CFs with a perpendicular orientation were 0.04 ± 0.03%, 0.08 ± 0.02%, and 0.12 ± 0.05%. The area ratios in region B of the samples were calculated to be 1.19 ± 0.54%, 2.81 ± 0.42%, and 2.64 ± 0.76%, and those of CFs with a perpendicular orientation were 0.07 ± 0.04%, 0.12 ± 0.04%, and 0.14 ± 0.03%. According to the results of the orientations and ultrasonic images, CFs tended to distribute more

  12. Carbon Fiber Composites of Pure Polypropylene and Maleated Polypropylene Blends Obtained from Injection and Compression Moulding

    Directory of Open Access Journals (Sweden)

    D. Pérez-Rocha

    2015-01-01

    Full Text Available A comparative study of the mechanical performance of PP and PP/PP-g-MAH blends reinforced with carbon fibre (CF obtained by two different moulding techniques is presented. Three filler contents were used for fabricating the composites: 1, 3, and 5 pph (parts per hundred. The crystallisation behaviour of the composites was studied by differential scanning calorimetry. Morphological and structural features of these samples were observed by atomic field microscopy and Fourier-transform infrared spectroscopy, respectively. Mechanical properties of the injection and compression moulded composites were evaluated by means of tensile and impact resistance tests. The fracture surface of the impacted samples was observed by scanning electron microscopy. The processing method had a noticeable effect on the results obtained in these tests. Young’s modulus was enhanced up to 147% when adding 5 pph CF to a PP matrix when processed by compression moulding. Addition of PP-g-MAH and CF had a favourable effect on the tensile and impact strength properties in most samples; these composites showed improved performance as the filler content was increased.

  13. Study on Nickel Composite Coating on Carbon Fiber Surface%碳纤维表面复合镀镍研究

    Institute of Scientific and Technical Information of China (English)

    叶根; 张云鹏; 安乐

    2011-01-01

    Electroplating Ni on carbon fiber surface, and then shorter the fiber and subsequently chemical plating Ni-P alloy coating on the surface of carbon fiber to meet the requirement for the protection of the fiber. The optimum nickel plating process were obtained by orthogonal experiment The surface morphology of the carbon fiber was observed and the adhesion strength of the coating was tested. The chemical composition of the coating was measured. The results show that the nickel deposite of carbon fiber obtained by the method is uniform ,compact and. Adhesive. The electroplating can obtain pure Ni coating, but the composite plating can obtain Ni-P alloy coating.%采用电镀法在碳纤维表面沉积一层纯Ni镀层,然后将纤维剪短,采用化学镀法使短纤维表面以及两端包覆一层Ni-P合金镀层,并使纤维表面金属层加厚,来满足保护纤维的需要.通过不同正交体系研究碳纤维增重率,得到了优化的镀镍工艺.观察了镀层的表面形貌,测试了镀层的结合力,并对镀层的成分进行了分析.结果表明,纤维表面镀层均匀、致密、表面光亮和结合力强;电镀获得了纯Ni镀层,而复合镀获得了Ni-P合金镀层.

  14. A comprehensive study of woven carbon fiber-reinforced nylon 6 composites

    Science.gov (United States)

    Pillay, Selvum

    Liquid molding of thermoset composites has become very popular in all industry sectors, including aerospace, automotive, mass transit, and sporting goods, but the cost of materials and processing has limited the use to high-end applications. Thermoplastic composites are relatively cheap; however, the use has been limited to components with short fiber reinforcing. The high melt viscosity and short processing window precludes their use in the liquid molding of large structures and applications with continuous fiber reinforcement. The current research addresses the processing parameters, methodology, and limitations of vacuum assisted resin transfer molding (VARTM) of carbon fabric-reinforced, thermoplastic polyamide 6 (PA6). The material used is casting grade PA6. The process developed for using VARTM to produce carbon fabric-reinforced PA6 composites is explained in detail. The effects of infusion temperature and flow distance on the fiber weight fraction and crystallinity of the PA6 resin are presented. The degree of conversion from monomer to polymer was determined. Microscopic studies to show the wet-out of the fibers at the filament level are also presented. Tensile, flexural, short beam shear strength (SBSS), and low-velocity impact test results are presented and compared to a equivalent thermoset matrix composite. The rubber toughened epoxy system (SC-15) was chosen for the comparative study because the system has been especially developed to overcome the brittle nature of epoxy composites. The environmental effects of moisture and ultraviolet (UV) radiation on the carbon/nylon 6 composite were investigated. The samples were immersed in boiling water for 100 hr, and mechanical tests were conducted. Results showed that moisture causes plasticization of the matrix and attacks the fiber matrix interface. This leads to deterioration of the mechanical properties. The samples were also exposed to UV for up to 600 hr, and post exposure tests were conducted. The

  15. Damage tolerance and assessment of unidirectional carbon fiber composites: An experimental and numerical study

    Science.gov (United States)

    Flores, Mark David

    Composites are beginning to be used in a variety of different applications throughout industry. However, certification and damage tolerance is a growing concern in many aerospace and marine applications. Although compression-after-impact have been studied thoroughly, determining a damage tolerance methodology that accurately characterizes the failure of composites has not been established. An experimental investigation was performed to study the effect of stacking sequence, low-velocity impact response, and residual strength due to compression and fatigue. Digital Image Correlation (DIC) captured the strains and deformation of the plate due to compression. Computational investigations integrated non-destructive techniques (C-Scan, X-Ray) to determine the extent of the damage created by the manufacturing process and impact to accurately create a representative of the pre-existing damage. Fiber/matrix cracking, delamination growth, buckling, as well as other failures mechanisms occur in compression-after-impact laminated specimens examined experimentally. The results from this study provide knowledge of the compression after impact strength of plates, and a basis for validation of detailed modeling of progressive failure from impact damaged composites.

  16. Mechanical and Vibration Testing of Carbon Fiber Composite Material with Embedded Piezoelectric Sensors

    Science.gov (United States)

    Duffy, Kirsten P.; Lerch, Bradley A.; Wilmoth, Nathan G.; Kray, Nicholas; Gemeinhardt, Gregory

    2012-01-01

    Piezoelectric materials have been proposed as a means of decreasing turbomachinery blade vibration either through a passive damping scheme, or as part of an active vibration control system. For polymer matrix fiber composite (PMFC) blades, the piezoelectric elements could be embedded within the blade material, protecting the brittle piezoceramic material from the airflow and from debris. Before implementation of a piezoelectric element within a PMFC blade, the effect on PMFC mechanical properties needs to be understood. This study attempts to determine how the inclusion of a packaged piezoelectric patch affects the material properties of the PMFC. Composite specimens with embedded piezoelectric patches were tested in four-point bending, short beam shear, and flatwise tension configurations. Results show that the embedded piezoelectric material does decrease the strength of the composite material, especially in flatwise tension, attributable to failure at the interface or within the piezoelectric element itself. In addition, the sensing properties of the post-cured embedded piezoelectric materials were tested, and performed as expected. The piezoelectric materials include a non-flexible patch incorporating solid piezoceramic material, and two flexible patch types incorporating piezoelectric fibers. The piezoceramic material used in these patches was Navy Type-II PZT.

  17. Supersonic Retropulsion Surface Preparation of Carbon Fiber Reinforced Epoxy Composites for Adhesive Bonding

    Science.gov (United States)

    Palmieri, Frank L.; Belcher, Marcus A.; Wohl, Christopher J.; Blohowiak, Kay Y.; Connell, John W.

    2013-01-01

    Surface preparation is widely recognized as a key step to producing robust and predictable bonds in a precise and reproducible manner. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, can lack precision and reproducibility, which can lead to variation in surface properties and subsequent bonding performance. The use of a laser to ablate composite surface resin can provide an efficient, precise, and reproducible means of preparing composite surfaces for adhesive bonding. Advantages include elimination of physical waste (i.e., grit media and sacrificial peel ply layers that ultimately require disposal), reduction in process variability due to increased precision (e.g. increased reproducibility), and automation of surface preparation, all of which improve reliability and process control. This paper describes a Nd:YAG laser surface preparation technique for composite substrates and the mechanical performance and failure modes of bonded laminates thus prepared. Additionally, bonded specimens were aged in a hot, wet environment for approximately one year and subsequently mechanically tested. The results of a one year hygrothermal aging study will be presented.

  18. Effect of carbon nanotubes upon emissions from cutting and sanding carbon fiber-epoxy composites

    Energy Technology Data Exchange (ETDEWEB)

    Heitbrink, William A. [LMK OSH Consulting LLC (United States); Lo, Li-Ming, E-mail: LLo@cdc.gov [Centers for Disease Control and Prevention (CDC), Division of Applied Research and Technology, National Institute for Occupational Safety and Health (NIOSH) (United States)

    2015-08-15

    Carbon nanotubes (CNTs) are being incorporated into structural composites to enhance material strength. During fabrication or repair activities, machining nanocomposites may release CNTs into the workplace air. An experimental study was conducted to evaluate the emissions generated by cutting and sanding on three types of epoxy-composite panels: Panel A containing graphite fibers, Panel B containing graphite fibers and carbon-based mat, and Panel C containing graphite fibers, carbon-based mat, and multi-walled CNTs. Aerosol sampling was conducted with direct-reading instruments, and filter samples were collected for measuring elemental carbon (EC) and fiber concentrations. Our study results showed that cutting Panel C with a band saw did not generate detectable emissions of fibers inspected by transmission electron microscopy but did increase the particle mass, number, and EC emission concentrations by 20–80 % compared to Panels A and B. Sanding operation performed on two Panel C resulted in fiber emission rates of 1.9 × 10{sup 8} and 2.8 × 10{sup 6} fibers per second (f/s), while no free aerosol fibers were detected from sanding Panels A and B containing no CNTs. These free CNT fibers may be a health concern. However, the analysis of particle and EC concentrations from these same samples cannot clearly indicate the presence of CNTs, because extraneous aerosol generation from machining the composite epoxy material increased the mass concentrations of the EC.

  19. Fabrication and characterization of Polymer laminate composites reinforced with bi-woven carbon fibers

    Directory of Open Access Journals (Sweden)

    P.V.Sanjeev Kumar

    2015-04-01

    Full Text Available The present paper evaluate slaminatedcarbonbi-wove fibers Reinforced with vinyl ester composites. Vinyl ester was used as a matrix to prepare composites by in situ polymerization technique. Four planar layers were made simultaneously by keeping one over the other and each layer made sure to be weighed off by 15% which was maintained in all layers with different orientations. Pre-assumed Layer-1 is (50/5050%,0º; Layer-2 is (35/35/30 35% 0º, 35% +45º,30%,0;Layer-3is (25/50/25 25% 0º, 50%+45º,25-45º; and Layer-4is (25/25/25/25 (25% 0º, 25% +45º,25% -45º,25% 90º.The composite was prepared with the help of hand layup technique. Test ready specimens were tested with the help of shearing machine in accordance with ASTM Standards .It was observed that vinyl ester made good interface with parent fiber material. Flexural strength and Tensile strength have improved up to 3rd layer and decreased afterwards whereas Flexural modulus and Tensile modulus have linearly increased up to 4th layer. Thermal stability and Glass transition temperature have also been found to be satisfactory for all the laminated layers. Chemical resistance was good for the entire chemicals except sodium hydroxide.

  20. Carbonization in polyacrylonitrile (PAN) based carbon fibers studied by ReaxFF molecular dynamics simulations.

    Science.gov (United States)

    Saha, Biswajit; Schatz, George C

    2012-04-19

    The carbonization mechanism in polyacrylonitrile (PAN) based carbon nanofibers is studied using ReaxFF molecular dynamics simulations. Simulations are performed at two carbonization temperatures, 2500 and 2800 K, and also at two densities, 1.6 and 2.1 g/cm(3), that are relevant to the experimental carbonization conditions. The results are analyzed by examining the evolution of species with time, including carbon-only ring structures and gaseous species. Formation mechanisms are proposed for species like N(2), H(2), NH(3), and HCN and five-, six-, and seven-membered carbon-only rings, along with polycyclic structures. Interestingly, the formation of five-membered rings follows N(2) formation and usually occurs as a precursor to six-membered rings. Elimination mechanisms for the gaseous molecules are found that are in agreement with previously proposed mechanisms; however, alternative mechanisms are also proposed.

  1. In Situ Tomography of Microcracking in Cross Ply Carbon Fiber Composites with Pre-existing Debonding Damage

    KAUST Repository

    Traudes, Daniel

    2012-07-01

    Carbon fiber based composites are an essential material in weight-critical applications such as in the aerospace industry. However, these materials are susceptible to damage such as matrix microcracking and fiber/matrix debonding (diffuse damage), which occurs at stresses much lower than the failure stress. A T700/M21 [0/90]s laminate was tensile loaded to introduce diffuse damage and prepared for a study on the initiation of transverse microcracks. The material was tensile loaded in a [+45/-45]s orientation to induce diffuse damage. A diffuse damage indicator was developed by measuring the decrease in shear stiffness. Samples with diffuse damage levels of 0, 0.05, 0.10, 0.15, 0.20, and 0.25 were prepared to be tensile tested in a [0/90]s orientation to induce microcracks. A successful development of the microcracking test procedure was performed. The edge of the material was studied with optical microscopy and x-ray to establish the structure of the fiber bundle geometry when undamaged. A sample containing microcracks was treated with diiodomethane dye penetrant, which successfully highlighted microcracks during x-ray imaging. The application time was not sufficient to produce consistent x-ray images over time, so a 45 minute soak time was recommended instead. The same damaged sample was subjected to a tomographic scan without a dye penetrant and while unloaded. Transverse microcracks were successfully identified from the data, although the results were not clean enough and likely omitted some smaller microcracks. Results are expected to be cleaner if performed during tensile testing. Future tensile testing will quantify the induced crack density of samples containing various degrees of initial diffuse damage, either using x-rays with a dye penetrant or using x-ray microtomography.

  2. Forming of carbon fiber reinforced thermoplastic composite tubes - Experimental and numerical approaches

    Science.gov (United States)

    Maron, Bernhard; Garthaus, Christian; Lenz, Florian; Hornig, Andreas; Hübner, Michael; Gude, Maik

    2016-10-01

    Continuous-reinforced thermoplastic composites are of growing importance for series production of lightweight components in manifold industrial areas. Novel manufacturing technologies allow the production of hollow semi-finished products that are post formed to enhance functionality. To maximize efficiency in the development process of such components it is necessary to map the forming processes numerically using Finite Elements(FE)-methods. The aim is to perform feasibility studies at an early stage, reduce development time by virtual process optimization and to generate a detailed understanding of the post formed fiber architecture for further structural-mechanical analysis.

  3. Micro-Mechanical Analysis About Kink Band in Carbon Fiber/Epoxy Composites Under Longitudinal Compression

    Science.gov (United States)

    Zhang, Mi; Guan, Zhidong; Wang, Xiaodong; Du, Shanyi

    2016-12-01

    Kink band is a typical phenomenon for composites under longitudinal compression. In this paper, theoretical analysis and finite element simulation were conducted to analyze kink angle as well as compressive strength of composites. Kink angle was considered to be an important character throughout longitudinal compression process. Three factors including plastic matrix, initial fiber misalignment and rotation due to loading were considered for theoretical analysis. Besides, the relationship between kink angle and fiber volume fraction was improved and optimized by theoretical derivation. In addition, finite element models considering fiber stochastic strength and Drucker-Prager constitutive model for matrix were conducted in ABAQUS to analyze kink band formation process, which corresponded with the experimental results. Through simulation, the loading and failure procedure can be evidently divided into three stages: elastic stage, softening stage, and fiber break stage. It also shows that kink band is a result of fiber misalignment and plastic matrix. Different values of initial fiber misalignment angle, wavelength and fiber volume fraction were considered to explore the effects on compressive strength and kink angle. Results show that compressive strength increases with the decreasing of initial fiber misalignment angle, the decreasing of initial fiber misalignment wavelength and the increasing of fiber volume fraction, while kink angle decreases in these situations. Orthogonal array in statistics was also built to distinguish the effect degree of these factors. It indicates that initial fiber misalignment angle has the largest impact on compressive strength and kink angle.

  4. Enhancement of high-speed flywheel energy storage via carbon-fiber composite reinforcement

    Science.gov (United States)

    Conteh, Michael Abu

    This study on the enhancement of high-speed flywheel energy storage is to investigate composite materials that are suitable for high-speed, high-energy density for energy storage and/or energy recovery. The main motivation of the study is to explore the application of the flywheel in the aviation industry for recovering some of the energy that is currently being lost at the wheel brakes of an aircraft due to the high temperature developed in the brake stack as a result of landing, frequent brake applications during taxiing in or out of heavy traffic airports and rejected take-off. Lamina and laminate mechanical properties of materials suitable for flywheel high-speed energy storage were investigated. Design and optimum stress analysis were used to determine the shape factor, maximum stress and energy density for a flywheel with a constant stress disk and a constant thickness rim. Analytical studies along with the use of the CADEC-online software were used to evaluate the lamina and laminate properties. This study found that the use of hybrid composite material with higher strength (based on first ply failure strength) and lower density and lower elastic moduli for the disk than the rim material will yield high-speed and high-energy density. The materials designed based on the results from this study show outperformance compared to previous published results of standard flywheel material combinations. The safe rotational velocity and energy density were found to be 166,000 RPM and 2.73 MJ/kg respectively. Therefore, results from this study will contribute to aiding further development of the flywheel that has recently re-emerged as a promising application for energy storage due to significant improvements in composite materials and technology. Further study on flywheel energy recovery from aircraft brakes revealed that more than half of the energy dissipated at the wheel brake as heat could be recovered and converted to some useful form. In this way, the operating

  5. Feasibility of Carbon Fiber/PEEK Composites for Cryogenic Fuel Tank Applications

    Science.gov (United States)

    Doyle, K.; Doyle, A.; O Bradaigh, C. M.; Jaredson, D.

    2012-07-01

    This paper investigates the feasibility of CF/PEEK composites for manufacture of cryogenic fuel tanks for Next Generation Space Launchers. The material considered is CF/PEEK tape from Suprem SA and the proposed manufacturing process for the fuel tank is Automated Tape Placement. Material characterization was carried out on test laminates manufactured in an autoclave and also by Automated Tape Placement with in-situ consolidation. The results of the two processes were compared to establish if there is any knock down in properties for the automated tape placement process. A permeability test rig was setup with a helium leak detector and the effect of thermal cycling on the permeability properties of CF/PEEK was measured. A 1/10th scale demonstrator was designed and manufactured consisting of a cylinder manufactured by automated tape placement and an upper dome manufactured by autoclave processing. The assembly was achieved by Amorphous Interlayer Bonding with PEI.

  6. Surface characterization in composite and titanium bonding: Carbon fiber surface treatments for improved adhesion to thermoplastic polymers

    Science.gov (United States)

    Devilbiss, T. A.; Wightman, J. P.

    1987-01-01

    The effect of anodization in NaOH, H2SO4, and amine salts on the surface chemistry of carbon fibers was examined by X-ray photoelectron spectroscopy (XPS). The surfaces of carbon fibers after anodization in NaOH and H2SO4 were examined by scanning transmission electron microscopy (STEM), angular dependent XPS, UV absorption spectroscopy of the anodization bath, secondary ion mass spectrometry, and polar/dispersive surface energy analysis. Hercules AS-4, Dexter Hysol XAS, and Union Carbide T-300 fibers were examined by STEM, angular dependent XPS, and breaking strength measurement before and after commercial surface treatment. Oxygen and nitrogen were added to the fiber surfaces by anodization in amine salts. Analysis of the plasmon peak in the carbon 1s signal indicated that H2SO4 anodization affected the morphological structure of the carbon fiber surface. The work of adhesion of carbon fibers to thermoplastic resins was calculated using the geometric mean relationship. A correlation was observed between the dispersive component of the work of adhesion and the interfacial adhesion.

  7. Coating Carbon Fibers With Platinum

    Science.gov (United States)

    Effinger, Michael R.; Duncan, Peter; Coupland, Duncan; Rigali, Mark J.

    2007-01-01

    A process for coating carbon fibers with platinum has been developed. The process may also be adaptable to coating carbon fibers with other noble and refractory metals, including rhenium and iridium. The coated carbon fibers would be used as ingredients of matrix/fiber composite materials that would resist oxidation at high temperatures. The metal coats would contribute to oxidation resistance by keeping atmospheric oxygen away from fibers when cracks form in the matrices. Other processes that have been used to coat carbon fibers with metals have significant disadvantages: Metal-vapor deposition processes yield coats that are nonuniform along both the lengths and the circumferences of the fibers. The electrical resistivities of carbon fibers are too high to be compatible with electrolytic processes. Metal/organic vapor deposition entails the use of expensive starting materials, it may be necessary to use a furnace, and the starting materials and/or materials generated in the process may be hazardous. The present process does not have these disadvantages. It yields uniform, nonporous coats and is relatively inexpensive. The process can be summarized as one of pretreatment followed by electroless deposition. The process consists of the following steps: The surfaces of the fiber are activated by deposition of palladium crystallites from a solution. The surface-activated fibers are immersed in a solution that contains platinum. A reducing agent is used to supply electrons to effect a chemical reduction in situ. The chemical reduction displaces the platinum from the solution. The displaced platinum becomes deposited on the fibers. Each platinum atom that has been deposited acts as a catalytic site for the deposition of another platinum atom. Hence, the deposition process can also be characterized as autocatalytic. The thickness of the deposited metal can be tailored via the duration of immersion and the chemical activity of the solution.

  8. ULTRASONIC PENETRATION C-SCAN TECHNIQUE FOR CARBON FIBER COMPOSITE CYLINDERS%复合材料气瓶超声穿透C扫描检测技术

    Institute of Scientific and Technical Information of China (English)

    章清乐; 李宏

    2012-01-01

    For a particular model of aviation with carbon fiber composite cylinder structure, common defects and its effect on properties of composite materials were analyzed. The technology of ultrasonic penetration C-scan was used and achieved good results.%针对某型号航空用碳纤维复合材料气瓶的结构特点,分析了其常见的缺陷及其对复合材料性能的影响,运用超声穿透C扫描技术进行检测,取得了较好的效果.

  9. Fabrication of very-low-density, high-stiffness carbon fiber/aluminum hybridized composite with ultra-low density and high stiffness (M-11)

    Science.gov (United States)

    Suzuki, Tomoo

    1993-01-01

    Fabrication of a composite material with ultra-low density and high stiffness in microgravity is the objective of the investigation. The composite structure to be obtained is a random three-dimensional array of high modulus, short carbon fibers bonded at contact points by an aluminum alloy coated on the fibers. The material is highly porous and thus has a very low density. The motivation toward the investigation, simulation experiments, choice of the component materials, and on-flight experiment during ballistic trajectory of a NASDA rocket, are described.

  10. The improvement of the hygrothermal and mechanical properties of bismaleimide and K3B/IM7 carbon-fiber composites through a systematic study of the interphase

    Science.gov (United States)

    Wilenski, Mark Stewart

    Advanced aircraft travel at speeds in excess of mach 2 result in external skin temperatures ranging from {-}60sp°C to +190sp°C with extreme heating and cooling rates in the presence of moisture. This combination of environments presents a challenge to current materials. IM7 carbon fiber composites made with either bismaleimide (a thermoset) or K3B (a thermoplastic polyimide) resin are being considered for this use. The overall objective of this research was to develop a greater understanding of both the macroscopic response of these materials to hygrothermal and thermal spike environments, as well as the molecular level interactions which affect the ability of the resins to bond to the fiber. Hygrothermal testing of BMI/IM7 composites showed that resin properties are reduced by the presence of moisture while composite properties are virtually unaffected. Exposure of composites to a relatively small number of thermal spikes between room temperature and 250sp°C was shown to have little effect on BMI/IM7 composites, but causes excessive blistering of wet K3B/IM7 composites. A macroscopic microcracking phenomenon is observed in cross-ply laminates of the BMI/IM7 system. This was shown to be due to the generation of thermal residual stresses formed during cool down from a "stress-free temperature." Both finite element and analytical models were utilized to analyze the causes of this microcracking with a focus on methods for minimizing the resultant stresses. Several methods with potential were identified and suggestions for future work are made. Microscopically, tests of the bond strength between both the BMI and K3B resins with the unsized IM7 fiber indicated that the adhesion was low. Experimentation on the BMI/IM7 system was able to identify that the only active adhesion promoting mechanism was mechanical interlocking and not chemical bonds between functionalities on the fiber surface and the resin. Various methods for improving the adhesion in the BMI/IM7 system

  11. Construction of three-dimensional graphene interfaces into carbon fiber textiles for increasing deposition of nickel nanoparticles: flexible hierarchical magnetic textile composites for strong electromagnetic shielding

    Science.gov (United States)

    Bian, Xing-Ming; Liu, Lin; Li, Hai-Bing; Wang, Chan-Yuan; Xie, Qing; Zhao, Quan-Liang; Bi, Song; Hou, Zhi-Ling

    2017-01-01

    Since manipulating electromagnetic waves with electromagnetic active materials for environmental and electric engineering is a significant task, here a novel prototype is reported by introducing reduced graphene oxide (RGO) interfaces in carbon fiber (CF) networks for a hierarchical carbon fiber/reduced graphene oxide/nickel (CF-RGO-Ni) composite textile. Upon charaterizations of the microscopic morphologies, electrical and magnetic properties, the presence of three-dimensional RGO interfaces and bifunctional nickel nanoparticles substantially influences the related physical properties in the resulting hierarchical composite textiles. Eletromagnetic interference (EMI) shielding performance suggests that the hierarchical composite textiles hold a strong shielding effectiveness greater than 61 dB, showing greater advantages than conventional polymeric and foamy shielding composites. As a polymer-free lightweight structure, flexible CF-RGO-Ni composites of all electromagnetic active components offer unique understanding of the multi-scale and multiple mechanisms in electromagnetic energy consumption. Such a novel prototype of shielding structures along with convenient technology highlight a strategy to achieve high-performance EMI shielding, coupled with a universal approach for preparing advanced lightweight composites with graphene interfaces.

  12. 碳纤维复合材料螺旋桨铺层角度研究%Ply Angle of Carbon Fiber Composite Propeller

    Institute of Scientific and Technical Information of China (English)

    张建国; 岳金; 宋春生; 张锦光

    2014-01-01

    与传统的金属螺旋桨相比,碳纤维复合材料螺旋桨具有低振动、低噪音、轻质高效、耐海水腐蚀和易维修等特点。然而由于复合材料各向异性,碳纤维复合材料螺旋桨铺层角度对其性能有较大影响,因此,首先在Fluent中对螺旋桨进行桨叶压力分析,得到在设计工况下螺旋桨桨叶表面压力;其次对碳纤维复合材料螺旋桨进行铺层设计,得到了几种铺层方案,求解分析得到了铺层角度与碳纤维复合材料螺旋桨桨叶最大位移的关系;最后考虑到螺旋桨几何特征,对设计铺层方案的主铺层角进行了修正,修正作用使桨叶变形范围更大,为复合材料螺旋桨铺层角度设计提供了参考。%Compared with traditional metal propellers , carbon fiber composite propellers are of low vibration , low noise, light and efficient , resistant to seawater corrosion , and easy to maintain .Because of anisotropy characteristics of composite materials , ply angles of carbon fiber composite propellers have a greater impact on its performance .Firstly, blade stress analysis was taken in Fluent and propeller surface stress was gained in the design conditions .And then, ply angle design of carbon fiber composite propellers was conducted; the relations between ply angle and carbon fiber composite propeller blades maximum displacement were obtained;and finally taking the geometric characteristics of the propeller into account , the ply angle was modified .It can provide a reference for the ply angle design of composite propeller .

  13. Synergetic effect between adsorption and photodegradation on nanostructured TiO2/activated carbon fiber felt porous composites for toluene removal.

    Science.gov (United States)

    Li, Min; Lu, Bin; Ke, Qin-Fei; Guo, Ya-Jun; Guo, Ya-Ping

    2017-03-15

    The low quantum efficiency and limited adsorption efficiency of TiO2 makes it only fit for the removal of VOCs with low concentrations. Herein, we for the first time fabricated nanostructured TiO2/activated carbon fiber felt (TiO2/ACFF) porous composites by the in situ deposition of TiO2 microspheres on the carbon fibers in ACFF. Interestingly, the TiO2 microspheres exhibit hierarchical nanostructures constructed by nanocrystals as building blocks. The TiO2/ACFF porous composites possess excellent adsorption and photodegradation properties for toluene because of the synergetic effects between the nanostructured TiO2 and ACFF. The adsorption efficiencies of the TiO2/ACFF porous composites reach approximately 98% at the toluene concentration (TiO2/ACFF porous composites significantly enhances photocatalytic property for toluene by hindering the recombination of electron-hole pairs, reducing the TiO2 band gap energy (Eg) to 2.95eV and accelerating toluene adsorption. At the toluene concentrations of 230ppm and 460ppm, the photocatalytic oxidation efficiency of toluene into CO2 arrives at 100% and 81.5%, respectively. Therefore, the TiO2/ACFF porous composites with synergetic adsorption and photocatalytic activities have great potentials for toluene removal.

  14. Fundamental study of a refractory-based carbon fiber reinforced composite made by reactive melt infiltration for hypersonic applications

    Science.gov (United States)

    Wali, Natalie Alice

    Ceramic matrix composites are excellent candidates for ultrahigh temperature applications due their good physical properties, which are a combination of a chemically stable matrix and tough fiber reinforcement. This work is a fundamental study of a carbon fiber reinforced zirconium carbide composite (Cf/ZrC). The background chapter reviews reactive melt infiltration, which is the processing method used to make the Cf/ZrC composite. The first chapter discusses the microstructural characterization and development of Cf/ZrC. A formation mechanism of the unique matrix microstructure is proposed based on the characterization results. In the second chapter the mechanical properties of Cf/ZrC were determined. The fracture toughness at room temperature is obtained with a standard four point bend test, while flexural strength of Cf/ZrC is obtained to the ultra high temperature regime. For high temperatures a testing rig was modified to operate in inert atmosphere and tests were conducted at 1100 °C, 1350 °C and 1650 °C. Correlation is made between the flexural strength and fiber coatings of two different composite types. In situ compression tests were performed a modified SEM. Digital image correlation was used to monitor strains during compression. The stress-strain information is correlated to surface deformation. The environmental durability and oxidation behavior of Cf/ZrC and ZrC is detailed in the third and fourth chapters. The oxidation and shock behavior of Cf/ZrC were observed under both slow and rapid heating rates to ultra high temperatures. For rapid heating rates a panel was subjected to heating at steady-state and non-steady state heat flux. For slow heating rates specimen coupons were heated at 2000 °C in a bottom-loading furnace. Specimens were characterized post-test by x-ray diffraction, electron microscopy, electron probe microanalysis, and optical microscopy. The oxidation kinetics of Cf/ZrC composites and ZrC powders (45 micron and 60 nanometer

  15. Edge Delamination and Residual Properties of Drilled Carbon Fiber Composites with and without Short-Aramid-Fiber Interleaf

    Science.gov (United States)

    Sun, Zhi; Hu, Xiaozhi; Shi, Shanshan; Guo, Xu; Zhang, Yupeng; Chen, Haoran

    2016-10-01

    Edge delamination is frequently observed in carbon fiber reinforced plastic (CFRP) laminates after machining, due to the low fracture toughness of the resin interfaces between carbon fiber plies. In this study, the effects of incorporating tough aramid fibers into the brittle CFRP system are quantified by measuring the residual properties of bolted CFRP. By adding short-aramid-fiber interleaves in CFRP laminates, the residual tensile strength have been substantially increased by 14 % for twill-weave laminates and 45 % for unidirectional laminates respectively. Moreover, tensile failure was observed as the major mode of toughened laminates, in contrast to shear failure of plain laminates. The qualitative FEM results agreed well with the experimental results that edge delamination would cause relatively higher shear stress and therefore alter the failure mode from tensile failure to shear failure.

  16. Bootstrap Method for Detecting Damage in Carbon Fiber Reinforced Plastic Using a Macro Fiber Composite Sensor

    OpenAIRE

    DJANSENA, Alradix; 田中, 宏明; 工藤, 亮

    2015-01-01

    CFRP has been used in aircraft structures for decades. Although CFRP is light, its laminationis its main weakness. We have developed a new method to increase the probability of detectingdelamination in carbon fiber reinforced plastic (CFRP) by narrowing the confidence interval ofthe changes in natural frequency. The changes in the natural frequency in delaminated CFRPare tiny compared with measurement errors. We use the bootstrap method, a statisticaltechnique that increases the estimation ac...

  17. 碳纤维复合材料在笔记本电脑外壳上的应用%Application of carbon fiber composite in forming notebook computer case

    Institute of Scientific and Technical Information of China (English)

    边彬辉; 尹高喜; 张赛军; 练绪波; 汪智勇

    2011-01-01

    Carbon fiber has good resistance to weather and corrosion and shows excellent Performance: light and strong. On identical strength conditions, the thickness and weight of notebook computer case made of carbon fiber compounded with engineering plastic, epoxy resin or PMMA can be reduced by 50%~60% and 40%~50% respectively compared to that made of traditional engineering plastics, In this paper, the application of four kinds of carbon fiber composites, short carbon fiber reinforced composite plastic, thermosetting continuous carbon fiber composite sheet, thermoplastic continuous carbon fiber composite sheet and carbon fiber composite film in notebook computer case was introduced.%介绍了短碳纤维增强复合塑料、热固性连续性碳纤维复合板材、热塑性连续性碳纤维复合板材、碳纤维复合薄膜等4种碳纤维复合材料在笔记本电脑外壳上的应用,并作出了展望.碳纤维与工程塑料、环氧树脂、PMMA等树脂复合后制备的笔记本电脑外壳,在同等强度条件下,相比传统工程塑料制备的笔记本电脑外壳,厚度可减薄50%~60%,重量减轻40%~50%,而且拥有良好的耐候性和耐腐蚀性.指出碳纤维复合材料研究的快速发展将会推动笔记本电脑市场的巨大变革,使笔记本电脑向着"更轻、更薄、更强"方向快速发展.

  18. 聚酯/碳纤维复合材料的自修复性能研究%Self-healing properties of polyester/carbon fiber composites

    Institute of Scientific and Technical Information of China (English)

    倪卓; 林燕玲; 王帅; 林柳丽; 邱利明

    2011-01-01

    合成了脲醛树脂/环氧树脂微胶囊,并作为功能材料设计自修复聚醋/碳纤维复合材料.采用力学性能测试,扫描电子显微镜(SEM)和光学显微镜(OM)对微胶囊功能材料和自修复材料进行研究.碳纤维能够提高材料的弹性模量,在材料损伤过程中,控制裂缝的宽度.微胶囊具有增韧效果和自修复能力.经过拉伸复合材料内部产生裂纹.微胶囊在裂纹前端应力的作用下,囊壁破裂,囊芯流出润湿裂纹表面粘接裂纹,实现材料自修复.裂纹终止的形式包括微胶囊破裂终止、碳纤维阻碍终止和裂纹交叉终止.%In this work, urea-formaldehyde resin/epoxy microcapsules were synthesized and used to design self-healing polyester/carbon fiber composite materials. Mechanical properties, scanning electron microscopy (SEM) and optical microscope (OM) were employed for a study on the microcapsules and self-repairing materials. Carbon fiber can improve the elastic modulus and control the width of cracks. Microcapsules have not only a toughening effect but also a self-healing effect. After stretching, the composite materials appear an internal cracks resulting from the front tip in stress response. Wall ruptures, core materials flow out and wet cracked surfaces, eventually bond cracking. Crack termination is observed in various forms including micro-capsules rupture, carbon fiber termination and other crack hinders across the cracking.

  19. Preparation of Carbon Fiber Composites by Chemical Coating%碳纤维复合材料化学镀工艺研究

    Institute of Scientific and Technical Information of China (English)

    尹艳华; 赵京磊; 王春芳

    2013-01-01

    为确定最佳化学镀制备碳纤维复合材料工艺条件,用X射线衍射仪(XRD)、扫描电镜(SEM)等表征涂镀产物的组成及形貌.实验结果表明:温度、pH值、装载量、纤维长度和搅拌方式对施镀效果有影响,镀铜最佳工艺条件为温度60℃,pH=12,装载量60 mg/250 mL,碳纤维长度为1 mm.镀铜镍碳纤维(CNCF)的镀层元素为铜和镍,镀层均匀,铜、镍为多晶,结晶质量、表面一致性良好,电镜确定铜层厚度约为1 μm,与理论计算0.96μm基本吻合.%To optimize the processing conditions of chemical metal coating for preparing carbon fiber composites, X-ray diffractions (XRD) and scanning electron microscope (SEM) were used to determine the composition and observe the morphology of the coating. Experiment results show that the factors that affect the coating quality are PH value of the solution, temperature, coated load, carbon fiber length and the stirring way. Under experimental environment, the optimized copper coating conditions are T=60℃ , pH = 12, loading 60 mg/250 mL and the length of the carbon fiber is 1 mm. SEM of chemical copper coating of nickel-carbon fiber (CNCF) shows that the coating is uniform with good quality and the copper and nickel present poly-crystal status. The observed surface copper thickness of CNCF is about 1 μm, which nearly coincides with the calculation thickness of 0. 96 μm.

  20. Influence of locational states of submicron fibers added into matrix on mechanical properties of plain-woven Carbon Fiber Composite

    Science.gov (United States)

    Kumamoto, Soichiro; Okubo, Kazuya; Fujii, Toru

    2016-01-01

    The aim of this study was to show the influence of locational states of submicron fibers added into epoxy matrix on mechanical properties of modified plane-woven carbon fiber reinforced plastic (CFRP). To change the locational states of submicron fibers, two kinds of fabrication processes were applied in preparing specimen by hand lay-up method. Submicron fibers were simply added into epoxy resin with ethanol after they were stirred by a dispersion process using homogenizer to be located far from the interface between reinforcement and matrix. In contrast, submicron fibers were attached onto the carbon fibers by injecting from a spray nozzle accompanying with ethanol to be located near the interface, after they were tentatively contained in ethanol. The plain-woven CFRP plates were fabricated by hand lay-up method and cured at 80 degree-C for 1 hour and then at 150 degree-C for 3 hours. After curing, the plain-woven CFRP plates were cut into the dimension of specimen. Tensile shear strength and Mode-II fracture toughness of CFRP were determined by tensile lap-shear test and End-notched flexure(ENF) test, respectively. When submicron fibers were located far from the interface between carbon fibers and epoxy resin, tensile shear strength and Mode-II fracture toughness of CFRP were improved 30% and 18% compared with those of unmodified case. The improvement ratio in modified case was rather low (about few percentages) in the case where submicron fibers were located near the interface. The result suggested that crack propagation should be prevented when submicron fibers were existed far from the interface due to the effective stress state around the crack tip.

  1. Influence of locational states of submicron fibers added into matrix on mechanical properties of plain-woven Carbon Fiber Composite

    Directory of Open Access Journals (Sweden)

    Kumamoto Soichiro

    2016-01-01

    Full Text Available The aim of this study was to show the influence of locational states of submicron fibers added into epoxy matrix on mechanical properties of modified plane-woven carbon fiber reinforced plastic (CFRP. To change the locational states of submicron fibers, two kinds of fabrication processes were applied in preparing specimen by hand lay-up method. Submicron fibers were simply added into epoxy resin with ethanol after they were stirred by a dispersion process using homogenizer to be located far from the interface between reinforcement and matrix. In contrast, submicron fibers were attached onto the carbon fibers by injecting from a spray nozzle accompanying with ethanol to be located near the interface, after they were tentatively contained in ethanol. The plain-woven CFRP plates were fabricated by hand lay-up method and cured at 80 degree-C for 1 hour and then at 150 degree-C for 3 hours. After curing, the plain-woven CFRP plates were cut into the dimension of specimen. Tensile shear strength and Mode-II fracture toughness of CFRP were determined by tensile lap-shear test and End-notched flexure(ENF test, respectively. When submicron fibers were located far from the interface between carbon fibers and epoxy resin, tensile shear strength and Mode-II fracture toughness of CFRP were improved 30% and 18% compared with those of unmodified case. The improvement ratio in modified case was rather low (about few percentages in the case where submicron fibers were located near the interface. The result suggested that crack propagation should be prevented when submicron fibers were existed far from the interface due to the effective stress state around the crack tip.

  2. HPLC-ED of low-molecular weight brominated phenols and tetrabromobisphenol A using pretreated carbon fiber microelectrode.

    Science.gov (United States)

    Bartosova, Zdenka; Jirovsky, David; Riman, Daniel; Halouzka, Vladimir; Svidrnoch, Martin; Hrbac, Jan

    2014-05-01

    Electrochemically pretreated carbon fiber microelectrode was used to develop a simple, fast and sensitive HPLC-ECD method for the determination of brominated phenols. In addition to simple mono-, di- and tri-bromophenols (4-bromophenol, 2,4-dibromophenol, 2,6-dibromophenol, 2,4,6-tri-bromophenol) the possibility of electrochemical detection of 3,3',5,5'-tetrabromobisphenol A in oxidation mode is reported for the first time. The isocratic separation was achieved within 14 min using ternary mobile phase consisting of 50mM-phosphate buffer (pH 3.5), acetonitrile and methanol (35/15/50, v/v), and detection potential of E=+1450 mV (vs. Ag/AgCl). The carbon fiber microelectrode permitted to use high anodic potentials (up to +1800 mV vs. Ag/AgCl), the optimum analytical response was achieved at +1450 mV vs. Ag/AgCl. The limits of detection (LOD) for the studied analytes were within the range of 1.8-56.6 ng mL(-1). The developed method was applied to determination of brominated phenols in spiked water samples. Furthermore, after simple extraction with methyl tert-butyl ether, it was possible to quantify tetrabromobisphenol A (TBBA) in a piece of CRT monitor plastic casing. The found amount of TBBA was 10.22 mg kg(-1) (±0.43).

  3. Energy-related application of composite material. Carbon fiber reinforced plastics (CFRP); Enerugi kanren yoto to CFRP

    Energy Technology Data Exchange (ETDEWEB)

    Higuchi, T. [Toray Industries, Tokyo (Japan)

    2000-01-15

    Carbon fiber reinforced plastics (CFRP) with advantages such as high strength, high relative elastic modulus, high chemical stability, and excellent thermal/electric properties, is widely used in aviation/space, sports, and industries. This paper takes up CNG tank, flywheel, and windmill blade, as examples of energy-related application development. For the purpose of weight reduction of CNG car, big three car manufacturers of the U.S. and Honda adopted CNG tank. Flywheel with CFRP rotor can store 3.8 times energy compared with that of steel. Windmill blade used in windmill power generation is mostly made of 3 blades and presently GFRP is used, but CFRP will become a main stream when the windmill is scaled up. In the future, it is necessary to reduce the cost of carbon fiber and its treatment process, as well as to solve the targets such as standardization of design, recognition by users, and verification in environmental use, and to develop further applications. (NEDO)

  4. The impact of hygrothermal preconditioning on mode II interlaminar fracture toughness in unidirectional carbon fiber reinforced epoxy composites: An experimental investigation

    Science.gov (United States)

    Hempowicz, Michael L.

    The correlation between the interlaminar Mode II fracture toughness (GIIC) of a carbon fiber reinforced epoxy and other material properties across different conditioning regimes was investigated. Specimens were preconditioned using select hygrothermal criteria to evaluate how changes in the material and mechanical properties in a carbon fiber/epoxy composite correlations with changes in GIIC for each regime. An increase in GIIC from baseline values was demonstrated across all conditions from end-notched flexure (ENF) testing. Dynamic mechanical analysis (DMA) and tensile tests had varying responses based on preconditioning environment. Since tensile and some DMA properties rely on fiber strength and show property loss with increased plasticization, fiber strength may not have a large impact on GIIC properties. Test data also implied that the GIIC increased when consolidation of the polymer chains occurred in the arid condition as well as when crosslink density increased in the moisture exposed conditions. From these results it is believed that the chemical and physical changes in matrix cohesion are more important to GIIC behavior prediction than fiber behavior.

  5. The Oxidation Kinetics of Continuous Carbon Fibers in a Cracked Ceramic Matrix Composite. Degree awarded by Case Western Reserve Univ., May 2000

    Science.gov (United States)

    Halbig, Michael C.

    2001-01-01

    Experimental observations and results suggest two primary regimes as a function of temperature, i.e., diffusion and reaction controlled kinetics. Thermogravimetric analysis of carbon fiber in flowing oxygen gave an activation energy of 64.1 kJ/mol in the temperature range of 500 to 600 C and an apparent activation energy of 7.6 kJ/mol for temperatures from 600 to 1400 C. When C/SiC composite material was unstressed, matrix effects at temperatures from 900 to 1400 C protected the internal fibers. When under stress, self-protection was not observed. Increasing the stress from 10 to 25 ksi caused a 67 to 82 percent reduction in times to failure at temperatures from 750 to 1500 C. Based on experimental results, observation, and theory, a finite difference model was developed, which simulates the diffusion of oxygen into a matrix crack that is bridged by carbon fibers. The model allows the influence of important variables on oxidation kinetics to be studied systematically, i.e., temperature, reaction rate constant, diffusion coefficient, environment, and sample geometry.

  6. Coating of Carbon Fiber with Polyhedral Oligomeric Silsesquioxane (POSS to Enhance Mechanical Properties and Durability of Carbon/Vinyl Ester Composites

    Directory of Open Access Journals (Sweden)

    Mujib Khan

    2011-09-01

    Full Text Available Our continuing quest to improve the performance of polymer composites under moist and saltwater environments has gained momentum in recent years with the reinforcement of inorganic nanoparticles into the polymer. The key to mitigate degradation of composites under such environments is to maintain the integrity of the fiber/matrix (F/M interface. In this study, the F/M interface of carbon/vinyl ester composites has been modified by coating the carbon fiber with polyhedral oligomeric silsesquioxane (POSS. POSS is a nanostructured inorganic-organic hybrid particle with a cubic structure having silicon atoms at the core and linked to oxygen atoms. The advantage of using POSS is that the silicon atoms can be linked to a substituent that can be almost any chemical group known in organic chemistry. Cubic silica cores are ‘hard particles’ and are about 0.53 nm in diameter. The peripheral organic unit is a sphere of about 1–3 nm in diameter. Further, cubic structure of POSS remains intact during the polymerization process and therefore with appropriate functional groups, if installed on the fiber surface, would provide a stable and strong F/M interface. Two POSS systems with two different functional groups; namely, octaisobutyl and trisilanolphenyl have been investigated. A set of chemical and mechanical procedures has been developed to coat carbon fibers with POSS, and to fabricate layered composites with vinyl ester resin. Interlaminar shear and low velocity impact tests have indicated around 17–38% improvement in mechanical properties with respect to control samples made without the POSS coating. Saltwater and hygrothermal tests at various environmental conditions have revealed that coating with POSS reduces water absorption by 20–30% and retains the composite properties.

  7. Piezoresistivity of carbon fiber mat/epoxy resin composites%碳纤维毡/环氧树脂复合材料的力阻效应∗

    Institute of Scientific and Technical Information of China (English)

    郑华升; 朱四荣; 李卓球

    2015-01-01

    The piezoresistive responses of the composites fabricated by short-cut carbon fiber mat and epoxy res-in were studied by uniaxial tension tests.Positive piezoresistive effect of this composite was found in the test. The gauge factor for single-lamina carbon fiber mat/epoxy resin composite is as high as 13.9,but the resistance for this composite is observed to be decreased gradually.More stable piezoresistivity was attained in laminated composite and the gauge factors were observed to decrease with the increase of the number of the laminas.The gauge factor for 5-lamina carbon fiber mat/epoxy resin composite is 5.7.The improvement in stability and the decrease in gauge factor for the laminated composite are due to the solid conductive network of this composite. The laminated carbon fiber mat/epoxy resin composites were used as smart layers on the beam surfaces,and based on their piezoresistivities,the structural deformation monitoring upon cyclic load and the damage detec-ting upon monotonous load were conducted.%以短切碳纤维毡和环氧树脂为原材料制成复合材料,考察了该材料在单向拉伸载荷下的力阻响应.实验结果表明,该材料具有正力阻效应(拉应变引起材料的电阻增大).其中,单层碳纤维毡/环氧树脂复合材料的力阻灵敏度可达13.9,但在加载过程中其电阻表现出逐渐衰减趋势;多层碳纤维毡/环氧树脂复合材料的力阻性能更为稳定,但随着层数的增加灵敏度逐渐降低,5层复合材料的力阻灵敏度下降到5.7.多层复合材料的立体导电网络是其稳定性提升和灵敏度下降的主要原因.将碳纤维毡/环氧树脂多层复合材料敷设在梁结构表面形成智能表层,利用其力阻性能实现了梁结构在循环载荷下的变形监测以及在单调载荷作用下损伤监测.

  8. Polarization dependence of laser interaction with carbon fibers and CFRP.

    Science.gov (United States)

    Freitag, Christian; Weber, Rudolf; Graf, Thomas

    2014-01-27

    A key factor for laser materials processing is the absorptivity of the material at the laser wavelength, which determines the fraction of the laser energy that is coupled into the material. Based on the Fresnel equations, a theoretical model is used to determine the absorptivity for carbon fiber fabrics and carbon fiber reinforced plastics (CFRP). The surface of each carbon fiber is considered as multiple layers of concentric cylinders of graphite. With this the optical properties of carbon fibers and their composites can be estimated from the well-known optical properties of graphite.

  9. Research progress on Domestic Carbon Fiber Reinforced Thermoplastic Composite%国内碳纤维增强热塑性复合材料研究进展

    Institute of Scientific and Technical Information of China (English)

    徐秋红; 谭臻; 闫烨; 刘丽慧; 耿志; 李云英

    2014-01-01

    综述了近几年国内碳纤维(CF)增强热塑性复合材料的研究进展,主要概述了CF不同预处理方式、CF含量、制备工艺、试验条件等对CF增强热塑性复合材料力学、摩擦磨损等性能的影响。%The research progresses on domestic carbon fiber (CF) reinforced thermoplastic composites in recent years were summarized. The influences of different pretreatment methods about CF,CF content,preparation technology and test conditions on mechanical,friction and wear properties of the composites were reviewed mainly.

  10. Mechanical Properties of Carbon Fiber Reinforced PP/EVA Composite%碳纤维增强P P/E VA复合材料力学性能研究

    Institute of Scientific and Technical Information of China (English)

    任庆龙; 夏英; 张锋锋; 丛世杰; 张桂霞

    2016-01-01

    The PP/EVA/C composite was prepared by blending the carbon fiber (C) with PP and EVA. The effects of the different amount of carbon fiber, carbon fiber modified by coupling agent,carbon fiber modified by both acid etching and coupling agent on the mechanical properties,water contact angle and the fracture surface microstructure of composites were investigated.The results show that when the amount of carbon fiber is 30 phr,the mechanical of PP/EVA/C composite is better.The reinforcement effect of the carbon fiber modified by both acid etching and coupling agent is better than that of the carbon fiber modified by coupling agent in the PP/EVA composites.Compared with the PP/EVA/C composites containing 30 phr carbon fiber,the tensile strength and flexur-al strength of the PP/EVA/SSiC composites increase respectively by 6.26 MPa and 7.20 MPa,however,the impact strength decreases slightly.%将碳纤维(C)与聚丙烯(PP)、乙烯-乙酸乙烯共聚物(EVA)共混,制备了PP/EVA/C复合材料。研究了碳纤维用量以及偶联剂改性、酸刻蚀并偶联剂改性的碳纤维对PP/EVA 复合材料力学性能、水接触角和断面微观形貌的影响。结果表明:碳纤维添加量为30份时,PP/EVA/C复合材料的力学性能较好;酸刻蚀并偶联剂改性的碳纤维(SSiC)增强效果优于单独偶联剂改性的碳纤维。与添加碳纤维30份的PP/EVA/C复合材料相比,PP/EVA/SSiC 复合材料的拉伸强度、弯曲强度分别提高了6.26,7.20 MPa,但冲击强度略有降低。

  11. Boron nitride converted carbon fiber

    Science.gov (United States)

    Rousseas, Michael; Mickelson, William; Zettl, Alexander K.

    2016-04-05

    This disclosure provides systems, methods, and apparatus related to boron nitride converted carbon fiber. In one aspect, a method may include the operations of providing boron oxide and carbon fiber, heating the boron oxide to melt the boron oxide and heating the carbon fiber, mixing a nitrogen-containing gas with boron oxide vapor from molten boron oxide, and converting at least a portion of the carbon fiber to boron nitride.

  12. ELECTRODEPOSITION OF POLYMERS ON CARBON FIBERS

    Institute of Scientific and Technical Information of China (English)

    HE Jiasong; WU Renjie

    1983-01-01

    Styrene-co-maleic anhydride, vinyl acetate-co-maleic anhydride, methyl methacrylate-co-maleic anhydride copolymers were deposited on the surface of carbon fibers by an electrodeposition technique.The anion-free radical mechanism of this process and the physical adhesion to the surface were preliminarily confirmed. The adhesion at fiber-resin matrix interface in carbon fiber reinforced plastics was improved by the electrodeposited polymer interlayer and the shear failure occurred mainly in the matrix.Interlaminar shear strength of the unidirectional carbon fiber reinforced epoxy composite is increased from about 600 kg/cm2 to 1000 kg/cm2 by electrodeposition of polymers and the strength loss of the composite which has been immersed in boiling water for 100 hrs is decreased.

  13. Heat Treated Carbon Fiber Material Selection Database

    Science.gov (United States)

    Effinger, M.; Patel, B.; Koenig, J.

    2008-01-01

    Carbon fibers are used in a variety high temperature applications and materials. However, one limiting factor in their transition into additional applications is an understanding of their functional properties during component processing and function. The requirements on the fibers are governed by the nature of the materials and the environments in which they will be used. The current carbon fiber vendor literature is geared toward the polymeric composite industry and not the ceramic composite industry. Thus, selection of carbon fibers is difficult, since their properties change as a function of heat treatment, processing or component operational temperature, which ever is greatest. To enable proper decisions to be made, a program was established wherein multiple fibers were selected and heat treated at different temperatures. The fibers were then examined for their physical and mechanical properties which are reported herein.

  14. 化学镀铜短碳纤维-铜-石墨复合材料的性能研究%Properties of Electroless Copper Plating on Short Carbon Fiber-Copper-Graphite Composite

    Institute of Scientific and Technical Information of China (English)

    许少凡; 许少平; 霍金元; 顾斌

    2012-01-01

    The surfaces of short carbon fibers were coated by electroless copper plating method, and the long carbon fibers coated by continuous electroplating copper method were cut short. The carbon fiber-copper-graphite composites with the two kinds of short carbon fibers and the copper-graphite composite without short carbon fibers were prepared by the powder metallurgy method. Their physical and mechanical properties were tested. The dry friction tests of the composites under sliding velocity of 15 m/s and load of 4. 9 N were conducted for 30 h . The results show that such properties of the electroless copper plating on short carbon fiber-copper-graphite composite as electric conductivity, hardness, bending strength and wear resistance are increased much more remarkably than those of the electroplating copper short carbon fiber-copper-graphite and copper-graphite composite without short carbon fiber.%本文采用化学镀铜法对短碳纤维表面进行镀铜,并用电镀法对长碳纤维表面进行连续镀铜后,再切割成镀铜短碳纤维.随后用粉末冶金法制备了含有这两种镀铜短碳纤维的碳纤维-铜-石墨复合材料和不含碳纤维的铜-石墨复合材料,对它们的物理和力学性能进行了测试,并在滑动速度为15 m/s、载荷为4.9N的干摩擦条件下进行了30 h磨损试验,结果表明:化学镀铜短碳纤维-铜-石墨复合材料的导电性、硬度、抗弯强度和耐磨性优于电镀铜短碳纤维-铜-石墨复合材料和不含碳纤维的铜-石墨复合材料.

  15. 碳纤维增强聚甲醛复合材料的制备及性能研究%Study on Preparation and Properties of Carbon Fibers Reinforced Polyoxymethylene Composites

    Institute of Scientific and Technical Information of China (English)

    马小丰; 金旺; 杨大志; 刘莉莉; 李建华

    2014-01-01

    以碳纤维为增强体,用双螺杆挤出机共混制备了碳纤维增强聚甲醛复合材料,研究了碳纤维含量对复合材料的力学性能、热性能、熔体流动性能的影响。结果表明,碳纤维的加入大幅提高了复合材料的力学性能,改善了热稳定性能,但熔体流动速率减小;当碳纤维质量分数为25%时,复合材料的弯曲弹性模量、弯曲强度、拉伸强度、缺口冲击强度、断裂伸长率分别为19.8 GPa,187 MPa,153 MPa,16.2 kJ/m2,0.52%,综合力学性能最佳。%Carbon fibers reinforced polyoxymethylene composites were prepared in twin-screw extruder with carbon fibers as reinforced material. The effects of carbon fibers content on mechanical properties,thermal properties and melt flow properties of the composites were studied. The results show that the mechanical properties and thermal properties of the composites are greatly improved by adding carbon fibers,but melt flow rates are decreased by adding carbon fibers. The comprehensive mechanical properties reach the best when the mass fraction of carbon fibers is 25%,and the flexural modulus,flexural strength,tensile strength, notched impact strength and elongation at break are 19.8 GPa,187 MPa,153 MPa,16.2 kJ/m2 and 0.52%respectively.

  16. All-solid-state lithium secondary batteries using NiS-carbon fiber composite electrodes coated with Li₂S-P₂S₅ solid electrolytes by pulsed laser deposition.

    Science.gov (United States)

    Aso, Keigo; Sakuda, Atsushi; Hayashi, Akitoshi; Tatsumisago, Masahiro

    2013-02-01

    Composite materials including NiS active materials, sulfide-based solid electrolytes (SE), and conductive additives (VGCF: vapor grown carbon fiber) were prepared by coating a highly conductive Li(2)S-P(2)S(5) solid electrolyte onto NiS-VGCF composite using pulsed laser deposition (PLD). From scanning electron microscopy, NiS nanoparticles were on VGCF surface after coating of solid electrolytes using PLD. All-solid-state cells using the SE-coated NiS-VGCF composite and the uncoated NiS-VGCF composite were fabricated, and then the coating effects on the electrochemical performance by forming the SE thin film onto the NiS-VGCF composite were investigated. At a high current density of 3.8 mA cm(-2) (corresponding to ca. 1 C), an all-solid-state cell fabricated using the SE-coated NiS-VGCF composite as a working electrode showed the initial discharge capacity of 300 mA h g(-1), and exhibited better cycle performance than the cell using the uncoated NiS-VGCF composite.

  17. Design and construction of the structure of the DEMONSTRATOR of the CALIFA detector for R3B-FAIR using carbon-fiber composites

    Directory of Open Access Journals (Sweden)

    Casarejos E.

    2014-03-01

    Full Text Available In this paper we describe the DEMONSTRATOR structures and active units (PETALs developed for the detector CALIFA of the experiment R3B - FAIR. The design is based in the CALIFA BARREL mechanical solutions, but adapted to the characteristics of the PETALs, namely in what concerns the load distribution during setup and service. The R&D program defined the materials and procedures for both producing the pieces of carbon fiber (CF composites as well as the mounting of the bundles to make an alveolar structure. The procedures also include a quality control program to ensure the dimensional properties of the CF assemblies. We are also developing the use of tomographic imaging analysis for this quality program, that will be of mayor interest in the construction of the future CALIFA CF-structure.

  18. Polypropylene/Expanded Graphite/Carbon Fiber Thermal Conductive Composite%聚丙烯/膨胀石墨/碳纤维导热复合材料

    Institute of Scientific and Technical Information of China (English)

    徐睿杰; 雷彩红; 杨志广; 廖敦锃; 刘舜莉

    2012-01-01

    The thermal conductivity, mechanical properties and processing property of polypropylene ( PP)/expanded graphite (EG)/carbon fiber(CF) composite were studied. The results showed that the thermal conductivity of the composite with 20 % content of EC was 2 times that of pure PP,but its melt flow rate was decreased. The PE wax at the weight fraction of 1 % could improve the melt flow rate. When the content of carbon fiber was 5 % , the thermal conductivity reached 0.91 W ? M-1K-1 and was five times of pure PP. The melt flow rate was 1.72 g/10 min and the mechanical properties were good.%研究了聚丙烯(PP)/膨胀石墨(EG)/碳纤维(CF)复合材料的导热、力学以及加工性能.研究发现:当膨胀石墨的质量含量达到20%时,热导率是纯聚丙烯的2倍,但熔体流动性能有所下降;添加1%的聚乙烯蜡可以明显改善体系的熔体流动性能;将膨胀石墨与5%的碳纤维杂化使用,热导率达0.91 W·m-1K-1,是纯聚丙烯的5倍,熔体指数达到1.72 g/10 min,同时该复合材料具有较好的力学性能.

  19. Wettability of a Single Carbon Fiber.

    Science.gov (United States)

    Qiu, Si; Fuentes, Carlos A; Zhang, Dongxing; Van Vuure, Aart Willem; Seveno, David

    2016-09-27

    Wettability as determined from contact angle measurements is a suitable parameter for characterizing the physical bonding of a polymer matrix and reinforcing fibers, but it is very challenging to measure the capillary force exerted by a probe liquid on a fiber accurately for very fine fibers such as single carbon fibers. Herein, we propose an innovative method for measuring dynamic contact angles with a tensiometer, considering both the intrinsic variability of the carbon fiber diameter and the extremely small amplitude of the capillary forces, allowing the measurement of reliable dynamic contact angles over a large range of contact line velocities. The analysis of the contact angle dynamics by the molecular-kinetic theory permits us to check the relevancy of the measured contact angles and to obtain the static contact angle value, improving the prospect of employing tensiometry to better understand the wetting behavior of carbon fibers.

  20. Microstructure of carbon fiber preform and distribution of pyrolytic carbon by chemical vapor infiltration

    Institute of Scientific and Technical Information of China (English)

    陈建勋; 黄伯云

    2004-01-01

    The carbon/carbon composites were made by chemical vapor infiltration(CVI) with needled felt preform. The distribution of the pyrolytic carbon in the carbon fiber preform was studied by polarized light microscope(PLM) and scanning electronic microscope(SEM). The experimental results indicate that the amount of pyrolytic carbon deposited on the surface of chopped carbon fiber is more than that on the surface of long carbon fiber. The reason is the different porosity between the layer of chopped carbon fiber and long carbon fiber. The carbon precursor gas which passes through the part of chopped carbon fibers decomposes and deposits on the surface of chopped carbon fiber. The pyrolytic carbon on the surface of long carbon fibers is produced by the carbon precursor gas diffusing from the chopped fiber and the Z-d fiber. Uniform pore distribution and porosity in preform are necessary for producing C/C composites with high properties.

  1. Quantitative Damage Detection and Sparse Sensor Array Optimization of Carbon Fiber Reinforced Resin Composite Laminates for Wind Turbine Blade Structural Health Monitoring

    Directory of Open Access Journals (Sweden)

    Xiang Li

    2014-04-01

    Full Text Available The active structural health monitoring (SHM approach for the complex composite laminate structures of wind turbine blades (WTBs, addresses the important and complicated problem of signal noise. After illustrating the wind energy industry’s development perspectives and its crucial requirement for SHM, an improved redundant second generation wavelet transform (IRSGWT pre-processing algorithm based on neighboring coefficients is introduced for feeble signal denoising. The method can avoid the drawbacks of conventional wavelet methods that lose information in transforms and the shortcomings of redundant second generation wavelet (RSGWT denoising that can lead to error propagation. For large scale WTB composites, how to minimize the number of sensors while ensuring accuracy is also a key issue. A sparse sensor array optimization of composites for WTB applications is proposed that can reduce the number of transducers that must be used. Compared to a full sixteen transducer array, the optimized eight transducer configuration displays better accuracy in identifying the correct position of simulated damage (mass of load on composite laminates with anisotropic characteristics than a non-optimized array. It can help to guarantee more flexible and qualified monitoring of the areas that more frequently suffer damage. The proposed methods are verified experimentally on specimens of carbon fiber reinforced resin composite laminates.

  2. 碳纤维/氰酸酯复合材料尺寸稳定性能%Stability of Carbon Fiber Reinforced Cyanate Ester Composite

    Institute of Scientific and Technical Information of China (English)

    诸静; 郝旭峰; 叶周军

    2013-01-01

    对碳纤维/氰酸酯复合材料的吸湿、空间放气、吸湿变形性能进行了研究,并与传统碳纤维/环氧复合材料的性能进行对比.研究表明:氰酸酯基复合材料的吸湿性能优于碳纤维/环氧树脂复合材料,且其各项空间环境性能均与环氧树脂基复合材料相当.%In this paper,moisture absorption,outgas capacity in vacuum and deformation after moisture absorption of carbon fiber reinforced cyanate ester composite were studied,and were compared with corresponding capacity of epoxy resin composites.Result show that the moisture absorption of cyanate ester composite is lower than epoxy resin composites,and capacity in simulated space environment is compatible with epoxy resin composites.

  3. Considerable different frequency dependence of dynamic tensile modulus between self-heating (Joule heat) and external heating for polymer--nickel-coated carbon fiber composites.

    Science.gov (United States)

    Zhang, Rong; Bin, Yuezhen; Dong, Enyuan; Matsuo, Masaru

    2014-06-26

    Dynamic tensile moduli of polyethylene--nickel-coated carbon fiber (NiCF) composites with 10 and 4 vol % NiCF contents under electrical field were measured by a homemade instrument in the frequency range of 100--0.01 Hz. The drastic descent of the storage modulus of the composite with 10 vol % was verified in lower frequency range with elevating surface temperature (T(s)) by self-heating (Joule heat). The composite was cut when T(s) was beyond 108 °C. On the other hand, the measurement of the composite with 4 vol % beyond 88 °C was impossible, since T(s) did not elevate because of the disruption of current networks. Incidentally, the dynamic tensile moduli by external heating could be measured up to 130 and 115 °C for 10 and 4 vol %, respectively, but the two composites could be elongated beyond the above temperatures. Such different properties were analyzed in terms of crystal dispersions, electrical treeing, and thermal fluctuation-induced tunneling effect.

  4. Quantitative Damage Detection and Sparse Sensor Array Optimization of Carbon Fiber Reinforced Resin Composite Laminates for Wind Turbine Blade Structural Health Monitoring

    Science.gov (United States)

    Li, Xiang; Yang, Zhibo; Chen, Xuefeng

    2014-01-01

    The active structural health monitoring (SHM) approach for the complex composite laminate structures of wind turbine blades (WTBs), addresses the important and complicated problem of signal noise. After illustrating the wind energy industry's development perspectives and its crucial requirement for SHM, an improved redundant second generation wavelet transform (IRSGWT) pre-processing algorithm based on neighboring coefficients is introduced for feeble signal denoising. The method can avoid the drawbacks of conventional wavelet methods that lose information in transforms and the shortcomings of redundant second generation wavelet (RSGWT) denoising that can lead to error propagation. For large scale WTB composites, how to minimize the number of sensors while ensuring accuracy is also a key issue. A sparse sensor array optimization of composites for WTB applications is proposed that can reduce the number of transducers that must be used. Compared to a full sixteen transducer array, the optimized eight transducer configuration displays better accuracy in identifying the correct position of simulated damage (mass of load) on composite laminates with anisotropic characteristics than a non-optimized array. It can help to guarantee more flexible and qualified monitoring of the areas that more frequently suffer damage. The proposed methods are verified experimentally on specimens of carbon fiber reinforced resin composite laminates. PMID:24763210

  5. Vertically aligned carbon nanotubes/carbon fiber paper composite to support Pt nanoparticles for direct methanol fuel cell application

    Science.gov (United States)

    Zhang, Jing; Yi, Xi-bin; Liu, Shuo; Fan, Hui-Li; Ju, Wei; Wang, Qi-Chun; Ma, Jie

    2017-03-01

    Vertically aligned carbon nanotubes (VACNTs) grown on carbon fiber paper (CFP) by plasma enhanced chemical vapor deposition is introduced as a catalyst support material for direct methanol fuel cells (DMFCs). Well dispersed Pt nanoparticles on VACNTs surface are prepared by impregnation-reduction method. The VACNTs on CFP possess well-maintained alignment, large surface area and good electrical conductivity, which leading to the formation of Pt particles with a smaller size and enhance the Pt utilization rate. The structure and nature of resulting Pt/VACNTs/CFP catalysts for methanol oxidation are investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD) and scanning electron microscope (SEM). With the aid of VACNTs, well-dispersed Pt catalysts enable the reversibly rapid redox kinetic since electron transport efficiently passes through a one-dimensional pathway, which leads to enhance the catalytic activity and Pt utilization rate. Compared with the Pt/XC-72/CFP electrode, the electrochemical measurements results display that the Pt/VACNTs/CFP catalyst shows much higher electrocatalytic activity and better stability for methanol oxidation. In addition, the oxidation current from 200 to 1200 s decayed more slowly for the Pt/VACNTs/CFP than that of the Pt/XC-72/CFP catalysts, indicating less accumulation of adsorbed CO species. All those results imply that the Pt/VACNTs/CFP has a great potential for applications in DMFCs.

  6. Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - FY 2014 First Quarterly Report

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep; Sanborn, Scott E.; Simmons, Kevin L.; Mathur, Raj N.; Sangid, Michael D.; Jin, Xiaoshi; Costa, Franco; Gandhi, Umesh N.; Mori, Steven; Tucker III, Charles L.

    2014-02-19

    The CRADA between PNNL, Autodesk, Toyota and Magna has been effective since October 28th, 2013. The whole team including CRADA and subcontract partners kicked off the project technically on November 1st, 2013. This report describes work performed during the first quarter of FY 2014. The following technical progresses have been made toward project milestones: 1) The project kickoff meeting was organized at PlastiComp, Inc. in Winona on November 13th, 2013 involving all the project partners. During this meeting the research plan and Gantt chart were discussed and refined. The coordination of the research activities among the partners was also discussed to ensure that the deliverables and timeline will be met. 2) Autodesk delivered a research version of ASMI to PNNL for process modeling using this tool under the project. PNNL installed this research version on a PNNL computer and tested it. Currently, PNNL is using ASMI to prepare the models for PlastiComp plaques. 3) PlastiComp has compounded long carbon-fiber reinforced polypropylene and polyamide 6,6 compounds for rheological and thermal characterization tests by the Autodesk laboratories in Melbourne, Australia. 4) Initial mold flow analysis was carried out by PlastiComp to confirm that the 3D complex part selected by Toyota as a representative automotive part is moldable. 5) Toyota, Magna, PlastiComp and PNNL finalized the planning for molding the Toyota 3D complex part. 6) Purdue University worked with PNNL to update and specify the test matrix for characterization of fiber length/orientation. 7) Purdue University developed tools to automate the data collection and analysis of fiber length and orientation measurements. 8) Purdue University designed and specified equipment to replace the need for equipment using the technology established by the University of Leeds at General Motors.

  7. Tribological Behaviors of Carbon Fiber Reinforced Ekonol Composites%碳纤维填充聚苯酯基复合材料摩擦学性能

    Institute of Scientific and Technical Information of China (English)

    吴振宇; 冯丽; 赵峰

    2013-01-01

    According to the load characteristics of ship stern shaft sealing friction pairs,a new type of self-lubricating material of carbon fiber filled ekonol-based composites was prepared,its tribological behaviors were investigated in the friction and wear testing machine under dry sliding,water lubrication and seawater lubrication,and the tribological mechanism was discussed. The results show that under dry sliding,the friction coefficient and wear mass loss are large for composites,and they are obviously decreased under water lubrication and seawater lubrication. Under seawater lubrication, the friction coefficient and wear mass loss are the lowest,therefore carbon fiber filled ekonol-based composites used as sealing ring can meet the requirement of ship stern shaft sealing materials under seawater lubrication. The tribological mechanism of the composites is main fatigue wear and adhesive wear under dry sliding,main adhesive wear under water lubrication,and main adhesive wear and corrosive wear under seawater lubrication.%  针对舰船艉轴密封摩擦副的载荷特点,采用碳纤维填充聚苯酯基复合材料制备出一种新型自润滑复合材料,在摩擦磨损试验机上研究其在干摩擦、水润滑和海水润滑条件下的摩擦磨损性能,并探讨其摩擦磨损机制。结果表明,在干摩擦条件下,复合材料的摩擦因数和磨损量较大,而在水润滑和海水润滑条件下的摩擦因数和磨损量明显下降,其中在海水润滑条件下的摩擦因数最低,磨损量最小,因此该复合材料在海水介质中作为密封环使用,满足舰船艉轴密封材料的使用条件。复合材料在干摩擦条件下磨损机制以疲劳磨损和黏着磨损为主,在水润滑条件下以黏着磨损为主,在海水润滑条件下以黏着磨损和腐蚀磨损为主。

  8. Numerical Simulation of Thermal Conductivity of Carbon-fiber/Resin Composites%炭纤维/树脂复合材料导热性能的数值模拟

    Institute of Scientific and Technical Information of China (English)

    胡妞; 李布楠; 高本征

    2014-01-01

    采用有限元方法对炭纤维/树脂复合材料的导热性能进行了数值模拟,分别建立一维结构和二维结构炭纤维/树脂复合材料计算分析模型,研究炭纤维含量、界面接触热阻、以及炭纤维直径对复合材料有效热导率的影响。研究结果表明炭纤维作为复合材料增强相,其含量越高复合材料的热导率越高;界面的接触热阻在10-3~10-5(m2 K)/W范围内对复合材料有效热导率有较大的影响,超出范围之后改变接触热阻对材料热导率的影响可以忽略;接触热阻比较大时,炭纤维的直径对复合材料的热导率有较大的的影响,当接触热阻比较小时,炭纤维的直径对于复合材料热导率的影响非常小。%Thermal conductivity of carbon-fiber/resin composites was simulated by finite element method. Simulation models of one-dimensional structure and two-dimensional structure were respectively built. Effects of carbon fiber content, interface contact resistance and diameter of carbon fiber on effective thermal conductivity of carbon-fiber/resin composite were studied. The results show that thermal conductivity of carbon-fiber /resin composites increases with increasing of carbon fiber volume fraction;the interface contact resistance in the range of 10-3~10-5 m2 K/W has obvious influence on the effective thermal conductivity, while out of range, the influence can be ignored; the diameter of carbon fiber has a remarkable influence on the thermal conductivity when the interface contact resistance is larger, but the influence is very small when the interface contact resistance is lesser.

  9. Machinability of drilling T700/LT-03A carbon fiber reinforced plastic (CFRP) composite laminates using candle stick drill and multi-facet drill

    Science.gov (United States)

    Wang, Cheng-Dong; Qiu, Kun-Xian; Chen, Ming; Cai, Xiao-Jiang

    2015-03-01

    Carbon Fiber Reinforced Plastic (CFRP) composite laminates are widely used in aerospace and aircraft structural components due to their superior properties. However, they are regarded as difficult-to-cut materials because of bad surface quality and low productivity. Drilling is the most common hole making process for CFRP composite laminates and drilling induced delamination damage usually occurs severely at the exit side of drilling holes, which strongly deteriorate holes quality. In this work, the candle stick drill and multi-facet drill are employed to evaluate the machinability of drilling T700/LT-03A CFRP composite laminates in terms of thrust force, delamination, holes diameter and holes surface roughness. S/N ratio is used to characterize the thrust force while an ellipse-shaped delamination model is established to quantitatively analyze the delamination. The best combination of drilling parameters are determined by full consideration of S/N ratios of thrust force and the delamination. The results indicate that candle stick drill will induce the unexpected ellipse-shaped delamination even at its best drilling parameters of spindle speed of 10,000 rpm and feed rate of 0.004 mm/tooth. However, the multi-facet drill cutting at the relative lower feed rate of 0.004 mm/tooth and lower spindle speed of 6000 rpm can effectively prevent the delamination. Comprehensively, holes quality obtained by multi-facet drill is much more superior to those obtained by candle stick drill.

  10. Characteristics of Resistivity-temperature for Carbon Fiber Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The resistance response to temperature change of carbon fiber reinforced cement-based composites (CFRC) is reported, which shows some outstanding phenomena of positive temperature coefficient (PTC) of resistance and negative temperature coefficient (NTC) of resistance during the temperature rising.The influences of carbon fiber, cement-based matrix and thermal cycles on the characteristics of temperature-resistivity for the system were also discussed.Because of the special characteristics for temperature resistivity, carbon fiber cement based composites can be useful in structure with the function of alarm for fire.

  11. Mechanical Properties of Self-Lubricating Carbon Fiber Knitted Fabric Composite Materials%碳纤维针织物自润滑复合材料力学性能研究

    Institute of Scientific and Technical Information of China (English)

    张强; 张鹏; 孙友松; 程永奇

    2015-01-01

    The effects of vacuum treatment and double reinforce by short fiber on the me-chanical properties of carbon fiber plain cloth or carbon fiber knitting fabric composite materials were studied.The results show that their compression strength increase by 8.86% and 8.08%and the impact strength increase by 15.55% and 9.43% through vacuum treatment respective-ly.Double reinforce by short fiber has significant influence on the compressive strength and pro-mote the compressive strength of carbon fiber plain cloth and carbon fiber knitting fabric by 9. 91% and 22.52%respectively,but the impact strength decreases slightly.%研究了真空处理和短切纤维二次增强对碳纤维平纹布和碳纤维针织物复合材料力学性能的影响。结果表明:真空处理前后其压缩强度分别提高了8.86%和8.08%,冲击强度则分别提高了15.55%和9.43%;短切纤维二次增强效果明显,压缩强度分别提高了9.91%和22.52%,但冲击强度略有下降。

  12. Multimetallic Electrodeposition on Carbon Fibers

    Science.gov (United States)

    Böttger-Hiller, F.; Kleiber, J.; Böttger, T.; Lampke, T.

    2016-03-01

    Efficient lightweight design requires intelligent materials that meet versatile functions. One approach is to extend the range of properties of carbon fiber reinforced plastics (CFRP) by plating the fiber component. Electroplating leads to metalized layers on carbon fibers. Herein only cyanide-free electrolytes where used. Until now dendrite-free layers were only obtained using current densities below 1.0 A dm-2. In this work, dendrite-free tin and copper coatings were achieved by pre-metalizing the carbon fiber substrates. Furthermore, applying a combination of two metals with different sized thermal expansion coefficient lead to a bimetallic coating on carbon fiber rovings, which show an actuatory effect.

  13. 碳纤维加固钢-混凝土组合梁承载力极限状态计算%Analysis of Ultimate Load-carrying Capacity of Strengthening Steel-concrete Composite Beam Using Carbon Fiber

    Institute of Scientific and Technical Information of China (English)

    荣学亮; 黄侨

    2011-01-01

    Carbon fiber is a kind of optimal materials for bridge maintenance and reinforcement. Design method of strengthening steel-concrete composite bridges using carbon fiber was studied. Characteristic of bridge reinforce-ment under load and phasing of stress features were considered, and calculation method of ultimate limit state was suitable for existing bridge design code . Ultimate strain of carbon fiber in ultimate limit state is firstly established based on plane-section assumption and strain-lag of carbon fiber. Then computational scheme and calculation meth-od of flexural capacity in positive moment area and negative moment area for strengthening steel-concrete composite beam using carbon fiber are established respectively, which is reference for design of bridge strengthening.%碳纤维复合材料是进行桥梁维修和加固的理想材料.对采用碳纤维复合材料加固钢-混凝土组合梁桥的设计方法进行了分析.考虑桥梁结构带载加固分阶段受力的特点,与现行桥梁设计规范中承载能力极限状态计算方法相适应.首先基于平截面假设和碳纤维应变滞后的特点,确定承载能力极限状态下碳纤维片材的极限应变值.然后分别建立了碳纤维片材加固钢-混凝土组合梁在正弯矩区和负弯矩区抗弯承载力的计算图式和计算方法,可供桥梁加固工程设计参考.

  14. Hybrid Composite Ni(OH)(2)@NiCo2O4 Grown on Carbon Fiber Paper for High-Performance Supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Huang, L; Chen, DC; Ding, Y; Wang, ZL; Zeng, ZZ; Liu, ML

    2013-11-13

    We have successfully fabricated and tested the electrochemical performance of supercapacitor electrodes consisting of Ni(OH)(2) nanosheets coated on NiCo2O4 nanosheets grown on carbon fiber paper (CFP) current collectors. When the NiCo2O4 nanosheets are replaced by Co3O4 nanosheets, however, the energy and power density as well as the rate capability of the electrodes are significantly reduced, most likely due to the lower conductivity of Co3O4 than that of NiCo2O4. The 3D hybrid composite Ni(OH)(2)/ NiCo2O4/CFP electrodes demonstrate a high areal capacitance of 5.2 F/cm(2) at a cycling current density of 2 rnA/cm(2), with a capacitance retention of 79% as the cycling current density was increased from 2 to 50 mA/cm(2). The remarkable performance of these hybrid composite electrodes implies that supercapacitors based on them have potential for many practical applications.

  15. Hybrid composite Ni(OH)2@NiCo2O4 grown on carbon fiber paper for high-performance supercapacitors.

    Science.gov (United States)

    Huang, Liang; Chen, Dongchang; Ding, Yong; Wang, Zhong Lin; Zeng, Zhengzhi; Liu, Meilin

    2013-11-13

    We have successfully fabricated and tested the electrochemical performance of supercapacitor electrodes consisting of Ni(OH)2 nanosheets coated on NiCo2O4 nanosheets grown on carbon fiber paper (CFP) current collectors. When the NiCo2O4 nanosheets are replaced by Co3O4 nanosheets, however, the energy and power density as well as the rate capability of the electrodes are significantly reduced, most likely due to the lower conductivity of Co3O4 than that of NiCo2O4. The 3D hybrid composite Ni(OH)2/NiCo2O4/CFP electrodes demonstrate a high areal capacitance of 5.2 F/cm(2) at a cycling current density of 2 mA/cm(2), with a capacitance retention of 79% as the cycling current density was increased from 2 to 50 mA/cm(2). The remarkable performance of these hybrid composite electrodes implies that supercapacitors based on them have potential for many practical applications.

  16. Flexural strengthening of reinforced concrete beams with carbon fibers reinforced polymer (CFRP sheet bonded to a transition layer of high performance cement-based composite

    Directory of Open Access Journals (Sweden)

    V. J. Ferrari

    Full Text Available Resistance to corrosion, high tensile strength, low weight, easiness and rapidity of application, are characteristics that have contributed to the spread of the strengthening technique characterized by bonding of carbon fibers reinforced polymer (CFRP. This research aimed to develop an innovate strengthening method for RC beams, based on a high performance cement-based composite of steel fibers (macro + microfibers to be applied as a transition layer. The purpose of this transition layer is better control the cracking of concrete and detain or even avoid premature debonding of strengthening. A preliminary study in short beams molded with steel fibers and strengthened with CFRP sheet, was carried out where was verified that the conception of the transition layer is valid. Tests were developed to get a cement-based composite with adequate characteristics to constitute the layer transition. Results showed the possibility to develop a high performance material with a pseudo strain-hardening behavior, high strength and fracture toughness. The application of the strengthening on the transition layer surface had significantly to improve the performance levels of the strengthened beam. It summary, it was proven the efficiency of the new strengthening technique, and much information can be used as criteria of projects for repaired and strengthened structures.

  17. Current Situation of the Carbon Fiber and Related Composites Industry%碳纤维及复合材料产业链现状分析

    Institute of Scientific and Technical Information of China (English)

    张传雄

    2015-01-01

    By discussing the spinning, pre-oxidation, carbonization, compounding and recycling technologies for making carbon ifber and related composites, the paper discussed the present situation of technological development in the field of carbon fiber and related composites; analyzed the market situation of such products and their application prospects in aerospace, national defense, wind turbine, sport and leisure, transportation vehicles, civil-engineering, etc. It also pointed out some problems existing in China’s carbon ifber industry and gave related solutions.%从碳纤维纺丝、预氧化、碳化、复合成型和回收利用等方面概述碳纤维及复合材料产业链技术现状,分析碳纤维及复合材料市场现状以及在国防航空、交通工具、风力发电、运动休闲、土木建筑等领域的应用前景,指出中国碳纤维产业发展存在的问题及建议。

  18. Φ10mm 碳纤维复合材料管成型工艺及性能研究%Forming Process and Properties of Φ10 mm Carbon Fiber Reinforced Composite Pipe

    Institute of Scientific and Technical Information of China (English)

    赵锐霞; 尹亮; 潘玲英; 董波

    2012-01-01

    The forming process and properties of carbon fiber reinforced composite pipe with the diameter of 10mm were investigated. The results show that the carbon fiber reinforced composite pipe fabricated by the thermal shrinkage process has the advantages of simple forming process and better quality reliability. Compared to the stainless steel pipe with the diamemer of 10 mm, the carbon fiber reinforced composite pipe with the same diameter has the e-quivalent flexural stiffness. While the flexural strength of composite pipe is more than three times of the stainless steel with the same diameter, and its weight is only half of the stainless steel pipe. In addition, the composite has good dimension precision which can meet the design requirements.%对外径为Φ10 mm 碳纤维复合材料管成型工艺及性能进行了研究.结果表明,采用热缩工艺成型的碳纤维复合材料管工艺简单、质量可靠,Φ10 mm 碳纤维复合材料管件弯曲刚度与不锈钢管相当,弯曲强度为不锈钢的3倍以上,质量仅为不锈钢的50%,尺寸精度满足设计要求.

  19. Fabrication of nano-Fe3O4 3D structure on carbon fibers as a microwave absorber and EMI shielding composite by modified EPD method

    Science.gov (United States)

    Gholampoor, Mahdi; Movassagh-Alanagh, Farid; Salimkhani, Hamed

    2017-02-01

    Recently, electromagnetic interference (EMI) shielding materials have absorbed a lot of attention due to a growing need for application in the area of electronic and wireless devices. In this study, a carbon-based EMI shielding composite was fabricated by electrophoretic deposition of Fe3O4 nano-particles on carbon fibers (CFs) as a 3D structure incorporated with an epoxy resin. Co-precipitation method was employed to synthesize Fe3O4 nano-particles. This as-synthesized Fe3O4 nano-powder was then successfully deposited on CFs using a modified multi-step electrophoretic deposition (EPD) method. The results of structural studies showed that the Fe3O4 nano-particles (25 nm) were successfully and uniformly deposited on CFs. The measured magnetic properties of as-synthesized Fe3O4 nano-powder and nano-Fe3O4/CFs composite showed that the saturation magnetization of bare Fe3O4 was decreased from Ms = 72.3 emu/g to Ms = 33.1 emu/g for nano-Fe3O4/CFs composite and also corecivity of Fe3O4 was increased from Hc = 4.9 Oe to Hc = 168 Oe for composite. The results of microwave absorption tests revealed that the reflection loss (RL) of an epoxy-based nano-Fe3O4/CFs composite are significantly influenced by layer thickness. The maximum RL value of -10.21 dB at 10.12 GHz with an effective absorption bandwidth about 2 GHz was obtained for the sample with the thickness of 2 mm. It also exhibited an EMI shielding performance of -23 dB for whole the frequency range of 8.2-12.4 GHz.

  20. Characterization of electrospun lignin based carbon fibers

    Science.gov (United States)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri

    2015-05-01

    The production of lignin fibers has been studied in order to replace the need for petroleum based precursors for carbon fiber production. In addition to its positive environmental effects, it also benefits the economics of the industries which cannot take advantage of carbon fiber properties because of their high price. A large amount of lignin is annually produced as the byproduct of paper and growing cellulosic ethanol industry. Therefore, finding high value applications for this low cost, highly available material is getting more attention. Lignin is a biopolymer making about 15 - 30 % of the plant cell walls and has a high carbon yield upon carbonization. However, its processing is challenging due to its low molecular weight and also variations based on its origin and the method of separation from cellulose. In this study, alkali solutions of organosolv lignin with less than 1 wt/v% of poly (ethylene oxide) and two types of lignin (hardwood and softwood) were electrospun followed by carbonization. Different heating programs for carbonization were tested. The carbonized fibers had a smooth surface with an average diameter of less than 5 µm and the diameter could be controlled by the carbonization process and lignin type. Scanning electron microscopy (SEM) was used to study morphology of the fibers before and after carbonization. Thermal conductivity of a sample with amorphous carbon was 2.31 W/m.K. The electrospun lignin carbon fibers potentially have a large range of application such as in energy storage devices and water or gas purification systems.

  1. Research Progress on Thermal Conductivity of Carbon Fiber Reinforced Polymer Matrix Composites%导热型碳纤维增强聚合物基复合材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    李仕通; 彭超义; 邢素丽; 肖加余

    2012-01-01

    The present state and development of thermal conductivity of carbon fiber reinforced polymer matrix composites (CFRP) are reviewed. Phonon and photon thermal conduction mechanism of CFRP are described. The computing models and testing methods for the thermal conductivity of CFRP, prepared by different ply angles and different packing fractions, are illustrated. The effects of the resin systems (including epoxy resin, cyanate ester, bisma-leimide resin), carbon fibers (including PAN carbon fibers, mesophase pitch carbon fibers, vapor grown carbon fibers, carbon nanotube fibers), processing technologies etc. on the thermal conductivity of CFRP are also analyzed.%综述了导热型连续碳纤维增强聚合物基复合材料(CFRP)的研究与应用现状和进展,阐述了CFRP的声子导热和光子导热机理,介绍了不同铺层角度和铺层比的CFRP面内和厚度方向热导率计算模型及测试方法,分析了环氧树脂、氰酸酯、双马来酰亚胺等3类树脂体系和聚丙烯腈基(PAN)碳纤维、中间相沥青基碳纤维、气相生长碳纤维、碳纳米管纤维等4类增强体以及工艺方法等因素对CFRP热导率的影响.

  2. Predictive Engineering Tools for Injection-Molded Long-Carbon-Fiber Thermoplastic Composites - Second FY 2015 Quarterly Report

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kijewski, Seth A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sangid, Michael D. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Wang, Jin [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Costa, Franco [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Tucker, III, Charles L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mathur, Raj N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gandhi, Umesh N. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mori, Steven [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-05-19

    During the second quarter of FY 2015, the following technical progress has been made toward project milestones: 1) Autodesk reviewed 3D fiber orientation distribution (FOD) comparisons and provided support on improving accuracy. 2) Autodesk reviewed fiber length distribution (FLD) data comparisons and provided suggestions, assisted PNNL in FOD and FLD parameter settings optimization, and advised PNNL on appropriate through thickness thermal conductivity for improved frozen layer effect on FOD predictions. Autodesk also participated in project review meetings including preparations and discussions towards passing the go/no-go decision point. 3) Autodesk implemented an improved FOD inlet profile specification method through the part thickness for 3D meshes and provided an updated ASMI research version to PNNL. 4) The University of Illinois (Prof. C.L. Tucker) provided Autodesk with ideas to improve fiber orientation modeling 5) Purdue University re-measured fiber orientation for the fast-fill 50wt% LCF/PA66 edge-gated plaque, and delivered the fiber orientation data for this plaque at the selected locations (named A, B, and C, Figure 1) to PNNL. Purdue also re-measured fiber orientation for locations A on the fast-fill 30wt% LCF/PP and 50wt% LCF/PA66 center-gated plaques, which exhibited anomalous fiber orientation behavior. 6) Purdue University conducted fiber length measurements and delivered the length data to PNNL for the purge materials (slow-fill 30wt% LCF/PP and 30wt% LCF/PA66 purge materials) and PlastiComp plaques selected on the go/no-go list for fiber length model validation (i.e., slow-fill edge-gated 30wt% LCF/PP and 30wt% LCF/PA66 plaques, Locations A, B, and C). 7) PNNL developed a method to recover intact carbon fibers from LCF/PA66 materials. Isolated fibers were shipped to Purdue for length distribution analysis. 8) PNNL completed ASMI mid-plane analyses for all the PlastiComp plaques defined on the go/no-go list for fiber orientation (FO) model

  3. Study on Preparation and Fatigue Property of Short Carbon Fiber Reinforced Thermoplastics Composites%短碳纤维增强热塑性树脂复合材料的制备及其疲劳性能研究

    Institute of Scientific and Technical Information of China (English)

    盛永华; 李力

    2012-01-01

    Thermoplastic composites of polyethylene and chopped carbon fiber were prepared via injection molding. The influence of carbon fiber content on the fatigue property of the composites was studied, and the fracture mechanism of the composites was analyzed. The lifespan of the composites was prolonged with increasing content of carbon fiber.%采用注射成型的方法,以短切碳纤维为增强体,聚乙烯为基体制备了碳纤维增强热塑性树脂复合材料,并研究了碳纤维含量对该复合材料疲劳:I生能的影响,分析了短碳纤维增强热塑性树脂复合材料的断裂机理。结果表明,短碳纤维增强热塑性树脂复合材料的疲劳寿命随着碳纤维含量的增加而延长。

  4. Effect of surface roughness on osteogenesis in vitro and osseointegration in vivo of carbon fiber-reinforced polyetheretherketone-nanohydroxyapatite composite.

    Science.gov (United States)

    Deng, Yi; Liu, Xiaochen; Xu, Anxiu; Wang, Lixin; Luo, Zuyuan; Zheng, Yunfei; Deng, Feng; Wei, Jie; Tang, Zhihui; Wei, Shicheng

    2015-01-01

    As United States Food and Drug Administration-approved implantable material, carbon fiber-reinforced polyetheretherketone (CFRPEEK) possesses an adjustable elastic modulus similar to cortical bone and is a prime candidate to replace surgical metallic implants. The bioinertness and inferior osteogenic properties of CFRPEEK, however, limit its clinical application as orthopedic/dental implants. In this study, CFRPEEK-nanohydroxyapatite ternary composites (PEEK/n-HA/CF) with variable surface roughness have been successfully fabricated. The effect of surface roughness on their in vitro cellular responses of osteoblast-like MG-63 cells (attachment, proliferation, apoptosis, and differentiation) and in vivo osseointegration is evaluated. The results show that the hydrophilicity and the amount of Ca ions on the surface are significantly improved as the surface roughness of composite increases. In cell culture tests, the results reveal that the cell proliferation rate and the extent of osteogenic differentiation of cells are a function of the size of surface roughness. The composite with moderate surface roughness significantly increases cell attachment/proliferation and promotes the production of alkaline phosphatase (ALP) activity and calcium nodule formation compared with the other groups. More importantly, the PEEK/n-HA/CF implant with appropriate surface roughness exhibits remarkably enhanced bioactivity and osseointegration in vivo in the animal experiment. These findings will provide critical guidance for the design of CFRPEEK-based implants with optimal roughness to regulate cellular behaviors, and to enhance biocompability and osseointegration. Meanwhile, the PEEK/n-HA/CF ternary composite with optimal surface roughness might hold great potential as bioactive biomaterial for bone grafting and tissue engineering applications.

  5. Preparation and properties of graphene oxide-carbon fiber/phenolic resin composites%石墨烯/酚醛树脂/炭纤维层次复合材料的制备及其性能

    Institute of Scientific and Technical Information of China (English)

    刘燕珍; 李永锋; 杨永岗; 温月芳; 王茂章

    2012-01-01

    Graphene oxide-carbon fiber/phenolic resin, chemically-reduced graphene oxide-carbon fiber/phenolic resin, and thermally-reduced graphene oxide-carbon fiber/phenolic resin composites were prepared by blending a graphene oxide suspension in an ethanol solution of phenolic resin with carbon fibers, followed by vacuum drying and hot pressing. The effects of the type of graphene oxide on structure, compressive performance and friction properties of the composites were investigated. Results showed that the compressive properties of the composites were greatly improved with a 0. 1 mass graphene oxide % loading compared with the pure carbon fiber/phenolic resin composite. The compressive strength and modulus of the thermally-reduced graphene oxide/phenolic resin/carbon fiber composites were increased by 178.9% , 129.5% , respectively, and the highest energy storage modulus of the chemically-reduced graphene oxide/phenolic resin/carbon fiber composite was increased by 75. 2% compared with the pure carbon fiber/phenolic resin composite. The glass transition temperatures of all the composites containing graphene oxide decreased.%分别以氧化石墨粉(GO)、还原氧化石墨烯乙醇悬浮液(RGO)和热法还原石墨烯粉(TRG)为填料,分散于酚醛树脂(PR)的乙醇溶液中,再将这些基体混合物涂覆于炭纤维(CF)布上,经热压成型工艺制备氧化石墨烯/酚醛树脂/炭纤维、还原氧化石墨烯乙醇悬浮液/酚醛树脂/炭纤维、热法还原氧化石墨烯/酚醛树脂/炭纤维层次复合材料.研究了GO、RGO和TRG对复合材料结构、压缩性能、弯曲性能及磨擦性能的影响.结果表明,与纯酚醛树脂/炭纤维复合材料相比,当纳米填料的质量分数仅为0.1%时,层次复合材料的压缩性能可显著提高,其中,热法还原氧化石墨烯/酚醛树脂/炭纤维的压缩强度和模量分别提高了178.9%,129.5%;弯曲性能也可得到一定的改善.还原氧化石墨烯乙醇悬浮液/

  6. An Experimental Study on Non-Compression X-Bracing Systems Using Carbon Fiber Composite Cable for Seismic Strengthening of RC Buildings

    Directory of Open Access Journals (Sweden)

    Kang Seok Lee

    2015-09-01

    Full Text Available Cross-bracing (X-bracing is one of the most popular methods of seismic retrofitting, and has been shown to significantly increase the structural stiffness and strength of buildings. Conventional steel X-bracing methods typically exhibit brittle failure at the connection between the brace and the building, or buckling failure of the braces. This study investigated the structural properties of a new type of non-compression X-bracing system using carbon fiber composite cable (CFCC. This non-compression X-bracing system uses CFCC bracing and bolt connections between structural members and the terminal fixer of the CFCC, instead of conventional steel bracing. The aim is to overcome the brittle and buckling failures that can occur at the connection and bracings with conventional steel X-bracing methods. We carried out cyclic loading tests, and the maximum load carrying capacity and deformation were investigated, as well as hysteresis in the lateral load–drift relations. The test results revealed that the CFCC X-bracing system installed in reinforced concrete frames enhanced the strength markedly, and buckling failure of the bracing was not observed.

  7. Core-shell N-doped active carbon fiber@graphene composites for aqueous symmetric supercapacitors with high-energy and high-power density

    Science.gov (United States)

    Xie, Qinxing; Bao, Rongrong; Xie, Chao; Zheng, Anran; Wu, Shihua; Zhang, Yufeng; Zhang, Renwei; Zhao, Peng

    2016-06-01

    Graphene wrapped nitrogen-doped active carbon fibers (ACF@GR) of a core-shell structure were successfully prepared by a simple dip-coating method using natural silk as template. Compared to pure silk active carbon, the as-prepared ACF@GR composites exhibit high specific surface area in a range of 1628-2035 m2 g-1, as well as superior energy storage capability, an extremely high single-electrode capacitance of 552.8 F g-1 was achieved at a current density of 0.1 A g-1 in 6 M KOH aqueous electrolyte. The assembled aqueous symmetric supercapacitors are capable of deliver both high energy density and high power density, for instance, 17.1 Wh kg-1 at a power density of 50.0 W kg-1, and 12.2 Wh kg-1 at 4.7 kW kg-1 with a retention rate of 71.3% for ACF@GR1-based supercapacitor.

  8. 碳纤维表面改性对C_f/Mg复合材料微观组织和界面的影响%Effect of Carbon Fiber Surface Modification on nicrostructure and Interface of Cf/Mg Composites

    Institute of Scientific and Technical Information of China (English)

    黄元飞; 刘越; 王全兆; 孙毅

    2009-01-01

    研究在碳纤维表面分别用化学法镀Ni和溶胶-凝胶法涂SiO_2两种涂层,用真空压力浸渗法制备C_f/Mg复合材料.用SEM、EDS和TEM对C_f/Mg复合材料微观组织和界面特征进行分析.结果表明:无涂层的碳纤维与Mg基体浸润性较差,碳纤维在C_f/Mg复合材料微观组织巾分布不均匀,界面结合强度较弱.碳纤维表面包覆Ni或SiO_2涂层改善了碳纤维与Mg基体的润湿性;包覆Ni涂层的碳纤维在Mg基体中分布均匀,并在其界面处生成金属间化合物Mg_2Ni,界面为强结合;碳纤维表面的SiO_2涂层与Mg进行少量的反应生成MgO和Si,界面结合好.能很好地传递载荷.%C_f/Mg composites with three kinds of carbon fiber (without coating, coated with Ni or SiO_2) were fabricated by vacuum pressing method. The microstructure and fracture surface were characterized by SEM, EDS and TEM. The results show that the wettability between carbon fiber without coatings and Mg was low. And the wettability is enhanced by coating the carbon fiber with Ni or SiO_2. The Ni coating reacting with Mg obtains Mg_2Ni. The flat fracture of the Mg matrix composite reinforced by carbon fiber with Ni coating shows that the combination of the carbon fiber with Mg matrix is very strong. The fracture surface of the Mg matrix composite reinforced by carbon fiber with SiO_2 coating shows that the combination of the interface is optimum.

  9. Distribution of Triangle-shape Carbon Fibers in Composite Materials%三角形截面碳纤维在复合材料中的分布规律

    Institute of Scientific and Technical Information of China (English)

    刘新; 武湛君; 王荣国; 刘文博; 严佳

    2013-01-01

    三角形截面碳纤维在复合材料内部的排布结构像微波暗室一样,能够对入射的电磁波进行多次反射,从而衰减电磁波,使三角形截面碳纤维复合材料具有吸波性能,因此,研究三角形截面碳纤维在复合材料中的排布规律对研究其吸波机理非常重要.采用实验和模拟的方法对三角形截面碳纤维在复合材料中的排布规律进行了分析.首先,通过扫描电子显微镜(SEM)观察了多组三角形截面碳纤维复合材料试样的截面微观形貌,分析了三角形碳纤维在复合材料中的排布角度及均匀性;其次,为进一步研究三角形截面碳纤维复合材料的吸波机理,根据蒙特卡洛原理,通过Matlab软件对三角形截面碳纤维在复合材料中的排布情况进行了模拟.实验及数值模拟结果吻合较好,均表明三角形截面碳纤维在复合材料中的排布是以各种排布角度随机排布的,而三角形碳纤维分布是比较均匀的,没有明显的密布区域和稀疏区域,该模拟方法可以用于模拟不同含量的三角形截面碳纤维在复合材料中的排布规律.%The triangle cross-section carbon fiber reinforced plastics could be used as absorbing composite materials, in which the incident microwave can be reflected many times to be greatly attenuated. The microwave absorbing property is affected significantly by the distribution of the triangle cross-section carbon fibers in the composite materials. In this study, the distribution of the triangle cross-section carbon fibers in the triangle cross -section carbon fiber reinforced plastics is investigated by experimental and theoretical simulations. In order to study the angle arrangement and the homogeneity of the carbon fibers in the composite materials, the cross -section morphology of the samples is observed by the SEM. And a process based on the Monte Carlo Method is established to simulate the distribution of the triangle cross-section carbon

  10. INFLUENCE OF CARBON FIBER SURFACE TREATMENT ON MECHANICAL PROPERTIES OF CF/PMR-15 COMPOSITES%炭纤维表面处理对CF/PMR-15复合材料力学性能的影响

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    研究了炭纤维表面不同处理方法对复合材料力学性能的影响。采用等离子体和等离子体接枝技术对炭纤维表面进行处理后,CF/PMR-15复合材料的界面剪切强度与层间剪切强度均有所提高,随着界面状态的改善,界面剪切强度提高的幅度比层间剪切强度提高的大。本文为指导炭纤维的表面处理、评价处理效果,进一步预报复合材料的宏观性能打下了基础。%The influence of carbon fiber surface treatment on the mechanical Properties of CF/PMR-15 composites is dicussed.After carbon fiber Surface was treated with plasma and plasma grafting technique,the interfacial shear strength(IFSS)and interlaminar shear strength(ILSS)of CF/PMR-15 composites are all increased.With improvement of interface properties,there is a bigger increase in IFSS than in ILSS.This has laid foundations for directing carbon fiber surface treatment ,evaluating treatment effect and predicting general properties of composites.

  11. 表面处理对碳纤维复合材料导电性的影响%Influence of Surface Treatments on Conductive Properties of Carbon Fiber/Epoxy Resin Composites

    Institute of Scientific and Technical Information of China (English)

    陈红燕; 黄华波

    2014-01-01

    In order to improve the stability of electrical properties of carbon fiber /epoxy resin composites .The resistance-temperature property of carbon fiber/epoxy resin composites was investigated using carbon fiber ( CF ) mat treated with titanate coupling agent as conductive fillers .The result showed that as the CF fraction increased , the stability of dectrical resistance of composites was enhanced under temperature variation .In addition of the electric resistivity of composities was remarkly enhanced and temperature-dependent fluctuation of resistance value was langely decreased after the surface treatment of CF .%为提高碳纤维/环氧树脂复合材料电性能的稳定性,采用钛酸酯偶联剂对碳纤维表面进行了处理,研究了以短切碳纤维毡为导电填料、环氧树脂为基体的导电复合材料的电阻-温度特性。结果表明:随碳纤维含量的增高,复合材料的电阻在温度变化下的稳定性增强;碳纤维经表面处理后,其复合材料的电阻率显著降低,且电阻值随温度的波动性也大幅下降。

  12. Lightning Strike Ablation Damage Influence Factors Analysis of Carbon Fiber/Epoxy Composite Based on Coupled Electrical-Thermal Simulation

    Science.gov (United States)

    Yin, J. J.; Chang, F.; Li, S. L.; Yao, X. L.; Sun, J. R.; Xiao, Y.

    2016-12-01

    According to the mathematical analysis model constructed on the basis of energy-balance relationship in lightning strike, and accompany with the simplified calculation strategy of composite resin pyrolysis degree dependent electrical conductivity, an effective three dimensional thermal-electrical coupling analysis finite element model of composite laminate suffered from lightning current was established based on ABAQUS, to elucidate the effects of lighting current waveform parameters and thermal/electrical properties of composite laminate on the extent of ablation damage. Simulated predictions agree well with the composite lightning strike directed effect experimental data, illustrating the potential accuracy of the constructed model. The analytical results revealed that extent of composite lightning strike ablation damage can be characterized by action integral validly, there exist remarkable power function relationships between action integral and visual damage area, projected damage area, maximum damage depth and damage volume of ablation damage, and enhancing the electrical conductivity and specific heat of composite, ablation damage will be descended obviously, power function relationships also exist between electrical conductivity, specific heat and ablation damage, however, the impact of thermal conductivity on the extent of ablation damage is not notable. The conclusions obtained provide some guidance for composite anti-lightning strike structure-function integration design.

  13. Surface State of Carbon Fibers Modified by Electrochemical Oxidation

    Institute of Scientific and Technical Information of China (English)

    Yunxia GUO; Jie LIU; Jieying LIANG

    2005-01-01

    Surface of polyacrylonitrile (PAN)-based carbon fibers was modified by electrochemical oxidation. The modification effect on carbon fibers surface was explored using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Results showed that on the modified surface of carbon fibers, the carbon contents decreased by 9.7% and the oxygen and nitrogen contents increased by 53.8% and 7.5 times, respectively. The surface roughness and the hydroxyl and carbonyl contents also increased. The surface orientation index was reduced by 1.5%which decreased tensile strength of carbon fibers by 8.1%, and the microcrystalline dimension also decreased which increased the active sites of carbon fiber surface by 78%. The physical and chemical properties of carbon fibers surface were modified through the electrochemical oxidative method, which improved the cohesiveness between the fibers and resin matrix and increased the interlaminar shear strength (ILSS) of carbon fibers reinforced epoxy composite (CFRP) over 20%.

  14. Dry Process for Manufacturing Hybridized Boron Fiber/Carbon Fiber Thermoplastic Composite Materials from a Solution Coated Precursor

    Science.gov (United States)

    Belvin, Harry L. (Inventor); Cano, Roberto J. (Inventor)

    2003-01-01

    An apparatus for producing a hybrid boron reinforced polymer matrix composite from precursor tape and a linear array of boron fibers. The boron fibers are applied onto the precursor tapes and the precursor tape processed within a processing component having an impregnation bar assembly. After passing through variable-dimension forming nip-rollers, the precursor tape with the boron fibers becomes a hybrid boron reinforced polymer matrix composite. A driving mechanism is used to pulled the precursor tape through the method and a take-up spool is used to collect the formed hybrid boron reinforced polymer matrix composite.

  15. [Carbon fiber-reinforced plastics as implant materials].

    Science.gov (United States)

    Bader, R; Steinhauser, E; Rechl, H; Siebels, W; Mittelmeier, W; Gradinger, R

    2003-01-01

    Carbon fiber-reinforced plastics have been used clinically as an implant material for different applications for over 20 years.A review of technical basics of the composite materials (carbon fibers and matrix systems), fields of application,advantages (e.g., postoperative visualization without distortion in computed and magnetic resonance tomography), and disadvantages with use as an implant material is given. The question of the biocompatibility of carbon fiber-reinforced plastics is discussed on the basis of experimental and clinical studies. Selected implant systems made of carbon composite materials for treatments in orthopedic surgery such as joint replacement, tumor surgery, and spinal operations are presented and assessed. Present applications for carbon fiber reinforced plastics are seen in the field of spinal surgery, both as cages for interbody fusion and vertebral body replacement.

  16. The Effect of Externally Retrofitted Carbon Fiber Reinforced Polymer Composites on the Ductility of Reinforced Concrete Beams

    Science.gov (United States)

    2007-11-02

    Reinforcement Ratios 84 8-5 Ductility Indices 86 5 LIST OF FIGURES FIGURE PAGE 2-1 Failure Modes of Concrete Beams 17 2-2 Composite Jacket Installation...20 2-3 Composite Jacket Application 20 2-4 Four Point Bending Configuration 21 3-1 Stress-Strain Relationship for Concrete 27 3-2 Standard Rebar 28 3...researchers around the world, such as reinforcing and prestressing concrete structures, seismic retrofitting of concrete and unreinforced masonry

  17. Integration of Carbon Fiber Composite Materials into Air-Cooled Reciprocating Piston Engines for UA V Applications

    Science.gov (United States)

    2012-05-04

    Composite MMC: …………………...………..Metal Matrix Composite OHC: …………………...………...Overhead Camshaft ...chosen as the test platform because it is inexpensive, air-cooled (similar to UAV engines), and uses an overhead camshaft (OHC) design which...facilitated the design of the crankcase. An OHC design avoids the necessity to align the camshaft as well as. Extending this study to a diesel engine would

  18. External reinforcing of fiber concrete constructions by carbon fiber tapes

    OpenAIRE

    S.V. Klyuyev; Yu.V. Guryanov

    2013-01-01

    Strengthening the concrete and reinforced concrete structures with carbon fiber tapes is very actively applied in Europe nowadays. In Russia composites based on carbon fiber have also widely spread recently. The main advantages of these materials for strengthening structures are its high specific strength (strength-weight ratio) and strength-to-density ratio.Experimental studies on strengthening and restoration of the constructions were held. Flexible fiber concrete constructions based on man...

  19. Evaluation of Nanomaterial Approaches to Damping in Epoxy Resin and Carbon Fiber/Epoxy Composite Structures by Dynamic Mechanical Analysis

    Science.gov (United States)

    Miller, G.; Heimann, Paula J.; Scheiman, Daniel A.; Duffy, Kirsten P.; Johnston, J. Chris; Roberts, Gary D.

    2013-01-01

    Vibration mitigation in composite structures has been demonstrated through widely varying methods which include both active and passive damping. Recently, nanomaterials have been investigated as a viable approach to composite vibration damping due to the large surface available to generate energy dissipation through friction. This work evaluates the influence of dispersed nanoparticles on the damping ratio of an epoxy matrix. Limited benefit was observed through dispersion methods, however nanoparticle application as a coating resulting in up to a three-fold increase in damping.

  20. Thermoplastic coating of carbon fibers

    Science.gov (United States)

    Edie, D. D.; Lickfield, G. C.; Drews, M. J.; Ellison, M. S.; Gantt, B. W.

    1989-01-01

    A process is being developed which evenly coats individual carbon fibers with thermoplastic polymers. In this novel, continuous coating process, the fiber tow bundle is first spread cover a series of convex rollers and then evenly coated with a fine powder of thermoplastic matrix polymer. Next, the fiber is heated internally by passing direct current through the powder coated fiber. The direct current is controlled to allow the carbon fiber temperature to slightly exceed the flow temperature of the matrix polymer. Analysis of the thermoplastic coated carbon fiber tows produced using this continuous process indicates that 30 to 70 vol pct fiber prepregs can be obtained.

  1. Modification of carbon fiber / epoxy matrix interphase in a composite material : Design of a self-healing interphase by introducing thermally reversible Diels-Alder adducts

    OpenAIRE

    2014-01-01

    A thermally self-healable carbon/epoxy interphase was designed based on Diels-Alder (D-A) thermally reversible covalent bonds. The D-A modified interphase was formed between maleimide groups grafted on carbon fiber surface and furan groups introduced into epoxy network. The self-healing ability was characterized by a micromechanical approach using the micro-droplet debonding test. In this work, carbon fiber surface underwent a three-step treatment to graft maleimide groups, including HNO3 oxi...

  2. The effects of eccentricities on the fracture of off-axis fiber composites. [carbon fiber reinforced plastics

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1978-01-01

    Finite element analyses were performed to investigate theoretically the effects of in-plane and out-of-plane eccentricities, bending or twisting, and thickness nonuniformity on the axial stress and strain variations across the width of off-axis specimens. The results are compared with measured data and are also used to assess the effects of these eccentricities on the fracture stress of off-axis fiber composites. Guidelines for detecting and minimizing the presence of eccentricities are described.

  3. Application of microdebond test to evaluation of interfacial properties of carbon fiber/epoxy resin composites%微脱黏法在碳纤维/环氧树脂界面性能评价中的应用

    Institute of Scientific and Technical Information of China (English)

    钱鑫; 王雪飞; 欧阳琴; 陈友汜

    2012-01-01

    The authors determined the interfacial shear strength (IFSS) of carbon fiber reinforced epoxy resin composites with microbond test and analyzed the influential factors that caused the divergence in IFSS values. The results show that the maximum debonding force increases linearly with the embedment length of the carbon fiber in epoxy resin during the debonding course; the maximum debonding force tend to stabilization when the embedment length exceeds a certain value. The contact angle between the carbon fiber and epoxy resin exerts an influence on the IFSS of the composites; the larger the contact angle, the higher the IFSS. The divergence of the IFSS values is also relevant to meniscus region of the resin microsphere and vise region. The IFSS of the untreated carbon fiber reinforced composites is just 39.6 Mpa, lower than that of the composites with the surface treated carbon fiber (60.6 Mpa).%利用微脱黏法测定碳纤维/环氧树脂复合材料的界面剪切强度,并分析了造成测试结果分散的影响因素.结果表明:在脱黏过程中,最大脱黏力随碳纤维埋人环氧树脂内长度的增加而线性递增,当埋人长度超过一定值后最大脱黏力趋于稳定:碳纤维与环氧树脂间的接触角对复合材料界面剪切强度有一定影响,接触角越大,界面剪切强度越高;测试结果的分散性与树脂微球的半月板区域、钳口区等因素有关;未经表面处理的碳纤维增强环氧树脂复合材料的界面剪切强度仪为39.4 MPa,低于处理后的复合材料(60.6 MPa).

  4. The Preparation and Properties of Continuous Carbon Fiber Reinforced Aluminum Matrix Composite%碳纤维增强铝基复合材料的制备及其拉伸性能

    Institute of Scientific and Technical Information of China (English)

    王德庆; 石子源; 高宏

    2000-01-01

    The tensile test specimen of the continuous carbon fiber reinforced aluminum matrix com- posites were prepared by using squeeze casting under three different solidification conditions. The tensile test was also conducted. The tensile strength and elastic modulus of the composite are in- creased with the increase in the carbon fiber content. The tensile strength of the composite with 48 Vol.% carbon fiber is 50% higher than that of the matrix material. However, the plasticities of the composite are decreased dramatically with the increase in the carbon content. When the carbon fiber content is small, the solodification conditions have greater effect on tensile strength but smaller on elastic modulus of the composite, while large amount of carbon fibers are added, solidification condi- tions affect elastic modulus more and tensile strength less.%利用挤压铸造方法,采用三种不同的凝固条件,制备了连续长碳纤维增强铝基复合材料的拉伸试样,并对其拉伸性能进行了试验.试验结果表明,该复合材料的抗拉强度和弹性模量皆随碳纤维的体积含量增加而增加.含48%碳纤维的复合材料比基体材料的拉伸强度高50%以上.但塑性指标随碳纤维含量的增加而显著降低.当连续碳纤维的体积含量较小时,凝固条件对该复合材料的抗拉强度影响较大,对弹性模量的影响较小;当碳纤维的体积含量较大时,凝固条件对该复合材料的抗拉强度影响较小,而对弹性模量的影响较大.

  5. Thermoplastic coated carbon fibers for textile preforms

    Science.gov (United States)

    Allen, L. E.; Edie, D. D.; Lickfield, G. C.; Mccollum, J. R.

    1988-01-01

    A continuous process for producing prepreg from carbon fiber and thermoplastic matrix is described. After the tow has been spread using a pneumatic device, the process utilizes a fluidized bed to apply thermoplastic powder to the bundle. Finally, direct electrical heating of the coated fiber tow melts the polymer on the individual fibers, creating a uniform and extremely flexible prepreg. The efficiency of the process was evaluated during initial trials in which a thermoplastic polyimide, LaRC-TPI, was applied to T-300, 3K (3000 filament) carbon fiber tow. The physical properties of unidirectional composite specimens fabricated from this prepreg were measured, and the matrix uniformity and void content of the samples was determined. The results of these evaluations are detailed and discussed.

  6. Studies on copper coating on carbon fibers

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    The weak interface bonding of metal matrix reinforced by carbon fibers is the central problem of fabricating such composites. Depositing copper coating on carbon fibers is regarded as a feasible method to solve the problem. In this paper, copper coating has been deposited on the fibers through both electroless deposition and electroplating methods. Two kinds of complexing agents and two stabilizing agents are taken during the electroless plating process. The solution is stable, and little extraneous component is absorbed on the surface. After adding additive agents and increasing the concentration of H2SO4 to the acid cupric sulfate electrolyte, the "black core" during usual electroplating process is avoided. The quality of copper coating is analyzed using SEM and XRD, etc.

  7. Computational modeling of ring textures in mesophase carbon fibers

    Directory of Open Access Journals (Sweden)

    de Andrade Lima Luiz Rogério Pinho

    2003-01-01

    Full Text Available Carbon fibers are widely used in many industrial applications due the fact of their excellent properties. Carbonaceous mesophases are liquid crystalline precursor materials that can be spun into high performance carbon fibers using the melt spinning process, which is a flow cascade consisting of pressure driven flow-converging die flow-free surface extensional spinline flow that modifies the precursor molecular orientation structure. Carbon fiber property optimization requires a better understanding of the principles that control the structure development during the fiber formation processes and the rheological processing properties. This paper presents the elastic and continuum theory of liquid crystalsand computer simulations of structure formation for pressure-driven flow of carbonaceous liquid crystalline precursors used in the industrial carbon fiber spinning process. The simulations results capture the formation of characteristic fiber macro-textures and provide new knowledge on the role of viscous and elastic effects in the spinning process.

  8. Numerical simulating and experimental study on the woven carbon fiber-reinforced composite laminates under low-velocity impact

    Science.gov (United States)

    Liu, Hanyang; Tang, Zhanwen; Pan, Lingying; Zhao, Weidong; Sun, Baogang; Jiang, Wenge

    2016-05-01

    Impact damage has been identified as a critical form of the defects that constantly threatened the reliability of composite structures, such as those used in the aerospace structures and systems. Low energy impacts can introduce barely visible damage and cause the degradation of structural stiffness, furthermore, the flaws caused by low-velocity impact are so dangerous that they can give rise to the further extended delaminations. In order to improve the reliability and load carrying capacity of composite laminates under low-velocity impact, in this paper, the numerical simulatings and experimental studies on the woven fiber-reinforced composite laminates under low-velocity impact with impact energy 16.7J were discussed. The low velocity impact experiment was carried out through drop-weight system as the reason of inertia effect. A numerical progressive damage model was provided, in which the damages of fiber, matrix and interlamina were considered by VUMT subroutine in ABAQUS, to determine the damage modes. The Hashin failure criteria were improved to cover the failure modes of fiber failure in the directions of warp/weft and delaminations. The results of Finite Element Analysis (FEA) were compared with the experimental results of nondestructive examination including the results of ultrasonic C-scan, cross-section stereomicroscope and contact force - time history curves. It is found that the response of laminates under low-velocity impact could be divided into stages with different damage. Before the max-deformation of the laminates occurring, the matrix cracking, fiber breakage and delaminations were simulated during the impactor dropping. During the releasing and rebounding period, matrix cracking and delaminations areas kept increasing in the laminates because of the stress releasing of laminates. Finally, the simulating results showed the good agreements with the results of experiment.

  9. Osteogenesis and cytotoxicity of a new Carbon Fiber/Flax/Epoxy composite material for bone fracture plate applications.

    Science.gov (United States)

    Bagheri, Zahra S; Giles, Erica; El Sawi, Ihab; Amleh, Asma; Schemitsch, Emil H; Zdero, Radovan; Bougherara, Habiba

    2015-01-01

    This study is part of an ongoing program to develop a new CF/Flax/Epoxy bone fracture plate to be used in orthopedic trauma applications. The purpose was to determine this new plate's in-vitro effects on the level of bone formation genes, as well as cell viability in comparison with a medical grade metal (i.e. stainless steel) commonly employed for fabrication of bone plates (positive control). Cytotoxicity and osteogenesis induced by wear debris of the material were assessed using Methyl Tetrazolium (MTT) assay and reverse transcription polymerase chain reaction (RT-PCR) for 3 osteogenesis specific gene markers, including bone morphogenetic proteins (BMP2), runt-related transcription factor 2 (Runx2) and Osterix. Moreover, the Flax/Epoxy and CF/Epoxy composites were examined separately for their wettability properties by water absorption and contact angle (CA) tests using the sessile drop technique. The MTT results for indirect and direct assays indicated that the CF/Flax/Epoxy composite material showed comparable cell viability with no cytotoxicity at all incubation times to that of the metal group (p≥0.05). Osteogenesis test results showed that the expression level of Runx2 marker induced by CF/Flax/Epoxy were significantly higher than those induced by metal after 48 h (p=0.57). Also, the Flax/Epoxy composite revealed a hydrophilic character (CA=68.07°±2.05°) and absorbed more water up to 17.2% compared to CF/Epoxy, which reached 1.25% due to its hydrophobic character (CA=93.22°±1.95°) (p<0.001). Therefore, the new CF/Flax/Epoxy may be a potential candidate for medical applications as a bone fracture plate, as it showed similar cell viability with no negative effect on gene expression levels responsible for bone formation compared to medical grade stainless steel.

  10. Finite element simulations on cutting process for carbon fiber composite%碳纤维复合材料切削过程的有限元模拟

    Institute of Scientific and Technical Information of China (English)

    熊威龙; 戴斌煜; 商景利; 王薇薇

    2014-01-01

    Based on failure criterion of Hashin,the two-dimensional orthogonal cutting model of carbon fiber composite material was presented in ABAQUS/Explicit. Effects of cutting condition on surface quality were analyzed by the model. In two-dimensional cutting simulation,the forming process of break,and the curve of force-tool stroke,and the stress distribution in chip and workpiece were obtained. The effects of tools with back engagement of cutting edge on the cutting process,surface quality and chip morphology were analyzed,and the methods to improve the surface quality of these materials were proposed theoretically.%基于Hashin失效准则,在ABAQUS/Explicit中建立碳纤维复合材料的二维正交切削模型。采用此模型研究切削条件对复合材料切削表面质量的影响。模拟得到了崩碎切屑的形成过程、切削力随刀具行程的变化曲线、应力在刀具及工件中的分布,并分析背吃刀量对切削过程中加工表面质量及切屑形貌的影响,从理论上提出改善复合材料切削表面质量的分析方法。

  11. Carbon Fiber Technology Facility (CFTF)

    Data.gov (United States)

    Federal Laboratory Consortium — Functionally within the MDF, ORNL operates DOE’s unique Carbon Fiber Technology Facility (CFTF)—a 42,000 ft2 innovative technology facility and works with leading...

  12. Preparation and mechanical properties of carbon fiber reinforced WF/HDPE composites%碳纤维增强木粉/聚乙烯复合材料的制备及其力学性能

    Institute of Scientific and Technical Information of China (English)

    杜凤; 王伟宏

    2015-01-01

    将短切碳纤维( SCF)与木粉( WF)、高密度聚乙烯( HDPE)塑料和其他添加剂共混、熔融复合后,用模压成型方法制备了短切碳纤维增强木塑( SCF/WF/HDPE)复合材料;将碳布放置于木塑板上下表面,经模压成型制备碳纤维布增强木塑( CFC/WF/HDPE)复合材料。研究了碳纤维用量对碳纤维增强WF/HDPE复合材力学性能的影响,并利用扫描电镜( SEM)和红外光谱( FTIR)对碳纤维进行表征。结果表明:与纯WF/HDPE复合材相比,碳纤维加入量为10%时,复合材料的力学强度提高幅度最大,拉伸强度和弯曲强度分别提高了8�4%和10�6%;当碳纤维加入量为6%时,复合材料的韧性提高幅度最大,断裂伸长率提高了25�9%,冲击强度提高了24�4%。使用丙酮清洗掉碳纤维表面的上浆剂后,其增强效果比未经过处理的碳纤维略有下降。与短切碳纤维相比,碳布的增强效果更好,与短切碳纤维增强木塑( SCF/WF/HDPE)复合材料相比,碳布平铺在木塑板表面的结构拉伸性能可提高62%,断裂伸长率提高148%,弯曲强度提高71%,冲击强度提高313%。%Short carbon fibers ( SCF) , wood flour ( WF) , high density polyethylene ( HDPE) plastic, and other addi⁃tives were mixed and compounded, then they were hot⁃press molded to SCF/WF/HDPE composite board. The effects of the carbon fiber content and surface sizing agent on the mechanical properties of the hybrid composites were studied. Car⁃bon fibers were characterized by SEM and FTIR. The results showed that the tensile strength and bending strength of SCF/WF/HDPE increased by 8.4% and 10.6%, respectively, comparing with the control sample without carbon fiber when SCF content was 10%. When SCF content was 6%, the elongation at break and impact strength of SCF/WF/HDPE composite increased by 25.9% and 24.4%, respectively. The sizing

  13. Role of surface chemistry in adhesion between ZnO nanowires and carbon fibers in hybrid composites.

    Science.gov (United States)

    Ehlert, Gregory J; Galan, Ulises; Sodano, Henry A

    2013-02-01

    Low interface strength is a persistent problem in composite materials and cascades to limit a variety of bulk material properties such as lamina shear strength. Whiskerization has long been pursued as a method to reinforce the interphase and improve both the single fiber interface strength as well as the bulk properties. Recent developments have shown that ZnO nanowire whiskerization can effectively improve the properties of a bulk composite without requiring the high temperatures that previous deposition processes needed. Although the efficacy of a ZnO nanowire interphase has been established, the mechanism for adhesion of the interphase to the fiber has not been identified. Specifically, the addition of the ZnO nanowires to the surface of the fibers requires that the ZnO nanowires have strong chemical adhesion to the fiber surface. This work will create a variety of chemical environments on the surface of the fibers through new and common chemical functionalization procedures and quantify the surface chemistry through X-ray photoelectron spectroscopy. The effect of fiber surface chemistry on the adhesion of the ZnO is assessed through single fiber fragmentation testing. The interface strength is found to strongly correlate with the concentration of ketone groups on the surface of the fibers. Following the experimental observations, liftoff of a ZnO crystal from a graphene surface was simulated with a variety of surface functionalizations. The computational models confirm the preference for ketone groups in promoting adhesion between ZnO and graphite.

  14. Effect of surface roughness on osteogenesis in vitro and osseointegration in vivo of carbon fiber-reinforced polyetheretherketone–nanohydroxyapatite composite

    Directory of Open Access Journals (Sweden)

    Deng Y

    2015-02-01

    Full Text Available Yi Deng,1,2 Xiaochen Liu,2 Anxiu Xu,3 Lixin Wang,4 Zuyuan Luo,2 Yunfei Zheng,1 Feng Deng,3 Jie Wei,5 Zhihui Tang,1 Shicheng Wei1–3 12nd Dental Center, Laboratory of Interdisciplinary Studies, School and Hospital of Stomatology, 2Center for Biomedical Materials and Tissue Engineering, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, 3Chongqing Key Laboratory of Oral Diseases and Biomedical Sciences, Chongqing Medical University, 4Department of Stomatology, Beijing Shijitan Hospital, Capital Medical University, Beijing, 5Key Laboratory for Ultrafine Materials of Ministry of Education, and Engineering Research Center for Biomedical Materials of Ministry of Education, East China University of Science and Technology, Shanghai, People’s Republic of China Abstract: As United States Food and Drug Administration-approved implantable material, carbon fiber-reinforced polyetheretherketone (CFRPEEK possesses an adjustable elastic modulus similar to cortical bone and is a prime candidate to replace surgical metallic implants. The bioinertness and inferior osteogenic properties of CFRPEEK, however, limit its clinical application as orthopedic/dental implants. In this study, CFRPEEK–nanohydroxyapatite ternary composites (PEEK/n-HA/CF with variable surface roughness have been successfully fabricated. The effect of surface roughness on their in vitro cellular responses of osteoblast-like MG-63 cells (attachment, proliferation, apoptosis, and differentiation and in vivo osseointegration is evaluated. The results show that the hydrophilicity and the amount of Ca ions on the surface are significantly improved as the surface roughness of composite increases. In cell culture tests, the results reveal that the cell proliferation rate and the extent of osteogenic differentiation of cells are a function of the size of surface roughness. The composite with moderate surface roughness significantly increases cell attachment

  15. Oxidation Protection of Carbon Fiber Reinforced Ceramic Matrix Composites%碳纤维增强陶瓷基复合材料抗氧化技术研究

    Institute of Scientific and Technical Information of China (English)

    卢国锋; 侯君涛

    2012-01-01

    Carbon fiber reinforced ceramic matrix composites (CFRCMCs) are the ideal thermostructure materials owing to its perfect high - temperature mechanical property and good hot property. However, the carbon fiber in the CFRCMCs could be oxidized easily, so the oxidation protection of the CFRCMCs had attracted the interest of researchers. In this paper, the methods for oxidation protection, such as modification of the carbon fibers, oxidation protection by matrix, and oxidation protection by interphase and coat- ing technology, were discussed, and their mechanics and features were summarized. The development trend of the antioxidation technology was prospected.%碳纤维增强陶瓷基复合材料(CFRCMCs)具有良好的高温力学性能和热性能,是航空航天领域非常理想的热结构材料.但CFRCMCs中的碳纤维极易发生氧化,因此CFRCMCs的氧化防护问题一直是CFRCMCs研究的热点.文章对碳纤维改性、基体抗氧化技术、界面层抗氧化技术和表面涂层技术这四种CFRCMCs的抗氧化技术及其原理进行了评述,分析了各类抗氧化技术的特点并对其发展趋势进行了展望.

  16. 被动毫米波成像系统探测碳纤维复合材料研究%Detection Carbon Fiber Composites Using Passive Millimeter-Wave Radiometric Imaging System

    Institute of Scientific and Technical Information of China (English)

    尹艳华; 王春芳; 赵京磊; 孙健

    2013-01-01

    To improve the effect of detecting base materials by using passive millimeter wave imaging system (PMMW),the man-made chemical coated carbon fiber were added in detected materials and the composites were tested.Test results show that,for silver-nickel-coating carbon fiber (ANCF),copper-nickel-coating carbon fiber (CNCF) and nickel coated carbon fiber (NCF),the detected comparative voltage is decreased successively,but then the imaging distinguishing effect is improved accordingly.For base materials detected by PMMW,the esters or flour has little effect on imaging,while the graphite has slight one.After adding NCF with 0.3 % weight into the above three base materials,the images are improved greatly in PMMW.%为提高基质材料在被动毫米波成像系统(PMMW)的检出率,向基质材料内添加自制碳纤维化学镀材料.实验结果表明:镀银镍碳纤维(ANCF)、镀铜镍碳纤维(CNCF)、镀镍碳纤维(NCF)在PMMW中显示的相对电压值依次降低,成像效果依次增强;单纯基质材料矿酯和面粉几乎不能成像,石墨粉稍有成像,添加质量分数为0.3%的镀镍碳纤维(NCF)后,3种基质成像效果均明显提高.

  17. Paper-based energy-storage devices comprising carbon fiber-reinforced polypyrrole-cladophora nanocellulose composite electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Razaq, Aamir; Sjoedin, Martin; Stroemme, Maria; Mihranyan, Albert [Nanotechnology and Functional Materials, Department of Engineering Sciences, Uppsala (Sweden); Department of Chemistry, Angstroem Laboratory, Uppsala (Sweden); Nyholm, Leif [Department of Chemistry, Angstroem Laboratory, Uppsala (Sweden)

    2012-04-15

    Composites of polypyrrole (PPy) and Cladophora nanocellulose, reinforced with 8 {mu}m-thick chopped carbon filaments, can be used as electrode materials to obtain paper-based energy-storage devices with unprecedented performance at high charge and discharge rates. Charge capacities of more than 200 C g{sup -1} (PPy) are obtained for paper-based electrodes at potential scan rates as high as 500 mV s{sup -1}, whereas cell capacitances of {proportional_to}60-70 F g{sup -1} (PPy) are reached for symmetric supercapacitor cells with capacitances up to 3.0 F (i.e.,0.48 F cm{sup -2}) when charged to 0.6 V using current densities as high as 31 A g{sup -1} based on the PPy weight (i.e., 99 mA cm{sup -2}). Energy and power densities of 1.75 Wh kg{sup -1} and 2.7 kW kg{sup -1}, respectively, are obtained when normalized with respect to twice the PPy weight of the smaller electrode. No loss in cell capacitance is seen during charging/discharging at 7.7 A g{sup -1} (PPy) over 1500 cycles. It is proposed that the nonelectroactive carbon filaments decrease the contact resistances and the resistance of the reduced PPy composite. The present straightforward approach represents significant progress in the development of low-cost and environmentally friendly paper-based energy-storage devices for high-power applications. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Fabrication and Characterization of Multi-Walled Carbon Nanotube (MWCNT) and Ni-Coated Multi-Walled Carbon Nanotube (Ni-MWCNT) Repair Patches for Carbon Fiber Reinforced Composite Systems

    Science.gov (United States)

    Johnson, Brienne; Caraccio, Anne; Tate, LaNetra; Jackson, Dionne

    2011-01-01

    Multi-walled carbon nanotube (MWCNT)/epoxy and nickel-coated multi-walled carbon nanotube (Ni-MWCNT)/epoxy systems were fabricated into carbon fiber composite repair patches via vacuum resin infusion. Two 4 ply patches were manufactured with fiber orientations of [90/ 90/ 4590] and [0/90/ +45/ -45]. Prior to resin infusion, the MWCNT/Epoxy system and NiMWCNT/ epoxy systems were optimized for dispersion quality. Scanning electron microscopy (SEM) and optical microscopy (OM) were used to determine the presence ofcarbon nanotubes and assess dispersion quality. Decomposition temperatures were determined via thermogravametric analysis (TGA). SEM and TGA were also used to evaluate the composite repair patches.

  19. Piezoresistivity of carbon fiber reinforced cement-matrix composites%碳纤维增强水泥基复合材料的压阻效应

    Institute of Scientific and Technical Information of China (English)

    赵晓华; 李国宝; 王玉林; 李庚英

    2011-01-01

    The piezoresistivity of short carbon fiber reinforced cement-matrix composites(CFRC) was experimentally studied.The whole process of transition from positive to negative piezoresistivity was observed.The results show that under continuously drying and uniaxially cyclic loading,both positive and negative piezoresistivity occur in CFRC due to the variation of moisture content in the composites.For most cases the electrical resistivity of the composites decreases monotonically upon longitudinal compression,and piezoresistivity tends to be positive.However,its magnitude varies.Lower moisture content leads to stronger piezoresistivity.When moisture content reduces to about 3.19%~4.04%,the electrical resistivity of the composites increases monotonically upon compressive strain,and piezoresistivity tends to be negative.This effect is much stronger than that of positive piezoresistivity.It is proposed that the occurrence of these phenomena is attributable to both the tunneling effect between fibers and decreasing in pore network connectivity during compression.%试验研究了短切碳纤维增强水泥基复合材料(CFRC)的压阻效应,获得了正、负两种压阻效应相互转换的全过程。从隧道效应和孔隙的连通性角度对该现象的产生机理进行了探讨。结果表明,在连续烘干和单向循环加载条件下,CFRC的压阻效应会随含水量变化而发生改变。多数情况下,CFRC的体积电阻率随压应变单调减少,压阻效应为正。含水量越少,正压阻效应越明显。当含水量减少到约3.19%~4.04%的范围时,CFRC的体积电阻率随压应变单调增加,压阻效应为负。与正压阻效应相比,负压阻效应表现更强。CFRC的正、负压阻效应及其相互转换是隧道效应和孔隙连通性两方面相互影响的必然结果。

  20. On the nature of interface of carbon nanotube coated carbon fibers with different polymers

    Science.gov (United States)

    Singh Bedi, Harpreet; Padhee, Srikant S.; Agnihotri, Prabhat K.

    2016-07-01

    Experimental investigations are carried out to analyse the wetting behaviour of carbon nanotube (CNT) coated carbon fiber to determine their suitability to process carbon nanotube coated carbon fiber/polymer multiscale composites for structural applications. To overcome the problem of agglomeration, CNTs are grown directly on the surface of carbon fibers as well as fabric using thermal chemical vapour deposition (CVD) technique. The term multiscale is used because different reinforcement mechanisms operate at the scale of long fibers and CNTs which are of few micrometers in length. The load carrying capacity of these multiscale composites critically depends on the efficiency and extent of load transfer from low strength matrix to high strength fiber which in turn depends on the interfacial strength between CNT coated carbon fiber and polymer matrix. A systematic analysis of wetting behaviour of CNT coated carbon fiber with epoxy and polyester matrix is carried out in this study. It is shown that CNT coated carbon fibers as well as fabric show better wettability with epoxy matrix as compared to polyester matrix. This results in stronger interface of CNT coated carbon fiber with epoxy as compared to polyester in multiscale composite system. A similar observation is made in nanoindentation testing of single fiber multiscale composites processed with epoxy and polyester matrix. In addition, it is observed that wettability, interfacial strength and average properties of CNT coated carbon fiber/polymer composites are a function of CNT density on the surface of carbon fibers.

  1. Raman Spectroscopy for the Nondestructive Testing of Carbon Fiber

    Directory of Open Access Journals (Sweden)

    Glenn Washer

    2008-01-01

    Full Text Available The goal of this research is to evaluate the potential of Raman spectroscopy as a method of condition assessment for carbon fiber composite materials used in high performance situations such as composite overwrapped pressure vessels (COPVs. There are currently limited nondestructive evaluation (NDE technologies to evaluate these composite materials in situ. Variations in elastic strain in the composite material can manifest from degradation or damage, and as such could provide a tool for condition assessment. The characterization of active Raman bands and the strain sensitivity of these bands for commercially available carbon fibers are reported.

  2. Predictive engineering tools for injection-molded long-carbon-fiber thermoplastic composites - FY 2015 third quarterly report

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Ba Nghiep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Fifield, Leonard S. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mori, Steven [MAGNA Exteriors and Interiors Corp. Aurora, ON (Canada); Gandhi, Umesh N. [Toyota Research Institute North America, Ann Arbor, MI (United States); Wang, Jin [Autodesk, Inc., Ithaca, NY (United States); Costa, Franco [Autodesk, Inc., Ithaca, NY (United States); Wollan, Eric J. [PlastiComp, Inc., Winona, MN (United States); Tucker, III, Charles L. [Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States)

    2015-07-01

    During the third quarter of FY 2015, the following technical progress has been made toward project milestones: 1) Magna oversaw the tool build and prepared the molding plan for the complex part of Phase II. 2) PlastiComp hosted a visit by Magna and Toyota on April 23rd to finalize the molding scope and schedule. The plan for molding trials including selection of molding parameters for both LFT and D-LFT for the U-shape complex part was established. 3) Toyota shipped the U-shape complex part tool to Magna on May 28th, 2015. 4) Plasticomp provided 30wt% LCF/PP and 30wt% LCF/PA66 compounded pellets to Magna for molding the complex part. 5) Magna performed preliminary molding trials on June 2nd, 2015 to validate wall thickness, fill profile, tool temperature and shot size requirements for the complex part. 6) Magna performed the first complex part run on June 16th and 17th, 2015 at Magna’s Composite Centre of Excellence in Concord, ON, Canada. Dale Roland of Plasticomp, and Umesh Gandhi of Toyota also attended the molding. 7) Magna discussed and finalized the plan with PNNL and the team for cutting samples from molded parts at selected locations for fiber orientation and length measurements. 8) Magna provided the computer-aided design (CAD) files of the complex parts with and without ribs to PNNL and Autodesk to build the corresponding ASMI models for injection molding simulations. Magna also provided the actual parameters used. 9) Plasticomp’s provided knowledge and experience of molding LCF materials essential to the successful molding of the parts including optimization of fill speed, tool temperatures, and plasticizing conditions for the 30wt% LCF/PP and 30wt% LCF/PA66 materials in both rib and non-rib versions. 10) Magna molded additional parts for evaluation of mechanical property testing including torsional stiffness on June 29th and 30th, 2015 at Magna’s Composite Center of Excellence. 11) Toyota began preparation for the torsion test of the specimens

  3. 碳纤维复合材料方管硅橡胶热膨胀成型工艺研究%FABRICATING SQUARE TUBE OF CARBON FIBER COMPOSITES USING THERMAL EXPANSION PROCESS WITH SILICONE RUBBER

    Institute of Scientific and Technical Information of China (English)

    曹晓明; 顾轶卓; 李超; 李敏; 张佐光

    2012-01-01

    Square tubes of carbon fiber/bismaleimide resin composite laminate and carbon fiber/ epoxy resin composite laminate were fabricated in a designed processing mold using the thermal expansion process with silicone rubber mold, respectively. The temperature variation of the silicone rubber during the process was studied. The forming quality of the composite square tube and its influence factors were investigated. The results show that the size of silicone rubber mold and the process gap can be calculated by the established formula. The air convection in the mold cavity has important influence on the temperature distribution of the silicone rubber mold. The process gap has a great effect on the forming quality of the composite square tubes. When the square tubes of carbon fiber/ epoxy resin composite are fabricated using the calculated process gap, the qualities on the surfaces and inside the tube are good, and the thickness matches the designed value as well. However for the tube of carbon fiber/bismaleimide resin composite, porosity defects are easily developed in the composite part, and they can be effectively eliminated by using the vacuum to assist the silicone rubber thermal expansion process.%针对碳纤维复合材料方管,设计制备了硅橡胶热膨胀工艺成型模具,并制备了碳纤维/双马树脂和碳纤维/环氧树脂复合材料方管,研究了成型过程中硅橡胶的温度变化规律,考察了方管的成型质量及其影响因素.结果表明,按照所建立的热膨胀工艺模具尺寸设计公式,可给出硅橡胶芯模的尺寸和工艺间隙;模具内腔的空气对流情况对硅橡胶的温度变化有重要影响;工艺间隙对方管成型质量有很大影响,当工艺间隙与理论计算值相符时,碳纤维/环氧树脂管件的表面和内部质量良好,厚度与设计值一致;碳纤维/双马树脂管件成型时,复合材料内部容易产生孔隙缺陷,采用真空辅助的热膨胀工艺方法,能够有效消除孔隙缺陷.

  4. Carbon Fiber from Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Milbrandt, Anelia [Clean Energy Manufacturing Analysis Center, Godlen, CO (United States); Booth, Samuel [Clean Energy Manufacturing Analysis Center, Godlen, CO (United States)

    2016-09-01

    Carbon fiber (CF), known also as graphite fiber, is a lightweight, strong, and flexible material used in both structural (load-bearing) and non-structural applications (e.g., thermal insulation). The high cost of precursors (the starting material used to make CF, which comes predominately from fossil sources) and manufacturing have kept CF a niche market with applications limited mostly to high-performance structural materials (e.g., aerospace). Alternative precursors to reduce CF cost and dependence on fossil sources have been investigated over the years, including biomass-derived precursors such as rayon, lignin, glycerol, and lignocellulosic sugars. The purpose of this study is to provide a comprehensive overview of CF precursors from biomass and their market potential. We examine the potential CF production from these precursors, the state of technology and applications, and the production cost (when data are available). We discuss their advantages and limitations. We also discuss the physical properties of biomass-based CF, and we compare them to those of polyacrylonitrile (PAN)-based CF. We also discuss manufacturing and end-product considerations for bio-based CF, as well as considerations for plant siting and biomass feedstock logistics, feedstock competition, and risk mitigation strategies. The main contribution of this study is that it provides detailed technical and market information about each bio-based CF precursor in one document while other studies focus on one precursor at a time or a particular topic (e.g., processing). Thus, this publication allows for a comprehensive view of the CF potential from all biomass sources and serves as a reference for both novice and experienced professionals interested in CF production from alternative sources.

  5. Characterization of electrospun lignin based carbon fibers

    Energy Technology Data Exchange (ETDEWEB)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri [School of Engineering, Thornbrough Building, University of Guelph, Guelph, N1G 2W1, Ontario (Canada); Bioproducts Discovery and Development Centre, Department of Plant Agriculture, Crop Science Building, University of Guelph, Guelph, N1G 2W1, Ontario (Canada)

    2015-05-22

    The production of lignin fibers has been studied in order to replace the need for petroleum based precursors for carbon fiber production. In addition to its positive environmental effects, it also benefits the economics of the industries which cannot take advantage of carbon fiber properties because of their high price. A large amount of lignin is annually produced as the byproduct of paper and growing cellulosic ethanol industry. Therefore, finding high value applications for this low cost, highly available material is getting more attention. Lignin is a biopolymer making about 15 – 30 % of the plant cell walls and has a high carbon yield upon carbonization. However, its processing is challenging due to its low molecular weight and also variations based on its origin and the method of separation from cellulose. In this study, alkali solutions of organosolv lignin with less than 1 wt/v% of poly (ethylene oxide) and two types of lignin (hardwood and softwood) were electrospun followed by carbonization. Different heating programs for carbonization were tested. The carbonized fibers had a smooth surface with an average diameter of less than 5 µm and the diameter could be controlled by the carbonization process and lignin type. Scanning electron microscopy (SEM) was used to study morphology of the fibers before and after carbonization. Thermal conductivity of a sample with amorphous carbon was 2.31 W/m.K. The electrospun lignin carbon fibers potentially have a large range of application such as in energy storage devices and water or gas purification systems.

  6. Patterned functional carbon fibers from polyethylene

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Marcus A [ORNL; Saito, Tomonori [ORNL; Brown, Rebecca H [ORNL; Kumbhar, Amar S [University of North Carolina, Chapel Hill; Naskar, Amit K [ORNL

    2012-01-01

    Patterned, continuous carbon fibers with controlled surface geometry were produced from a novel melt-processible carbon precursor. This portends the use of a unique technique to produce such technologically innovative fibers in large volume for important applications. The novelties of this technique include ease of designing and fabricating fibers with customized surface contour, the ability to manipulate filament diameter from submicron scale to a couple of orders of magnitude larger scale, and the amenable porosity gradient across the carbon wall by diffusion controlled functionalization of precursor. The geometry of fiber cross-section was tailored by using bicomponent melt-spinning with shaped dies and controlling the melt-processing of the precursor polymer. Circular, trilobal, gear-shaped hollow fibers, and solid star-shaped carbon fibers of 0.5 - 20 um diameters, either in self-assembled bundle form, or non-bonded loose filament form, were produced by carbonizing functionalized-polyethylene fibers. Prior to carbonization, melt-spun fibers were converted to a char-forming mass by optimizing the sulfonation on polyethylene macromolecules. The fibers exhibited distinctly ordered carbon morphologies at the outside skin compared to the inner surface or fiber core. Such order in carbon microstructure can be further tuned by altering processing parameters. Partially sulfonated polyethylene-derived hollow carbon fibers exhibit 2-10 fold surface area (50-500 m2/g) compared to the solid fibers (10-25 m2/g) with pore sizes closer to the inside diameter of the filaments larger than the sizes on the outer layer. These specially functionalized carbon fibers hold promise for extraordinary performance improvements when used, for example, as composite reinforcements, catalyst support media, membranes for gas separation, CO2 sorbents, and active electrodes and current collectors for energy storage applications.

  7. Friction and wear behavior of carbon fiber reinforced brake materials

    Institute of Scientific and Technical Information of China (English)

    Du-qing CHENG; Xue-tao WANG; Jian ZHU; Dong-bua QIU; Xiu-wei CHENG; Qing-feng GUAN

    2009-01-01

    A new composite brake material was fabri-cated with metallic powders, barium sulphate and modified phenolic resin as the matrix and carbon fiber as the reinforced material. The friction, wear and fade character-istics of this composite were determined using a D-MS friction material testing machine. The surface structure of carbon fiber reinforced friction materials was analyzed by scanning electronic microscopy (SEM). Glass fiber-reinforced and asbestos fiber-reinforced composites with the same matrix were also fabricated for comparison. The carbon fiber-reinforced friction materials (CFRFM) shows lower wear rate than those of glass fiber- and asbestos fiber-reinforced composites in the temperature range of 100℃-300℃. It is interesting that the frictional coefficient of the carbon fiber-reinforced friction materials increases as frictional temperature increases from 100℃ to 300℃, while the frictional coefficients of the other two composites decrease during the increasing temperatures. Based on the SEM observation, the wear mechanism of CFRFM at low temperatures included fiber thinning and pull-out. At high temperature, the phenolic matrix was degraded and more pull-out enhanced fiber was demonstrated. The properties of carbon fiber may be the main reason that the CFRFM possess excellent tribological performances.

  8. The influence of fatigue loading on the quality of the cement layer and retention strength of carbon fiber post-resin composite core restorations.

    Science.gov (United States)

    Bolhuis, Peter; de Gee, Anton; Feilzer, Albert

    2005-01-01

    Clinical studies have shown that endodontically treated teeth restored with short posts or deficient ferrules show a high failure risk. This study. evaluated the influence of fatigue loading on the quality of the cement layer between prefabricated quartz coated carbon fiber posts with restricted length and the root canal wall in maxillary pre-molars. Two adhesive resin composite cements, chemical-cured Panavia 21 (Group 1) and dual-cured RelyX-ARC (Group 2), and one resin-modified glass-ionomer cement, chemical-cured RelyX (Group 3), delta were selected for this study. Post- and-core restorations were made on single-rooted human maxillary premolars from which the coronal sections were removed at the level of the proximal cemento-enamel junction (CEJ). Following endodontic treatment, a post-and-core restoration with 6-mm post length was prepared for each tooth. The posts were directly cemented into the root canal and, after applying an adhesive (Clearfil Photo Bond), they were built up with a core build-up composite (Clearfil Photo Core). For each group (n=8), half of the specimens were exposed to fatigue loading (10(6) load cycles) almost perpendicular to the axial axis (85 degrees), while the other half were used as the control. Three parallel, transverse root sections, 1.5-mm thick, were cut from each specimen at the apical, medial and coronal location. These sections were examined by Scanning Electron Microscopy (SEM) to evaluate the integrity of the cement layer, while the retention strength of the cemented post sections was determined with the push-out test. The multivariate results of MANOVA showed that the condition main effect (fatigue or control) was not significant (p=0.059); the two other main effects, type of cement and section location, were significant (p=0.001 and p=0.008). For both the push-out strength and SEM evaluation of the cement layer integrity, the results significantly improved from RelyX to RelyX-ARC to Panavia 21 and also from apical to

  9. Nanowire modified carbon fibers for enhanced electrical energy storage

    Science.gov (United States)

    Shuvo, Mohammad Arif Ishtiaque; (Bill) Tseng, Tzu-Liang; Ashiqur Rahaman Khan, Md.; Karim, Hasanul; Morton, Philip; Delfin, Diego; Lin, Yirong

    2013-09-01

    The study of electrochemical super-capacitors has become one of the most attractive topics in both academia and industry as energy storage devices because of their high power density, long life cycles, and high charge/discharge efficiency. Recently, there has been increasing interest in the development of multifunctional structural energy storage devices such as structural super-capacitors for applications in aerospace, automobiles, and portable electronics. These multifunctional structural super-capacitors provide structures combining energy storage and load bearing functionalities, leading to material systems with reduced volume and/or weight. Due to their superior materials properties, carbon fiber composites have been widely used in structural applications for aerospace and automotive industries. Besides, carbon fiber has good electrical conductivity which will provide lower equivalent series resistance; therefore, it can be an excellent candidate for structural energy storage applications. Hence, this paper is focused on performing a pilot study for using nanowire/carbon fiber hybrids as building materials for structural energy storage materials; aiming at enhancing the charge/discharge rate and energy density. This hybrid material combines the high specific surface area of carbon fiber and pseudo-capacitive effect of metal oxide nanowires, which were grown hydrothermally in an aligned fashion on carbon fibers. The aligned nanowire array could provide a higher specific surface area that leads to high electrode-electrolyte contact area thus fast ion diffusion rates. Scanning Electron Microscopy and X-Ray Diffraction measurements are used for the initial characterization of this nanowire/carbon fiber hybrid material system. Electrochemical testing is performed using a potentio-galvanostat. The results show that gold sputtered nanowire carbon fiber hybrid provides 65.9% higher energy density than bare carbon fiber cloth as super-capacitor.

  10. The surface properties of carbon fibers and their adhesion to organic polymers

    Science.gov (United States)

    Bascom, W. D.; Drzal, L. T.

    1987-01-01

    The state of knowledge of the surface properties of carbon fibers is reviewed, with emphasis on fiber/matrix adhesion in carbon fiber reinforced plastics. Subjects treated include carbon fiber structure and chemistry, techniques for the study of the fiber surface, polymer/fiber bond strength and its measurement, variations in polymer properties in the interphase, and the influence of fiber matrix adhesion on composite mechanical properties. Critical issues are summarized and search recommendations are made.

  11. High efficient preparation of carbon nanotube-grafted carbon fibers with the improved tensile strength

    Science.gov (United States)

    Fan, Wenxin; Wang, Yanxiang; Wang, Chengguo; Chen, Jiqiang; Wang, Qifen; Yuan, Yan; Niu, Fangxu

    2016-02-01

    An innovative technique has been developed to obtain the uniform catalyst coating on continuously moving carbon fibers. Carbon nanotube (CNT)-grafted carbon fibers with significantly improved tensile strength have been succeeded to produce by using chemical vapor deposition (CVD) when compared to the tensile strength of untreated carbon fibers. The critical requirements for preparation of CNT-grafted carbon fibers with high tensile strength have been found, mainly including (i) the obtainment of uniform coating of catalyst particles with small particle size, (ii) the low catalyst-induced and mechano-chemical degradation of carbon fibers, and (iii) the high catalyst activity which could facilitate the healing and strengthening of carbon fibers during the growth of CNTs. The optimum growth temperature was found to be about 500 °C, and the optimum catalyst is Ni due to its highest activity, there is a pronounced increase of 10% in tensile strength of carbon fibers after CNT growth at 500 °C by using Ni catalyst. Based on the observation from HRTEM images, a healing and crosslink model of neighboring carbon crystals by CNTs has been formulated to reveal the main reason that causes an increase in tensile strength of carbon fibers after the growth of CNTs. Such results have provided the theoretical and experimental foundation for the large-scale preparation of CNT-grafted carbon fibers with the improved tensile strength, significantly promoting the development of CNT-grafted carbon fiber reinforced polymer composites.

  12. 架空导线用碳纤维复合芯固化剂应用研究%Application of Curing Agent in Carbon Fiber Composite Core For Overhead Transmission Lines

    Institute of Scientific and Technical Information of China (English)

    何州文; 陈新; 药宁娜; 杨长龙; 陈懿夫

    2012-01-01

    A compound curing agent was prepared with methyl tetrahydrophthalic anhydride curing agent and a kind of flexible curing agent by a certain percentage for carbon fiber composite core epoxy matrix toughening. The structure of curing agent was studied by means of FTIR. The effects of the compound curing agent on impact strength, winding performance, apparent shear strength and temperature resistance of the carbon fiber composite core were investigated. The results showed that the flexible curing agent contained long-chain flexible segments, which could improve the impact strength, winding performance and apparent shear strength and had less effect on the temperature resistance for the carbon fiber composite core.%将甲基四氢苯酐固化剂与柔性固化剂按一定比例复配,用于碳纤维复合芯环氧树脂基体的增韧改性.采用傅里叶变换红外光谱分析固化剂的结构;研究了固化剂对碳纤维复合芯冲击强度、卷绕性能、剪切强度及耐温性的影响.结果表明,柔性固化剂含有长链结构的柔性链段,提高了碳纤维复合芯冲击强度、卷绕性能及表观剪切强度,并且对碳纤维复合芯的耐温性影响较小.

  13. Development Status and Application of Carbon Fiber Composites in Wind Turbine Blade%风电发展现状与碳纤维材料在风电中的应用

    Institute of Scientific and Technical Information of China (English)

    李峰

    2011-01-01

    综述了国内外风电产业的发展现状和生产企业的生产现状,并从结构、制造等方面对碳纤维复合材料在风电行业的应用及发展优势进行了详细的介绍.%The development of wind power industry and production status at home and abroad, is reviewed and the advantages of carbon fiber composite in view of the structure, manufacturing and other aspects as used in wind power industry are introduced.

  14. The Evaluation of the Possibilities of Using PLGA Co-Polymer and Its Composites with Carbon Fibers or Hydroxyapatite in the Bone Tissue Regeneration Process – in Vitro and in Vivo Examinations

    Directory of Open Access Journals (Sweden)

    Tadeusz Cieślik

    2009-07-01

    Full Text Available Synthetic polymers belonging to the aliphatic polyester group have become highly promising biomaterials for reconstructive medicine. The purpose of the present work is a biological evaluation of lactide-glycolide co-polymer (PLGA and its composites with carbon fibers (PLGA+CF or hydroxyapatite (PLGA+HA. The cytotoxicity of the evaluated materials towards hFOB 1.19 human osteoblast-like cells was assessed. Moreover, during the one-year contact of the assessed materials with living osseous tissue, the progress of bone formation was analyzed and the accompanying process of the materials’ degradation was evaluated. The materials under evaluation proved to be biocompatible.

  15. The evaluation of the possibilities of using PLGA co-polymer and its composites with carbon fibers or hydroxyapatite in the bone tissue regeneration process - in vitro and in vivo examinations.

    Science.gov (United States)

    Cieślik, Magdalena; Mertas, Anna; Morawska-Chochól, Anna; Sabat, Daniel; Orlicki, Rajmund; Owczarek, Aleksander; Król, Wojciech; Cieślik, Tadeusz

    2009-07-15

    Synthetic polymers belonging to the aliphatic polyester group have become highly promising biomaterials for reconstructive medicine. The purpose of the present work is a biological evaluation of lactide-glycolide co-polymer (PLGA) and its composites with carbon fibers (PLGA+CF) or hydroxyapatite (PLGA+HA). The cytotoxicity of the evaluated materials towards hFOB 1.19 human osteoblast-like cells was assessed. Moreover, during the one-year contact of the assessed materials with living osseous tissue, the progress of bone formation was analyzed and the accompanying process of the materials' degradation was evaluated. The materials under evaluation proved to be biocompatible.

  16. Effect of Position of Carbon Fiber Cloth on Properties of Wood Fiber/HDPE Composite Board%碳布位置对木粉/高密度聚乙烯复合板性能影响

    Institute of Scientific and Technical Information of China (English)

    周晨; 杜凤; 王伟宏

    2015-01-01

    引入碳纤维作为增强手段,通过设计不同的工艺结构,探究其对木塑复合材力学性能的增强效果。板材结构设计方案有CF313(3 mm表层木塑板+碳布+1 mm芯层木塑板+碳布+3 mm表层木塑板)、CF232(2 mm表层木塑板+碳布+3 mm芯层木塑板+碳布+2 mm表层木塑板)、 CF151(1 mm表层木塑板+碳布+5 mm芯层木塑板+碳布+1 mm表层木塑板)、CF070(碳布贴在最外层)、CF7(不添加碳布的空白实验)。研究结果表明,CF070复合材的弯曲强度最大;CF151的弹性模量最大,即碳纤维放在近表层位置时,弯曲性能较好,但拉伸时木塑表层容易拉断;放在靠近中心位置时复合材的拉伸强度和冲击强度提高幅度较大。综合考虑各性能,表层厚度为2 mm时可最大程度发挥碳布优势、增强木塑复合材料力学性能。%We used carbon fiber as reinforcing method through different design of the process structures to study the reinforcing effect on the mechanical properties of wood fiber/high density polyethylene ( WF/HDPE) composites.The first structure of the board was called“CF313”, which meant that the composite board consisted of a piece of WF/HDPE board as surface another same piece as back and a piece of 1 mm WF/HDPE core board, and the internally inserted carbon fiber cloth among the surface, core board and back.Accordingly, we designed “CF232” and “CF151” laminated board.The following fourth structure was called“CF070”, and carbon fiber cloth were attached to the surface and back.The last was the comparison structure.The carbon fiber cloth significantly enhanced the mechanical properties of wood plastic composites.During the experiment, the “CF070” was with the highest bending strength, “CF151” was with the highest elastic modulus,“CF313” was with the highest tensile strength, and“CF232” was with the highest impact strength.The closer the carbon

  17. Formation of aromatic thermoplastic and carbon-fiber prepreg by electrochemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Li Hong.

    1991-01-01

    A new technique was developed and demonstrated for combining carbon fibers with aromatic thermoplastic matrices to form a high-quality towpreg. The developed technique utilizes an in-situ electrochemical process (Electrochemical polymerization - ECP) to create the entire polymer matrix surrounding the fiber array by direct polymerization of monomer. Poly-paraxylylene (PPX) and derivatives are successfully polymerized in-situ on carbon fiber surfaces through ECP. A PPX/carbon-fiber towpreg with 40 vol % of matrix is achieved in a fairly short reaction time with a high polymer-coating efficiency. Vapor deposition polymerization (VDP) was also studied. PPX and carbon-fiber towpreg were made successfully by this process. A comparison between ECP and VDP was conducted. A study on electrochemical oxidation (ECO) of carbon fibers was also performed. The ECO treatment may be suitable for carbon fibers incorporated in composites with high-temperature curing resins and thermoplastic matrices.

  18. ELECTRO-THERMAL EFFECTS AND DEFORMATION RESPONSE OF CARBON FIBER MAT CEMENT BEAMS

    Institute of Scientific and Technical Information of China (English)

    ZhuSirong; LiZhuoqiu; SongXianhui

    2003-01-01

    A carbon fiber mat is a sheet composed of intercrossing short carbon fibers, which has more stable and lower electrical resistivity compared with dispersed short carbon fiber mixed in cement. Thereby carbon fiber mat cement could exhibit obvious electro-thermal effect. When electrified, the temperature of composite structures made up of cement mortar and carbon fiber mat will rise rapidly. If the temperature field is not uniform, temperature difference will cause structures to deform, which can be used to adjust the deformation of structures. The temperature field and deformation response driven by the electro-thermal effects of a type of carbon fiber mat cement beams are studied. Firstly, the temperature and deformation responses are studied using theories of thermal conduction and elasticity. Secondly, experimental results are given to verify the theoretical solution. These two parts lay the foundation for temperature and deformation adjustment.

  19. Oxidation of Carbon Fibers in Water Vapor Studied

    Science.gov (United States)

    Opila, Elizabeth J.

    2003-01-01

    T-300 carbon fibers (BP Amoco Chemicals, Greenville, SC) are a common reinforcement for silicon carbide composite materials, and carbon-fiber-reinforced silicon carbide composites (C/SiC) are proposed for use in space propulsion applications. It has been shown that the time to failure for C/SiC in stressed oxidation tests is directly correlated with the fiber oxidation rate (ref. 1). To date, most of the testing of these fibers and composites has been conducted in oxygen or air environments; however, many components for space propulsion, such as turbopumps, combustors, and thrusters, are expected to operate in hydrogen and water vapor (H2/H2O) environments with very low oxygen contents. The oxidation rate of carbon fibers in conditions representative of space propulsion environments is, therefore, critical for predicting component lifetimes for real applications. This report describes experimental results that demonstrate that, under some conditions, lower oxidation rates of carbon fibers are observed in water vapor and H2/H2O environments than are found in oxygen or air. At the NASA Glenn Research Center, the weight loss of the fibers was studied as a function of water pressure, temperature, and gas velocity. The rate of carbon fiber oxidation was determined, and the reaction mechanism was identified.

  20. PROGRESS ON ACTIVATED CARBON FIBERS

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Activated carbon fiber is one kind of important adsorption materials. These novel fibrousadsorbents have high specific surface areas or abundant functional groups, which make them havegreater adsorption/desorption rates and larger adsorption capacities than other adsorbents. They canbe prepared as bundle, paper, cloth and felt to meet various technical requirement. They also showreduction property. In this paper the latest progress on the studies of the preparation and adsorptionproperties of activated carbon fibers is reviewed. The application of these materials in drinking waterpurification, environmental control, resource recovery, chemical industry, and in medicine and healthcare is also presented.

  1. Application of Carbon Fiber Reinforced Composites on Automotive Auxiliary Frame%碳纤维增强复合材料在汽车副车架中的应用

    Institute of Scientific and Technical Information of China (English)

    任昌义

    2015-01-01

    采用碳纤维布、聚对苯二甲酸乙二酯(PET)泡沫和阻燃环氧树脂,经真空辅助成型工艺制备了碳纤维泡沫夹芯复合材料。利用碳纤维泡沫夹芯复合材料代替原有的金属材料,采用真空导入工艺制作汽车副车架,为考虑承重及安装方便,设计了边梁、主梁和横梁的制作及搭接工艺。结果表明,采用此工艺大大减轻了汽车副车架的质量,整个副车架的总重仅为116 kg。%Carbon fiber foam sandwich composites was prepared by using carbon fiber cloth,polyethylene terephthalate (PET) foam and flame retardant epoxy resin through vacuum assisted resin transfer molding process. Auxiliary frame was made by using carbon fiber foam sandwich composites instead of metal materials through import vacuum technology. In order to consider the load bearing and convenient installation,and overlapping process of edge beam, main beam and side beam was designed. The results show that the weight of auxiliary frame is greatly reduced and the total weight of the whole auxiliary frame is 116 kg only.

  2. Preparation and mechanical properties of MWCNT and carbon fiber reinforced bismaleimide resin composite%碳纳米管及炭纤维协同强韧双马来酰亚胺树脂复合材料

    Institute of Scientific and Technical Information of China (English)

    邱军; 王宗明; 金磊; 李旦; 邱挺挺

    2012-01-01

    采用氨基化碳纳米管(CNTs)强韧双马来酰亚胺树脂(BMI)基体树脂,制备碳纳米管/炭纤维(CNT/CF)协同增强BMI的三相复合材料.结果表明,乙二胺以共价键的形式接枝到了MWCNTs表面,MWCNTs-NH2表面的N元素质量分数达3.53%;质量分数为0.5% MWCNTs-NH2的三相复合材料的弯曲模量、弯曲强度及冲击强度分别为43.85 GPa、1 160.62 MPa和28.50 kJ/m2,与CF/BMI复合材料相比,分别提高了49.56%、17.41%和19.65%.%Bismaleimide reinforced with both MWCNTs and carbon fibers was prepared by mold-pressing carbon fiber paper stacks impregnated with a bismaleimide acetone solution containing MWCNTs grafted with ethyl-ene diamine. The MWCNTs were oxidized by concentrated HNO3 to form carboxyl groups before grafting. Results show that the flexural modulus, flexural strength and impact strength of composite with a 0. 5 mass% of MWCNTs is 43. 85 GPa, 1 160. 62 MPa and 28. 50 kJ/m2, which represent increases of 49. 56% , 17.41% and 19.65% respectively compared with the carbon fiber/BMI composite.

  3. X-ray microtomography, ultrasound and thermography for the characterization of defects in fiberglass and carbon fiber composite materials and elements; Roentgen-Mikrotomografie, Ultraschall und Thermographie fuer die Charakterisierung von Defekten in GFK- und CFK-Verbundwerkstoffen und -Elementen

    Energy Technology Data Exchange (ETDEWEB)

    Brunner, Andreas J.; Jerjen, Iwan; Plamondon, Mathieu; Furrer, Roman; Neuenschwander, Juerg [EMPA Eidgenoessische Materialpruefungs- und Forschungsanstalt, Duebendorf (Switzerland)

    2015-07-01

    Glass and carbon fiber reinforced plastics (GRP or CFRP composites) may have different defects that arise on the one hand in the manufacturing process and on the other hand occur or propagate under quasi-static or oscillating mechanical load. The characterization of the nature, location and size of defects is important among other things for optimization of manufacturing processes, modeling of material or component behavior and for the estimation of the useful life of components or structures from GFK or CFK composites. The contribution shows selected examples of the application of X-ray microtomography, ultrasound and thermography for the characterization of defects in fiberglass or carbon fiber composite components. In ''thick'' laminates and complex shapes the X-ray method is particularly suitable. [German] Glas- und Kohlenstoff-faserverstaerkte Kunststoffe (GFK- bzw. CFK-Verbundwerkstoffe) koennen unterschiedliche Defekte ausweisen, die einerseits im Herstellungsprozess entstehen und sich andererseits bei der Nutzung unter quasistatischer oder schwingender mechanischer Belastung ausbilden oder sich ausbreiten. Die Charakterisierung der Art, der Lage und der Groesse der Defekte ist u.a. fuer Optimierung der Herstellungsprozesse, Modellierung des Werkstoff- oder Bauteilverhaltens sowie der Abschaetzung der Nutzungsdauer von Komponenten oder Strukturen aus GFK- oder CFK-Verbundwerkstoffen wichtig. Der Beitrag zeigt ausgewaehlte Beispiele der Anwendung von Roentgen-Mikrotomografie, Ultraschall und Thermographie zur Charakterisierung von Defekten in GFK- oder CFK-Verbundwerkstoff-Bauteilen. Bei ''dicken'' Laminaten und komplexen Geometrien ist das Roentgenverfahren besonders geeignet.

  4. 聚合物/镀镍碳纤维导电复合材料的研究进展%Research Development of Polymer/Nickel-Coated Carbon Fiber Conductive Composites

    Institute of Scientific and Technical Information of China (English)

    陈彤; 薛平; 贾明印; 韩宇

    2014-01-01

    综述了聚合物/镀镍碳纤维(NiCF)导电复合材料的优点及其导电机理,介绍了该种导电复合材料的几种制备方法,包括单螺杆挤出机法、双螺杆挤出机法、密炼机法和Brabender塑化仪法,并详细地分析和总结了影响聚合物/NiCF导电复合材料导电性的NiCF长度、表面改性与分散、填充量以及加工工艺等因素。%The advantages and conductive mechanism of polymer/nickel-coated carbon fiber conductive composites were reviewed. The several preparation methods of the kind of conductive composites were introduced,which include single-screw extruder,twin-screw extruder,mixer method and Brabender plasti-corder. The effects such as the length,surface treatment and dispersion,addition amounts of the nickel-coated carbon fiber and processing technology on the conductivity of the conductive composites were discussed and summarized.

  5. 碳纤维增强热塑性树脂基复合材料的研究现状%Advance of the Research in Carbon Fiber Reinforced Thermoplastic Resin Matrix Composite

    Institute of Scientific and Technical Information of China (English)

    尹翔宇; 朱波; 刘洪正; 郑连勇; 张春雷

    2011-01-01

    综述了国内碳纤维增强聚酰胺(PA6)、聚醚砜(PES)、聚碳酸酯(PC)、聚苯硫醚(PPS)、聚醚砜酮(PPESK),聚醚醚酮(PEEK)、热塑性聚酰亚胺(PI)等热塑性树脂基复合材料研究现状,对比了热固性树脂基复合材料与热塑性树脂基复合材料性能及成型工艺方面的差异,并对碳纤维增强热塑性树脂基复合材料的成型方法,碳纤维质量分数、长度和表面处理方法对复合材料性能影响的一般规律作了总结。%The domestic situation of carbon fiber reinforced thermoplastic (PA, PES, PC, PPS, PPESK, PEEK, PI and so on) composites were synthetically discussed in the paper, meanwhile, the differences of molding process and properties between thermosetting and thermoplastic matrix composite materials were contrasted. In addition we summarized the regular influences of molding method and carbon fiber including their content, length, surface treatment on the performance of composite materials.

  6. Preparation and selective laser sintering behavior of carbon fiber/polyamide 1 2 composite%炭纤维/尼龙12复合粉体的制备及选择性激光烧结行为

    Institute of Scientific and Technical Information of China (English)

    吴琼; 陈惠; 巫静; 夏笑虹; 许小曙; 边宏; 刘洪波

    2016-01-01

    采用液相氧化法对PAN基短切炭纤维进行表面改性,再与尼龙12混合,采用选择性激光烧结成形技术制备炭纤维/尼龙12复合粉体试样。利用扫描电子显微镜(SEM)、傅里叶变换红外光谱(FT-IR)表征炭纤维改性前后的表面状态、复合粉体的分散状况及烧结试样的断口形貌。探讨了复合粉体的烧结行为及烧结试样的力学性能与孔隙率的关系。结果表明,改性炭纤维表面的含氧基团在激光烧结时热分解产生气体,导致烧结试样孔隙率较高、力学性能较差。改性炭纤维经高温热处理可以在保留炭纤维表面粗糙度的同时有效降低烧结试样的孔隙率,与未改性炭纤维/尼龙12试样相比,拉伸强度、拉伸模量、弯曲强度和弯曲模量均有不同程度的提高。%The PAN-based chopped carbon fibers were surface modified by liquid-phase oxidation,mixed with polyamide 12,and the carbon fiber reinforced polyamide 12 composites were prepared by selective laser sinte-ring technology.Scanning electron microscope and Fourier transform infrared spectrum were applied to the characterization of the surface state on the carbon fibers before and after modification,the dispersity of compos-ite powder,and fracture morphology of the sintered components.The sintering behavior of composite powder, the relationship between mechanical property and porosity of the sintered components were also discussed.The results show that the oxygen-containing groups on the surface of modified carbon fibers are thermal decomposed and release gas in the process of laser sintering,which cause a high porosity and poor mechanical properties of the sintered components.While the carbon fibers treated under high temperature after modification can preserve the surface roughness,lower the porosity at the same time,and compared with the unmodified carbon fiber re-inforced polyamide 1 2 sintered components,the tensile strength,tensile modulus

  7. Methods of making carbon fiber from asphaltenes

    Energy Technology Data Exchange (ETDEWEB)

    Bohnert, George; Bowen, III, Daniel E.

    2017-02-28

    Making carbon fiber from asphaltenes obtained through heavy oil upgrading. In more detail, carbon fiber is made from asphaltenes obtained from heavy oil feedstocks undergoing upgrading in a continuous coking reactor.

  8. Synthesis of Y2O3-ZrO2-SiO2 composite coatings on carbon fiber reinforced resin matrix composite by an electro-plasma process

    Science.gov (United States)

    Zhang, Yuping; Lin, Xiang; Chen, Weiwei; Cheng, Huanwu; Wang, Lu

    2016-05-01

    In the present paper the Y2O3-ZrO2-SiO2 composite coating was successfully synthesized on carbon fiber reinforced resin matrix composite by an electro-plasma process. The deposition process, microstructures and oxidation resistance of the coatings with different SiO2 concentrations were systematically investigated. A relatively dense microstructure was observed for the Y2O3-ZrO2-SiO2 composite coating with the SiO2 concentration above 5 g/L. The coating exhibited very good oxidation resistance at 1273 K with the mass loss rate as low as ∼30 wt.%, compared to 100 wt.% of the substrate. The formation of the ceramic composites was discussed in detail based on the electrochemical mechanism and the deposition dynamics in order to explain the effect of the plasma discharge. We believe that the electro-plasma process will find wide applications in preparing ceramics and coatings in industries.

  9. Study on the Properties of HDPE/Graphite/Carbon Fiber Thermal Conductivity Composite%高密度聚乙烯/石墨/碳纤维导热复合材料性能的研究

    Institute of Scientific and Technical Information of China (English)

    冯博; 冷金华; 陈弦; 何波兵

    2013-01-01

    采用高密度聚乙烯(HDPE)、石墨、碳纤维制备高导热、高强度的复合材料.通过SEM照片考察高密度聚乙烯/石墨/碳纤维复合体系的微观结构;研究石墨及碳纤维的加入是否可以形成导热通道以及随着石墨的添加量的提高,复合材料的导热性能及其力学性能的变化.结果表明:当石墨的质量分数为60%,碳纤维的质量分数为5%时,复合材料的导热系数达到7.938 W/(m·K),是纯HDPE的20倍.%High density polyethylene,graphite and carbon fiber were chosen to prepare a composite material with high thermal conductivity and high strength.Its microstructure was observed by SEM as well as whether it can form a thermal channel by using graphite and carbon fiber.The changes of the material's thermal conductivity and mechanical properties with the increasing of the addition of graphite were studied.When using 60w% graphite and 5 w% carbon fiber,the coefficient index of thermal conductivity reached at 7.938 W/(m · K) which was 20 times of the pure HDPE.

  10. Effects of recording media composition on the responses of Nafion-coated carbon fiber microelectrodes measured using high-speed chronoamperometry.

    Science.gov (United States)

    Gerhardt, G A; Hoffman, A F

    2001-08-15

    The present study concerns methodological issues of electrochemical recordings using Nafion-coated 30 microm diameter single carbon fiber microelectrodes for high-speed chronoamperometric measurements of biogenic amines. First, the single carbon fiber microelectrodes were coated with Nafion and dried at 85 vs. 200 degrees C and their recording properties were determined. Second, the effects of shifts in solution pH, ionic strength, changes in recording solution levels of Ca(2+) or Mg(2+) and temperature on the recording characteristics and sensitivity of Nafion-coated high temperature dried (200 degrees C) single carbon fiber microelectrodes for measures of dopamine were studied. These studies showed that the high temperature drying of the Nafion produced a microelectrode with better recording properties: higher selectivity for cations versus anions, increased differences between the reduction and oxidation current ratios for the identification of dopamine versus serotonin, and more rapid response times. In addition, these studies demonstrated that the chronoamperometric recordings were insensitive to small changes in pH and divalent cations such as Ca(2+) or Mg(2+). However, increases in ionic strength decreased the sensitivity of the microelectrodes, while increases in temperature produced increases in the sensitivity of the microelectrodes for biogenic amines. These data support that Nafion-coated high temperature (200 degrees C) dried microelectrodes have enhanced recording properties as compared to microelectrodes, which are coated with Nafion and dried at 85 degrees C. In addition, high-speed chronoamperometric recordings of biogenic amines are not affected by solution changes in divalent cations (Ca(2+) or Mg(2+)).

  11. 碳纤维复合涂层在高压脉冲电场下的杀菌性能研究%Research on Bactericidal Properties of Carbon Fiber Composite Coatings in High-voltage Pulse Electric Field

    Institute of Scientific and Technical Information of China (English)

    杨鹏鹏; 吴进怡; 柴柯; 林海强; 宋春蕾

    2015-01-01

    ABSTRACT:Objective To explore the inhibition effects and mechanism of high-voltage pulsed electric field ( HPEF) in marine environment on microbial fouling. Methods Carbon fiber / epoxy composite anti-corrosion coating was prepared by brushing meth-od, and the effects of the carbon fiber length and content on the dielectric properties and surface energy of the composite coating as well as the bactericidal performance of the carbon fiber composite coating in high-voltage pulsed electric field. Results The results showed that the carbon fiber length and content were the main factors affecting the dielectric properties of the composite coating un-der high frequency. With the increase of electric field intensity and frequency within the set range, the sterilization rate of the coat-ing obviously increased, while with the increase of duty cycle, the sterilization rate of the coating first increased and then decreased and finally tended to be stable. When the duty cycle was 0. 5, the maximum sterilization rate of 99. 8% was reached. Conclusion The composite coating with a doping content of 0. 1% 5 mm carbon fiber had excellent dielectric properties. High-voltage pulsed e-lectric field had a good killing effect on bacteria and the sterilization rate of the coating could reach 99. 97%.%目的:研究海洋环境下高压脉冲电场对微生物污损的抑制效果和机理。方法采用刷涂法制备碳纤维/环氧防腐涂料复合涂层,研究碳纤维长度和含量对复合涂层的介电性能和表面能的影响以及碳纤维复合涂层在高压脉冲电场作用下的杀菌性能。结果高频电场下,碳纤维长度和含量是影响复合涂层介电性能的主要因素,随着电场强度、频率在设定范围内增加,涂层的杀菌率显著增大;而随占空比的增大,涂层的杀菌率呈先增后减最后趋于平缓的趋势,占空比为0.5时涂层的杀菌率最高达99.8%。结论掺杂0.1%(质量分数)5 mm碳纤维的

  12. RESEARCH DEVELOPMENT OF CARBON FIBER REINFORCED BENZOXAZINE RESIN COMPOSITES%碳纤维增强苯并噁嗪树脂基复合材料的研究进展

    Institute of Scientific and Technical Information of China (English)

    王智; 顾宜

    2011-01-01

    苯并噁嗪是近年来发展起来的一种新型的高性能复合材料基体树脂.本文较系统地综述了国内外碳纤维增强苯并噁嗪复合材料的研究进展,介绍了苯并噁嗪树脂及其复合材料的性能特点,指出了进一步的发展趋势.%Benzoxazine is a kind of high performance matrix resin of composites developed in recent years. The research development of carbon fiber reinforced benzoxazine resin composites was reviewed systematically in this paper. The property features of benzoxazine and composites were introduced, and the development tendency was pointed out.

  13. 国产T800碳纤维/双马来酰亚胺复合材料的界面及力学性能%Interfacial and mechanical properties of domestic T800 carbon fiber/bismaleimide composites

    Institute of Scientific and Technical Information of China (English)

    李伟东; 张金栋; 刘刚; 钟翔屿; 张代军; 包建文; 肇研

    2016-01-01

    分别采用日本东丽T800H 和国产T800碳纤维作为增强体,采用热压罐工艺制备双马来酰亚胺树脂基复合材料。研究了2种碳纤维的表面物理和化学状态,复合材料的微观界面性能及力学性能。结果表明:国产T800碳纤维表面沟槽分布较多,表面粗糙度较高,有利于与树脂基体形成更好的物理结合作用。同时,国产T800碳纤维表面具有较多的含氧官能团,有利于与基体树脂形成更好的化学结合作用。因此,国产T800碳纤维的界面剪切强度较T800H 碳纤维高约27%。国产 T800/HT-280复合材料的力学性能均普遍高于 T800H/HT-280复合材料,其中,90°拉伸强度高约25%,面内剪切强度、弯曲强度高约12%,层间剪切强度高约7%。%Japan Toray T800H and domestic T800 carbon fibers were used as reinforcements to prepare bismaleim-ide resin matrix composites by autoclave process.Surface physical and chemical states of the two kinds of carbon fi-bers,as well as micro interfacial properties and mechanical properties of the composites were studied.The results show that the domestic T800 carbon fibers can form better physical adhesion with the resin matrix,which have more grooves on the surface and higher surface roughness.Simultaneously,the domestic T800 carbon fibers can form bet-ter chemical adhesion with the resin matrix,as they have more oxygenic functional groups.Hence,the interfacial shear strength of domestic T800 carbon fibers is higher than that of T800H carbon fibers by about 27%.Moreover, the mechanical properties of domestic T800/HT-280 composites are generally higher than those of T800H/HT-280 composites.The 90°tensile strength improves by about 25%,the in-plane shear strength and bending strength im-proves by about 1 2%,and the interlaminar shear strength improves by about 7%.

  14. Property and Shape Modulation of Carbon Fibers Using Lasers.

    Science.gov (United States)

    Blaker, Jonny J; Anthony, David B; Tang, Guang; Shamsuddin, Siti-Ros; Kalinka, Gerhard; Weinrich, Malte; Abdolvand, Amin; Shaffer, Milo S P; Bismarck, Alexander

    2016-06-29

    An exciting challenge is to create unduloid-reinforcing fibers with tailored dimensions to produce synthetic composites with improved toughness and increased ductility. Continuous carbon fibers, the state-of-the-art reinforcement for structural composites, were modified via controlled laser irradiation to result in expanded outwardly tapered regions, as well as fibers with Q-tip (cotton-bud) end shapes. A pulsed laser treatment was used to introduce damage at the single carbon fiber level, creating expanded regions at predetermined points along the lengths of continuous carbon fibers, while maintaining much of their stiffness. The range of produced shapes was quantified and correlated to single fiber tensile properties. Mapped Raman spectroscopy was used to elucidate the local compositional and structural changes. Irradiation conditions were adjusted to create a swollen weakened region, such that fiber failure occurred in the laser treated region producing two fiber ends with outwardly tapered ends. Loading the tapered fibers allows for viscoelastic energy dissipation during fiber pull-out by enhanced friction as the fibers plough through a matrix. In these tapered fibers, diameters were locally increased up to 53%, forming outward taper angles of up to 1.8°. The tensile strength and strain to failure of the modified fibers were significantly reduced, by 75% and 55%, respectively, ensuring localization of the break in the expanded region; however, the fiber stiffness was only reduced by 17%. Using harsher irradiation conditions, carbon fibers were completely cut, resulting in cotton-bud fiber end shapes. Single fiber pull-out tests performed using these fibers revealed a 6.75-fold increase in work of pull-out compared to pristine carbon fibers. Controlled laser irradiation is a route to modify the shape of continuous carbon fibers along their lengths, as well as to cut them into controlled lengths leaving tapered or cotton-bud shapes.

  15. Hygrothermal effects on fiber reinforced polyphenylene sulphide composites : humidity uptake and temperature influence on mechanical properties of glass and carbon fiber reinforced polyphenylene sulphide composites

    OpenAIRE

    Suárez Cabrera, Emmanuel

    2011-01-01

    In the ever-continuing quest for greener and cheaper aerospace materials, the Durability Group, part of the Design and Production of Composite Structures Department at the faculty of Aerospace Engineering of the Delft University of Technology is focusing on the use of new thermoplastic composites for aerospace structures. Currently the introduction of Nylon composites in the aerospace industry is being investigated. Nylon as a thermoplastic matrix for fibre reinforced composites can be bought...

  16. CARBON FIBERS AND INTERFACIAL PROPERTIES OF THEIR REINFORCED RESIN MATRIX COMPOSITES%两种T700碳纤维表面特性及其复合材料界面性能

    Institute of Scientific and Technical Information of China (English)

    郝华; 李鹏; 凌辉; 孙宏杰; 于运花; 杨小平

    2013-01-01

    分别用扫描电子显微镜(SEM)、X射线光电子能谱(XPS)以及接触角测量仪分析了国产MT700C碳纤维和东丽T700SC两种碳纤维的表面微结构、表面化学特性以及与树脂的浸润性,并对其环氧树脂复合材料MT700C/603和T700SC/603在干态和湿态下的界面性能进行了研究.结果表明,MT700C碳纤维表面O/C比和活性碳原子含量比T700SC碳纤维高,并且表面具有明显的沟槽,因此MT700C与树脂的浸润性好于T700SC碳纤维,可以与603树脂形成具有良好界面粘结的MT700C/603复合材料.在室温干态条件下,MT700C/603复合材料的层间剪切强度(ILSS)大于T700SC/603复合材料.但是在湿热老化环境中,T700SC/603复合材料最终的剪切强度保留率大于MT700C/603复合材料.%Surface properties including surface physical morphology, chemical elements and wetting properties of MT700C-6K-42B-l ( abbr. MT700C) and T700SC-12K-50C ( abbr. T700SC) carbon fibers were analyzed by SEM.XPS and contact angle analyzer. The interfacial properties of their reinforced resin matrix composites MT700C/603 and T700SC/603 were also studied at dry / hygrothermal ageing conditions. Results show MT700C carbon fibers present better wetting property and stronger adhesion with resin matrix due to higher O/C ratio and active carbon ratio than T700SC carbon fibers. MT700C/603 composite has higher ILSS than T7OOSC/6O3 composite at dry and RT conditions. While, through hygrothermal aging, the T700SC/603 composite has better ILSS retention rate than MT700C/603 composite.

  17. NiCF/ABS复合材料的制备及电磁屏蔽效能研究%Study on EMI Properties of Nickel Coated Carbon Fibers/ABS Composites

    Institute of Scientific and Technical Information of China (English)

    唐萍; 程真真; 张荣; 刘俊; 史然; 宾月珍

    2013-01-01

    This research investigated the metal-coating method of carbon fibers (CF). Nickel-coated carbon fibers (NiCF) were fabricated by electroless plating, and ABS composites filled with CF and NiCF were prepared by kneading method. The influence of CF and NiCF contents on the electrical conductivity and electromagnetic shielding effectiveness of ABS based composites was studied. The results indicated that an even and intact nickel coating could be plated on carbon fibers under a suiltable pretreatment and plating conditions, and the electrical resistivity of CF decreased 2 orders of magnitude when the plating time was 5min. The electrical resistivity of composites decreased with CF and NiCF content increasing. The corresponding electromagnetic shielding effectiveness of composites increased as filler content increasing, and the value reached 51 dB for the composite containing 25wt% (13. 3vol%) NiCF.%探讨了碳纤维(CF)表面镍金属的化学镀工艺,制备了镀镍碳纤维(NiCF),采用密炼工艺制备了ABS基体复合材料,研究了CF和NiCF含量对复合材料的导电性能及电磁屏蔽效能的影响.结果表明:采用化学镀的方法在碳纤维表面镀覆了金属镍,所形成的镀层均匀致密;镀覆时间为5min时,镀镍后的碳纤维电阻率降低两个数量级;复合材料电阻率随CF、NiCF含量的增加而逐渐减小;复合材料电磁屏蔽效能随CF、NiCF含量的增加而逐渐增加,当NiCF含量为25%(wt)(约13.3vo1%)时,电磁屏蔽效能最高可达51dB.

  18. Electrical Properties of Carbon Fiber Support Systems

    CERN Document Server

    Cooper, W; Demarteau, M; Fast, J; Hanagaki, K; Johnson, M; Kuykendall, W; Lubatti, H; Matulik, M; Nomerotski, A; Quinn, B; Wang, J

    2005-01-01

    Carbon fiber support structures have become common elements of detector designs for high energy physics experiments. Carbon fiber has many mechanical advantages but it is also characterized by high conductivity, particularly at high frequency, with associated design issues. This paper discusses the elements required for sound electrical performance of silicon detectors employing carbon fiber support elements. Tests on carbon fiber structures are presented indicating that carbon fiber must be regarded as a conductor for the frequency region of 10 to 100 MHz. The general principles of grounding configurations involving carbon fiber structures will be discussed. To illustrate the design requirements, measurements performed with a silicon detector on a carbon fiber support structure at small radius are presented. A grounding scheme employing copper-kapton mesh circuits is described and shown to provide adequate and robust detector performance.

  19. Mechanical Properties of Heat-treated Carbon Fibers

    Science.gov (United States)

    Effinger, Michael R.; Patel, Bhavesh; Koenig, John; Cuneo, Jaques; Neveux, Michael G.; Demos, Chrystoph G.

    2004-01-01

    Carbon fibers are selected for ceramic matrix composites (CMC) are based on their as-fabricated properties or on "that is what we have always done" technical culture while citing cost and availability when there are others with similar cost and availability. However, the information is not available for proper selection of carbon fibers since heat-treated properties are not known for the fibers on the market currently. Heat-treating changes the fiber's properties. Therefore, an effort was undertaken to establish fiber properties on 19 different types of fibers from six different manufactures for both PAN and pitch fibers. Heat-treating has been done at three different temperatures.

  20. Oxidation Behaviors and Oxidation Protection of Carbon Fiber Reinforced Ceramic Matrix Composites%连续碳纤维增强陶瓷基复合材料的氧化行为和氧化防护研究

    Institute of Scientific and Technical Information of China (English)

    卢国锋; 许艳

    2012-01-01

    The characteristics of the carbon fiber reinforced ceramic matrix composites (CFRCMCs) are analyzed through an overview about the oxidation behaviors of C/C and C/SiC. The four methods for oxidation protection, including the modification of the carbon fiber, the matrix antioxidation technology, the interlayer antioxidation technology and the surface coating technology, are summarized from the aspects of the fibers, matrix, interphase and exterior surface. The mechanisms and features of the four methods are analyzed.%通过叙述C/C和C/SiC两种复合材料的氧化特点分析了碳纤维增强陶瓷基复合材料(CFRCMCs)的氧化行为,分别从纤维、基体、界面层及外表面4个方面综述了碳纤维改性、基体抗氧化技术、界面层抗氧化技术和表面涂层技术4种CFRCMCs的抗氧化技术,分析了4类抗氧化技术的原理和特点.

  1. Raman Spectroscopy for the Nondestructive Testing of Carbon Fiber

    OpenAIRE

    Glenn Washer; Frank Blum

    2008-01-01

    The goal of this research is to evaluate the potential of Raman spectroscopy as a method of condition assessment for carbon fiber composite materials used in high performance situations such as composite overwrapped pressure vessels (COPVs). There are currently limited nondestructive evaluation (NDE) technologies to evaluate these composite materials in situ. Variations in elastic strain in the composite material can manifest from degradation or damage, and as such could provide a tool for co...

  2. 碳纤维布表面处理对酚醛树脂复合材料力学性能的影响%Effects of Surface Treatment of Carbon Fiber Cloth on Mechanical Properties of Phenolic Resin Composites

    Institute of Scientific and Technical Information of China (English)

    田琳娜; 崔善子

    2012-01-01

    Carbon fiber cloth (CB ) reinforced phenolic resin ( PF ) composites were prepared through compression molding process with CB as reinforcement, styrene butadiene rubber as toughening agent, PF as matrix.The results showed that the carbon fiber cloth immersed with acetone and oxidized by the concentrated sulfuric acid, and raise of the processing molding temperature could improve the bonding and mechanical properties of PF / CB composites. But with the improvement of molding temperature, CB oxidized easily brokened, and weakened the inhancement for composite.When the amount of styrene butadiene rubber was 12%, the processing and impact properties of PF / CB composite was the best.%以碳纤维布(CB)为增强相,丁苯橡胶为增韧剂,酚醛树脂(PF)为基体,通过模压成型工艺制得了PF/CB复合材料,研究了CB表面处理方式、丁苯橡胶含量及加工成型温度对PF/CB复合材料的界面结合及力学性能的影响.结果表明,丙酮处理CB、氧化处理CB及加工成型温度的提高都能改善纤维与基体的结合程度,提高界面结合力.但氧化处理CB随着加工成型温度的提高,易断裂,对复合材料的增强作用有所减弱.丁苯橡胶加入量为12%时PF的加工及冲击性能为最佳.

  3. Progress in Interface of Carbon Fiber Reinforced Ceramic Matrix Composites%碳纤维增强陶瓷基复合材料界面的研究进展

    Institute of Scientific and Technical Information of China (English)

    何柏林; 孙佳

    2009-01-01

    界面相作为复合材料基本组元之一,其结构组成与性能对材料的性能有着极其重要的影响.综述了碳纤维增强陶瓷基复合材料界面相的功能要求、界面结合类型.阐述了界面相厚度对复合材料性能的影响,适当的界面厚度有利于复合材料获得最佳性能.重点介绍了目前碳纤维表面涂层工艺的研究现状,并分析了各种制备工艺的优缺点.最后指出了今后碳纤维增强陶瓷基复合材料界面的研究方向.%Interface is one of the basic elements of composites and its structure and properties play a very role influence on properties of materials. The feature requirement and combined types of interface of carbon fiber reinforced ceramic matrix composites are reviewed. The effect of interface thickness on properties of the composites are also sum-marized, and the appropriate value of interface thickness makes composites with the best properties. The research sta-tus of preparing interface coating on carbon fiber are introduced, and the advantage and disadvantage of every method are analyzed. Finally, the research direction are pointed out.

  4. Analysis on ablation properties of domestic carbon fibers braided carbon/carbon composite throat%国产碳纤维编织碳/碳喉衬烧蚀分析

    Institute of Scientific and Technical Information of China (English)

    吴书锋; 张玲; 周绍建; 程文; 刘建军

    2013-01-01

    采用国产T300级碳纤维进行轴棒法编织结构碳/碳(C/C)复合材料制备,并对C/C复合材料喉衬进行固体火箭发动机(SRM)地面点火试验,结合扫描电子显微镜(SEM),分别对烧蚀后喉衬入口部位、喉部和出口部位的烧蚀形貌进行分析.结果表明,在7.432 MPa压力下,国产T300级碳纤维轴棒法编织结构C/C喉衬的烧蚀性能较为稳定,烧蚀均匀,烧蚀后型面光滑,烧蚀率较低,平均线烧蚀率为0.159 6 mm/s,国产T300级碳纤维的性能满足发动机的工作要求.%Axial carbon rod woven 4D carbon/carbon(C/C) composite were fabricated by domestic T300 PANbased Carbon fibers,and a firing test was carried out for testing the ablation properties of C/C composite throat.The ablation morphologies of its different parts (entrance part,throat and exit part) were investigated by scanning electron microscopy (SEM).The results showed that under the pressure of 7.432 MPa,the composite have stable ablation rates of about 0.1596 mm/s and homogeneous properties,the contours of composite after test were smooth.The property of domestic T300 PAN-based Carbon fibers can be applied for throat of SRM.

  5. Fracture of Carbon Nanotube - Amorphous Carbon Composites: Molecular Modeling

    Science.gov (United States)

    Jensen, Benjamin D.; Wise, Kristopher E.; Odegard, Gregory M.

    2015-01-01

    Carbon nanotubes (CNTs) are promising candidates for use as reinforcements in next generation structural composite materials because of their extremely high specific stiffness and strength. They cannot, however, be viewed as simple replacements for carbon fibers because there are key differences between these materials in areas such as handling, processing, and matrix design. It is impossible to know for certain that CNT composites will represent a significant advance over carbon fiber composites before these various factors have been optimized, which is an extremely costly and time intensive process. This work attempts to place an upper bound on CNT composite mechanical properties by performing molecular dynamics simulations on idealized model systems with a reactive forcefield that permits modeling of both elastic deformations and fracture. Amorphous carbon (AC) was