Sample records for aramids

  1. Statistical Constitutive Equation of Aramid Fiber Bundles

    Institute of Scientific and Technical Information of China (English)

    熊杰; 顾伯洪; 王善元


    Tensile impact tests of aramid (Twaron) fiber bundles were carried om under high strain rates with a wide range of 0. 01/s~1000/s by using MTS and bar-bar tensile impact apparatus. Based on the statistical constitutive model of fiber bundles, statistical constitutive equations of aramid fiber bundles are derived from statistical analysis of test data at different strain rates. Comparison between the theoretical predictions and experimental data indicates statistical constitutive equations fit well with the experimental data, and statistical constitutive equations of fiber bundles at different strain rates are valid.

  2. Nano-Aramid Fiber Reinforced Polyurethane Foam (United States)

    Semmes, Edmund B.; Frances, Arnold


    Closed cell polyurethane and, particularly, polyisocyanurate foams are a large family of flexible and rigid products the result of a reactive two part process wherein a urethane based polyol is combined with a foaming or "blowing" agent to create a cellular solid at room temperature. The ratio of reactive components, the constituency of the base materials, temperature, humidity, molding, pouring, spraying and many other processing techniques vary greatly. However, there is no known process for incorporating reinforcing fibers small enough to be integrally dispersed within the cell walls resulting in superior final products. The key differentiating aspect from the current state of art resides in the many processing technologies to be fully developed from the novel concept of milled nano pulp aramid fibers and their enabling entanglement capability fully enclosed within the cell walls of these closed cell urethane foams. The authors present the results of research and development of reinforced foam processing, equipment development, strength characteristics and the evolution of its many applications.

  3. Surface modification and characterization of aramid fibers with hybrid coating

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Jianrui; Zhu, Yaofeng; Ni, Qingqing; Fu, Yaqin, E-mail:; Fu, Xiang


    Graphical abstract: - Highlights: • Aramid fibers modification sizing synthesized by sol–gel in the absence of water. • The strength and interfacial adhesion property of modified fibers were improved. • Modified fibers show a special surface structure. • The mechanism explains the function of structure. - Abstract: Aramid fibers were modified through solution dip-coating and interfacial in situ polymerization using a newly synthesized SiO{sub 2}/shape memory polyurethane (SiO{sub 2}/SMPU) hybrid. Fourier transform infrared and X-ray photoelectron spectroscopy indicated that the synthesized SiO{sub 2}/SMPU hybrid successfully coated the fiber surface. The surface morphology of the aramid fibers and the single fiber tensile strength and interfacial shear strength (IFSS) of the composites were determined. The IFSS of the fiber coated with the hybrid improved by 45%, which benefited from a special “pizza-like” structure on the fiber surface.

  4. Effects of Environment on Strengths of UHMWPE and Aramid Fiber

    Institute of Scientific and Technical Information of China (English)

    曹涛; 李显波


    This paper is devoted on influences of acid-base,high and low temperature on strength of UHMWPE and aramid fiber, characterized by fracture strength, SEM’s effects on fiber strength and surface morphology. It turns out to be that UHMWPE fiber has a superior acid-base, low temperature and light aging resistance property,with strength keeping above 90% in acid-base environment. Comparing with UHMWPE fiber, aramid fiber does well in mechanical properties, temperature resistant performances and alkali resistances at room temperature, with strength losing less than 10%in alkaline environment.

  5. Facile Fabrication of Multifunctional Aramid Nanofiber Films by Spin Coating (United States)

    Lyu, Jing; Liu, Lehao; Zhao, Xing; Shang, Yudong; Zhao, Tingkai; Li, Tiehu


    Polymer matrices with excellent mechanical properties, thermal stability and other features are highly demanded for the effective utilization within nanocomposites. Here, we fabricate free-standing aramid nanofiber films via spin coating of an aramid nanofiber/dimethyl sulfoxide solution. Compared with traditional film fabrication methods, this process is time-saving and also able to easily tune the thickness of the films. The resultant films show greatly improved stretchability than that of Kevlar threads and relatively high mechanical strength. Typically, these films with a thickness of 5.5 µm show an ultimate strength of 182 MPa with an ultimate tensile strain of 10.5%. We also apply a finite element modeling to simulate the strain and strength distributions of the films under uniaxial tension, and the results of the simulation are in accordance with the experimental data. Furthermore, the aramid nanofiber films exhibit outstanding thermostability (decomposition at 550 °C under N2 atmosphere and 500 °C in air) and chemical inertness, which would endure acid and alkali. The simple method demonstrated here provides an important way to prepare high-performance aramid nanofiber films for designing new composite systems.

  6. Strain-induced internal fibrillation in looped aramid filaments

    DEFF Research Database (Denmark)

    Pauw, Brian Richard; Vigild, Martin Etchells; Mortensen, Kell;


    By mapping the small-angle X-ray scattering (SAXS) from a looped poly-(para-phenylene terephtalamide) (aramid, PPTA) filament using a synchrotron X-ray microbeam, we investigate the effects of axially compressive and tensile strain on internal fibrillar structures. Unique observations of oscillat...

  7. Extrusion instability in an aramid fibre spinning process

    NARCIS (Netherlands)

    Drost, S.


    The efficiency of polymer extrusion processes can be severely limited by the occurrence of viscoelastic extrusion instabilities. In a para-aramid fibre spinning process, for example, a μm-scale extrusion instability is responsible for the waste of tons of polymer per year. At present, a considerab

  8. Tissue biocompatibility of kevlar aramid fibers and polymethylmethacrylate, composites in rabbits. (United States)

    Henderson, J D; Mullarky, R H; Ryan, D E


    Two groups of female NZW rabbits were implanted in the paravertebral muscles with aramid (du Pont Kevlar aramid 49) fibers and aramid-polymethylmethacrylate (PMMA) composites for 14 and 28 days. Rabbits were killed at these times periods, necropsies performed, sites scored for gross tissue response, and tissue specimens containing the implants removed for histopathological evaluation. A mild fibrous tissue reaction was observed around all implants containing aramid fiber similar to that observed around the silicone control implant. Some foreign body giant cells were also present adjacent to the fibers. An intense necrotic inflammatory reaction was present around the positive control material (PVC Y-78). The tissue response to implantation of aramid fiber and fiber-PMMA composites indicates that aramid is a biocompatible material.

  9. Progress in reinforcing fibers of carbon and aramid

    Energy Technology Data Exchange (ETDEWEB)

    Blumberg, H.


    Since the early eighties, carbon and aramid fibres have increasingly been used in composites based on polymers. Combined with thermosetting and thermoplastic matrices, they have considerably extended the range of materials now available to the designer. This paper describes the properties of both fibres, dealing in particular with the significant improvements in the properties of carbon fibres that have been achieved during the last few years. The two fibres are compared with glass fibres, ceramic fibres and high-tenacity polyethylene fibres. The paper is concluded by a summary of the different production processes, a cost comparison and a description of current market trends. (orig.).

  10. Improvement of high-strength carbon and aramid reinforcing fibers. Fortschritte bei hochfesten Verstaerkungsfasern aus Kohlenstoff und Aramid

    Energy Technology Data Exchange (ETDEWEB)

    Blumenberg, H. (Akzo GmbH, Wuppertal (Germany, F.R.). Unternehmensbereich Fasern und Polymere)


    Since the early eighties, carbon and aramid fibres have increasingly been used in composites based on polymers. Combined with thermosetting and thermoplastic matrices, they have considerably extended the range of materials now available to the designer. This paper describes the properties of both fibres, dealing in particular with the significant improvements in the properties of carbon fibres that have been achieved during the last few years. The two fibres are compared with glass fibres, ceramic fibres and high-tenacity polyethylene fibres. The paper is concluded by a summary of the different production processes, a cost comparison and a description of current market trends. (orig.).

  11. Dispersions of Aramid Nanofibers: A New Nanoscale Building Block

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Ming; Cao, Keqin; Sui, Lang; Qi, Ying; Zhu, Jian; Waas, Anthony; Arruda, Ellen; Kieffer, John; Thouless, M. D.; Kotov, Nicholas A.


    Stable dispersions of nanofibers are virtually unknown for synthetic polymers. They can complement analogous dispersions of inorganic components, such as nanoparticles, nanowires, nanosheets, etc. as a fundamental component of a toolset for design of nanostructures and metamaterials via numerous solvent-based processing methods. As such, strong flexible polymeric nanofibers are very desirable for the effective utilization within composites of nanoscale inorganic components such as nanowires, carbon nanotubes, graphene, and others. Here stable dispersions of uniform high-aspect-ratio aramid nanofibers (ANFs) with diameters between 3 and 30 nm and up to 10 μm in length were successfully obtained. Unlike the traditional approaches based on polymerization of monomers, they are made by controlled dissolution of standard macroscale form of the aramid polymer, that is, well-known Kevlar threads, and revealed distinct morphological features similar to carbon nanotubes. ANFs are successfully processed into films using layer-by-layer (LBL) assembly as one of the potential methods of preparation of composites from ANFs. The resultant films are transparent and highly temperature resilient. They also display enhanced mechanical characteristics making ANF films highly desirable as protective coatings, ultrastrong membranes, as well as building blocks of other high performance materials in place of or in combination with carbon nanotubes.

  12. Statistical Tensile Strength for High Strain Rate of Aramid and UHMWPE Fibers

    Institute of Scientific and Technical Information of China (English)

    YANG Bin; XIONG Tao; XIONG Jie


    Dynamic tensile impact properties of aramid (Technora(R)) and UHMWPE (DC851) fiber bundles were studied at two high strain rates by means of reflecting type Split Hopkinson Bar, and stress-strain curves of fiber yarns at different strain rates were obtained. Experimental results show that the initial elastic modulus, failure strength and unstable strain of aramid fiber yarns are strain rate insensitive, whereas the initial elastic modulus and unstable strain of UHMWPE fiber yarns are strain rate sensitive. A fiber-bundle statistical constitutive equation was used to describe the tensile behavior of aramid and UHMWPE fiber bundles at high strain rates. The good consistency between the simulated results and experimental data indicates that the modified double Weibull function can represent the tensile strength distribution of aramid and UHMWPE fibers and the method of extracting Weibull parameters from fiber bundles stress-strain data is valid.

  13. Prediction of Final Velocity of Aramid Fabric-Resin Composite Laminates Subjected to Ballistic Impact

    Institute of Scientific and Technical Information of China (English)

    熊杰; 萧庆亮; 刘冠峰; 顾伯洪; 王善元


    The strain rate effects of aramid fiber material,quasi-static and ballistic impact perforation of composite laminates made of aramid fabric and phenolic resin/PVB are investigated respectively by means of MTS, split Hopkinson tension bars and ballistic impact apparatus. The tensile impact experiments on aramid fiber material are performed in strain rate range from 0.01/ s to 1 000/ s. Experinental results show that the mechanical properties of aramid fiber material are insensitive to strain rate in the range from 0. 01/s to 1 000/s. An energy model to predict final velocity of composite laminates subjected to ballistic impact is proposed on the basis of experimental data of quasi-static perforation through the targets. The predicted final velocities show good agreement with the experimental final velocity.

  14. Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez-Uicab, O. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Avilés, F., E-mail: [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Gonzalez-Chi, P.I; Canché-Escamilla, G.; Duarte-Aranda, S. [Centro de Investigación Científica de Yucatán A.C., Unidad de Materiales, Calle 43 No.130, Col. Chuburna de Hidalgo, C.P. 97200 Mérida, Yucatán (Mexico); Yazdani-Pedram, M. [Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, S. Livingstone 1007, Independencia, Santiago (Chile); Toro, P. [Facultad de Ciencias Físicas y Matemáticas, Universidad de Chile, Av. Beauchef 850, Santiago (Chile); Gamboa, F. [Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Mérida, Depto. de Física Aplicada, Km. 6 Antigua Carretera a Progreso, 97310 Mérida, Yucatán (Mexico); Mazo, M.A.; Nistal, A.; Rubio, J. [Instituto de Cerámica y Vidrio (ICV-CSIC), Kelsen 5, 28049 Madrid (Spain)


    Highlights: • The surface of aramid fibers was functionalized by two acid treatments. • The treatment based on HNO{sub 3}/H{sub 2}SO{sub 4} reduced the mechanical properties of the fibers. • CNTs were deposited on the aramid fibers, reaching electrical conductivity. • Homogeneous CNT distribution was achieved by using pristine fibers or chlorosulfonic acid. - Abstract: Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating (“sizing”), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

  15. Molecular Dynamics Modeling of PPTA Crystals in Aramid Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Mercer, Brian Scott [Univ. of California, Berkeley, CA (United States)


    In this work, molecular dynamics modeling is used to study the mechanical properties of PPTA crystallites, which are the fundamental microstructural building blocks of polymer aramid bers such as Kevlar. Particular focus is given to constant strain rate axial loading simulations of PPTA crystallites, which is motivated by the rate-dependent mechanical properties observed in some experiments with aramid bers. In order to accommodate the covalent bond rupture that occurs in loading a crystallite to failure, the reactive bond order force eld ReaxFF is employed to conduct the simulations. Two major topics are addressed: The rst is the general behavior of PPTA crystallites under strain rate loading. Constant strain rate loading simulations of crystalline PPTA reveal that the crystal failure strain increases with increasing strain rate, while the modulus is not a ected by the strain rate. Increasing temperature lowers both the modulus and the failure strain. The simulations also identify the C N bond connecting the aromatic rings as weakest primary bond along the backbone of the PPTA chain. The e ect of chain-end defects on PPTA micromechanics is explored, and it is found that the presence of a chain-end defect transfers load to the adjacent chains in the hydrogen-bonded sheet in which the defect resides, but does not in uence the behavior of any other chains in the crystal. Chain-end defects are found to lower the strength of the crystal when clustered together, inducing bond failure via stress concentrations arising from the load transfer to bonds in adjacent chains near the defect site. The second topic addressed is the nature of primary and secondary bond failure in crystalline PPTA. Failure of both types of bonds is found to be stochastic in nature and driven by thermal uctuations of the bonds within the crystal. A model is proposed which uses reliability theory to model bonds under constant strain rate loading as components with time-dependent failure rate

  16. Damage detection of hybrid aramid/metal–PVB composite materials using optical fiber sensors

    Directory of Open Access Journals (Sweden)

    A. Kojović


    Full Text Available Embedding optical fiber sensors within laminar thermoplastic composite material results in forming a system known as «smart structure». These sensors present the information about the inner structure health during the material exploitation and especially in the case of exterior impacts when a geometric configuration or the property changes of the material should be expected. This paper evaluates the feasibility of the real-time monitoring of indentation and low energy impact damage in composite laminates from indentation loading and Charpy pendulum impact, using the embedded intensity-based optical fiber sensors. An optical fiber sensing system, which relies solely on monitoring light intensity for providing the indication of the composite structural health, offers simplicity in design and cost-effectiveness. For this, aramid/polyvinylbutyral (PVB and aramid/metal/PVB laminates with embedded optical fibers were fabricated. Four configurations of woven composites were tested, namely, aramid/PVB, and aramid/metal/PVB in three stacking sequences of aramid and metallic woven layers. The initiation of damage and fracture during testing was detected by observation of the intensity drop of light signal transmitted through an optical fiber.

  17. 75 FR 34943 - Defense Federal Acquisition Regulation Supplement; Para-Aramid Fibers and Yarns Manufactured in a... (United States)


    ... does not produce within the U.S. yarns made from staple para-aramid fiber. DoD has now identified 72... there are many small entities involved in the weaving and production of para-aramid fabrics and that it would be devastating to the textile industry to expand the rule to cover the import of woven fabric...

  18. Influence of fiber type and coating on the composite properties of EPDM compounds reinforced with short aramid fibers

    NARCIS (Netherlands)

    Hintze, C.; Shirazi, S.; Wiessner, S.; Talma, A.G.; Heinrich, G.; Noordermeer, J.W.M.


    There is a renewed interest in the application of short aramid fibers in elastomers because of the considerable improvement in mechanical and dynamic properties of the corresponding rubber composites. Possible applications of short aramid fiber–reinforced elastomers are tires, dynamically loaded rub

  19. Accelerated Creep Testing of High Strength Aramid Webbing (United States)

    Jones, Thomas C.; Doggett, William R.; Stnfield, Clarence E.; Valverde, Omar


    A series of preliminary accelerated creep tests were performed on four variants of 12K and 24K lbf rated Vectran webbing to help develop an accelerated creep test methodology and analysis capability for high strength aramid webbings. The variants included pristine, aged, folded and stitched samples. This class of webbings is used in the restraint layer of habitable, inflatable space structures, for which the lifetime properties are currently not well characterized. The Stepped Isothermal Method was used to accelerate the creep life of the webbings and a novel stereo photogrammetry system was used to measure the full-field strains. A custom MATLAB code is described, and used to reduce the strain data to produce master creep curves for the test samples. Initial results show good correlation between replicates; however, it is clear that a larger number of samples are needed to build confidence in the consistency of the results. It is noted that local fiber breaks affect the creep response in a similar manner to increasing the load, thus raising the creep rate and reducing the time to creep failure. The stitched webbings produced the highest variance between replicates, due to the combination of higher local stresses and thread-on-fiber damage. Large variability in the strength of the webbings is also shown to have an impact on the range of predicted creep life.

  20. Surface modification of aramid fiber by plasma induced vapor phase graft polymerization of acrylic acid. I. Influence of plasma conditions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, C.X., E-mail: [College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu 224003 (China); School of Textile and Clothing, Nantong University, Jiangsu 226019 (China); Du, M. [College of Textiles and Clothing, Yancheng Institute of Industry Technology, Jiangsu 224000 (China); Lv, J.C.; Zhou, Q.Q. [College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu 224003 (China); Ren, Y. [School of Textile and Clothing, Nantong University, Jiangsu 226019 (China); Liu, G.L.; Gao, D.W. [College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu 224003 (China); Jin, L.M. [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204 (China)


    Highlights: • Aramid fiber surface was modified by PIVPGP of AA to improve wettability, adhesion. • Surface modification effect by PIVPGP of AA increased and then decreased with time. • Surface modification effect increased and then stayed unaltered with output power. • Ar plasma was the most effective in PIVPGP of AA on aramid fiber surface. • In studied range, optimum technology of PIVPGP of AA: Ar plasma, 15 min, 300 W. - Abstract: Plasma induced vapor phase graft polymerization (PIVPGP) method was applied to modify aramid fiber surface. In this study, aramid fibers were pretreated under various plasma conditions such as different treatment times, output powers and working gases to see how these plasma processing parameters influenced the PIVPGP of acrylic acid (AA) on aramid fiber surface and its surface structure and properties. The analysis results of atomic force microscope (AFM) and X-ray photoelectron spectroscope (XPS) showed the increase of surface roughness and the introduction of O=C−OH, which confirmed that the PIVPGP of AA on aramid fiber surface was achieved. The contact angle and interfacial shear strength (IFSS) of the aramid fibers modified by PIVPGP of AA prominently decreased and increased, respectively, indicating the obvious improvements of surface wettability and adhesion between aramid fiber and matrix. The surface modification effects of aramid fiber by PIVPGP of AA firstly increased and then after 15 min slightly decreased with the increasing plasma treatment time, and but firstly increased and then after 300 W nearly remained unchanged with the increasing output power, respectively. Among different working gases, Ar plasma occupied first place, O{sub 2} plasma and N{sub 2} plasma came second and third in the aspect of PIVPGP of AA on aramid fiber surface, respectively. It could be concluded that the PIVPGP of AA on aramid fiber surface could effectively improve surface wettability and adhesion. Plasma conditions had signally

  1. Pulmonary response to inhaled Kevlar aramid synthetic fibers in rats. (United States)

    Lee, K P; Kelly, D P; Kennedy, G L


    Groups of male rats were exposed to specially prepared ultrafine Kevlar pulp fibers (du Pont's registered trademark for certain aramid fibers) at atmospheric concentrations of either 0.1, 0.5, 3.0, or 18 mg/m3 for 2 weeks. Rats were killed at 0 and 2 weeks and 3 and 6 months postexposure (PE) except the rats exposed to 18 mg/m3, which were killed 0, 4, and 14 days and 1, 3, and 6 months PE. Another group of male rats was exposed to 18 mg/m3 (respirable dust approximately 2.5 mg/m3) of commercial Kevlar fibers for 2 weeks and were killed at 0 and 2 weeks and 3 and 6 months PE. Inhaled ultrafine Kevlar fibers were mostly phagocytized by alveolar macrophages (dust cells) in the alveolar ducts and adjoining alveoli after exposure to either 0.1 or 0.5 micrograms/m3. Most dust cells had disappeared and lungs showed a normal appearance throughout 6 months PE. The pulmonary response almost satisfied the biological criteria for a nuisance dust. Rats exposed to 3 mg/m3 ultrafine Kevlar fibers revealed occasional patchy thickening of alveolar ducts with dust cells and inflammatory cells but with no collagen fibers deposited throughout 6 months PE. After exposure to 18 mg/m3 ultrafine Kevlar, the respiratory bronchioles, alveolar ducts, and adjoining alveoli showed granulomatous lesions with dust cells by 2 weeks PE. The granulomatous lesions converted to patchy fibrotic thickening with dust cells after 1 month PE. The fibrotic lesions were markedly reduced in cellularity, size, and numbers from 3 to 6 months PE but revealed networks of reticulum fibers with slight collagen fiber deposition.

  2. Hybrid repowering of transformers using aramids; Repotenciacao hibrida de transformadores com utilizacao de aramida

    Energy Technology Data Exchange (ETDEWEB)

    Neri Junior, Almir Laranjeira; Correia, Fidelis Botelho [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil)


    Santiago substation of the PETROBRAS, operated with two transformers fabricated in 1971. To preserve the reliability of power supply, it was relaborated a reformation and repowering project of the equipment using aramids, a special polymeric material. This paper describes the phases of the project, and presents the benefits obtained, and also the characteristics of the electric system of the production unit. (author)

  3. Study of Aramid Fiber/Polychloroprene Recycling Process by Thermal Degradation

    Directory of Open Access Journals (Sweden)

    Igor Dabkiewicz


    Full Text Available Aramid fiber is an important polymer applied as reinforcement in high-performance composites, which, due its exceptional properties, becomes an excellent impact absorption material. It has been broadly utilized in aeronautic industry and ballistic protection. In aircrafts, it is mainly used in secondary structures, such as fairings, floor panels, and bullet proof structures in helicopters, whereas, in ballistic protection industry, it is applied in automotive armor and bullet proof vest. Under environmental perspective, it is worrying the development and application of composites, which generate proportional discards of these materials, whether originated from manufacturing process, spare parts or end of life cycle. High-performance composite materials like those using aramid fiber are generally difficult to recycle due to their properties and the difficulty for the separation of the components, making their recycling economically unviable. From the characteristics of composite materials and environmental viewpoint, this paper presents a new aramid fiber recycling process. The main objective of this research was to study different recycling methods in aramid fibers/Neoprene® composites. To promote the Neoprene® degradation, it was used a pyrolysis oven with controlled atmosphere and CO 2 injection. For the degraded separation, it was designed a mechanical washing machine in which the most degraded separation occurred. To complete the materials separation, it was employed a manual cleaning process, and, at least to prove the efficacy of the process, it was applied a tensile test in the yarns.

  4. Short aramid-fiber reinforced ultra-high molecular weight polyethylene

    NARCIS (Netherlands)

    Hofste, JM; Bergmans, KJR; deBoer, J; Wevers, R; Pennings, AJ


    Ultra-High Molecular Weight Polyethylene (UHMWPE) is frequently used in artificial joints because of its high wear resistance. To extend the lifetime of these joints even further, it is necessary to decrease the wear rate. The wear rate may be decreased by blending UHMWPE with short aramid fibers. O

  5. Deposition of carbon nanotubes onto aramid fibers using as-received and chemically modified fibers (United States)

    Rodríguez-Uicab, O.; Avilés, F.; Gonzalez-Chi, P. I.; Canché-Escamilla, G.; Duarte-Aranda, S.; Yazdani-Pedram, M.; Toro, P.; Gamboa, F.; Mazo, M. A.; Nistal, A.; Rubio, J.


    Multiwall carbon nanotubes (MWCNTs) oxidized by an acid treatment were deposited on the surface of as-received commercial aramid fibers containing a surface coating ("sizing"), and fibers modified by either a chlorosulfonic treatment or a mixture of nitric and sulfuric acids. The surface of the aramid fiber activated by the chemical treatments presents increasing density of CO, COOH and OH functional groups. However, these chemical treatments reduced the tensile mechanical properties of the fibers, especially when the nitric and sulfuric acid mixture was used. Characterization of the MWCNTs deposited on the fiber surface was conducted by scanning electron microscopy, Raman spectroscopy mapping and X-ray photoelectron spectroscopy. These characterizations showed higher areal concentration and more homogeneous distribution of MWCNTs over the aramid fibers for as-received fibers and for those modified with chlorosulfonic acid, suggesting the existence of interaction between the oxidized MWCNTs and the fiber coating. The electrical resistance of the MWCNT-modified aramid yarns comprising ∼1000 individual fibers was in the order of MΩ/cm, which renders multifunctional properties.

  6. Validation of the numerical model of single-layer composites reinforced with carbon fiber and aramid (United States)

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


    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.

  7. Isolation of Aramid Nanofibers for High Strength and Toughness Polymer Nanocomposites. (United States)

    Lin, Jiajun; Bang, Sun Hwi; Malakooti, Mohammad H; Sodano, Henry A


    The development of nanoscale reinforcements that can be used to improve the mechanical properties of a polymer remains a challenge due to the long standing difficulties with exfoliation and dispersion of existing materials. The dissimilar chemical nature of common nanofillers (e.g. carbon nanotubes, graphene) and polymeric matrix materials is the main reason for imperfect filler dispersion and consequently, low mechanical performance of their composites relative to theoretical predictions. Here, aramid nanofibers that are intrinsically dispersible in many polymers are prepared from commercial aramid fibers (Kevlar) and isolated through a simple, scalable, and low-cost controlled dissolution method. Integration of the aramid nanofibers in an epoxy resin results in nanocomposites with simultaneously improved elastic modulus, strength and fracture toughness. The improvement of these two mutually exclusive properties of nanocomposites is comparable to the enhancement of widely reported carbon nanotube reinforced nanocomposites but with a cost-effective and more feasible method to achieve uniform and stable dispersion. The results indicate the potential for aramid nanofibers as a new class of reinforcements for polymers.

  8. Forbidden reflections from the aramid PPTA—A novel correlation with stacking faults

    Indian Academy of Sciences (India)

    Anjana Jain; Kalyani Vijayan


    The occurrence of space group forbidden reflections in the X-ray diffraction patterns from the aramid PPTA has been correlated with the presence of stacking faults. The fraction of sample affected by the presence of such faults has also been estimated.

  9. Liquid Crystal Sulfonated Aramids as Proton Exchange Membranes for Fuel Cell Applications

    NARCIS (Netherlands)

    Gao, J.


    Two sulfonated aramids, poly(2,2’-disulfonylbenzidine terephthalamide) (PBDT) and poly(2,2’-disulfonylbenzidine isophthalamide) (PBDI) were synthesized with the aim to explore their unique morphology for proton exchange membrane applications. Due to the different polymer structures, PBDT forms a nem

  10. Wear Behavior of Woven Roving Aramid / Epoxy Composite under Different Conditions

    Directory of Open Access Journals (Sweden)

    Asad A. Khalid


    Full Text Available Wear behavior studies of aramid woven roving /epoxy composite has been conducted. Sliding the material against smooth steel counter face under dry and  lubricated with oil conditions has been investigated. Powder of Silicon carbide has been mixed with the epoxy resin and tested also. The powder was mixed in a volumetric fraction of 10% with the epoxy resin. Four Laminates of six layers were fabricated by hand lay up  method. A pin on disc apparatus has been fabricated to conduct the sliding wear tests on specimens of (4 mm   4 mm   12 mm in size have been cut from the four laminates. The effect of sliding condition including dry, lubricated, dry with additives and lubricated with additives have been studied. Wear rate tests have been conducted at different sliding speeds and loads. Results show that the wear characteristics are influenced by the operating conditions and the construction of the composite material used. It was also found that the wear of aramid /epoxy composite onto the steel counter face were significantly reduced by using lubricant and additives but still took place.Keywords: Wear, Composite materials, Woven roving aramid, Epoxy, Additives, Lubricant.

  11. Exploring a novel multifunctional agent to improve the dispersion of short aramid fiber in polymer matrix

    Directory of Open Access Journals (Sweden)

    K. Naskar


    Full Text Available Composites based on resorcinol formaldehyde latex (RFL coated aramid short fiber and a polyolefin based thermoplastic elastomer, namely ethylene octene copolymer (EOC were prepared by melt mixing technique. The effects of both fiber loading and its length on the mechanical and thermal characteristics of the composite under natural and sheared conditions were investigated. Both the low strain modulus and Young’s modulus were increased as a function of fiber loading and length. However, thermal stability of the composite was found to enhance with increase in fiber loading and was independent of fiber length. Due to poor interfacial interaction between the fiber and the matrix and the formation of fiber aggregation especially with 6 mm fiber at high loading, the elongation and toughness of the composite were found to decrease drastically. In order to solve this problem, a maleic anhydride adducted polybutadiene (MA-g-PB was applied on the aramid fiber. The improvements in tensile strength, elongation at break, toughness to stiffness balance and a good quality of fiber dispersion especially with 6 mm short fiber were achieved. These results indicate the potential use of maleic anhydride adducted PB as a multifunctional interface modifying coupling agent for the aramid short fiber reinforced polymers to enhance the mechanical properties as well as fiber dispersion. FTIR analyses of the treated fiber and SEM analyses of the tensile fractured surfaces of the composite strongly support and explain these results.

  12. From Fragile to Resilient Insulation: Synthesis and Characterization of Aramid-Honeycomb Reinforced Silica Aerogel Composite Materials

    Directory of Open Access Journals (Sweden)

    Marina Schwan


    Full Text Available The production of a new composite material embedding aramid honeycomb materials into nano-porous silica aerogels is studied. Our aim is to improve the poor mechanical strength of silica aerogels by aramid honeycombs without losing the amazing properties of the aerogels like little density and low thermal conductivity. The composite materials were prepared using two formulations of silica aerogels in combination with aramid honeycomb materials of different cell sizes. The silica aerogels are prepared using silicon alkoxides methyltrimethoxysilane and tetraethylorthosilicate as precursors in a two-step acid–base sol–gel process. Shortly in advance of the gelation point, the aramid honeycombs were fluted by the sol, gelation occurred and, after the aging process, the gel bodies were supercritically dried. The properties of the received composite materials are satisfying. Even the thermal conductivities and the densities are a bit higher than for pure aerogels. Most importantly, the mechanical strength is improved by a factor of 2.3 compared to aramid honeycomb materials and by a factor of 10 compared to the two silica aerogels themselves. The composite materials have a good prospective to be used as an impressive insulation material.

  13. Experimental study on the thermostable property of aramid fiber reinforced PE-RT pipes

    Directory of Open Access Journals (Sweden)

    Guoquan Qi


    Full Text Available Flexible composite pipes are advantageous in ultra high strength, high modulus, pH and corrosion resistance and light weight, but there are still some hidden safety troubles because they are poorer in thermostable capacity. Therefore, test samples of flexible composite pipes were prepared with high-temperature polythene (PE-RT as the neck bush and aramid fiber as the reinforcement layer. Experimental study was conducted by using HPHT vessel and differential thermal scanner for different working conditions, different temperatures, whole-pipe pressure-bearing capacity and 1000 h viability. It is shown by the environmental compatibility test that high temperature has little effect on the weight, Vicat softening temperature, mechanical properties and structures of neck bush PE-RT, but exerts an obvious effect on the tensility and whole-pipe water pressure blasting of the reinforcement aramid fiber. Besides, the drop of whole-pipe pressure-bearing capacity is caused by deformation and breaking of aramid fibers when the reinforcement layer is under the force of internal pressure. Finally, disorientation and crystallization of molecular thermal motion occur with the rise of temperature, so amorphous orientation reduces, crystallinity factor and crystalline orientation factor increase gradually, thus, disorientation of macromolecular chains increases and tensile strength decreases. It is concluded that this type of flexible composite pipe can smoothly pass 1000 h viability test. And it is recommended that it be used in the situations with temperature not higher than 95 °C and internal pressure not higher than 4 MPa.

  14. Shape-Memory Properties of Segmented Polymers Containing Aramid Hard Segments and Polycaprolactone Soft Segments

    Directory of Open Access Journals (Sweden)

    Arno Kraft


    Full Text Available A series of segmented multiblock copolymers containing aramid hard segments and extended polycaprolactone soft segments (with an Mn of 4,200 or 8,200 g mol–1 was prepared and tested for their shape-memory properties. Chain extenders were essential to raise the hard segment concentration so that an extended rubbery plateau could be observed. Dynamic mechanical thermal analysis provided a useful guide in identifying (i the presence of a rubbery plateau, (ii the flow temperature, and (iii the temperature when samples started to deform irreversibly.

  15. Plasma penetration depth and mechanical properties of atmospheric plasma-treated 3D aramid woven composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, X.; Yao, L.; Xue, J.; Zhao, D.; Lan, Y.; Qian, X. [Key Laboratory of Textile Science and Technology, Donghua University, Ministry of Education (China); Department of Textile Materials Science and Product Design, College of Textiles, Donghua University, Shanghai 201620 (China); Wang, C.X. [Key Laboratory of Textile Science and Technology, Donghua University, Ministry of Education (China); Department of Textile Materials Science and Product Design, College of Textiles, Donghua University, Shanghai 201620 (China); College of Textiles and Clothing, Yancheng Institute of Technology, Jiangsu 224003 (China); Qiu, Y. [Key Laboratory of Textile Science and Technology, Donghua University, Ministry of Education (China); Department of Textile Materials Science and Product Design, College of Textiles, Donghua University, Shanghai 201620 (China)], E-mail:


    Three-dimensional aramid woven fabrics were treated with atmospheric pressure plasmas, on one side or both sides to determine the plasma penetration depth in the 3D fabrics and the influences on final composite mechanical properties. The properties of the fibers from different layers of the single side treated fabrics, including surface morphology, chemical composition, wettability and adhesion properties were investigated using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), contact angle measurement and microbond tests. Meanwhile, flexural properties of the composites reinforced with the fabrics untreated and treated on both sides were compared using three-point bending tests. The results showed that the fibers from the outer most surface layer of the fabric had a significant improvement in their surface roughness, chemical bonding, wettability and adhesion properties after plasma treatment; the treatment effect gradually diminished for the fibers in the inner layers. In the third layer, the fiber properties remained approximately the same to those of the control. In addition, three-point bending tests indicated that the 3D aramid composite had an increase of 11% in flexural strength and 12% in flexural modulus after the plasma treatment. These results indicate that composite mechanical properties can be improved by the direct fabric treatment instead of fiber treatment with plasmas if the fabric is less than four layers thick.

  16. Mutual irradiation grafting on indigenous aramid fiber-3 in diethanolamine and epichlorohydrin and its effect on interfacially reinforced epoxy composite

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Lixin [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001,China (China); Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Liu, Li, E-mail: [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001,China (China); Xie, Fei [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001,China (China); Huang, Yudong [School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001,China (China); State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150001 (China)


    Highlights: • High energy gamma rays were used to decorate the surface of aramid fiber via mutual irradiation grafting process in two medium. • The effects of different grafting medium on aramid fiber surface were investigated through SEM, AFM, XPS, wettability and adsorption measurements. • Interfacial properties of aramid reinforced polymer composites were remarkable improved after mutual irradiation. - Abstract: The surface of indigenous aramid fiber-3 (IAF3) was decorated via mutual irradiation grafting process in diethanolamine (DEA) and epichlorohydrin (ECH), respectively, with the assist of high energy gamma rays. This modification method with great permeability produced the homogeneous and ameliorative AF3 surfaces, which were observed by the scanning electron microscopy (SEM) and atom forced microscopy (AFM). Enhanced surface free energy and reduced contact angles of irradiated AF3 verified the fabulous effectiveness of mutual irradiation without seriously injured tensile strength. The composites based on epoxy resin (ER) polymer as the matrix and irradiated IAF3 grafted DEA and ECH as the reinforcement. By capitalizing on the irradiated IAF3 which has higher wettability and adsorption on resin, the irradiated IAF3-ECH/ER composites exhibit admirable interfacial mechanical performance as compared to the pristine IAF3 contained composites. The interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and flexural strength of composites were remarkable improved to 86.5, 60.13 and 511 MPa respectively, from the pristine IAF3/ER composite with IFSS of 65.9 MPa, ILSS of 48.1 MPa, and flexural strength of 479 MPa.

  17. Pyrolysis Process in Aramid Fibers Investigated by Py-GC/MS & TGA-DTA/MS

    Institute of Scientific and Technical Information of China (English)

    WANG Xin-wei; HU Zu-ming; LIU Zhao-feng


    Poly(m-phenylene isophthalamine) (PMIA) and Poly( p-phenylene terphthalamine) (PPTA) are among the most important high-temperature resistant aramid fibers. The pyrolysis behaviors of these two fibers under inert gases were studied using pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) and thermogravimetric analysis coupled with mass spectrometry ( TGA-DTA/MS ). The pyrolysis processes of PMIA and PPTA are distinguishing, and the stepwise pyrolysates reflect these differences. A mechanism system of pyrolysis is suggested, which involving hydrolysis and homolysis. At low pyrolysis temperatures, hydrolysis is a primary reaction, and it is very noticeable in the first-step pyrolysis region of PMIA. Elevating pyrolysis temperature, homolysis is enhanced and keep a large advantage in the high temperature range. On the other hand, at higher temperatures, carbonization appens and the homolysis and carbonization of PPTA are emphasized more than of PMIA.

  18. Edge Delamination and Residual Properties of Drilled Carbon Fiber Composites with and without Short-Aramid-Fiber Interleaf (United States)

    Sun, Zhi; Hu, Xiaozhi; Shi, Shanshan; Guo, Xu; Zhang, Yupeng; Chen, Haoran


    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.

  19. Dynamic Mechanical Properties of Aramid Fabrics Impregnated with Carbon Nanotube/Poly (Vinyl Butyral/Ethanol Solution

    Directory of Open Access Journals (Sweden)

    V. Obradović


    Full Text Available In this study six samples of polyurethane/p-aramid multiaxial fabric forms (Colon fabrics were coated with 10 wt.% poly (vinyl butyral (PVB/ethanol solution with the addition of multiwalled carbon nanotubes (MWCNT. The solution was impregnated on both sides of each of the fabrics. All composite samples consisted of four layers of the impregnated fabrics. The MWCNT/PVB content was 0, 0.1 and 1 wt.%. The three samples of the fabrics with different MWCNT/PVB content were coated with γ-aminopropyltriethoxysilane (AMEO silane/ethanol solution due to the surface modification. The mechanical properties of the prepared composite samples were studied by dynamic mechanical analysis (DMA. The 60% increase in storage modulus was achieved by addition of MWCNT and impregnation of aramid fabrics with AMEO silane. The pristine multiwalled carbon nanotubes (MWCNT were introduced in order to enhance additionally the mechanical properties of the materials for ballistic protection.

  20. Deposition, clearance, and shortening of Kevlar para-aramid fibrils in acute, subchronic, and chronic inhalation studies in rats. (United States)

    Kelly, D P; Merriman, E A; Kennedy, G L; Lee, K P


    The deposition and clearance of lung-deposited Kevlar para-aramid fibrils (subfibers) have been investigated as part of a subchronic and chronic inhalation toxicity testing program. Fibrils recovered from lung tissue in para-aramid-exposed Sprague-Dawley rats were microscopically counted and measured after exposures to airborne fibrils which were about 12 microns median length (ML) and < 0.3 micron median diameter. In each of three studies lung-recovered fibrils were progressively shorter with increasing residence time in the lungs. Twenty-eight days after a single 6-hr exposure at 400 respirable fibrils per cubic centimeter (f/cm3) the ML of recovered fibrils decreased to about 5 microns. Twenty-four months after a 3-week exposure to 25 or 400 f/cm3, fibrils reached about 2 microns ML. After 2 years of continuous exposure at 2.5, 25, or 100 f/cm3 or 1 year exposure plus 1 year recovery at 400 f/cm3, fibril ML approached 4 microns. In the 2-year study, the lung-fiber accumulation rate/exposure concentration was similar for the three highest concentrations and was about 3 x greater than that seen at 2.5 f/cm3, indicating that concentrations of about 25 f/cm3 or more may overwhelm clearance mechanisms. Time required for fibrils to be reduced to < 5 microns in the lung was markedly less at lower exposure concentration and shorter exposure time. The primary shortening mechanism is proposed to be long fibril cutting by enzymatic attack at fibril defects. However, length-selective fibril deposition and clearance may contribute to shortening in the first few days after exposure. The enzymatic cutting hypothesis is supported by measured increases in numbers of short fibers following cessation of exposures, continued shortening of the fibril length distribution up to 2 years following exposure, and in vitro fibril shortening after 3 months in a proteolytic enzyme preparation. The conclusion is that para-aramid fibrils are less durable in the lungs of rats than expected from

  1. A Computational Study on the Use of an Aluminium Metal Matrix Composite and Aramid as Alternative Brake Disc and Brake Pad Material

    Directory of Open Access Journals (Sweden)

    Nosa Idusuyi


    Full Text Available A computational model for the heat generation and dissipation in a disk brake during braking and the following release period has been formulated. The model simulates the braking action by investigating the thermal behaviour occurring on the disc and pad surfaces during this period. A comparative study was made between grey cast iron (GCI, asbestos, Aluminium metal matrix composite (AMC, and aramid as brake pad and disc materials. The braking process and following release period were simulated for four material combinations, GCI disc and Asbestos pad, GCI disc and Aramid pad, AMC disc and Asbestos pad, AMC disc and Aramid pad using COMSOL Multiphysics software. The results show similarity in thermal behaviour at the contact surface for the asbestos and aramid brake pad materials with a temperature difference of 1.8 K after 10 seconds. For the brake disc materials, the thermal behaviour was close, with the highest temperature difference being 9.6 K. The GCI had a peak temperature of 489 K at 1.2 seconds and AMC was 465.5 K but cooling to 406.4 K at 10 seconds, while the GCI was 394.7 K.

  2. 国产芳纶在丁腈绝热层的应用研究%Study on the application of domestic aramid ifbre in nitrile in-sulation blanket

    Institute of Scientific and Technical Information of China (English)

    李兰英; 林志娇; 何鑫业; 王凤德


    试验研究了不同长度芳纶短切纤维、浆粕和浆粕母料对丁腈绝热层开炼工艺的影响,不同芳纶单丝纤度对丁腈绝热层力学性能的影响,不同纤维表面处理对芳纶与丁腈橡胶粘合性的影响,以及不同模量芳纶对丁腈绝热层线性烧蚀率的影响。结果表明:芳纶短切纤维以及浆粕母料可满足丁腈绝热层开炼混炼工艺性要求;选用单丝纤度1.33 dtex的高模量芳纶,可获得高于石棉纤维的抗拉强度、伸长率以及线性烧蚀率;选用初始沸点高于160℃的表面处理剂,其芳纶与丁腈橡胶粘合力较好;国产化芳纶完全可以替代致癌物质石棉纤维,用于丁腈绝热层的纤维增强。%Domestic aramid fibre has been used to replace asbestos fiber and the influences of aramid fibre on the properties of ablation resistance nitrile insulation blanket have been studied. Experiments were conducted to study the influences of different lengths of aramid chopped fibre, pulp, pulp masterbatch on nitrile insulation blanket mixing process; different diameters of aramid filament on the mechanical property of nitrile insulation blanket; different fibre surface treatments on the adhesivity between aramid and NBR; different modulus of aramid on the linear ablative rate of nitrile insulation blanket. The results show that:aramid chopped fibre and pulp masterbatch meet the requirements of nitrile insulation blanket’s mixing process; Choosing high modulus aramid filament can obtain higher tensile strength, elongation and linear ablative rate than asbestos fibre; The boiling point of the oil which is used to treat the aramid surface should be higher than 160℃, then the adhesive force between aramid fi-bre and nitrile rubber can be better; Domestic aramid can completely replace carcinogens asbestos fiber to be used as fibre reinforcment in nitrile insulation blanket.

  3. Effect of fibre orientations on the mechanical properties of kenaf–aramid hybrid composites for spall-liner application

    Institute of Scientific and Technical Information of China (English)



    This paper presents the effect of kenaf fibre orientation on the mechanical properties of kenaf–aramid hybrid composites for military vehicle's spall liner application. It was observed that the tensile strength of woven kenaf hybrid composite is almost 20.78%and 43.55%higher than that of UD and mat samples respectively. Charpy impact strength of woven kenaf composites is 19.78%and 52.07%higher than that of UD and mat kenaf hybrid composites respectively. Morphological examinations were carried out using scanning electron microscopy. The results of this study indicate that using kenaf in the form of woven structure could produce a hybrid composite material with high tensile strength and impact resistance properties.

  4. The Research Status and Progress of Aramid Fibers%芳纶纤维的研究现状与进展

    Institute of Scientific and Technical Information of China (English)

    孔海娟; 张蕊; 周建军; 马禹; 滕翠青; 余木火


    This paper reviewed the progress of the aramid fibers and the market demand and the necessity of aramid fiber in China.The related preparation technology and study methods are introduced progress of aramid polymer polymerization methods , the processability of polymer and the comprehensive performance of fiber were improved through the introduction of new polymerization monomer to copolymerization , aramid fiber filament, short-fiber and plasma pulp fiber spinning technology were mentioned , the anionzation of PPTA resin alkylation technology and its application .The surface treatment and modification of the research including surface coating , high-energy rays, plasma processing of physical method and through the surface activeness, surface chemical graft method of aramid fiber were referred , The focus on new technology synchrotron radiation observed aramid fiber structure .With consideration of practical situation in China , authors give some proposals for the domestic Aramid fiber industry , including strengthening fundamental research for a leapfrog development , deepening cross-subject cooperation and integration of key equipment , enhancing the application of Aramid fiber domesti-cally, tightening control over production power , etc.%综述了国内外芳纶纤维生产现状与市场需求。介绍了芳纶纤维制备技术和研发进展包括:共聚合单体设计、聚合反应控制、纺丝工艺、表面改性和结构表征等。并对聚对苯二甲酰对苯二胺( PPTA )树脂的阴离子烷基化技术及其应用作了介绍。详细叙述了表面涂层、高能射线、等离子体处理的物理方法和通过表面活性化、表面接枝等化学方法对芳纶纤维表面进行改性的研究作了详述。给出了采用微聚焦同步辐射新技术观察芳纶纤维结构的结果。结合我国的实际情况,提出了发展我国芳纶产业的建议,包括加强基础研究以促进芳纶纤维工艺技术的完善和快

  5. Antioxidant activity of new aramide nanoparticles containing redox-active N-phthaloyl valine moieties in the hepatic cytochrome P450 system in male rats. (United States)

    Hassan, Hammed H A M; El-Banna, Sabah G; Elhusseiny, Amel F; Mansour, El-Sayed M E


    We report the synthesis of aramide nanoparticles containing a chiral N-phthaloyl valine moiety and their antioxidant activities on hepatic contents of cytochrome P₄₅₀, amidopyrene N-demethylase, aniline-4-hyroxylase and induced the hepatic content of cytochrome b5 and nicotinamide adenine dinucleotide phosphate (NADPH) cytochrome C-reductase. Polymers were obtained as well-separated spherical nanoparticles while highly aggregated particles via H-bonding organization of the aramide-containing pyridine led to a thin layer formation. The effects of the nanoparticles and CCl₄ on enzyme activities and thiobarbituric acid reactive substances (TBARS) levels of male rat liver were studied. Pretreatments of rats with the polyamides prior to the administration of CCl₄ decreased the hepatic content of the tested enzymes. Doses reduced the toxic effects exerted by (•CCl₃) upon the liver through inhibition of the cytochrome P₄₅₀ system. Inhibition of such metabolizing enzymes could reduce the carcinogenic effects of chemical carcinogens.

  6. In situ synthesis and hydrothermal crystallization of nanoanatase TiO2 -SiO2 coating on aramid fabric (HTiSiAF) for UV protection. (United States)

    Deng, Hui; Zhang, Hongda


    TiO2 -SiO2 thin film was prepared by sol-gel method and coated on the aramid fabric to prepare functional textiles. The aramid fabric was dipped and withdrawn in TiO2 -SiO2 gel and hydrothermal crystallization at 80(°) C, then its UV protection functionality was evaluated. The crystalline phase and the surface morphology of TiO2 -SiO2 thin film were characterized using SEM, XRD, and AFM respectively. SEM showed hydrothermal crystallization led to a homogeneous dispersion of anatase nonocrystal in TiO2 -SiO2 film, and XRD suggested the mean particle size of the formed anatase TiO2 was less than 30 nm. AFM indicated that hydrothermal treatment enhanced the crystallization of TiO2 . UV protection analysis suggested that the hydrothermally treated coated textile had a better screening property in comparison with TiO2 -SiO2 gel and native aramid fabric.

  7. The discussion of the photo-thermal fixation process for aramid 1313 fabric%芳纶1313织物使用光热固色工艺探讨

    Institute of Scientific and Technical Information of China (English)

    周东方; 高丽贤


    对芳纶1313织物用光线聚焦的方式进行还原染料染色;在光和热的作用下,激发芳纶纤维和还原染料分子的能量,从而完成对芳纶织物的上染。经过不同光热固色方法固色后的芳纶织物色牢度和上染情况较好,可以用于芳纶织物的染色。%The aramid 1313 fabric was dyed with the vat dyes via light focus The molecules energy of the aramid fibers and vat dyes were excited with light and heat treatment, and the aramid fabric completed dyeing. The color fastness and dyeing effect of the aramid fabric fixed with different methods of photo-thermal fixation were satisfactory. It was found that the photo-thermal fixation can be applied to aramid fabric dyeing process.

  8. Behavior of Aramid Fiber/Ultrahigh Molecular Weight Polyethylene Fiber Hybrid Composites under Charpy Impact and Ballistic Impact

    Institute of Scientific and Technical Information of China (English)


    The aramid fiber/UHMWPE (ultrahigh molecular weight polyethylene) fiber hybrid composites (AF/DF) were manufactured. By Charpy impact, the low velocity impact behavior of AF/DF composite was studied. And the high velocity impact behavior under ballistic impact was also investigated. The influence of hybrid ratio on the performances of low and high velocity impact was analyzed, and hybrid structures with good impact properties under low velocity impact and high velocity were optimized. For Charpy impact, the maximal impact load increased with the accretion of the AF layers for AF/DF hybrid composites. The total impact power was reduced with the decrease of DF layers and the delamination can result in the increase of total impact power. For ballistic impact, the DF ballistic performance was better than that of the AF and the hybrid ratio had a crucial influence. The failure morphology of AF/DF hybrid composite under Charpy impact and ballistic impact was analyzed. The AF/DF hybrid composites in suitable hybrid ratio could attain better performance than AF or DF composites.

  9. Mutual irradiation grafting on indigenous aramid fiber-3 in diethanolamine and epichlorohydrin and its effect on interfacially reinforced epoxy composite (United States)

    Xing, Lixin; Liu, Li; Xie, Fei; Huang, Yudong


    The surface of indigenous aramid fiber-3 (IAF3) was decorated via mutual irradiation grafting process in diethanolamine (DEA) and epichlorohydrin (ECH), respectively, with the assist of high energy gamma rays. This modification method with great permeability produced the homogeneous and ameliorative AF3 surfaces, which were observed by the scanning electron microscopy (SEM) and atom forced microscopy (AFM). Enhanced surface free energy and reduced contact angles of irradiated AF3 verified the fabulous effectiveness of mutual irradiation without seriously injured tensile strength. The composites based on epoxy resin (ER) polymer as the matrix and irradiated IAF3 grafted DEA and ECH as the reinforcement. By capitalizing on the irradiated IAF3 which has higher wettability and adsorption on resin, the irradiated IAF3-ECH/ER composites exhibit admirable interfacial mechanical performance as compared to the pristine IAF3 contained composites. The interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and flexural strength of composites were remarkable improved to 86.5, 60.13 and 511 MPa respectively, from the pristine IAF3/ER composite with IFSS of 65.9 MPa, ILSS of 48.1 MPa, and flexural strength of 479 MPa.

  10. Ballistic Impact Response of Ceramic-Faced Aramid Laminated Composites Against 7.62 mm Armour Piercing Projectiles

    Directory of Open Access Journals (Sweden)

    Nityananda Nayak


    Full Text Available Ballistic impact response of ceramic- composite armor, consisting of zirconia toughened alumina (ZTA ceramic front and aramid laminated composite as backing, against 7.62 mm armor piercing (AP projectiles has been studied. Two types of backing composite laminates i.e. Twaron-epoxy and Twaron-polypropylene (PP of 10 mm and 15 mm thickness were used with a ceramic face of 4mm thick ZTA. The ceramic- faced and the stand alone composite laminates were subjected to ballistic impact of steel core 7.62 mm AP projectiles with varying impact velocities and their V50 ballistic limit (BL was determined. A sharp rise in BL was observed due to addition of ceramic front layer as compared to stand alone ones. The impact energy was absorbed during penetration primarily by fracture of ceramic, deformation and fracture of projectile and elastic-plastic deformation of flexible backing composite layer. The breaking of ceramic tiles were only limited to impact area and did not spread to whole surface and projectile shattering above BL and blunting on impact below BL was observed. The ceramic- faced composites showed higher BL with Twaron-PP as backing than Twaron-epoxy laminate of same thickness. This combination of ceramic-composite laminates exhibited better multi-hit resistance capability; ideal for light weight armor.Defence Science Journal, 2013, 63(4, pp.369-375, DOI:

  11. Surface modification of aramid fibers by bio-inspired poly(dopamine) and epoxy functionalized silane grafting. (United States)

    Sa, Rina; Yan, Yan; Wei, Zhenhai; Zhang, Liqun; Wang, Wencai; Tian, Ming


    A novel biomimetic surface modification method for meta-aramid (MPIA) fibers and the improvement on adhesion with rubber matrix was demonstrated. Inspired by the composition of adhesive proteins in mussels, we used dopamine (DOPA) self-polymerization to form thin, surface-adherent poly(dopamine) (PDA) films onto the surface of MPIA fibers simply by immersing MPIA fibers in a dopamine solution at room temperature. An epoxy functionalized silane (KH560) grafting was then carried out on the surface of the poly(dopamine)-coated MPIA, either by a "one-step" or "two-step" method, to introduce an epoxy group onto the MPIA fiber surface. The surface composition and microstructure of the modified MPIA was characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The results indicated successful grafting of KH560 on the PDA-coated MPIA surface. A single-fiber pull-out test was applied to evaluate the adhesion of MPIA fibers with the rubber matrix. Compared with the untreated MPIA fibers, the adhesion strength between the modified MPIA fibers by "one step" method with rubber matrix has an increase of 62.5%.

  12. Interfacial Bond Property of Aramid Fibers Reinforced Polymer Matrix Composites%芳纶纤维增强树脂基复合材料的界面粘结性能研究

    Institute of Scientific and Technical Information of China (English)

    董超亮; 王耀先; 周洁鹏; 朱恒; 程树军


    In order to improve the interfacial adhesion of aramid fiber reinforced polymer matrix composites, a new thermosetting resin ( AFR-T ) had been developed according to law of similar mutual solubility and the structural characteristics of aramid fibers. With aramid fibers without surface treatment being used for reinforcing materials, AFR-T /aramid composites were prepared by hot-press molding. The interfacial adhesion properties of AFR-T/aramid composites were investigated by the methods of the solubility parameter, contact angle, coefficients of thermal expansion, interlaminar shear strength ( ILSS ) and transverse tensile strength etc.. The results showed that the solubility parameter of AFR-T casting was similar to that of aramid fiber. The contact angle ( 36.9 ° )between AFR-T resin and aramid fiber was smaller than the contact angle ( 53.2 °) between epoxy resin ( EP ) and aramid fiber, it indicated that the wettability of AFR-T resin to aramid fiber was better than that of EP. ILSS and transverse tensile strength of AFR-T / aramid composite were respectively 73.8 MPa and 25.3 MPa, increasing by 25.9% and 32.5% respectively compared with EP/aramid composite. Therefore, AFR-T resin had good interface bonding performance with aramid fiber.%为了改善芳纶纤维增强树脂基复合材料的界面粘结性能,从树脂基体入手,依据相似相容原理和芳纶的结构特点,合成出新型热固性树脂( AFR-T)用作芳纶复合材料的基体,以未经表面处理的芳纶作增强材料,采用热压成型法制备了AFR-T/芳纶纤维复合材料,并通过测定溶度参数、接触角、线膨胀系数、层间剪切强度(ILSS)和横向拉伸强度等方法研究了复合材料的界面粘结性能.结果表明,AFR-T树脂浇注体与芳纶的溶度参数相近,AFR-T 树脂溶液在芳纶纸表面的接触角为36.9°,小于环氧树脂(EP)溶液与芳纶纸的接触角(53.2°),说明AFR-T树脂对芳纶的浸润性优于EP;AFR-T/芳纶纤维复

  13. FT—IR分析芳纶纸基纤维氢键结构%Analysis on the Structure of Hydrogen Bond of Aramid Paper Fibers by FT-IR

    Institute of Scientific and Technical Information of China (English)

    杨斌; 张美云; 李涛; 张素风


    高性能芳纶纤维除了刚性芳环结构贡献外,分子链之间的氢键结构也对其性能有显著影响。本研究采用傅里叶红外光谱分析方法,对比了不同芳纶纤维的红外吸收峰与吸收强度的差异性,揭示不同芳纶纤维表观结晶性能的差异性。研究结果表明:所用的3种芳纶纤维化学结构并无明显差别,而吸收强度的不同很大程度来源于大分子链之间的氢键缔合程度的不同。本方法可以应用于其他含酰胺键的聚合物纤维研究工作。%Aramid fiber not only has rigid aromatic rings, the organizational structure built by the hydrogen bond also have a significant impact on its performance. In this paper, classical analysis on aramid fiber by FT-IR has been used, it has clearly revealed that aramid fiber with different manufacturing process has different apparent crystalline properties. The results showed that: there is no difference in chemical structure with the three samples, there is the difference of absorptivity mostly because of the the difference of crystallinity. Aslo, the crystallinity of aramid pulp are lower than aramid fiber. This method can also be applied to other polymer fibers containing amide bond.

  14. 芳纶1414纱线碱/酸改性的染色工艺%Dyeing process of aramid 1414 yarns modified with acid/alkali

    Institute of Scientific and Technical Information of China (English)

    王春梅; 李朝晖; 季涛


    In this paper, proper dyes, modification methods and dyeing methods are selected to dye the aramid 1414 yarns. Factors exerting influence on dyeing behaviors are studied, such as modification conditions, types and dosages of dyes, pH value of dye bath, dyeing temperature and time. The optimum dyeing process of alkali-modifying aramid with disperse dyes is determined as follows: the dosage of dyes less than 5 % (omf), pH value 5, dyeing at 130 ℃. For 60 min. The color fastness to washing of the dyeings is up to grade 4 ~5 and the color fastness to sublimation is dependent on dye properties. The optimum dyeing process of acid-modifying aramid with cationic dyes is determined as follows; the dosage of dyes less than 5% (omf), pH value 4 ~5, dyeing at 120 ℃ for 60 min. The color fastness to soaping is up to grade 4-5 and the color fastness to sublimation is up to grade 4.%通过选择合适的染料、纤维改性方法及染色方法,对芳纶1414纱线进行染色,探讨改性条件、染料种类和用量、染浴pH值、染色湿度、染色时间等对染色性能的影响.结果表明,经碱改性的芳纶用分散染料染色的最佳工艺为:染料质量分数不超过5%(omf),染液pH值5,在l30℃染色60 min;碱改性染色芳纶纱线的耐皂洗色牢度4~5级,耐升华色牢度与染料品种有较大关系.经酸改性的芳纶用阳离子染料染色的最佳工艺为:染料质量分数不超过5% (omf),染液pH值4~5,在120℃染色60 min;酸改性染色芳纶纱线的耐皂洗色牢度达到4~5级,耐升华色牢度达到4级.

  15. Antimicrobial and antitumor activity of platinum and palladium complexes of novel spherical aramides nanoparticles containing flexibilizing linkages: Structure-property relationship (United States)

    Elhusseiny, Amel F.; Hassan, Hammed H. A. M.


    Square planar Pd (II) and octahedral Pt (IV) complexes with novel spherical aramides nanoparticles containing flexible linkages ligands have been synthesized and characterized using analytical and spectral techniques. The synthesized complexes have been tested for their antimicrobial activity using Kirby-Bauer disc diffusion method. The antitumor activity has been performed using liver carcinoma (HEPG2), breast carcinoma (MCF7) and colon carcinoma (HCT 116) cell lines. Palladium complexes of polyamides containing sulfones showed the highest potency as antibacterial and antifungal agents. Platinum complexes containing sulfone and ether flexible linkages and chloro groups exhibited high potency as antitumor and antimicrobial agents. The uniform sizes of these nanomaterials could find biological uses such as immune assay and other medical purposes.

  16. Compatibility and mechanical properties of liquid crystalline modified aramid reinforced epoxy resin%液晶改性芳纶增强环氧树脂的相容性与力学性能

    Institute of Scientific and Technical Information of China (English)

    张爱玲; 刘慧; 吕震乾; 王松; 李三喜


    针对环氧树脂复合材料存在的应力开裂以及与基体界面相容性差等问题,采用液晶和离子单体对芳纶纤维进行改性,再与环氧树脂及固化剂按一定比例混合,制得液晶改性芳纶增强环氧树脂复合材料.正交试验结果表明,常温下固化20 min,芳纶、环氧树脂与固化剂的质量比为0.07∶35∶11,复合材料的弯曲应力为445.6 MPa,应变为0.975%,比水解芳纶增强环氧树脂复合材料、芳纶增强环氧树脂复合材料的弯曲应力分别提高了29%和33%.扫描电镜研究表明,复合材料中分散相在基体中的分散性较好,有良好的界面相容性,断面处的断裂方式由脆性断裂变为韧性断裂.红外光谱研究表明,加入液晶改性芳纶的复合材料出现了磺酸基团和氮氮双键的特征吸收峰.%To solve such problems as stress crack and poor interface compatibility in epoxy resin composites,a liquid crystalline modified aramid reinforced epoxy resin composite was prepared through modifying aramid fiber by liquid crystalline and ion monomer and then mixing with epoxy resin and curing agent in certain proportion.The results of orthogonal experiment reveal that when the mass ratio of aramid fiber,epoxy resin and curing agent is 0.07∶ 35∶ 11 as well as the curing time at room temperature is 20 minutes,the bending stress and strain of the fabricated composite are 445.6 MPa and 0.975%,respectively.The bending stress of liquid crystalline modified aramid reinforced epoxy resin composite increases by 29% and 33% than that of hydrolytic aramid reinforced epoxy resin composite and raw aramid reinforced epoxy resin composite,respectively.The scanning electron microscope observation shows that the modified aramid has good dispersion and interface compatibility in epoxy resin matrix.The fracture mode for the composite changes from brittle fracture to ductile fracture.The infrared spectroscopy(IR) investigation indicates that the S=O and N

  17. 芳纶毡体/阻尼弹性薄膜复合材料的吸声隔声性能%Sound Absorption and Sound Insulation Properties of Aramid Felt/Damping Elastic Film Composite

    Institute of Scientific and Technical Information of China (English)

    鲁灿灿; 李华; 康红梅; 刘河洲


    Nonwoven aramid felt, damping elastic films, and double, three layer compound structure nonwoven aramid felt/damping elastic film composite materials were prepared. Standing wave tube test method was used to investigate the influence of sound absorption coefficient in different thickness of aramid fdt and different compound structures of the composite. Aramid felt and damping elastic film were placed in reverberation and anechoic room to test the sound-insulation capabilities. The results showed that the sound absorption and sound insulation properties of the three-layer eomposite material was superior to a composite of two layers; for the same thickness of three layer compound materials, good sound-absorption property of the surface layer material should be selected.%制备了非织造芳纶毡体、阻尼弹性薄膜及双层、三层结构的非织造芳纶毡体/阻尼弹性薄膜复合材料.牙1用驻波管测试方法研究了非织造芳纶毡体厚度及不同复合结构对复合材料吸声性能的影响;利用混响室一消声室法研究了各试样的隔声性能。结果表明:三层复合材料的吸声隔声性能优于两层复合材料的;对于厚度相同的三层复合材料,表层材料应选择吸声性能较好的材料。

  18. Comparison Of Flat-Knitted Structures Made Of Poly(P-Phenylene-2,6-Benzobisoxazole) And Para-Aramid Referring To Their Stab Resistance (United States)

    Obermann, M.; Aumann, S.; Heimlich, F.; Weber, M. O.; Schwarz-Pfeiffer, A.


    In the field of protective gear, developers always aim for lighter and more flexible material in order to increase the wearing comfort. Suppliers now work on knitted garments in the sports-sector as well as in workwear and protective gear for policemen or security-agents. In a recent project different knitted structures made of a poly(p-phenylene-2,6-benzobisoxazole) (PBO)-multifilament were compared to their counterparts made of para-aramid. In focus of the comparison stood the stab-resistance linked to either the mass per unit area or the stitch density. The tested fabrics were produced on hand flat knitting machines as well as on electronical flat knitting machines of the type Stoll CMS 330TC4, in order to analyse fabrics with different tightness factor and machine gauges. The stab resistance of the different knitted fabrics was examined according to the standard of the Association of Test Laboratories for Bullet, Stab or Pike Resistant Materials and Construction Standards. The presentation includes the depiction of the results of the test series and their interpretation. Furthermore it will give an outlook on most suitable combinations of materials and structures to be used in protective gear.

  19. 短切芳纶纤维增强水泥砂浆准静态下力学性能研究%Research on Quasi-static Mechanical Properties of Short Cut Aramid Fiber-Reinforced Cement Mortar

    Institute of Scientific and Technical Information of China (English)

    胡海涛; 李妮; 熊杰


    Cement mortar reinforced with different volume fraction of aramid fiber is prepared by two-step dispersions of aramid fibers, the mechanical properties of composites materials are researched when adds cement additives sodium carboxymethylcellulose(CMC) and silicon powder. Result shows that sodium carboxymethylcellulose can improve fibers dispersion effectively. Silicon powder can improve samples' compression strength. The samples' bending strength is increased from 2. 6 MPa to 8. 3 MPa, and the compression strength increased from 29. 5 MPa to 54. 3 MPa, when the volume fraction of aramid fiber is 5vol%.%采用二步法制备不同纤维掺量的短切芳纶纤维增强水泥砂浆试样,研究添加剂羧甲基纤维素钠(CMC)和硅微粉对复合材料力学性能的影响.结果表明:羧甲基纤维素钠能够有效地促进纤维在水中的分散,进而促进其在水泥砂浆中的分散;掺加一定量的硅微粉能够进一步提高试样的压缩强度.当纤维体积分数为5%时,试样的力学性能最好,弯曲强度从2.6 MPa提高到了8.3 MPa,压缩强度也从29.5 MPa提高到了54.3 MPa.

  20. 新型芳纶纤维复合材料用于制造毫米波天线罩的研究%Research of Aramid Fiber Composite on Manufacturing Millimeter-Wave Antenna Radome

    Institute of Scientific and Technical Information of China (English)



    为弥补现有毫米波天线罩战场防护性差的缺点,根据毫米波天线罩的特点,在适用于制造毫米波天线罩的通用材料(E玻璃纤维、石英玻璃纤维复合材料)及新型材料(芳纶纤维复合材料)之间进行理论及试验比较,得出适合于制造具有防弹能力的毫米波天线罩的材料,并对使用该材料的天线罩在防护性、电性能和生产性等方面的性能提升做出评估。%For making up the deficiency of the ballistic resistance capability,with on the property of millimeter-wave an-tenna radome,compare the current material (E glass fiber,quartz glass fiber)and new material (aramid fiber)which are used in manufacturing millimeter-wave antenna radome.We conclude that aramid fiber is very suitable for manufacturing millimeter-wave antenna radome which has the capability of ballistic resistance.Then evaluate the electronic capability,the ballistic resistance capability and the manufacture efficiency.

  1. 碳/芳纶纤维增强混凝土温度变形自约束作用的研究%Research on Self-restraint for Temperature Deformation of Carbon/Aramid Fiber Reinforced Concrete

    Institute of Scientific and Technical Information of China (English)

    姚立宁; 张妃二; 郭仁俊; 谢灵


    用具有温度负膨胀特性参数的碳/芳纶纤维增强水泥及混凝土可以增加其强度及机械性能,同时还可以控制其温度变形以防止开裂.文章根据各向异性材料分析方法,对碳/芳纶纤维增强水泥及混凝土的温度变形自约束作用进行了研究和试验.%Cement and concrete reinforced by carbon and aramid fibers which have negative thermal expansion coefficients can improve strength and mechanical properties. And they can also control temperature deformation in the concrete in order to protect from cracks. This paper investigated on analysis and experiment for self-restraint of temperature deformation in carbon/aramid reinforced concrete according to analysis method in anisotropic materials.

  2. 热氧老化对芳纶Ⅲ纤维结构与性能的影响%Effects of thermal-oxidative aging on structure and properties of aramid fiber Ⅲ

    Institute of Scientific and Technical Information of China (English)

    彭涛; 蔡仁钦; 王凤德; 叶光斗; 徐建军


    采用高温干燥箱在230、250、275、300℃下制备了不同老化状态的芳纶Ⅲ样品,并对老化试样进行了单丝拉伸测试及相应的结构分析.结果表明,在实验温度范围内,芳纶Ⅲ的强度保留率随热氧老化时间的延长和温度的升高而降低;TG和IR分析表明,芳纶Ⅲ的化学结构未随热氧老化处理而发生明显改变;通过X射线衍射分析,发现纤维聚集态结构随温度升高发生重排;SEM测试表明,经过热氧老化纤维的断裂方式从劈裂断裂变成了脆性断裂;最后,结合纤维聚集态结构模型,解释了老化前后纤维力学性能下降的原因及原纤劈裂到脆性断裂的机理.%In order to prepare aramid fiber Ⅲ samples under different thermal-oxidative aging conditions, a series of thermal aging experiment was carried out at the temperatures of 230 ℃, 250 ℃, 270 ℃ and 300 ℃ with the high temperature oven. Single filaments tensile test and relevant structure analysis were implemented with the samples. Results of the single filaments tensile test show that the strength retention of aramid fiber decreases with the time going on as well as the temperature rising up. The TG and IR analysis shows that there's nearly no molecular structure change in the thermal-oxidative aging experiment. By wide angle X-ray scattering (WAXS) analysis, it is found that the aggregate structure changes with temperature rising under thermal-oxidative conditions. By the Scanning Electron Mieroecope ( SEM), it is proved that after thermal-oxidative experiment, the fracture morphology of the filaments changes from bond split failure to the brittle rupture. At last, combined with the model of aggregate structure of the aramid fiber, the reason why the tensile properties drop after thermo-oxidation aging and mechanism of fracture of the fiber was discussed.

  3. Para-Aramid Paper Composite Reinforced by Modified Phenolic Resin%改性酚醛树脂对芳纶1414纸基复合材料的增强作用

    Institute of Scientific and Technical Information of China (English)

    黄睿; 张美云; 陆赵情


    树脂增强是一种有效增强对位芳纶纸的方法。而增强树脂本身特性以及与纤维基体之间的相容性和黏结性是该增强技术的关键所在。针对对位芳纶纸的增强特性,本试验选用3种改性酚醛树脂增强剂制备芳纶1414特种纸基材料,初步探讨浸渍树脂特性、浸渍方式及固化工艺对纸页机械强度和介电性能的影响。在优化条件下增强制备的特种纸基材料各性能指标分别为:抗张指数109.75N·m·g^-1,撕裂指数25.38mN·m^2·g^-1,拉伸率1.91%,耐压强度21.15kV·mm^-1。%Modified phenolic resin was applied as reinforcing resin in para-aramid paper composite. The effects of resin properties, impregnation method and curing process on the performance of para-aramid paper composite were investigated in this study. Xhe performance of samples obtained under the optimized condition were: tensile strength 109.75 N·m·g^-1, tearing strength 25.38 mN·m^2·g^- 1, elongation 1.91%, and dielectric strength 21.15 kV·mm^-1.

  4. 对位芳纶浆粕在密封制品中的应用%The application of para-aramid (PPTA) pulp in sealing product

    Institute of Scientific and Technical Information of China (English)

    邱召明; 马千里; 姜茂忠; 陈文建; 周爱民; 侯春蕾


    介绍了对位芳纶浆粕的发展现状及其无石棉垫片的基本特性,通过应用实例表明泰普龙浆粕能满足无石棉垫片技术和市场的需求。指出随着石棉的禁用和限制以及国产对位芳纶生产质量与规模的快速发展,国产芳纶浆粕将有实质性突破,从而促进国产无石棉垫片的研究与生产。%The development of PPTA-pulp and the basic characters of non-asbestos gasket were introduced in this paper. The application examples show that Taparan pulp can meet the requirement of non-asbestos gasket. With the forbidden of asbestos and the rapid development of domestic Para-aramid, domestic PPTA-pulp will have a substantial breakthrough, so the research and production of domestic non-asbestos gasket will be promoted.

  5. Effect of penetrants on the aramid Nomex

    Indian Academy of Sciences (India)

    Anjana Jain; Kalyani Vijayan


    The response of Nomex sheets to some penetrants has been analyzed. The process of moisture uptake depends on the relative humidity (RH) of the ambient atmosphere and the initial characteristics of the polymer. In the case of common laboratory solvents, the uptake by the polymer shows an inverse dependence on the molar volume of the former. Although the calendered and the uncalendered Nomex sheets exhibit an overall similarity in their response to various penetrants, quantitative comparison reveals distinct differences.

  6. Analysing the nanoporous structure of aramid fibres

    DEFF Research Database (Denmark)

    Pauw, Brian Richard; Vigild, Martin Etchells; Mortensen, Kell;


    After consideration of the applicability of classical methods, a novel analysis method for the characterization of fibre void structures is presented, capable of fitting the entire anisotropic two-dimensional scattering pattern to a model of perfectly aligned, polydisperse ellipsoids. It is tested...... for validity against the computed scattering pattern for a simulated nanostructure, after which it is used to fit the scattering from the void structure of commercially available heat-treated poly(p-phenylene terephtalamide) fibre and its as-spun precursor fibre. The application shows a reasonable fit...

  7. 耐酸型玻纤填充芳纶1313复合针刺毡滤料的制备与性能%Preparation and Properties of Acid Resistant Glass Fiber/Aramid Fiber Compound Filter Materials of Needled Felt

    Institute of Scientific and Technical Information of China (English)

    郑玉婴; 蔡伟龙; 程雷


    By using domestic aramid fiber 1313 and glass fiber as main raw materials,the composite needled felts were prepared by reasonable structure design,process optimization and advanced non-woven needle technology,of which the process included high temperature heat-setting,singeing,calendering,acid-resisting treatment,and so on.The wearability,bursting strength,acid-resistance and filtration performance were characterized;it is found that the compound filter materials have excellent acid-resistance,filtering precision,abrasion resistance and high performance-cost ratio.The scanning electron microscope(SEM) photos show that the surface of composite filters is coated with polytetrafluoroethylene(PTFE),improving chemical resistance and friction coefficient of filter materials.%以国产芳纶1313为主要原料,通过合理的结构设计与工艺优化,填充一定比例的玻璃纤维,利用先进的无纺针刺工艺制作成毡,再经高温热定型、烧毛压光及耐酸处理等多种技术制作成产品。通过对其进行耐磨性、耐破性、耐酸性和过滤性能测试,研究发现,该复合滤料具有强耐酸性、过滤精度高、耐磨损、高性价比等特点。通过扫描电子显微镜观察发现,滤料表面形成一层聚四氟乙烯(PTFE)层,PTFE优良的抗化学性能和较低的摩擦系数大大改善了复合滤料的综合性能。

  8. Nanofibrous polymeric beads from aramid fibers for efficient bilirubin removal. (United States)

    Peng, Zihang; Yang, Ye; Luo, Jiyue; Nie, Chuanxiong; Ma, Lang; Cheng, Chong; Zhao, Changsheng


    Polymer based hemoperfusion has been developed as an effective therapy to remove the extra bilirubin from patients. However, the currently applied materials suffer from either low removal efficiency or poor blood compatibility. In this study, we report the development of a new class of nanofibrous absorbent that exhibited high bilirubin removal efficiency and good blood compatibility. The Kevlar nanofiber was prepared by dissolving micron-sized Kevlar fiber in proper solvent, and the beads were prepared by dropping Kevlar nanofiber solutions into ethanol. Owing to the nanofiborous structure of the Kevlar nanofiber, the beads displayed porous structures and large specific areas, which would facilitate the adsorption of toxins. In the adsorption test, it was noticed that the beads possessed an adsorption capacity higher than 40 mg g(-1) towards bilirubin. In plasma mimetic solutions, the beads still showed high bilirubin removal efficiency. Furthermore, after incorporating with carbon nanotubes, the beads were found to have increased adsorption capacity for human degradation waste. Moreover, the beads showed excellent blood compatibility in terms of a low hemolysis ratio, prolonged clotting times, suppressed coagulant activation, limited platelet activation, and inhibited blood related inflammatory activation. Additionally, the beads showed good compatibility with endothelial cells. In general, the Kevlar nanofiber beads, which integrated with high adsorption capacity, good blood compatibility and low cytotoxicity, may have great potential for hemoperfusion and some other applications in biomedical fields.

  9. Viscoelastic properties of short aramid fibres-reinforced rubbers

    NARCIS (Netherlands)

    Shirazi, S.; Talma, A.G.; Noordermeer, J.W.M.


    Among short fiber-reinforced composites, those with rubber matrices have gained great importance due to the advantages they have in processing and low cost, coupled with high strength. These composites combine the elastic behavior of rubbers with strength and stiffness of fibers. Reinforcement with

  10. 芳纶的市场需求与芳纶浆粕的应用%The Market Demand of Aramid Fiber and Application of Aramid Fiber Pulp

    Institute of Scientific and Technical Information of China (English)




  11. Filament-Level Modeling of Aramid-Based High-Performance Structural Materials (United States)


    is expected to be greatly affected by the specificities related to the polymer chemistry, polymer synthesis and fiber/ yarn /fabric fabrication...Derivation of the Materials Constitutive Relations for Carbon Nanotube Reinforced Poly-Vinyl-Ester-Epoxy Based Compos- ites, J. Mater. Sci., 2007, 42...of Covalent Functionalization of Carbon Nanotube Reinforcements on the Atomic- Level Mechanical Properties of Poly-vinyl-ester-epoxy, Appl. Surf. Sci

  12. The Effect of Moisture on the Properties of an Aramid/Epoxy Composite (United States)


    material. Altho ugh t he we t composi t e has a 10% highe r sing l e-cycle st r eng th , norma l- i zed S-N c urves o f wet and dr y composi t es s how tha...specimens were fabricated from these 8 .5"x0.5" strips. The first and most simple was a modification of the ASTM 03039 specimen which calls f or tabs...of conditioning on ASTM D1822 tensile specimens machin ed from plaques cast from the 934 epoxy (see Figure 25) . The epoxy plaques were - 73

  13. Wear behaviour of discontinuous aramid fibre reinforced ultra-high molecular weight polyethylene

    NARCIS (Netherlands)

    Hofste, JM; Smit, HHG; Pennings, AJ


    The wear of Ultra-High Molecular Weight Polyethylene has generated new concern regarding the long-term clinical performance of total joint replacements. To extend the lifetime of artificial joints, it is necessary to decrease tt-le wear rate of UHMWPE. One possible solution is the incorporation of a

  14. Lung response to ultrafine Kevlar aramid synthetic fibrils following 2-year inhalation exposure in rats. (United States)

    Lee, K P; Kelly, D P; O'Neal, F O; Stadler, J C; Kennedy, G L


    Four groups of 100 male and 100 female rats were exposed to ultrafine Kevlar fibrils at concentrations of 0, 2.5, 25, and 100 fibrils/cc for 6 hr/day, 5 days/week for 2 years. One group was exposed to 400 fibrils/cc for 1 year and allowed to recover for 1 year. At 2.5 fibrils/cc, the lungs had normal alveolar architecture with a few dust-laden macrophages (dust cell response) in the alveolar airspaces. At 25 fibrils/cc, the lungs showed a dust cell response, slight Type II pneumocyte hyperplasia, alveolar bronchiolarization, and a negligible amount of collagenized fibrosis in the alveolar duct region. At 100 fibrils/cc, the same pulmonary responses were seen as at 25 fibrils/cc. In addition, cystic keratinizing squamous cell carcinoma (CKSCC) was found in 4 female rats, but not in male rats. Female rats had more prominent foamy alveolar macrophages, cholesterol granulomas, and alveolar bronchiolarization. These pulmonary lesions were related to the development of CKSCC. The lung tumors were derived from metaplastic squamous cells in areas of alveolar bronchiolarization. At 400 fibrils/cc following 1 year of recovery, the lung dust content, average fiber length, and the pulmonary lesions were markedly reduced, but slight centriacinar emphysema and minimal collagenized fibrosis were found in the alveolar duct region. One male and 6 female rats developed CKSCC. The lung tumors were a unique type of experimentally induced tumors in the rats and have not been seen as spontaneous tumors in man or animals. Therefore, the relevance of this type of lung tumor to the human situation is minimal.

  15. Synthesis and properties of lyotropic poly(amide-block-aramid) copolymers

    NARCIS (Netherlands)

    De Ruijter, C.


    This thesis describes the synthesis and properties of liquid crystalline block copolymers comprised of alternating rigid and flexible blocks for the preparation of self-reinforcing materials. The incentive for this work was the expectation that the rigid segments would phase separate on a microscopi

  16. [Research on structure of MC-nylon 6/aramid composites by spectroanalysis method]. (United States)

    Wang, Can-Yao; Zheng, Yu-Ying


    The Kevlar fiber, treated with toluene-2,4-diisocyanate and caprolactam, was used to reinforce MC nylon 6. XPS showed the change in chemical components and spectra after fiber was treated. IR showed that the spectra of Kevlar fiber and MC-nylon 6 were incorporated purely when they were mixed, while the treated Kevlar fiber provided the activation in the ring-opening polymerization of caprolactam, and the amide groups of graft chains could form strong hydrogen bonds with matrix. These graft chains and hydrogen bonds would contribute to improving interfacial bonding between MC-nylon 6 and Kevlar fiber. XRD indicated that the induction of Kevlar fiber had no effect on the cryastalline style of MC-nylon 6 obviously, however, the crystals had better seasonal structure. The crystals of MC-nylon 6/Kevlar fiber composites were more perfect than that of MC-nylon 6/Kevlar untreated fiber composites with the same amount of Kevlar fiber. The increase of Kevlar fiber contributed to forming perfect a spherulite when the mass concentration of Kevlar fiber was less than 2%, however, the more the Kevlar fiber, the less the content of a spherulite when the mass concentration of Kevlar fiber was more than 2%.

  17. Multi Scale Modeling of Continuous Aramid Fiber Reinforced Polymer Matrix Composites Used in Ballistic Protection Applications (United States)


    discussed within the context of p-phenylene terephthalamide (PPTA) polymeric filaments such as Kevlar ®, Twaron®, etc. Molecular level: A pictorial...Grujicic, M., Bell, W. C., Glomski, P. S., Pandurangan, B., Yen, C.-F. & Cheeseman, B. A. “Multi-length Scale Computational Derivation of Kevlar ® Yarn...Pandurangan, B., Yen, C-.F., Cheeseman, B. A., Wang, Y., Miao, Y. & Zheng, J. Q. “Fiber-level Modeling of Dynamic Strength of Kevlar ® KM2 Ballistic

  18. Ballistic tests on packs made of stratified aramid fabrics LFT SB1 (United States)

    Pirvu, C.; Deleanu, L.; Lazaroaie, C.


    Ballistic experiments are fundamental for body armor new products and help to identify key factors influencing the damage processes of sophisticated materials these armors are made of. Tests made on packs made of LFT SB1 according to Ballistic Resistance of Body Armor NIJ Standard-0101.06-2008 gave good results for the packs made of 24 layers of this fabric and the backface signature (BFS - the depth of the deformation generated in the support material - ballistic clay) was measured. The average value of 23.11 mm recommends this system for protection level of II and IIA, according to the above-mentioned standard. Macro photography investigations pointed out the penetration process in both slim pack (with total penetration) and thick packs (with partial penetration).

  19. Development of Flame Resistant Combat Uniform Fabrics Made from Long Staple Wool and Aramid Blend Yarn (United States)


    loop dryer , slit and framed to a width of 62” with a maximum length overfeed setting on the pin tenter frame. The finished fabric was inspected and...smooth surface), and have very high color fastness properties. The fabrics are inherently FR, machine washable, and tumble dryable without requiring

  20. Adhesion of RFL-treated short-cut Aramid Fibres to Sulphur and Perioxide-cured Elastomers

    NARCIS (Netherlands)

    Shirazi, M.; Talma, A.G.; Noordermeer, J.W.M.


    The thermal history and in particular the mixing dump temperature is a parameter of paramount importance in mixing rubber and silica with a silane coupling agent in order to achieve proper silanization of silica and to avoid premature scorch reactions. In this work, the influence of mixing dump temp

  1. 芳纶Ⅲ防弹性能分析%Anti-ballistic properties of aramid fiber Ⅲ

    Institute of Scientific and Technical Information of China (English)

    刘克杰; 高虹; 黄献聪; 王凤德; 彭涛


    以Staramid F358芳纶Ⅲ作为防弹材料,通过单向复合工艺制造成靶板,采用V50靶板实验研究了芳纶Ⅲ的防弹性能,对其防弹性能进行了理论分析,并与芳纶Ⅱ防弹材料进行了比较.结果表明:芳纶Ⅲ靶板的V50值为572.1 m/s,比吸能值为153 Jm2/kg;芳纶Ⅲ防弹性能比芳纶Ⅱ提高近30%;超高的拉伸断裂强度是芳纶Ⅲ防弹性能更优的根本原因,芳纶Ⅲ的防弹性能还有进一步提升的空间.

  2. Pulmonary cellular effects in rats following aerosol exposures to ultrafine Kevlar aramid fibrils: evidence for biodegradability of inhaled fibrils. (United States)

    Warheit, D B; Kellar, K A; Hartsky, M A


    Previous chronic inhalation studies have shown that high concentrations of Kevlar fibrils produced fibrosis and cystic keratinizing tumors in rats following 2-year inhalation exposures. The current studies were undertaken to evaluate mechanisms and to assess the toxicity of inhaled Kevlar fibrils relative to other reference materials. Rats were exposed to ultrafine Kevlar fibers (fibrils) for 3 or 5 days at concentrations ranging from 600-1300 fibers/cc (gravimetric concentrations ranging from 2-13 mg/m3). A complete characterization of the fiber aerosol and dose was carried out. These measurements included gravimetric concentrations, mass median aerodynamic diameter, fiber number, and count median lengths and diameters of the aerosol. Following exposures, cells and fluids from groups of sham- and fiber-exposed animals were recovered by bronchoalveolar lavage (BAL). Alkaline phosphatase, lactate dehydrogenase (LDH), protein, and N-acetyl glucosaminidase (NAG) values were measured in BAL fluids at several time points postexposure. Alveolar macrophages were cultured and studied for morphology, chemotaxis, and phagocytosis by scanning electron microscopy. The lungs of additional exposed animals were processed for deposition, cell labeling, retained dose, and lung clearance studies, as well as fiber dimensions (from digested lung tissue), histopathology, and transmission electron microscopy. Five-day exposures to Kevlar fibrils elicited a transient granulocytic inflammatory response with concomitant increases in BAL fluid levels of alkaline phosphatase, NAG, LDH, and protein. Unlike the data from silica and asbestos exposures where inflammation persisted, biochemical parameters returned to control levels at time intervals between 1 week and 1 month postexposure. Macrophage function in Kevlar-exposed alveolar macrophages was not significantly different from sham controls at any time period. Cell labeling studies were carried out immediately after exposure, as well as 1 week and 1 month postexposure. Increased pulmonary cell labeling was measured in terminal bronchiolar cells immediately after exposure but returned to control values 1 week later. Fiber clearance studies demonstrated a transient increase in the numbers of retained fibers at 1 week postexposure, with rapid clearance of fibers thereafter. The transient increase in the number of fibers could be due to transverse cleaving of the fibers, since the average lengths of retained fibers continued to decrease over time. In this regard, a progressive decrease in the mean lengths and diameters of inhaled fibers was measured over a 6-month postexposure period.(ABSTRACT TRUNCATED AT 400 WORDS)

  3. Development of coating aramid conveyor belt%芳纶输送带贴胶的研制

    Institute of Scientific and Technical Information of China (English)

    曲成东; 安关福; 宋静芳; 蒋成名



  4. 英威达己二胺和尼龙66聚合物项目在中国上海奠基

    Institute of Scientific and Technical Information of China (English)



    Aluminum glue was made up to coat the outer layer of aramid1313 fabric for new fire insulation clothing . Combustion performance and thermal protective performance of aramid 1313 fabric, before aluminum glue coating and after , were compared .The results show that the damage length of aramid 1313 fabric , coated with aluminum glue , is less than that of aramid1313 fabric and the thermal protective coefficient of the former is higher than aramid1313 fabric.In conclusion, the aramid1313 fabric coated can be used as the outer layer of fire insulation protective clothing , having the advantages of retardant , insula-tion thermal and high temperature thermal protective .

  5. The effect of chromic acid treatment on the mechanical and tribological properties of aramid fibre reinforced ultra-high molecular weight polyethylene composite

    NARCIS (Netherlands)

    Hofste, JM; Pennings, AJ; Schut, J.A.


    Surface oxidation of ultra-high molecular weight polyethylene (UHMWPE) powder has an influence on the mixing procedure of chopped fibres and UHMWPE powder. Due to this oxidation hydrogen bonds can be formed between the fibres and powder particles, leading to a more homogeneous fibre-powder mixture.

  6. 几种高性能芳纶纤维的耐光性评价%Investigation on Photodegradation of High Performance Aramid Fibers

    Institute of Scientific and Technical Information of China (English)

    刘晓艳; 于伟东



  7. Study of the bullet-proof properties of the sandwich structure of armor steel reinforced by aramid fiber%装甲钢复合芳纶泡沫夹层结构防弹性能研究

    Institute of Scientific and Technical Information of China (English)

    李欢秋; 陈德兴; 王洪泳



  8. 芳纶1414纤维生产过程中的节能减排措施%Energy Saving and Emission Reducing Measures in P-Aramide Production

    Institute of Scientific and Technical Information of China (English)




  9. 芳纶Ⅲ与Kevlar-49纤维组成、结构与力学性能的对比%Comparision of Aramid Ⅲ Fibre's Component, Structure and Mechanical Properties With Kevlar-49 Fibre

    Institute of Scientific and Technical Information of China (English)

    周玉玺; 曾金芳; 王斌


    通过红外光谱和元素分析对芳纶Ⅲ和Kevlar-49纤维的进行对比研究得出,芳纶Ⅲ纤维中存在含氮的芳杂环结构,并结合X射线衍射方法分析芳纶Ⅲ和Kevlar-49纤维的晶体结构,其中芳纶Ⅲ纤维的结晶度为30.44%,明显低于Kevlar-49.芳纶Ⅲ力学性能优于Kevlar-49,其拉伸强度、弹性模量和断裂延伸率分别为4 250 MPa、139 MPa和3.2%.

  10. Examining the Relationship Between Ballistic and Structural Properties of Lightweight Thermoplastic Unidirectional Composite Laminates (United States)


    Kevlar KM2® Style 705 PVB phenolic woven aramid composite was included. A developmental unidirectional thermoplastic aramid fiber, Honeywell... discovery and development of the ARL X Hybrid architecture, which consists of 1) the balance of architecture in the panel being 75% [0°/90°] and 25

  11. To Knit a Wall, knit as matrix for composite materials for architecture

    DEFF Research Database (Denmark)

    Ramsgaard Thomsen, Mette; Hicks, Toni


    ), para aramids(Kevlar) and carbon fibre, as well as the new industrialisedand computer controlled fabrication techniques, thispaper examines how advanced technical textiles couldoffer new architectural solutions. Discussing newcomputer aided design (CAD) solutions for developingcomplex surfaces...

  12. Zinc Oxide Nanowire Interphase for Enhanced Lightweight Polymer Fiber Composites (United States)

    Sodano, Henry A.; Brett, Robert


    The objective of this work was to increase the interfacial strength between aramid fiber and epoxy matrix. This was achieved by functionalizing the aramid fiber followed by growth of a layer of ZnO nanowires on the fiber surface such that when embedded into the polymer, the load transfer and bonding area could be substantially enhanced. The functionalization procedure developed here created functional carboxylic acid surface groups that chemically interact with the ZnO and thus greatly enhance the strength of the interface between the fiber and the ZnO.

  13. The effect of particle addition and fibrous reinforcement on epoxy-matrix composites for severe sliding conditions

    DEFF Research Database (Denmark)

    Larsen, Thomas Ricco Ølholm; Løgstrup Andersen, Tom; Thorning, Bent


    This paper reports production and tribological testing of epoxy-matrix composites for dry-sliding conditions. The examined composites are produced using the following components: epoxy resin (EP), glass fiber weave (G), carbon/aramid hybrid weave (CA), PTFE particles and nano-scale CuO particles...... pv conditions all tested composites show signs of decomposition. Despite this, glass fiber reinforcement has a relatively steady behavior while carbon/aramid reinforcement gives raise to a gradually increasing frictional force, which ultimately results in complete failure of the test-specimen. (c...

  14. MOSES - Inflatable Causeway (United States)


    buoyant. Kevlar and Zylon are good alternatives, but they are denser then water, hence they will not float. The draw back from Supreme Protector...Retention % (due to UV rays after 6 Months) Zylon AS 5.8 1.54 3.5 90 35 Zylon HM 5.8 1.56 2.5 N/A 35 p-Aramid 2.8 1.45 2.4 100 N/A m-Aramid...Sites. Off- Shore Air Compressors. 15 June 2007. <> Toyobo Family of Sites. Zylon Fabric. 19

  15. Bio-Based Nanocomposites: An Alternative to Traditional Composites (United States)

    Tate, Jitendra S.; Akinola, Adekunle T.; Kabakov, Dmitri


    Polymer matrix composites (PMC), often referred to as fiber reinforced plastics (FRP), consist of fiber reinforcement (E-glass, S2-glass, aramid, carbon, or natural fibers) and polymer matrix/resin (polyester, vinyl ester, polyurethane, phenolic, and epoxies). Eglass/ polyester and E-glass/vinyl ester composites are extensively used in the marine,…

  16. High-pressure apparatus

    NARCIS (Netherlands)

    Schepdael, van L.J.M.; Bartels, P.V.; Berg, van den R.W.


    The invention relates to a high-pressure device (1) having a cylindrical high-pressure vessel (3) and prestressing means in order to exert an axial pressure on the vessel. The vessel (3) can have been formed from a number of layers of composite material, such as glass, carbon or aramide fibers which

  17. Surface charges in blending short fibres with polyethylene powder

    NARCIS (Netherlands)

    Hofste, JM; Kersten, MJE; van Turnhout, J; Pennings, AJ


    Short fibres and ultra-high molecular weight polyethylene (UHMWPE) powder were mixed by swirling in a glass jar with compressed nitrogen. It was found that a kind of attraction between the fibres and UHMWPE particles is crucial for making a composite with a proper fibre distribution. If aramid and U

  18. Man-made respirable-sized organic fibers: what do we know about their toxicological profiles? (United States)

    Warheit, D B; Reed, K L; Webb, T R


    Man-made organic fibers (MMOFs) have been manufactured for over 50 years. Until recently, there have been few concerns raised regarding the safety of organic fiber dusts. This is due, in large part, to the perception that the dimensions of most, if not all, of these products were too large to be inhaled into the distal lungs of workers, i.e., were considered to be nonrespirable. A brief review of some of the issues related to organic fiber toxicology is presented herein. Some of the organic fiber-types used in commerce are identified and some fundamental tenets of fiber toxicology are discussed. In addition, the European Union, in their recent consideration for banning chrysotile asbestos fibers, evaluated some organic fiber substitutes and compared them to the hazards of asbestos. A brief review of their conclusions is described below. Finally, the results of some recent studies assessing the mechanisms of biodegradability of para-aramid respirable-sized, fiber-shaped particulates (RFP) are presented. Para-aramid (p-aramid) RFP are the most extensively-studied respirable organic fiber-type and RFP is the new term which describes respirable-sized organic fibers (ECETOC, 1996) (1). The results of these studies provide clues regarding the mechanism(s) of p-aramid RFP shortening in the lungs of exposed animals, and may be relevant for humans.

  19. Mechanical anchorage of FRP tendons – A literature review

    DEFF Research Database (Denmark)

    Schmidt, Jacob W.; Bennitz, Anders; Täljsten, Björn


    anchorage systems for use with Aramid, Glass and Carbon FRP tendons have been proposed over the last two decades. Each system is usually tailored to a particular type of tendon. This paper presents a brief overview of bonded anchorage applications while the primary literature review discusses three methods...

  20. Inventory of Materials to be Used in Explosive Effects Mitigating Structures (Inventarisatie van materialen te gebruiken in constructies ter afscherming van explosie-effecten) (United States)


    PBO vezel ( Zylon ) en PIPD vezel (M5). Deze voorbeelden zullen kort worden besproken. TNO-rapport | TNO-DV 2008 A357 21 / 44 Aramide en PE... ZYLON ® (PBO fiber) Technical Information. Toyobo brochure, revision 2005.6, 2005. [8] Andres Leal, A., et al., Assessment of compressive

  1. Modelling poly(p-phenylene teraphthalamide) at Extreme Tensile Loading using Reactive Potentials (United States)

    Yilmaz, Dundar


    Aromatic polyamides classified as rigid-rod polymers due to orientation of their monomers. Because of their excellent mechanical and thermal properties, aramids are widely used in the industry. For example DuPont's brand Kevlar, for its commercial aromatic polyamide polymer, due to wide usage of this polymer in ballistic applications, habitually used as a nickname for bulletproof vests. In order to engineer these ballistic fabrics, material properties of aramid fibers should be studied. In this work we focused on the poly(p-phenylene teraphthalamide) PPTA fiber, known as brand name Kevlar. We employed Reactive potentials to simulate PPTA polymer under tensile loading. We first simulated both amorphous and crystalline phases of PPTA. We also introduced defects with varying densities. We further analysed the recorded atomic positions data to understand how tensile load distributed and failure mechanisms at extreme tensile loads. This work supported by TUBITAK under Grant No: 113F358.

  2. Method for Cleaning Laser-Drilled Holes on Printed Wiring Boards by Plasma Treatment (United States)

    Hirogaki, Toshiki; Aoyama, Eiichi; Minagi, Ryu; Ogawa, Keiji; Katayama, Tsutao; Matsuoka, Takashi; Inoue, Hisahiro

    We propose a new method for cleaning blind via holes after laser drilling of PWBs using oxygen plasma treatment. This report dealt with three kinds of PWB materials: epoxy resin and two kinds of aramid fiber reinforced plastics (AFRP: Technora or Kevlar fiber reinforcement). We observed the drilled holes after plasma treatment using both an optical and a scanning electric microscope (SEM). It was confirmed that adequate etching took place in the drilled holes by plasma treatment. We also compared the hole wall and hole bottom after plasma treatment with ones after chemical etching. It was clear that there was no damage to the aramid fiber tip on the hole wall, and that a smooth roughness of the hole wall was obtained by means of plasma treatment. As a result, we demonstrated that the plasma treatment is effective in cleaning the laser drilled holes of PWBs.

  3. Development of Textile Laminates for Improved Cut Resistance

    Directory of Open Access Journals (Sweden)

    G. Thilagavathi


    Full Text Available Mechanical properties of fibres viz. tensile modulus, tenacity, elongation are the key performance indicators of cut resistance besides yarn and fabric structure. p-aramid and UHDPE (Ultra High Density Polyethylene based high performance fibres are most commonly used for protection against mechanical risks. Specially engineered composite yarns and fabrics would help enhance cut resistance. This paper discusses on the influence textile structure configuration on the performance of cut resistant textiles. A three tier laminate composite was made using knitted Kevlar fabric (p-aramid as outer surface, Polyurethane foam in the middle and a knitted nylon fabric as skin contact layer. This specially engineered laminate showed a 20% increase in cut resistance force when compared with the Kevlar fabric used for lamination. The combination of breathable PU foam and knitted structure of fabric yielded high stretch with improved breathability and dexterity.

  4. Analysis of discontinuities influence on the differences between static and dynamic elastic modulus of composite materials (United States)

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


    The influence of discontinuities is important for a correct determination of static and dynamic elastic characteristics of the material. In this paper we presented differences arising between the elastic modulus static and dynamic, laminated composite materials reinforced with carbon fiber, aramid and carbon-aramid, depending on the non-uniformity coefficient. For the study were determined static elastic modulus by carrying out traction tests and dynamic elastic modulus by determining the vibration frequency, on specimens of each type of material with and without discontinuities [1]. The elastic properties of composite materials resistance and can be influenced by various defects that arise from technological manufacturing process. This is important for the production of large series of parts of fiber-reinforced composite material, the fibers in the matrix distribution is not uniform. Studies on the mechanical behavior of composites with random distribution of fabrics are made in [2].

  5. Strength Distribution Analysis of Typical Staple Fibers

    Institute of Scientific and Technical Information of China (English)


    The strength of staple fiber is an important property for yarns and fabrics. Usually there are variations in individual fiber strength, and this will affect the final strength of yarns and fabrics. In this study, Weibull distribution function is used to analyze the strength distribution of various staplefibers. The strengths of wool, silk, cotton, flax, acrylic, polyester, glass, aramid and carbon fiber are tested. It isfound that the strengths of cotton, polyester, glass, aramid and carbon fiber fit well with the two-factor Weibulldistribution, while those of wool and silk with the threefactir Weibull distribution. However, the strength distributionof flax cannot be expressed by either two- or three-factor Weibull distribution convincingly.

  6. Thermal fatigue of composites: Ultrasonic and SEM evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, D.S.; Kasap, S.O. (Univ. of Saskatchewan, Saskatoon (Canada). Dept. of Electrical Engineering); Wacker, I.; Yannacopoulos, S. (Univ. of Saskatchewan, Saskatoon (Canada). Dept. of Mechanical Engineering)


    Results are presented on the evaluation of thermal fatigue in three fiber reinforced polymer composites, using ultrasonic techniques and scanning electron microscopy. The composites examined were (a) continuous carbon fibers in a vinylester matrix (b) continuous aramid fibers in a vinylester matrix and (c) randomly oriented aramid fibers in a polyphenylene matrix. Specimens of these composites were subjected to thermal fatigue by thermal cycling from [minus]25 C to 75 C. Changes in ultrasonic attenuation and velocity were monitored during thermal cycling, and scanning electron microscopy was used to qualitatively evaluate any damage. It was observed that ultrasonic attenuation is sensitive to thermal fatigue, increasing with increasing number of thermal cycles. SEM evaluations showed that the primary damage due to thermal fatigue is due to fiber-matrix debonding.

  7. Processing and Evaluation of 3D-Reinforced Needled Composite Laminate (United States)


    laminates using the Vacuum Assisted Resin Transfer Molding ( VARTM ) process. Specimens were then cut from the cured parent panels and inspected with...before the panel was processed with VARTM . A significant quantity of aramid could be seen protruding from the backside of the laminate as well as...embedded in the foam backer, indicating inefficiency in this handheld processing method. After the panel was processed with VARTM , the TTR was observed


    Institute of Scientific and Technical Information of China (English)

    Ping-ping Zhang; Tao-yi Zhang; Chuan-feng Zhu; Yu-xia Diao; You-zhi Wan; Ping Xie; Rong-ben Zhang


    An ordered ladder polyester (LPE) was first synthesized through the ladder superstructure (LS) constructed by concerted interactions of hydroxyl- and aramide-based H-bonding and p-terphenyl (TP)-based π-stacking by dehydrochlorination condensation using phosgene (COCl2) as coupling agent. LPE was characterized by GPC, FTIR, NMR,XRD, DSC and AFM. Among them, a distinct image of regularly linear alignment corresponding to the ladder main chain of LPE was first revealed by high-resolution AFM.

  9. Tensile Properties of Fiber Materials under Different Strain Rates

    Institute of Scientific and Technical Information of China (English)

    XIONG Jie; GU Bo-hong; WANG Shan-yuan


    The quasi-static and dynamic tensile tests of aranid and high strength PVA fiber bundles are carried out under a wider range of strain rate by use of MTS (Materials Testing System) and bar-bar tensile impact apparatus.The influences of strain rate on mechanical properties of aramid and high strength polyvinyl alcohol fibers ar estudied. Micro failure mechanisms of fibers at different strain rates are examined by means of SEM.

  10. Soft Body Armor: An Overview of Materials, Manufacturing, Testing, and Ballistic Impact Dynamics (United States)


    manufacturing technology during the 20th century led to the discovery of advanced manmade textile materials (such as nylon, fiberglass, Kevlar , and...include Honeywell’s Spectra Shield (ultrahigh molecular weight polyethylene (UHMWPE) fibers) and Gold Shield ( Kevlar fibers)1 and DSM’s Dyneema...thermoplastic polymers require melt spinning, and thermoset polymers require dissolution in a solvent. Aramid ( Kevlar ) and UHMWPE (Dyneema and Spectra

  11. Use of composite materials in oil industry


    Trifunović, Prvoslav


    The most frequently used composites for fabrication of primary and secondary constructions within the oil industry are made of epoxy, phenolic or polymer matrix combined with glass, carbon or aramid fibers. For fabrication of risers, thermoplastic polymers (polyethylene, polyvinyldenefluoride, and polyamide) are used, which are to be wound around steel reinforcement of riser. Polymer may be reinforced with glass or carbon fibers. Instead of thermoplastic polymers, epoxy matrix reinforced with...

  12. Non-Destructive Evaluation of Aerospace Composites (United States)


    such as carbon and aramid fiber reinforced polymer composites . The results of such an effort would be improved by an enhanced THz imaging system...bending damage, and (e) sub-surface voids and delamination. ..................................39 14. Ultrasonic scans of fiberglass composite samples at...products [4], and polymer matrix composites (PMCs) [5, 6, 7]. This thesis provides a comparison study of pulsed terahertz imaging versus conventional

  13. Key Elements of Protection for Military Textiles (United States)


    a ballistic vest system consisting of composite, high-strength para -aramid fi bers (Kevlar), and boron carbide ceramic plates wrap- ped in ultra...iridescence because they possess no physiological means to control the refl ected colors aside from changing the angle of the iridescent surface...armor plates, e.g. boron nitride, tungsten carbide, tungsten disulfi de, aluminum nitride, and so forth, coated or contained in high-mod- ulus organic

  14. Strength Evaluation of Steel-Nylon Hybrid Fibre Reinforced Concrete


    Maniram Kumar; Er. Ankush Khadwal


    When fibres like steel, glass, polypropylene, nylon, carbon, aramid, polyester, jute, etc are mixed with concrete known as fibre reinforced concrete. To overcome the deficiencies of concrete; fibres are added to improve the performance of concrete. In this research hybrid reinforced concrete is made by using steel and nylon 6 fibres. The inclusion of both steel and nylon 6 fibres are used in order to combine the benefits of both fibers; structural improvements provided by stee...

  15. Improved Barriers to Turbine Engine Fragments: Interim Report IV (United States)


    Specifically, fabrics of certain aramids (Kevlar and Twaron), polyethylenes (Spectra and Dyneema), and polybenzobisoxazole (PBO, Zylon) appeared able to...stretching over one vertical frame segment, instead of the more modem, -0.25-in.-thick, plastic honeycomb/ fiber -reinforced resin composites, stretching accelerated down the barrel of the gas gun. Two fiber -optic light sensors located near the end of the barrel record the passage of alternate light

  16. Mulberry 21: Rapidly Deployable and Recoverable Harbor (United States)


    9: Pump Sketch Material Tensile Strength Density (g/cm3) Elongation % (at th Retention% (in l af Stren Kevlar and Zylon are good...damage after 6 months) 3.5% NaC ter 6 months ) (Gpa) failure) Zylon AS 5.8 1.54 3.5 90 35 Zylon HM 5.8 1.56 2.5 N/A 35 p-Aramid 2.8 1.45 2.4 100

  17. Influence of Chemical Surface Modification of Woven Fabrics on Ballistic and Stab Protection of Multilayer Packets

    Directory of Open Access Journals (Sweden)



    Full Text Available In order to achieve enhanced protective and wear (flexibility, less bulkiness properties of ballistic and stab protecting panels the investigation of chemical surface modification of woven p-aramid fabrics was performed applying different chemical composition shear thickening fluid (STF which improves friction inside fabric structure. For the chemical treatment silicic acid and acrylic dispersion water solutions were used and influence of their different concentrations on panels’ protective properties were investigated. Results of ballistic tests of multilayer protective panel have revealed that shear thickening effect was negligible when shooting at high energy range (E > 440 J. Determination of stab resistance of p-aramid panels has shown that different chemical composition of STFs had different influence on protective properties of the panels. Application of low concentrations of silicic acid determined higher stab resistance values comparing to higher concentrations of acrylic dispersion water solutions. At this stage of research stab tests results as ballistic ones determined that STF application for multilayer p-aramid fabrics protective panels is more efficient at low strike energy levels. DOI:

  18. Test study on the performance of shielding configuration with stuffed layer under hypervelocity impact (United States)

    Ke, Fa-wei; Huang, Jie; Wen, Xue-zhong; Ma, Zhao-xia; Liu, Sen


    In order to study the cracking and intercepting mechanism of stuffed layer configuration on the debris cloud and to develop stuffed layer configuration with better performance, the hypervelocity impact tests on shielding configurations with stuffed layer were carried out. Firstly, the hypervelocity impact tests on the shielding configuration with stuffed layer of 3 layer ceramic fibre and 3 layer aramid fibre were finished, the study results showed that the debris cloud generated by the aluminum sphere impacting bumper at the velocity of about 6.2 km/s would be racked and intercepted by the stuffed layer configuration efficiently when the ceramic fibre layers and aramid fibre layers were jointed together, however, the shielding performance would be declined when the ceramic fibre layers and aramid fibre layers were divided by some distance. The mechanism of stuffed layer racking and intercepting the debris cloud was analyzed according to the above test results. Secondly, based on the mechanism of the stuffed layer cracking and intercepint debirs cloud the hypervelocity impact tests on the following three stuffed layer structures with the equivalent areal density to the 1 mm-thick aluminum plate were also carried out to compare their performance of cracking and intercepting debris cloud. The mechanisms of stuffed layer racking and intercepting the debris cloud were validated by the test result. Thirdly, the influence of the stuffed layer position on the shielding performance was studied by the test, too. The test results would provide reference for the design of better performance shielding configuration with stuffed layer.

  19. 有机特种纤维介绍(一)%Introduction of the Organic Special Fiber

    Institute of Scientific and Technical Information of China (English)

    刘克杰; 杨琴; 朱华兰; 彭涛; 王凤德


    In this article, the organic special fibers of poly-m-phenylene isophthalamide fiber, poly-p-phenylene terephthalamide fiber, Technora (R) and heterocyclic copolymer aramid fiber Ⅲ are introduced systematically and briefly including structure and performance, development, preparation method and main application fields. Finally, the development process of aramid fiber is briefly summarized, the product improvement methods are analyzed and the prospect of aramid fiber is pointed out that it will be better and better.%对有机特种纤维中的芳纶1313、芳纶1414、Technora(R)纤维、杂环共聚芳纶Ⅲ的结构与性能、发展情况、制备方法以及主要应用领域进行了简要介绍.最后简要总结了芳纶的发展过程,分析了其产品改进方法,指出芳纶的发展前景将会越来越好.

  20. Fused Deposition Technique for Continuous Fiber Reinforced Thermoplastic (United States)

    Bettini, Paolo; Alitta, Gianluca; Sala, Giuseppe; Di Landro, Luca


    A simple technique for the production of continuous fiber reinforced thermoplastic by fused deposition modeling, which involves a common 3D printer with quite limited modifications, is presented. An adequate setting of processing parameters and deposition path allows to obtain components with well-enhanced mechanical characteristics compared to conventional 3D printed items. The most relevant problems related to the simultaneous feeding of fibers and polymer are discussed. The properties of obtained aramid fiber reinforced polylactic acid (PLA) in terms of impregnation quality and of mechanical response are measured.

  1. Durabilité des fibres polyaramides en milieu alcalin




    Les fibres polyamides aromatiques, appelées plus couramment "fibres aramides", sont des fibres polymères synthétiques à forte anisotropie. Ces fibres "hautes performances" présentent en outre un module élevé, une résistance mécanique et une rigidité excellentes ainsi qu'une faible densité et une grande résistance thermique qui ont rendu leur utilisation intéressante dans des applications telles que les vêtements de protection contre le feu, la balistique, les matériaux composites, la câblerie...

  2. Influence of Stacking Sequence and Notch Angle on the Charpy Impact Behavior of Hybrid Composites (United States)

    Behnia, S.; Daghigh, V.; Nikbin, K.; Fereidoon, A.; Ghorbani, J.


    The low-velocity impact behavior of hybrid composite laminates was investigated. The epoxy matrix was reinforced with aramid, glass, basalt, and carbon fabrics using the hand lay-up technique. Different stacking sequences and notch angles were and notch angles considered and tested using a Charpy impact testing machine to study the hybridization and notch angle effects on the impact response of the hybrid composites. The energy absorption capability of specimens with different stacking sequences and notch angles is compared and discussed. It is shown that the hybridization can enhance the mechanical performance of composite materials.

  3. 高强轻质的开夫拉(Kevlar)

    Institute of Scientific and Technical Information of China (English)


    @@ 开夫拉(Kevler),实际上是众所周知的HMA(High Modular Aramid,高模芳香尼龙),以极高的成纤强度著称,"Kevlar"为商品名,因杜邦公司最早批量生产这种纤维而使"Kevlar"声名远扬,甚至成为高强尼龙的代名词.因其超高的强力和较轻的比重,开夫拉纤维被优先应用于军用防弹防刺服及航空材料当中.

  4. Feasibility of Kevlar 49/PMR-15 polyimide for high temperature applications (United States)

    Hanson, M. P.


    Kevlar 49 aramid organic fiber reinforced PMR-15 polyimide laminates were characterized to determine the applicability of the material to high temperature aerospace structures. Kevlar 49/3501-6 epoxy laminates were fabricated and characterized for comparison with the Kevlar 49/PMR-15 polyimide material. Flexural strengths and moduli and interlaminar shear strengths were determined from 75 to 600 F for the PMR-15 and from 75 to 450 F for the Kevlar 49/3501-6 epoxy material. The study also included the effects of hydrothermal and long-term elevated temperature exposures on the flexural strengths and moduli and the interlaminar shear strengths.

  5. Fused Deposition Technique for Continuous Fiber Reinforced Thermoplastic (United States)

    Bettini, Paolo; Alitta, Gianluca; Sala, Giuseppe; Di Landro, Luca


    A simple technique for the production of continuous fiber reinforced thermoplastic by fused deposition modeling, which involves a common 3D printer with quite limited modifications, is presented. An adequate setting of processing parameters and deposition path allows to obtain components with well-enhanced mechanical characteristics compared to conventional 3D printed items. The most relevant problems related to the simultaneous feeding of fibers and polymer are discussed. The properties of obtained aramid fiber reinforced polylactic acid (PLA) in terms of impregnation quality and of mechanical response are measured.

  6. Machining of fiber reinforced composites (United States)

    Komanduri, Ranga; Zhang, Bi; Vissa, Chandra M.

    Factors involved in machining of fiber-reinforced composites are reviewed. Consideration is given to properties of composites reinforced with boron filaments, glass fibers, aramid fibers, carbon fibers, and silicon carbide fibers and to polymer (organic) matrix composites, metal matrix composites, and ceramic matrix composites, as well as to the processes used in conventional machining of boron-titanium composites and of composites reinforced by each of these fibers. Particular attention is given to the methods of nonconventional machining, such as laser machining, water jet cutting, electrical discharge machining, and ultrasonic assisted machining. Also discussed are safety precautions which must be taken during machining of fiber-containing composites.


    Directory of Open Access Journals (Sweden)

    Radek Zigler


    Full Text Available Modern, progressive methods of structures’ strengthening based on the use of composite materials composed of high strength fibers (carbon, glass, aramid or basalt and matrices based on epoxy resins brings, among many indisputable advantages (low weight, high effectiveness, easy application etc. also some disadvantages. One of the major disadvantages is a low fire resistance of these materials due to the low glass transition temperature Tg of the resin used. Based on an extensive research of strengthening of historic structures with FRP materials [1], the article outlines possible approaches to this problem, especially while strengthening timber load- bearing structures of historic buildings.

  8. Synthesis and application of hyperbranched polyester in PET fiber modification%超支化聚酯的合成及其对PET纤维的改性研究

    Institute of Scientific and Technical Information of China (English)

    徐德增; 柳雄辉; 程雪


    以三羟甲基丙烷作为中心核,二羟甲基丙酸为合成单体,对甲苯磺酸作为催化剂,采用一步法分别合成了第二代、第三代、第四代不同代数的端羟基超支化聚酯(HBP),并对其结构进行了表征.将不同代数的HBP与聚对苯二甲酸乙二醇酯(PET)共混纺丝制备了HBP/PET共混纤维,研究了纤维的流变性能、力学性能、染色性能和吸湿性能.结果表明:合成的不同代数的HBP结构单一,存在大量羟基;HBP/PET共混物表现出非牛顿流体特征;HBP/PET共混纤维的染色性和吸湿性提高,力学性能下降,但随着HBP代数增加,共混纤维断裂强度增加.HBP质量分数为2%时,第四代HBP/PET共混纤维的断裂强度达2.72 cN/dtex,上染率达47.6%,回潮率达0.817%.%Aramid fiber and ultrahigh-strength polyethylene fiber were subjected to helium/oxygen atmospheric pressure plasma treatment at the relatively humidity of 5% , 65% and 95% , respectively. The interlaminar shear strength of treated and untreated fibers with epoxy resin was measured by single fiber pull-out experiment. The change of fiber surface morphology and chemical composition was analyzed before and after plasma treatment with an atomic force microscope and X -ray phtoelection spectrosope. The results showed that moisture enhanced the etching on the surface of aramid fiber during plasma treatment, but provided less etching effect on the surface of ultrahigh-strength polyethylene when the environmental humidity was elevated. Meanwhile, the oxygen and nitrogen element contents were increased on the surface of aramid fiber and the oxygen element content was also increased on the surface of ultrahigh-strength polyethylene fiber. The interlaminar shear strength increased between aramid fiber and resin, but did not significantly increase between ultrahigh-strength polyethylene fiber and resin, and the tensile strength of the fibers did not obviously change.

  9. A new experimental setup to characterize the dynamic mechanical behaviour of ballistic yarns (United States)

    Chevalier, C.; Kerisit, C.; Boussu, F.; Coutellier, D.; Faderl, N.; Klavzar, A.


    Fabrics have been widely used as part of ballistic protections since the 1970s and the development of new ballistic solutions made from fabrics need numerical simulations, in order to predict the performance of the ballistic protection. The performances and the induced mechanisms in ballistic fabrics during an impact depend on the weaving parameters and also on the inner parameters of the yarns used inside these structures. Thus, knowing the dynamic behaviour of yarn is essential to determine the ballistic behaviour of fabrics during an impact. Two major experimental devices exist and are used to test ballistic yarns in a dynamic uniaxial tension. The first one corresponds to the Split Hopkinson Tensile Bars device, which is commonly used to characterize the mechanical properties of materials in uniaxial tension and under high loading. The second one is the transversal impact device. The real conditions of ballistic impact can be realized with this device. Then, this paper deals with a new experimental setup developed in our laboratory and called the ‘tensile impact test for yarn’ (TITY) device. With this device, specific absorbed energy measurements of para-aramid yarns (336 Tex, Twaron™, 1000 filaments) have been carried out and revealed that static and dynamic properties of para-aramid are different.

  10. Beyond steel : some producers give plastic production tubing a second look

    Energy Technology Data Exchange (ETDEWEB)

    Mahony, J.


    The oil and gas sector is considering the use of plastics as an alternative to steel for production tubing. Innovations in manufacturing have made exotic plastics more available. Among these is Aramid fibre, a patented plastic marketed by PolyFlow Inc. The tubing known as Thermoflex was designed to improve gas flow out of natural gas wells where liquid loading often occurs in older wells. Plastics have the advantage of being lighter and smoother than steel. A smooth surface and less friction results in less back-pressure downhole. Plastics are inert to many grades of oil and gas, including the corrosive kinds. As such, they are well suited for sour wells. The combination of criss-crossed Aramid fibres wrapped around a Fortron plastic core makes the Thermoflex tubing much stronger than steel. The key disadvantage of Thermoflex is its operating temperature. The tubing should not be installed below -18 degrees C. Warm water must be circulated through the tubing in cold weather applications. To date, operators using Thermoflex tubing in shallow gas wells have not experienced any bitumen buildup that sometimes occurs in steel tubing. 1 ref., 2 figs.

  11. The cryogenic bonding evaluation at the metallic-composite interface of a composite overwrapped pressure vessel with additional impact investigation (United States)

    Clark, Eric A.

    A bonding evaluation that investigated the cryogenic tensile strength of several different adhesives/resins was performed. The test materials consisted of 606 aluminum test pieces adhered to a wet-wound graphite laminate in order to simulate the bond created at the liner-composite interface of an aluminum-lined composite overwrapped pressure vessel. It was found that for cryogenic applications, a flexible, low modulus resin system must be used. Additionally, the samples prepared with a thin layer of cured resin -- or prebond -- performed significantly better than those without. It was found that it is critical that the prebond surface must have sufficient surface roughness prior to the bonding application. Also, the aluminum test pieces that were prepared using a surface etchant slightly outperformed those that were prepared with a grit blast surface finish and performed significantly better than those that had been scored using sand paper to achieve the desired surface finish. An additional impact investigation studied the post impact tensile strength of composite rings in a cryogenic environment. The composite rings were filament wound with several combinations of graphite and aramid fibers and were prepared with different resin systems. The rings were subjected to varying levels of Charpy impact damage and then pulled to failure in tension. It was found that the addition of elastic aramid fibers with the carbon fibers mitigates the overall impact damage and drastically improves the post-impact strength of the structure in a cryogenic environment.

  12. Toughening of phenolic foam (United States)

    Shen, Hongbin


    Phenolic foam has excellent FST performance with relatively low cost, and thus is an attractive material for many applications. However, it is extremely brittle and fragile, precluding it from load-bearing applications. In order to make it tougher and more viable for structural purposes, an effective approach has been proposed and investigated in this study. Composite phenolic foam with short fiber reinforcements resulted in significant improvement in mechanical performance while retaining FST properties comparable to conventional phenolic foam. For example, composite phenolic foam with aramid fibers exhibited a seven-fold increase in peel resistance together with a five-fold reduction in friability. In shear tests, aramid composite foam endured prolonged loading to high levels of strain, indicating the potential for use in structural applications. On the other hand, glass fiber-reinforced phenolic foam produced substantial improvement in the stiffness and strength relative to the unreinforced counterpart. In particular, the Young's modulus of the glass fiber composite foam was increased by as much as 100% relative to the plain phenolic foam in the foam rise direction. In addition, different mechanical behavior was observed for aramid and glass fiber-reinforced foams. In an attempt to understand the mechanical behavior of composite foam, a novel NDT technique, micro-CT, was used to acquire information on fiber length distribution (FLD) and fiber orientation distribution (FOD). Results from micro-CT measurements were compared with theoretical distribution models, achieving various degrees of agreement. Despite some limitations of current micro-CT technology, the realistic observation and measurement of cellular morphology and fiber distribution within composite foams portend future advances in modeling of reinforced polymer foam. To explain the discrepancy observed in shear stiffness between traditional shear test results and those by the short sandwich beam test, a

  13. Standard practice for infrared flash thermography of composite panels and repair patches used in aerospace applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia


    1.1 This practice describes a procedure for detecting subsurface flaws in composite panels and repair patches using Flash Thermography (FT), in which an infrared (IR) camera is used to detect anomalous cooling behavior of a sample surface after it has been heated with a spatially uniform light pulse from a flash lamp array. 1.2 This practice describes established FT test methods that are currently used by industry, and have demonstrated utility in quality assurance of composite structures during post-manufacturing and in-service examinations. 1.3 This practice has utility for testing of polymer composite panels and repair patches containing, but not limited to, bismaleimide, epoxy, phenolic, poly(amide imide), polybenzimidazole, polyester (thermosetting and thermoplastic), poly(ether ether ketone), poly(ether imide), polyimide (thermosetting and thermoplastic), poly(phenylene sulfide), or polysulfone matrices; and alumina, aramid, boron, carbon, glass, quartz, or silicon carbide fibers. Typical as-fabricate...

  14. 2nd International Conference on Historic Earthquake-Resistant Timber Frames in the Mediterranean Area

    CERN Document Server

    Machado, José; Costa, Alfredo; Candeias, Paulo; Ruggieri, Nicola; Catarino, José


    This book presents a selection of the best papers from the HEaRT 2015 conference, held in Lisbon, Portugal, which provided a valuable forum for engineers and architects, researchers and educators to exchange views and findings concerning the technological history, construction features and seismic behavior of historical timber-framed walls in the Mediterranean countries. The topics covered are wide ranging and include historical aspects and examples of the use of timber-framed construction systems in response to earthquakes, such as the gaiola system in Portugal and the Bourbon system in southern Italy; interpretation of the response of timber-framed walls to seismic actions based on calculations and experimental tests; assessment of the effectiveness of repair and strengthening techniques, e.g., using aramid fiber wires or sheets; and modelling analyses. In addition, on the basis of case studies, a methodology is presented that is applicable to diagnosis, strengthening and improvement of seismic performance ...

  15. Terahertz imaging of composite materials in reflection and transmission mode with a time-domain spectroscopy system (United States)

    Sørgârd, Trygve R.; van Rheenen, Arthur D.; Haakestad, Magnus W.


    A fiber-coupled Terahertz time domain spectroscopy (THz-TDS) system based on photoconductive antennas, pumped by a 100-fs fiber laser, has been used to characterize materials in transmission and reflection mode. THz images are acquired by mounting the samples under investigation on an x-y stage, which is stepped through the beam while the transmitted or reflected THz waveform is captured. The samples include a carbon fiber epoxy composite and a sandwich-structured composite panel with an aramid fiber honeycomb core in between two skin layers of fiberglass reinforced plastic. The former has an artificially induced void, and from a comparison of recorded reflected time-domain signals, with and without the void, a simple model for the structure of the composite is proposed that describes the time-domain signals reasonably well.

  16. Cutting Tool Selection in CFRP and AFRP Machining%碳纤维与芳纶纤维复合材料机械加工刀具选用

    Institute of Scientific and Technical Information of China (English)

    刘汉良; 张加波; 王震; 张佳朋; 李光


    Cutting tool plays an significant role in composite machining.In this paper the special property of composite and its machining mechanism is analyzed,the requirement of cutting tool materials,structure and geometrical parameters for composite machining is discussed.Several kinds of drilling and milling tools which are fit for carbon fiber reinforced plastic (CFRP) and aramid fiber reinforced plastic (AFRP) are introduced.%通过对复合材料特性和加工机理的分析,论述了复合材料机械加工对刀具材质、结构和几何参数的要求,介绍了几种适合于碳纤维和芳纶纤维复合材料机械加工的钻削和铣削刀具.

  17. Performance of adhesives base on PU, Epoxy and silane in the Kevlar/alumina interface; Desempenho de adesivos a base de PU, epoxi e silano na interface Kevlar/alumina

    Energy Technology Data Exchange (ETDEWEB)

    Noronha, K.F.; Melo, F.C.L.; Lopes, C.M.A. [Divisao de Materiais, Instituto de Aeronautica e Espaco (IAE), Sao Jose dos Campos, SP (Brazil); Divisao de Engenharia Mecanica-Aeronautica, Instituto Tecnologico de Aeronautica (ITA), Sao Jose dos Campos, SP (Brazil)], e-mail:


    Hybrid ceramic/polymer composites are used for ballistic protection due to the good high-velocity impact absorption properties. The choice of the proper adhesive used to bond ceramic and polymer layers is one of the major issues for hybrid armor development due to its influence in the ballistic resistance behaviour. This work presents an adhesion study in composites of aramid textile (Kevlar) and alumina. Adhesives of different chemical nature, based on polyurethane, epoxy and silane were evaluated. T-Peel test was performed for the interface characterization and the post- failure surfaces were examined by optical microscopy. In all samples the failure occurred at the interface. The silane-based adhesive showed no interaction with the polymer, while the PU hot melt adhesive presented the highest adhesion strengths. (author)

  18. H.Ea.R.T. 2013 Conference

    CERN Document Server

    Tampone, Gennaro; Zinno, Raffaele; Historical Earthquake-Resistant Timber Frames in the Mediterranean Area


    This book presents a selection of the best papers from the HEaRT 2013 conference, held in Cosenza, Italy, which provided a valuable forum for engineers and architects, researchers, and educators to exchange views and findings concerning the technological history, construction features, and seismic behavior of historical timber-framed walls in the Mediterranean countries. The topics covered are wide ranging and include historical aspects and examples of the use of timber-framed construction systems in response to earthquakes, such as the gaiola system in Portugal and the Bourbon system in southern Italy; interpretation of the response of timber-framed walls to seismic actions based on calculations and experimental tests; assessment of the effectiveness of repair and strengthening techniques, e.g., using aramid fiber wires or sheets; and modelling analyses. In addition, on the basis of case studies, a methodology is presented that is applicable to diagnosis, strengthening, and improvement of seismic performance...

  19. Heating of thermoplastic-based unidirectional composite prepregs

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Weber, M.E.; Charrier, J.M. (McGill Univ., Montreal (Canada))


    Thermoplastic-based prepregs offer a potential for faster manufacture of composite products than with thermoset-based prepregs. The winding or controlled placement of thermoplastic-based prepreg tapes requires the rapid heating of the moving tape, just prior to its contact with the substrate on the mandrel. In the case of complex shapes, geometrical constraints and significant variations in tape speeds in the course of manufacture, make it particularly desirable to be able to model the heating process. A mathematical model and its experimental verification for convection/conduction heat transfer to and through either a homogeneous thermoplastic material, or thermoplastic-based unidirectional composites featuring glass, aramid and carbon fibers, is discussed. 12 refs.

  20. Analysis on Tribological Properties of Potentially New Friction Material with Response Surface Method

    Institute of Scientific and Technical Information of China (English)

    XU Lei; ZHU Zhencai; CHEN Guoan; LI Yilei


    The tribological properties of newly developed friction material were evaluated by statistical analysis of the major affecting factors. The material for investigation was non-metallic friction material synergistically reinforced with aramid fibre and CaSO4 whisker, which was developed for hoisting applications in coal mine. The response surface method (RSM) was employed to analyze the material performances affected by the independent and interactive effect of the factors under the normal working condition and severe working condition, respectively. Results showed that under the normal working condition, the newly developed material exhibited stable tribological properties which were insensitive to the test conditions. While under the severe working condition, the sliding velocity was the most dominant factor affecting the friction coefficient.Additionally, compared to the commercially available material, the modified material showed superior wear resistance and thermal stability.

  1. Knitting Technologies And Tensile Properties Of A Novel Curved Flat-Knitted Three-Dimensional Spacer Fabrics

    Directory of Open Access Journals (Sweden)

    Li Xiaoying


    Full Text Available This paper introduces a knitting technique for making innovative curved three-dimensional (3D spacer fabrics by the computer flat-knitting machine. During manufacturing, a number of reinforcement yarns made of aramid fibres are inserted into 3D spacer fabrics along the weft direction to enhance the fabric tensile properties. Curved, flat-knitted 3D spacer fabrics with different angles (in the warp direction were also developed. Tensile tests were carried out in the weft and warp directions for the two spacer fabrics (with and without reinforcement yarns, and their stress–strain curves were compared. The results showed that the reinforcement yarns can reduce the fabric deformation and improve tensile stress and dimensional stability of 3D spacer fabrics. This research can help the further study of 3D spacer fabric when applied to composites.

  2. Reinforcing materials in conveyor belts: their requirements and developments; Verstaerkungsmaterialien in Foerdergurten: Tendenzen, Anforderungen und Entwicklungen

    Energy Technology Data Exchange (ETDEWEB)

    Kopmels, P. [Akzo Nobel Fibers, Arnhem (Netherlands)


    During this century one can observe a gradual change in the textile materials used to reinforce conveyor belt. In the beginning of the 20th century only cotton was used, then rayon came up followed by polyamide and polyester. Nowadays aramid is also used for special applications. These changes in textile reinforcing materials were driven by a better fulfilment of the existing technical requirements and/or a better price/performance ratio. In addition to the search for new polymers, the fiber producers try to improve the yarn properties of existing polymers. An example of a newly developed polyester type is presented. By raising the yarn strength and at the same time improving the efficiency of the yarn in respect to the necessary converting steps like twisting, weaving and dipping the price/performance ratio of this new yarn type has been greatly improved. 11 figs.

  3. Effects of postcuring on mechanical properties of pultruded fiber-reinforced epoxy composites and the neat resin (United States)

    Long, Edward R., Jr.; Long, Sheila Ann T.; Funk, Joan G.; Collins, William D.; Gray, Stephanie L.


    The effects of postcuring on mechanical properties of pultruded fiber-reinforced epoxy-resin composites have been investigated. Composites with carbon, glass, and aramid reinforcement fibers were individually studied. The epoxy was a commercially-available resin that was especially developed for pultrusion fabrication. The pultrusions were conducted at 400 F with postcures at 400, 450, 500, and 550 F. Measurements of the flexural, shear, and interlaminar fracture-toughness properties showed that significant postcuring can occur during the pultrusion process. All three mechanical properties were degraded by the higher (500 and 550 F) temperatures; photomicrographs suggest that the degradation was caused at the fiber-resin interface for all three fiber types.

  4. Assessment of the fracture strength distribution and the Weibull parameters of fibres from a bundle test. Ermittlung der Festigkeitsverteilung und der Weibullparameter von Fasern aus einem Buendelzugversuch

    Energy Technology Data Exchange (ETDEWEB)

    Lienkamp, M. (Technische Hochschule Darmstadt, Fachgebiet Physikalische Metallkunde, Fachbereich Materialwissenschaft (Germany)); Exner, H.E. (Technische Hochschule Darmstadt, Fachgebiet Physikalische Metallkunde, Fachbereich Materialwissenschaft (Germany))


    Present test methods used to determine the strength distribution of high performance fibres are either time consuming or not very reliable. A method is used which enables the derivation of the strength distribution function from one single tensile test. The load/elongation diagram of a bundle of fibres is taken from an elongation-controlled tensile test. From the ratio of the measured load to a fictive load, necessary to obtain an identical elongation in the bundle assuming all fibres are intact, the fraction of broken fibres for each point of the load/elongation diagram is determined. From this the strength distribution function and the Weibull parametes of the fibres can be calculated. Application of this simple, but very effective method, is demonstrated for a schematic example and for three fibre materials (carbon, aramid and ceramic fibres). (orig.)


    Directory of Open Access Journals (Sweden)

    Rafael Barrionuevo GIMÉNEZ


    Full Text Available TSM is escape pipe in case of collapse of terrain. The TSM is a passive security tool placed underground to connect the work area with secure area (mining gallery mainly. TSM is light and hand able pipe made with aramid (Kevlar, carbon fibre, or other kind of new material. The TSM will be placed as a pipe line network with many in/out entrances/exits to rich and connect problem work areas with another parts in a safe mode. Different levels of instrumentation could be added inside such as micro-led escape way suggested, temperature, humidity, level of oxygen, etc.. The open hardware and software like Arduino will be the heart of control and automation system.

  6. Moisture dependence of positron lifetime in Kevlar-49 (United States)

    Singh, Jag J.; Holt, William H.; Mock, Willis, Jr.


    Because of filamentary character of Kevlar-49 aramid fibers, there is some concern about the moisture uptake and its effect on plastic composites reinforced with Kevlar-49 fibers. As part of continuing studies of positron lifetime in polymers, we have measured positron lifetime spectra in Kevlar-49 fibers as a function of their moisture content. The long lifetime component intensities are rather low, being only of the order of 2-3 percent. The measured values of long component lifetimes at various moisture levels in the specimens are as follows: 2072 +/- 173 ps (dry); 2013 +/- 193 ps (20.7 percent saturation); 1665 +/- 85 ps (25.7 percent saturation); 1745 +/- 257 ps (32.1 percent saturation); and 1772 +/- 217 ps (100 percent saturation). It is apparent that the long component lifetime at first decreases and then increases as the specimen moisture content increases. These results have been compared with those inferred from Epon-815 and Epon-815/K-49 composite data.

  7. Maxwell-Wagner-Silars relaxations due to glass occlusions in a thermoset composite (United States)

    Aldrich, P. D.; McGee, R. L.; Yalvaç, S.; Bonekamp, J. E.; Thurow, S. W.


    Maxwell-Wagner-Silars (MWS) dielectric relaxations have been studied in thermoset composites made with hollow glass microspheres and reinforced with aramid fiber. Over the temperature range reported (140-230 °C) the glass microspheres show a conductivity of 10-10-10-5 (Ω cm)-1 so that MWS loss peaks fall in the 102-105 Hz frequency range. The apparent activation energy for the relaxation is about 20 kcal/mole. The observed MWS relaxation times depend only on temperature and not on volume fraction of microspheres as predicted by MWS theory. Also, the enhancement of activation energy for the relaxation over the activation energy for conduction of the glass seems to be explainable from the standpoint of the frequency and temperature dependence of the glass dielectric constant.

  8. Controlled thermal expansion printed wiring boards based on liquid crystal polymer dielectrics (United States)

    Knoll, Thomas E.; Blizard, Kent; Jayaraj, K.; Rubin, Leslie S.


    Dielectric materials based on innovative Liquid Crystal Polymers (LCP's) have been used to fabricate surface mount printed wiring boards (PWB's) with a coefficient of thermal expansion matched to leadless ceramic chip carriers. Proprietary and patented polymer processing technology has resulted in self reinforcing material with balanced in-plane mechanical properties. In addition, LCP's possess excellent electrical properties, including a low dielectric constant (less than 2.9) and very low moisture absorption (less than 0.02%). LCP-based multilayer boards processed with conventional drilling and plating processes show improved performance over other materials because they eliminate the surface flatness problems of glass or aramid reinforcements. Laser drilling of blind vias in the LCP dielectric provides a very high density for use in direct chip attach and area array packages. The material is ideally suited for MCM-L and PCMCIA applications fabricated with very thin dielectric layers of the liquid crystal polymer.

  9. Impact and residual fatigue behavior of ARALL and AS6/5245 composite material (United States)

    Johnson, W. S.


    The impact sensitivity of aramide fiber-reinforced aluminum laminates (ARALL) was investigated by testing two types of ARALL (7075 aluminum prestrained and 2024 aluminum not prestrained), via static indentation, and the results were compared to those of sheet aluminum alloys 7075-T6 and 2024-T3 and to a state of the art composite AS6/5245. It was found that the impact resistance of the two ARALL samples was inferior to that of monolithic sheet aluminum samples, although the ARALL material made with 2024-T3 aluminum was superior to that made with 7075-T6 aluminum. The impact damage resistance of ARALL materials was at least equal to that of AS6/5245, and the AS6/5245 had higher residual tension-tension fatigue strength after impact than the ARALL samples. It was also found that the prestraining of the ARALL reduced the fatigue growth of impact damage.


    Institute of Scientific and Technical Information of China (English)

    孙志杰; 龚元明; 贺成红; 张佐光


    采用SHPB冲击试验装置,对AF/ZF(Aramid Fiber/Zylon Fiber)混杂纤维防弹复合材料进行了横向冲击试验,获得了不同混杂比的混杂复合材料的载荷历史与位移历史,进一步分析了其破坏过程和能量吸收特性.所得结果与不同混杂比的AF/ZF混杂纤维复合材料实弹靶试吸能特性变化趋势相似.结果表明,进行不同混杂比AF/ZF混杂纤维复合材料的横向冲击试验对预测实弹冲击的破坏吸能有参考价值.

  11. Copper-coated textiles: armor against MDR nosocomial pathogens. (United States)

    Irene, Galani; Georgios, Priniotakis; Ioannis, Chronis; Anastasios, Tzerachoglou; Diamantis, Plachouras; Marianthi, Chatzikonstantinou; Philippe, Westbroek; Maria, Souli


    Soft surfaces in the health-care setting harbor potentially pathogenic bacteria and fungi that can be transferred to patients and personnel. We evaluated the in vitro antimicrobial efficacy of two types of innovative copper-coated textiles against a variety of nosocomial multi-drug resistant (MDR) pathogens. Five isolates each of MDR Staphylococcus aureus, Klebsiella pneumoniae, Pseudomonas aeruginosa, Acinetobacter baumannii and Enterococcus faecium as well as three Candida parapsilosis were tested. The antimicrobial activity of copper-coated para-aramide and copper-coated polyester swatches was compared to that of non-copper coated controls using a quantitative method. Reduction of viable colonies by >3log10 from starting inoculum was characterized as bactericidal activity. No viable colonies of S. aureus, P. aeruginosa, E. faecium and C. parapsilosis were recovered after the first hour of contact while for A. baumannii, no viable colonies were recovered after only 15min of contact with either type of copper-coated textiles. Copper-coated para-aramide exhibited a bactericidal effect at 15min of contact with A. baumannii, at 1h with S. aureus, P. aeruginosa, E. faecium and C. parapsilosis and at 3h with K. pneumoniae. Copper-coated polyester was bactericidal at 15min of contact for A. baumannii and at 1h for the other species tested. Both copper-coated textiles exhibited a rapid and significant antimicrobial effect. Antimicrobial textiles may have a role in the arsenal of strategies aiming to reduce environmental contamination in the health-care setting.

  12. Etude de l'isolation hybride en vue de son application dans les transformateurs de puissance (United States)

    Kassi, Koutoua Simon

    For nearly a century the conventional insulation (oil / cellulose complex) was the type of insulation used in the power transformers and most electrical power equipments. But the cellulose paper, the solid part of this insulation has many weaknesses. Indeed, the aging of cellulose paper in power transformers is accelerated by moisture, oxygen, metal catalysts, temperature, etc.). The risk of failures is thereby increased. Another major weakness of cellulose paper is its inability to protect the electrical transformer windings against the harmful effects of corrosive sulfur. Given all the weaknesses of cellulose paper, several studies have been conducted to evaluate the performance of aramid paper, which has better thermal properties. The aramid paper is currently used as high temperature insulation, combined with high fire point oils (synthetic and vegetable oils), mainly in electric traction transformers. The hybrid solid insulation is associated with mineral oil or with high fire point oils; it finds application in transformers of fixed and mobile substations. Manufacturing technology is controlled by manufacturers but operators of electrical networks do not have baseline data (standards) as diagnostic tools, allowing them to monitor the health/condition of the isolation in this new type of transformer. The overall objective of this research was to study the hybrid insulation and to demonstrate its potential use in power transformers. This overall objective has been subdivided into three specific objectives, namely: (i) improving the diagnostic of the condition of solid hybrid insulation and conventional solid insulation; (ii) diagnosing the condition of oils sampled from hybrid, high temperature and conventional insulation and finally (iii) investigating the ability of aramid paper and cellulose paper to protect the copper (electrical windings) against harmful effects of corrosive sulfur. In order to achieve these objectives, thermal accelerated aging were

  13. Avaliação dos modos de falha sob impacto de compósitos de matriz polimérica reforçados por fibras

    Directory of Open Access Journals (Sweden)

    Marcelo M. M. Naglis


    Full Text Available RESUMO: Neste trabalho é feita uma avaliação dos modos de falha de compósitos de matriz polimérica reforçados por fibras de vidro, carbono ou aramida, submetidos a carregamento dinâmico. Os compósitos unidirecionais analisados foram fabricados por prensagem e cura à vácuo de lâminas de pré-impregnados. A energia total absorvida na fratura mostrou uma correlação inversamente proporcional ao módulo elástico das fibras usadas como reforço. Os compósitos com fibras de carbono falharam de um modo frágil. Para estes compósitos o comportamento ao impacto pode ser modelado usando-se uma análise puramente elástica. Para os compósitos com fibras de vidro a falha foi controlada por um mecanismo misto de cisalhamento ao longo da interface fibra-matriz e tensão normal trativa atuando perpendicularmente às fibras. O modelo elástico empregado para simular o comportamento ao impacto subestima a energia absorvida por estes compósitos, porém, a diferença entre os valores experimentais e os calculados não ultrapassou 20 %. A falha dos compósitos com fibras aramidas foi atribuída, principalmente, ao componente de tensão trativa atuando perpendicularmente às fibras. Nestes compósitos foi observado arrancamento superficial nas fibras aramidas e o comportamento ao impacto não obedece o modelo elástico empregado.ABSTRACT: In this work an evaluation of the fracture mode of fiber reinforced resin matrix composites submitted to three point bending dynamic impact testing was undertaken. The unidirectional glass, carbon and aramid fiber-epoxy matrix composites used were fabricated by vacuum bagging prepreg laminas. The energy absorbed to fracture the composites had an inverse correlation to the fibres' elastic modulus. The carbon fiber composites failed in a brittle mode. The analysis of the fracture surfaces showed that for the glass fiber composites, the failure is controlled by a coupled mechanism of shear along the fiber

  14. 主要高新技术纤维的最新发展%The newest development of main new & hi-tech fibers

    Institute of Scientific and Technical Information of China (English)



    全球高性能纤维的需求依然强劲,PAN基碳纤维(PAN-CF)的需求量预计将从2012年的4×104t左右,扩大至2015和2020年的7×104t和1.4×105t。碳纤维复合材料市场的平均增长率约为31.5%。中间相沥青基碳纤维将在大型风电叶片、隧道补强、导热材料、超导电材料等获得新发展。对位芳酰胺纤维新产品不断出现,其年均需求增长率约为7%~9%。超高相对分子质量聚乙烯(UHMWPE)薄膜切割纤维及条带作为新防护材料得到了新发展。聚乳酸(PLA)的复合纤维、混纺制品及改进产品,推动了其不断发展,而溶剂法纤维素纤维通过改进原纤化、起球等,也获得了长足发展。此外,间位芳酰胺、芳酰胺-酰亚胺、酚醛及聚苯并咪唑纤维,都有不同程度的新发展。%The demand of global high performance fibers are also powerful,the demand of PAN-based carbon fiber will expand from about 4×104t in 2012 to 7×104t and 14×104t in 2015 and 2020 respectively.The market of carbon fiber composite materials will grow about 31.5% annual.New developments for pitch-based carbon fiber in big wind blade,tunnel reinforcing,heat conductor ultra-electric conductor materials will be achieved.The annual demand of p-Aramid fiber will increase of about 7%~9%,and new products are arising.New developments of ultra-high molecular weight polyethylene(UHMWPE) tape and membrane cutting fiber for used as new protection materials are achieving.The development of polylactic acid(PLA) is promoting by their fibers,mixing fabrics and improved products,while solvent type cellulose fibers are also developed by improving their fibrillation and pile etc.Moreover,new developments of meta-aramid,aramid-amide,phenolic and poly benzimidazole(PBI) fibers are achieving in different level.

  15. Etude sur les tendons en materiaux composites et leur application aux ancrages postcontraints (United States)

    Chennouf, Adil

    L'objectif general de la presente these est d'evaluer le comportement a l'arrachement et au fluage d'ancrages injectes constitues de tendons en materiaux composites afin d'etablir des recommandations plus appropriees et realistes pour le dimensionnement et la conception. Quatre types de tendons en materiaux composites, deux a base de fibres d'aramide et deux a base de fibres de carbone, ont ete utilises dans l'etude. Les travaux de recherche de cette these ont porte notamment sur: (I) Une caracterisation physique et mecanique des tendons en materiaux composites utilises dans l'etude. (II) Une etude en laboratoire sur les coulis de scellement. La premiere etape de cette etude a concerne le developpement d'un coulis de scellement performant adapte aux tendons en materiaux composites et a differentes situations d'injection. La seconde etape a traite des essais de caracterisations physique et mecanique du coulis de scellement developpe comparativement a trois coulis de scellement usuels d'un meme rapport E/L de 0,4. (III) Une etude sur des modeles reduits d'ancrages injectes. (IV) Une etude sur des modeles d'ancrages a grande echelle. La synthese de ces etudes a permis d'enoncer les principales conclusions suivantes: (1) Les valeurs moyennes des charges de rupture des tendons en materiaux composites ont ete de 1% a 29% superieures a celles specifiees par les manufacturiers. (2) L'etude sur les coulis de scellement a permis le developpement de coulis de ciment repondant aux criteres fixes, soient une grande stabilite, une bonne fluidite, une legere expansion et de bonnes caracteristiques mecaniques. (3) Les tendons en materiaux composites ont montre des contraintes d'adherence maximum superieures a celles des tendons en acier. (4) Le type de fibre, la configuration et le fini de surface des tendons en materiaux composites gouvernent leur resistance a l'adherence. (5) L'introduction de sable et d'autres ajouts comme les fines de silice et la poudre d'aluminium au coulis

  16. Carbon fiber based composites stress analysis. Experimental and computer comparative studies (United States)

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


    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

  17. Analysis of composite structural elements

    Directory of Open Access Journals (Sweden)

    A. Baier


    Full Text Available Purpose: The themes of the study are composite structural components. For this purpose have been designed and built several research positions.Design/methodology/approach: Using different structural materials to build new device components requires multiple tests of the components. Research posts were designed in the advanced graphical program CAx Siemens NX 7.5. Analysed samples were made from the glass fibre, aramid and carbon of various weights. Due to the specific use of composite materials it focuses on the elements in the form of plates and flat bars. For the examination of experimental strain gauge technique was used bead, the force sensor and displacement sensor. The experimental methods were compared with computer simulation using the FEM.Findings: The aim of this study was to determine the basic material constants and a comparison of the experimental method and the method of computer simulation.Research limitations/implications: Change the number of layers and how to connect the laminate with the steel plate changes mechanical properties of the structural component.Practical implications: The ultimate result will be knowledge on the different forms of laminates, such as material properties, the stresses in all layers, strain and comparing the results obtained by two methods.Originality/value: The expected outcome of the study will be the composition and method of joining composite laminate with a steel plate to the possible application in the repair and construction of structural elements of freight wagons.

  18. Filled Ethylene-propylene Diene Terpolymer Elastomer as ThermalInsulator for Case-bonded Solid Rocket Motors

    Directory of Open Access Journals (Sweden)

    C. M. Bhuvaneswari


    Full Text Available Ethylene-propylene diene terpolymer (EPDM-based insulation system is being globallyused for case-bonded solid rocket motors. A study was undertaken using EPDM as base polymer,blended with hypalon and liquid EPDM and filled with fibrous and non-fibrous fillers. Theseformulations were evaluated as rocket motor insulation system. The basic objective of the studywas to develop an insulation system based on EPDM for case-bonded applications. A series ofrocket motor insulator compositions based on EPDM, filled with particulate and fibrous fillerslike precipitated silica, fumed silica, aramid, and carbon fibres have been studied for mechanical,rheological, thermal, and interface properties. Compositions based on particulate fillers wereoptimised for the filler content. Comparatively, fumed silica was found to be superior as fillerin terms of mechanical and interface properties. Addition of fibrous filler (5 parts improved thepeel strength, and reduced the thermal conductivity and erosion rate. All the compositions wereevaluated for sulphur and peroxide curing. Superior mechanical properties were achieved forsulphur-cured products, whereas peroxide-cured products exhibited an excellent ageing resistance.Rocket motors were insulated with optimised composition and propellant cast, and the motorswere evaluated by conducting static test in end-burning mode.Defence Science Journal, 2008, 58(1, pp.94-102, DOI :

  19. Research on ultimate bearing capacity of hybrid fiber reinforced concrete square column%混杂纤维加固混凝土方形短柱极限承载力研究

    Institute of Scientific and Technical Information of China (English)

    尹毓良; 张鸿梅


    采用碳纤维布、玻璃纤维布、芳纶纤维布层间混杂加固混凝土方形短柱,就不同加固类型柱体的极限承载力进行对比试验,结果表明混杂纤维的协调匹配能够充分发挥不同纤维的优势,扬长避短,提高承载力,降低成本。%The study adopts the hybrid reinforced concrete square columns with the carbon fiber sheet,the glass fiber and the aramid fiber reinforced plastic sheets,undertakes the comparative experiments on the ultimate loading capacity of columns with various reinforced types,and proves by the result that the coordinative matches of the hybrid fiber can fully exert the advantages of the different fibers,improve the loading capacity and lower the cost.

  20. Fiber-Reinforced Reactive Nano-Epoxy Composites (United States)

    Zhong, Wei-Hong


    An ultra-high-molecular-weight polyethylene/ matrix interface based on the fabrication of a reactive nano-epoxy matrix with lower surface energy has been improved. Enhanced mechanical properties versus pure epoxy on a three-point bend test include: strength (25 percent), modulus (20 percent), and toughness (30 percent). Increased thermal properties include higher Tg (glass transition temperature) and stable CTE (coefficient of thermal expansion). Improved processability for manufacturing composites includes faster wetting rates on macro-fiber surfaces, lower viscosity, better resin infusion rates, and improved rheological properties. Improved interfacial adhesion properties with Spectra fibers by pullout tests include initial debonding force of 35 percent, a maximum pullout force of 25 percent, and energy to debond at 65 percent. Improved mechanical properties of Spectra fiber composites (tensile) aging resistance properties include hygrothermal effects. With this innovation, high-performance composites have been created, including carbon fibers/nano-epoxy, glass fibers/nano-epoxy, aramid fibers/ nano-epoxy, and ultra-high-molecularweight polyethylene fiber (UHMWPE).

  1. Full metal jacket!

    CERN Multimedia

    Laëtitia Pedroso


    Ten years ago, standard issue clothing only gave CERN firemen partial protection but today our fire-fighters are equipped with state-of-the-art, full personal protective equipment.   CERN's Fire Brigade team. For many years, the members of CERN's Fire Brigade went on call-outs clad in their work trousers and fire-rescue coats, which only afforded them partial protection. Today, textile manufacturing techniques have moved on a long way and CERN's firemen are now kitted out with state-of-the-art personal protective equipment. The coat and trousers are three-layered, comprising fire-resistant aramide, a protective membrane and a thermal lining. The CERN Fire Brigade' new state-of-the-art personal protection equipment. "This equipment is fully compliant with the standards in force and is therefore resistant to cuts, abrasion, electrical arcs with thermal effects and, of course, fire," explains Patrick Berlinghi, the CERN Fire Brigade's Logistics Officer. You might think that su...

  2. Reinforcement and recovery of timber structures

    Directory of Open Access Journals (Sweden)

    Antonio Alves Dias


    Full Text Available Preservation of timber structures is a reason for constant concern because their deterioration often involves compromising the historical patrimony, besides endangering the safety of the structure, and consequently, of their users. Many are the examples of churches, residences or other constructions where this manifestation is a fact. The technique of reinforcing structurally endangered pieces with the addition of natural or synthetic fibers, is an alternative that has been researched. In the group of synthetic fibers, fiberglass, carbon and aramid ones are included. On the other hand, it has been frequent in the restoration of old buildings, especially in Europe, the employment of materials that were not available in the past, aiming to achieve structural, acoustic and aesthetic benefits. On an existing timber structure floor, a concrete slab has been carried out, with an appropriate connection system among the parts, constituting the composite timber-concrete structures. This alternative has been considered as extraordinarily viable, because it gathers a series of convenience related with the durability and it presents better mechanic performance than conventional timber structures. In this work, the state-of-the-art of the use of fibers as structural reinforcement and of the timber-concrete composite structures, is presented.

  3. Analysis of the ballistic impact response of a composite material using FAST Infrared Imagery (United States)

    Marcotte, Frederick; Ouellet, Simon; Farley, Vincent


    The level of protection offered by a given ballistic material is typically evaluated in terms of a set of projectiles and their associated velocity at which a certain percentage of the projectiles are expected to perforate. (i.e. FSP 17gr : V50 = 500m/s, 9mm FMJ; V0=500m/s). These metrics give little information about the physical phenomena by which energy is dispersed, spread or absorbed in a specific target material. Aside from post-test inspection of the impacted material, additional information on the target response is traditionally obtained during a test from the use of high speed imaging, whether it is from a single camera aimed at the impact surface or the backface, or from a set of camera allowing full 3-D reconstruction of a deformed surface. Again, this kind of data may be difficult to interpret if the interest is in the way energy is managed in the target in real time. Recent technological progress in scientific grade high-speed infrared (IR) camera demonstrated that these phenomena can straightforwardly be measured using IR thermal imaging. This paper presents promising results obtained from Telops FAST-IR 1500 infrared camera on an aramid-based ballistic composite during an impact from a small caliber fragment simulating projectile (FSP).

  4. Hypervelocity impact testing of advanced materials and structures for micrometeoroid and orbital debris shielding (United States)

    Ryan, Shannon; Christiansen, Eric L.


    A series of 66 hypervelocity impact experiments have been performed to assess the potential of various materials (aluminium, titanium, copper, stainless steel, nickel, nickel/chromium, reticulated vitreous carbon, silver, ceramic, aramid, ceramic glass, and carbon fibre) and structures (monolithic plates, open-cell foam, flexible fabrics, rigid meshes) for micrometeoroid and orbital debris (MMOD) shielding. Arranged in various single-, double-, and triple-bumper configurations, screening tests were performed with 0.3175 cm diameter Al2017-T4 spherical projectiles at nominally 6.8 km/s and normal incidence. The top performing shields were identified through target damage assessments and their respective weight. The top performing candidate shield at the screening test condition was found to be a double-bumper configuration with a 0.25 mm thick Al3003 outer bumper, 6.35 mm thick 40 PPI aluminium foam inner bumper, and 1.016 mm thick Al2024-T3 rear wall (equal spacing between bumpers and rear wall). In general, double-bumper candidates with aluminium plate outer bumpers and foam inner bumpers were consistently found to be amongst the top performers. For this impact condition, potential weight savings of at least 47% over conventional all-aluminium Whipple shields are possible by utilizing the investigated materials and structures. The results of this study identify materials and structures of interest for further, more in-depth, impact investigations.

  5. Dual Use Space Technology Transfer Conference Paper (United States)

    Orndoff, Evelyne


    New textile fibers have been developed or modified to meet the complex and constraining criteria of space applications. The most common of these criteria are light weight, nonflammability or flame retardancy, and high strength and durability in both deep space environment and the oxygen enriched crew bay area of the spacecraft. The fibers which successfully pass the tests of flammability and toxicity, and display the desired mechanical properties are selected for space applications. Such advanced fibers developed for the Crew and Thermal Systems Division (CTSD) at the Johnson Space Center include 'Beta' fiber, heat stabilized polybenzimidazole and polyimide, as well as modified aramid Durette(TM), multi-fibrous Ortho(TM) fabric, and flame resistant cotton. The physical, mechanical, and chemical properties of these fibers are briefly discussed. The testing capabilities in the CTSD laboratory to ascertain some of the properties of these and other fibrous materials are also discussed. Most of these materials developed for spacecraft, space suit, and flight equipment applications have found other commercial applications. These advanced textile fibers are used mostly for aircraft, transportation, public buildings, hospitals, and protective clothing applications.

  6. Weaving multi-layer fabrics for reinforcement of engineering components (United States)

    Hill, B. J.; Mcilhagger, R.; Mclaughlin, P.


    The performance of interlinked, multi-layer fabrics and near net shape preforms for engineering applications, woven on a 48 shaft dobby loom using glass, aramid, and carbon continuous filament yarns is assessed. The interlinking was formed using the warp yarns. Two basic types of structure were used. The first used a single warp beam and hence each of the warp yarns followed a similar path to form four layer interlinked reinforcements and preforms. In the second two warp beams were used, one for the interlinking yarns which pass from the top to the bottom layer through-the-thickness of the fabric and vice versa, and the other to provide 'straight' yarns in the body of the structure to carry the axial loading. Fabrics up to 15mm in thickness were constructed with varying amounts of through-the-thickness reinforcement. Tapered T and I sections were also woven, with the shaping produced by progressive removal of ends during construction. These fabrics and preforms were impregnated with resin and cured to form composite samples for testing. Using these two basic types of construction, the influence of reinforcement construction and the proportion and type of interlinking yarn on the performance of the composite was assessed.

  7. High velocity impact and armour design

    Directory of Open Access Journals (Sweden)


    Full Text Available Improving combat survivability is the most important aspect of military technology. Hence the development of new lightweight armour systems is a key requirement. A large number of new high performance polymer fibres have been developed in recent years, which include Aramid fibres, polyethylene fibres and polypropylene fibres, amongst others, and have been applied to soft armour systems. To gain a fundamental understanding of which fibre type is the best for a specific application requires the development of techniques which can span all length scales. It has been widely recognised that multiscale modelling, which encompasses the full range of length and time scales, will be an important factor in the future design and testing of novel materials, and their application to armour design. In the present paper a new material damage model suitable for the simulation of impact on thin laminated panels fabricated from high performance fibres is implemented into the commercial ls-dyna® finite element code. The new material model links the mesoscale behaviour of the individual fibres to the macroscale behaviour within a conventional shell finite element. The implemented model is used in a parametric high velocity study to illustrate the applicability of the model to the design of thin armour panels.

  8. A novel high-pressure vessel for simultaneous observations of seismic velocity and in situ CO2 distribution in a porous rock using a medical X-ray CT scanner (United States)

    Jiang, Lanlan; Nishizawa, Osamu; Zhang, Yi; Park, Hyuck; Xue, Ziqiu


    Understanding the relationship between seismic wave velocity or attenuation and CO2 saturation is essential for CO2 storage in deep saline formations. In the present study, we describe a novel upright high-pressure vessel that is designed to keep a rock sample under reservoir conditions and simultaneously image the entire sample using a medical X-ray CT scanner. The pressure vessel is composed of low X-ray absorption materials: a carbon-fibre-enhanced polyetheretherketone (PEEK) cylinder and PEEK vessel closures supported by carbon-fibre-reinforced plastic (CFRP) joists. The temperature was controlled by a carbon-coated film heater and an aramid fibre thermal insulator. The assembled sample cell allows us to obtain high-resolution images of rock samples during CO2 drainage and brine imbibition under reservoir conditions. The rock sample was oriented vertical to the rotation axis of the CT scanner, and seismic wave paths were aligned parallel to the rotation axis to avoid shadows from the acoustic transducers. The reconstructed CO2 distribution images allow us to calculate the CO2 saturation in the first Fresnel zone along the ray path between transducers. A robust relationship between the seismic wave velocity or attenuation and the CO2 saturation in porous rock was obtained from experiments using this pressure vessel.


    Institute of Scientific and Technical Information of China (English)

    陈平; 陆春; 王静; 张承双; 于祺


    groups; the plasma etched the fiber surface obviously, enhancing the surface roughness and surface free energy and improving the wettability of the fiber distinctly. Plasma treatment conditions should be appropriate during surface modification of fibers by clod plasma. After CF was treated for 5 min ,CF surface polar group was increased to a relatively higher level. However,the effect of plasma etching on CF surface is relatively slower. After CF was treated for 5 mmin, CF surface roughness was changed a little.However,after CF was treated for more than 15 min CF surface roughness was increased significantly. Based onthe study above, the interfacial adhesion and fracture mechanism of continuous fiber reinforced soluble polyaromatic ether resin composites was also systematically analysed by interlaminar shear strength ( ILSS),water absorption and scanning electron microscopy (SEM) measurements. It was found that CF reinforced poly(phthalazinone ether su]fone ketone)(PPESK) composite interracial adhesion mechanism analysis indicats that both chemical bonding and mechanical interlocking interaction has a positive effect on composite interfacial adhesion,however, mechanical interaction has a dominant effect on composite interfacial adhesion than chemical bonding interaction. Armos aramid fiber composite interlaminar shear strength increased from 59.5 MPa for untreated sample to 68.8 MPa for plasma treated for 10 rain under discharge power at 200 W,with an increase of 15.6%. The water absorption decrease of composite also indirectly showed that oxygen plasma treatment improved composite interfacial adhesion. The primary failure mode of Armos aramid or PBO/PPESK composites shifted from interface failure to matrix fracture after oxygen plasma treatment. The interfacial adhesion of Armos aramid or PBO/PPESK composites was improved by oxygen plasma treatment due to thechemical linkage and mechanical bonding between Armos aramid or PBO fibers and PPESK matrices, and the chemical

  10. Processing and Bending Performance Test of Three-dimensional Woven Angle Chain Fabric Composites%三维机织角连锁织物复合材料的加工与弯曲性能测试

    Institute of Scientific and Technical Information of China (English)

    万明达; 李亚滨


    文章利用多臂小样织机以玻璃纤维和芳纶为原料织造三维角连锁织物,并采用真空辅助成型法和手工成型法加工复合材料。对成型的复合材料进行弯曲性能测试,通过测试数据分析表明:织物组织结构、树脂浸透程度以及加工方法都会影响复合材料的弯曲性能。%Three-dimensional angle Chain fabrics made from glass fiber and aramid were weaved on dobby hand sample machine. Composite materials were processed with the method of vacum assisted molding and hand lay~up molding. The bending properties of composite material were tested. The anal- ysis on the test result show that the fabric structure, degree of soaked resin and processing methods have some effect on the bending properties of molded composite materials.

  11. Fiber Reinfoced Polymer Used for Flooding Protection of Engineering Structures Made of RC and Brick Masonry

    Directory of Open Access Journals (Sweden)

    Gabriel Oprişan


    Full Text Available Urban and rural floods are becoming nowadays a frequent problem to be dealt with, by both the population and the authorities. Floods and flood related natural disasters act against the civil, industrial and agricultural structures by the hydrostatic and hydrodynamic pressures of water. A set of protective solutions based on Fiber Reinforced Polymer (FRP composite materials, for structural elements of buildings subjected to flood loadings, is proposed and analysed. These solutions are achieved by using the hand lay-up forming technique utilizing glass, carbon or aramid fibers fabrics pre-impregnated with thermosetting epoxy, polyester or vynilester resins. The application of these FRP composites is carried out on reinforced concrete columns and beams as well as on brick masonry works aiming to increase in the overall load bearing capacity, especially against horizontal loads. An improved protection against excessive humidity is also envisaged. The Finite Elements Method based LUSAS software was used to simulate a partially flooded structure. The numerical modeling was carried out in both the un-strengthened and strengthened conditions of the structure in order to assess the increasing in load and deformation capacities of the structural elements. Volumetric finite elements were used for modeling the concrete and masonry members.

  12. Running performance of racing solar car; Kyogiyo solar car no soko seino

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, H. [Osaka Sangyo Univ., Osaka (Japan); Ando, Y.


    The paper reported on `96 World Solar Challenge which is a solar car race traveling a total of 3010km from Darwin to Adelaide of the Australian continent. We accomplished running with general cars on general roads at mean speed of 60.3km/h for 6 days. To reduce vehicle weight, the monocock structure honeycombed with carbon fiber and aramid was adopted to the whole vehicle, and a light alloy to driving system parts. To reduce air resistance, adopted were reduction in the front projection area and the smooth body form. The required power is 44.8 kWh, and the power consumption ratio during travel is very high, approximately 67 km/kWh. In the travel of solar car in the unstable weather, dependence upon battery becomes higher, and therefore the battery capacity of 3.5 kWh with which the car was loaded is small, which resulted in affecting the race totally. To predict the travel in the race and determine the travel method, needed are collection and management of realtime and accurate travel data. The measuring management system developed this time together with the vehicle was applicable to the actual race and high in practicality. 2 refs., 7 figs., 1 tab.

  13. Alternative fiber to asbestos. Asbesto daitai sen prime i

    Energy Technology Data Exchange (ETDEWEB)

    Ashizawa, M. (Nichias Corporation, Yokohama (Japan))


    Explanation is made of alternative fiber to asbestos. Being the finest of all the fibers, excellent in thermal resistivity, flexibility and chemical resistivity, and large in tensile force, the asbestos fiber is described to be used as fireproof spun fiber and other asbestos products as well as for the asbestos slate, for the most part, and other asbestos cement products to be heightened in strength and thermal resistivity by its utilization. Characteristics, etc. are then summarized of pulp, cotton, glass fiber, aramid fiber, potassium titanate fiber, carbon fiber and metallic fiber which are being all studied as alternative fiber to asbestos. Further in order to heighten the product in strength by a use of alternative fiber to asbestos, necessity is pointed out of not only heightening the strength (tensile force) of fiber proper but also heightening the aspect ratio (ratio of length to diameter) of fiber, adhesive force on the interface between the fiber and product matrix, and mutual holding/bonding force among the treads of fiber. 17 refs., 4 figs., 6 tabs.

  14. Synthesis and Characterization of Fibre Reinforced Silica Aerogel Blankets for Thermal Protection

    Directory of Open Access Journals (Sweden)

    S. Chakraborty


    Full Text Available Using tetraethoxysilane (TEOS as the source of silica, fibre reinforced silica aerogels were synthesized via fast ambient pressure drying using methanol (MeOH, trimethylchlorosilane (TMCS, ammonium fluoride (NH4F, and hexane. The molar ratio of TEOS/MeOH/(COOH2/NH4F was kept constant at 1 : 38 : 3.73 × 10−5 : 0.023 and the gel was allowed to form inside the highly porous meta-aramid fibrous batting. The wet gel surface was chemically modified (silylation process using various concentrations of TMCS in hexane in the range of 1 to 20% by volume. The fibre reinforced silica aerogel blanket was obtained subsequently through atmospheric pressure drying. The aerogel blanket samples were characterized by density, thermal conductivity, hydrophobicity (contact angle, and Scanning Electron Microscopy. The radiant heat resistance of the aerogel blankets was examined and compared with nonaerogel blankets. It has been observed that, compared to the ordinary nonaerogel blankets, the aerogel blankets showed a 58% increase in the estimated burn injury time and thus ensure a much better protection from heat and fire hazards. The effect of varying the concentration of TMCS on the estimated protection time has been examined. The improved thermal stability and the superior thermal insulation of the flexible aerogel blankets lead to applications being used for occupations that involve exposure to hazards of thermal radiation.

  15. Preparation and Properties of A Low-cost Triad Mica Tape Material%一种低成本三合一云母带材料的制备及性能研究

    Institute of Scientific and Technical Information of China (English)

    高云霞; 赵琬倩; 陈子荣


    A triad mica tape material was designed and prepared, and its mechanical properties and electri-cal properties were tested. The results show that comparing with the polyimide aramid mica tape, the triad mica tape has better mechanical properties and equivalent breakdown voltage. The dielectric loss factor of simulation bars prepared by the triad mica tape material is less than 8%. So the triad mica tape could be used as a kind of low cost alternative material for manufacturing low voltage motor.%设计并制备了一种三合一云母带材料,并对其力学性能和电气性能进行测试。结果表明:与二合一聚酰亚胺芳纶云母带材料相比,三合一云母带的力学性能更加优异,击穿电压与二合一云母带相当,采用三合一云母带制备的模拟线棒热态介损低于8%。因此三合一云母带可以作为一种低成本替代材料用于低压电机的制造。

  16. Investigation of Optimum Parameters for Mechanical Properties of Ecofriendly Molded Plant Fibre Polymer Matrix Composite by Experimental Methods

    Directory of Open Access Journals (Sweden)



    Full Text Available Natural fibre composites are mainly price-driven commodity composites, which have useable structural properties at relatively low cost. The manufacture of such types of composites are environmentally sustainable alternative to conventional composites made of glass, carbon and aramid fibres which are considered critical because of the growing environmental consciousness. Fibres derived from plants are renewable and have low levels of embodied energy compared to synthetic fibres. Therefore this research work explains the development of natural fibre composite, [9] to attain the optimum mechanical property parameters which are equivalent and better to the traditional reinforcing fibres such as glass and carbon. The research work illustrates the manufacture and tested values of one such composite manufactured from a plant fibre which is used as green manuring plant called Crotalaria juncea. Retted fibres after alkali treatment [17] is taken and plate preparation is done using polyester resin mixed with random orientation of the fibre of lengths 20,30,40 and 50mm to a weight of 21,28,31,35,42 and 45 grams as the first part. In the second part of the work woven orientation of biaxial, biaxially stitched and unidirectional mat in 2 layer and 3 layer separately and they are mixed with polyester resin and plates are prepared. Both the stages are tested for mechanical properties [10,16] such that the breakeven value of each property is analyzed, and the results acquired derive the usefulness of the material for required application.

  17. Influence of PEO and CPAM on the Formation of the Base Paper for Paper Based Friction Material%PEO和CPAM对纸基摩擦材料原纸性能的影响

    Institute of Scientific and Technical Information of China (English)

    陆赵情; 陈杰; 张大坤


    The experiment used carbon fiber, chopped Kevlar fiber and aramid pulp, bamboo fiber and sepiolite flocking as raw material to prepare paper based friction material by wet-forming process. Polyethylene oxide ( PEO) and cationic polyacrylamides ( CPAM) were used as chemical additives and the influence of the dosages of PEO and CPAM on furnish dispersion and the paper formation was studied. The results show that the furnish dispersion and the paper formation were the best when the dosages of PEO and CPAM were 0.2% and 0.16% respectively%采用碳纤维、短切芳纶纤维、芳纶浆粕、竹纤维以及海泡石绒为原料,并用抄纸的方法抄造纸基摩擦材料原纸;通过在抄造浆料中添加聚氧化乙烯(PEO)和阳离子聚丙烯酰胺(CPAM),探究了PEO和CPAM对浆料分散性能和纸张匀度和抗张强度的影响.结果表明,PEO对浆料有良好的分散作用,CPAM对纸张有很好的增强效果,当PEO用量为0.2%、CPAM用量为0.16%时,浆料分散效果最好,成纸的匀度最高.

  18. Novel self-sensing carbon nanotube-based composites for rehabilitation of structural steel members (United States)

    Ahmed, Shafique; Doshi, Sagar; Schumacher, Thomas; Thostenson, Erik T.; McConnell, Jennifer


    Fatigue and fracture are among the most critical forms of damage in metal structures. Fatigue damage can initiate from microscopic defects (e.g., surface scratches, voids in welds, and internal defects) and initiate a crack. Under cyclic loading, these cracks can grow and reach a critical level to trigger fracture of the member which leads to compromised structural integrity and, in some cases, catastrophic failure of the entire structure. In our research, we are investigating a solution using carbon nanotube-based sensing composites, which have the potential to simultaneously rehabilitate and monitor fatigue-cracked structural members. These composites consist of a fiber-reinforced polymer (FRP) layer and a carbon nanotube-based sensing layer, which are integrated to form a novel structural self-sensing material. The sensing layer is composed of a non-woven aramid fabric that is coated with carbon nanotubes (CNT) to form an electrically conductive network that is extremely sensitive to detecting deformation as well as damage accumulation via changes in the resistance of the CNT network. In this paper, we introduce the sensing concept, describe the manufacturing of a model sensing prototype, and discuss a set of small-scale laboratory experiments to examine the load-carrying capacity and damage sensing response.

  19. Breeding waterbirds (Pelecaniformes at Maracujá island, Babitonga bay estuary, north coast of Santa Catarina, Brazil

    Directory of Open Access Journals (Sweden)

    Alexandre Venson Grose


    Full Text Available Waterbirds usually breed in an aggregate way, forming large breeding colonies with different species. This study describes biological aspects of waterbirds from a colony at Maracujá island, in the Babitonga bay estuary, north coast of Santa Catarina, Brazil. We collected data on species richness, abundance, breeding chronology, predation, and nest distribution in the island. Within the period from September 2010 to February 2011, 15 waterbird species were identified using the feeding and resting site, and, out of them, 5 species bred in the island (Nycticorax nycticorax, Nyctanassa violacea, Egretta caerulea, Phimosus infuscatus, and Aramides cajanea. We registered 154 active nests, 79 nests of N. Nycticorax, 14 nests of N. violacea, 6 nests of P. infuscatus, 5 nests of E. caerulea, and only 1 nest of A. cajanea. The estimated local population was 308 breeding individuals, and N. nycticorax was the most abundant species, accounting for 51% of nests. The months with higher concentration of nests were September, October, and November. In addition to waterbirds, 4 birds of prey and scavenger species were registered, which were responsible for egg and/or chick losses, along with Larus dominicanus. Maracujá island has been used for breeding by at least 5 species and its protection deserves attention, in order to ensure the maintenance and possibility to expand this breeding site.

  20. Influence of Polymer Restraint on Ballistic Performanceof Alumina Ceramic Tiles

    Directory of Open Access Journals (Sweden)

    P.R.S. Reddy


    Full Text Available An experimental study has been carried out to evaluate the influence of confinement ofalumina ceramic tiles through polymer restraint, on its ballistic performance. Tiles of 99.5 per centpurity alumina were subjected to ballistic impact against 7.62 mm armour piercing projectiles atvelocities of about 820 m/s. The tiles of size 75 mm x 75 mm x 7 mm were confined on both facesby effectively bonding varying numbers of layers of polymer fabrics. These were then bondedto a 10 mm thick fibre glass laminate as a backing using epoxy resin. High performance polyethyleneand aramid polymer fabrics were used in the current set of experiments for restraining the tiles.Comparative effects of confinement on energy absorption of tiles with varied number of layersof fabrics were evaluated. It was observed that by providing effective confinement to the tile,energy absorption could be doubled with increase in areal density by about 13 per cent.Photographs of the damage and the effects of restraint on improvement in energy absorptionof ceramic tiles are presented and discussed.

  1. LDEF results for polymer matrix composite experiment AO 180 (United States)

    Tennyson, R. C.


    This report represents a summary of the results obtained to-date on a polymer matrix composite experiment (AO 180) located at station D-12, about 82 deg off the 'ram' direction. Different material systems comprised of graphite, boron, and aramid (Kevlar) fiber reinforcements were studied. Although previous results were presented on in-situ thermal-vacuum cycling effects, particularly dimensional changes associated with outgassing, additional comparative data will be shown from ground-based tests on control and flight samples. The system employed was fully automated for thermal-vacuum cycling using a laser interferometer for monitoring displacements. Erosion of all three classes of materials due to atomic oxygen (AO) will also be discussed, including angle of incidence effects. Data from this experiment will be compared to published results for similar materials in other LDEF experiments. Composite materials' erosion yields will be presented on an AO design nomogram useful for estimating total material loss for given exposure conditions in low Earth orbit (LEO). Optical properties of these materials will also be compared with control samples. A survey of the damage caused by micrometeoroids/debris impacts will be addressed as they relate to polymer matrix composites. Correlations between hole size and damage pattern will be given. Reference to a new nomogram for estimating the number distribution of micrometeoroid/debris impacts for a given space structure as a function of time in LEO will be addressed based on LDEF data.

  2. Mould design and manufacturing considerations of honeycomb biocomposites with transverse fibre direction for aerospace application (United States)

    Manan, N. H.; Majid, D. L.; Romli, F. I.


    Sandwich structures with honeycomb core are known to significantly improve stiffness at lower weight and possess high flexural rigidity. They have found wide applications in aerospace as part of the primary structures, as well as the interior paneling and floors. High performance aluminum and aramid are the typical materials used for the purpose of honeycomb core whereas in other industries, materials such as fibre glass, carbon fibre, Nomex and also Kevlar reinforced with polymer are used. Recently, growing interest in developing composite structures with natural fibre reinforcement has also spurred research in natural fibre honeycomb material. The majority of the researches done, however, have generally emphasized on the usage of random chopped fibre and only a few are reported on development of honeycomb structure using unidirectional fibre as the reinforcement. This is mainly due to its processing difficulties, which often involve several stages to account for the arrangement of fibres and curing. Since the use of unidirectional fibre supports greater strength compared to random chopped fibre, a single-stage process in conjunction with vacuum infusion is suggested with a mould design that supports fibre arrangement in the direction of honeycomb loading.

  3. Power generation from base excitation of a Kevlar composite beam with ZnO nanowires (United States)

    Malakooti, Mohammad H.; Hwang, Hyun-Sik; Sodano, Henry A.


    One-dimensional nanostructures such as nanowires, nanorods, and nanotubes with piezoelectric properties have gained interest in the fabrication of small scale power harvesting systems. However, the practical applications of the nanoscale materials in structures with true mechanical strengths have not yet been demonstrated. In this paper, piezoelectric ZnO nanowires are integrated into the fiber reinforced polymer composites serving as an active phase to convert the induced strain energy from ambient vibration into electrical energy. Arrays of ZnO nanowires are grown vertically aligned on aramid fibers through a low-cost hydrothermal process. The modified fabrics with ZnO nanowires whiskers are then placed between two carbon fabrics as the top and the bottom electrodes. Finally, vacuum resin transfer molding technique is utilized to fabricate these multiscale composites. The fabricated composites are subjected to a base excitation using a shaker to generate charge due to the direct piezoelectric effect of ZnO nanowires. Measuring the generated potential difference between the two electrodes showed the energy harvesting application of these multiscale composites in addition to their superior mechanical properties. These results propose a new generation of power harvesting systems with enhanced mechanical properties.

  4. What's new in intraperitoneal test on Kevlar (asbestos substitute)? (United States)

    Brinkmann, O A; Müller, K M


    The intraperitoneal test is a suitable experimental method for studying the different patterns of morphological reaction to foreign body substances of various kinds and concentrations as well as their transport within and elimination from the organism, Kevlar fibres are synthetic aromatic polyamid (aramid) fibres which, investigated by means of the intraperitoneal test in Wistar rats, show distinct pathogenetic reaction patterns: 1. In the early stage after application, the formation of multinucleated giant cells with phagocytosis of the amber-coloured Kevlar fibres, and an inflammatory reaction are foremost features. 2. The typical feature of the second stage is the development of granulomas with central necrosis indicating the cytotoxic nature of Kevlar fibres. 3. The third stage is dominated by the mesenchymal activation with capsular structures of collagenous fibres. Besides granulomatous foci, a slight submesothelial fibrosis is observed. 4. Fragments of Kevlar fibres are drained through lymphatic pathways and stored in lymph nodes where they lead to inflammatory reactions. 5. The reactive granulomatous changes in the greater omentum of rats are accompanied by proliferative mesothelial changes which, in one cases, even led to the development of a multilocular mesothelioma.

  5. Development of multifunctional fiber reinforced polymer composites through ZnO nanowire arrays (United States)

    Malakooti, Mohammad H.; Patterson, Brendan A.; Hwang, Hyun-Sik; Sodano, Henry A.


    Piezoelectric nanowires, in particular zinc oxide (ZnO) nanowires, have been vastly used in the fabrication of electromechanical devices to convert wasted mechanical energy into useful electrical energy. Over recent years, the growth of vertically aligned ZnO nanowires on various structural fibers has led to the development of fiber-based nanostructured energy harvesting devices. However, the development of more realistic energy harvesters that are capable of continuous power generation requires a sufficient mechanical strength to withstand typical structural loading conditions. Yet, a durable, multifunctional material system has not been developed thoroughly enough to generate electrical power without deteriorating the mechanical performance. Here, a hybrid composite energy harvester is fabricated in a hierarchical design that provides both efficient power generating capabilities while enhancing the structural properties of the fiber reinforced polymer composite. Through a simple and low-cost process, a modified aramid fabric with vertically aligned ZnO nanowires grown on the fiber surface is embedded between woven carbon fabrics, which serve as the structural reinforcement as well as the top and the bottom electrodes of the nanowire arrays. The performance of the developed multifunctional composite is characterized through direct vibration excitation and tensile strength examination.

  6. Optimizing the Flexural Strength of Beams Reinforced with Fiber Reinforced Polymer Bars Using Back-Propagation Neural Networks

    Directory of Open Access Journals (Sweden)

    Bahman O. Taha


    Full Text Available The reinforced concrete with fiber reinforced polymer (FRP bars (carbon, aramid, basalt and glass is used in places where a high ratio of strength to weight is required and corrosion is not acceptable. Behavior of structural members using (FRP bars is hard to be modeled using traditional methods because of the high non-linearity relationship among factors influencing the strength of structural members. Back-propagation neural network is a very effective method for modeling such complicated relationships. In this paper, back-propagation neural network is used for modeling the flexural behavior of beams reinforced with (FRP bars. 101 samples of beams reinforced with fiber bars were collected from literatures. Five important factors are taken in consideration for predicting the strength of beams. Two models of Multilayer Perceptron (MLP are created, first with single-hidden layer and the second with two-hidden layers. The two-hidden layer model showed better accuracy ratio than the single-hidden layer model. Parametric study has been done for two-hidden layer model only. Equations are derived to be used instead of the model and the importance of input factors is determined. Results showed that the neural network is successful in modeling the behavior of concrete beams reinforced with different types of (FRP bars.

  7. Armored garment for protecting (United States)

    Purvis, James W.; Jones, II, Jack F.; Whinery, Larry D.; Brazfield, Richard; Lawrie, Catherine; Lawrie, David; Preece, Dale S.


    A lightweight, armored protective garment for protecting an arm or leg from blast superheated gases, blast overpressure shock, shrapnel, and spall from a explosive device, such as a Rocket Propelled Grenade (RPG) or a roadside Improvised Explosive Device (IED). The garment has a ballistic sleeve made of a ballistic fabric, such as an aramid fiber (e.g., KEVLAR.RTM.) cloth, that prevents thermal burns from the blast superheated gases, while providing some protection from fragments. Additionally, the garment has two or more rigid armor inserts that cover the upper and lower arm and protect against high-velocity projectiles, shrapnel and spall. The rigid inserts can be made of multiple plies of a carbon/epoxy composite laminate. The combination of 6 layers of KEVLAR.RTM. fabric and 28 plies of carbon/epoxy laminate inserts (with the inserts being sandwiched in-between the KEVLAR.RTM. layers), can meet the level IIIA fragmentation minimum V.sub.50 requirements for the US Interceptor Outer Tactical Vest.

  8. Analysis of strain and stress in ceramic, polymer and metal matrix composites by Raman spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Colomban, P. [LADIR, Nanophases and Heterogeneous Solids Group, UMR 7075 CNRS and Universite Pierre et Marie Curie, 2 rue Henry-Dunant, 94320 Thiais (France)


    Raman scattering is a unique tool providing information on the structure and short-range order of matter. Stress-induced Raman shifts can be used to determine the stress/strain in films, fibres, particulate composites and, more generally, in any phase a few microns or more in scale. Quantitative results follow from a wavenumber calibration as a function of tensile strains or pressures applied to reference fibres or crystals. Furthermore, if the material is coloured, (near) resonant Raman scattering occurs, which enhances the scattered light intensity and simplifies the spectra - especially for harmonics - but drastically reduces the analysed volume (in-depth penetration {proportional_to}10-100 nm). This paper discusses the effective and potential advantages/drawbacks of Raman micro-spectrometry technique. The procedures to improve the sensitivity, the legibility and the reliability will be addressed. Examples will be chosen among (aramid, C, SiC) fibre- reinforced ceramic (CMCs), polymer (PMCs) or metal matrix (MMCs) composites. (Abstract Copyright[2002], Wiley Periodicals, Inc.)

  9. Impact and residual fatigue behavior of ARALL and AS6/5245 composite materials (United States)

    Johnson, W. S.


    Aramide fiber reinforced aluminum laminates (ARALL) represent a cross between resin matrix composites and metals. The purpose of this study was to evaluate the impact sensitivity of this concept. Two types of ARALL (7075 aluminum prestrained and 2024 aluminum not prestrained) were tested through static indentation and the results compared to sheet 2024-T3 and 7075-T6 aluminum alloys. A state-of-the-art composite (AS6/5245) was also tested and compared to the ARALL. Further, the two types of ARALL material and the composite were dynamically impacted at two energy levels and fatigue tested to determine residual fatigue strength. Both forms of the ARALL material had worse impact resistance than monolithic sheet aluminum. The ARALL material made with 2024-T3 aluminum had better impact resistance than did the laminates made with 7075-T6 aluminum. The ARALL materials are at least equal to the composite material in impact damage resistance and are better for impact detection. The composite material has higher residual fatigue strength after impact than the ARALL material and is 25 percent lighter. The prestraining of the ARALL greatly reduces the fatigue growth of impact damage.

  10. The Use of Zylon Fibers in ULDB Balloons (United States)

    Zimmerman, M.; Seely, L.; McLaughlin, J.

    Early in the development of the ULDB balloon, Zylon (PBO) was selected as the tendon material due to its favorable stress-strain properties. It is a next generation super fiber whose strength and modulus are almost double those of the p-Aramid fibers. In addition there are two versions of the Zylon, As Spun (AS) and High Modulus (HM). Data will be presented on why the HM was chosen. Early in the development process, it was learned that this material exhibited an unusual sensitivity to degradation by ambient light. This is in addition to the expected sensitivity to UV radiation (Ultraviolet). The fiber manufacturer reported all of these properties in their literature. Due to the operating environment of the ULDB (Ultra Long Duration Balloon) it is necessary to protect the tendons from both visible and UV radiation. Methods to protect the tendons will be discussed. In addition, information on the long term exposure of the braided tendon over a thirty-six month period in a controlled manufacturing plant will be provided.

  11. Concrete-Filled-Large Deformable FRP Tubular Columns under Axial Compressive Loading

    Directory of Open Access Journals (Sweden)

    Omar I. Abdelkarim


    Full Text Available The behavior of concrete-filled fiber tubes (CFFT polymers under axial compressive loading was investigated. Unlike the traditional fiber reinforced polymers (FRP such as carbon, glass, aramid, etc., the FRP tubes in this study were designed using large rupture strains FRP which are made of recycled materials such as plastic bottles; hence, large rupture strain (LRS FRP composites are environmentally friendly and can be used in the context of green construction. This study performed finite element (FE analysis using LS-DYNA software to conduct an extensive parametric study on CFFT. The effects of the FRP confinement ratio, the unconfined concrete compressive strength ( , column size, and column aspect ratio on the behavior of the CFFT under axial compressive loading were investigated during this study. A comparison between the behavior of the CFFTs with LRS-FRP and those with traditional FRP (carbon and glass with a high range of confinement ratios was conducted as well. A new hybrid FRP system combined with traditional and LRS-FRP is proposed. Generally, the CFFTs with LRS-FRP showed remarkable behavior under axial loading in strength and ultimate strain. Equations to estimate the concrete dilation parameter and dilation angle of the CFFTs with LRS-FRP tubes and hybrid FRP tubes are suggested.

  12. Energy storage on ultrahigh surface area activated carbon fibers derived from PMIA. (United States)

    Castro-Muñiz, Alberto; Suárez-García, Fabián; Martínez-Alonso, Amelia; Tascón, Juan M D; Kyotani, Takashi


    High-performance carbon materials for energy storage applications have been obtained by using poly(m-phenylene isophthalamide), PMIA, as a precursor through the chemical activation of the carbonized aramid fiber by using KOH. The yield of the process of activation was remarkably high (25-40 wt%), resulting in activated carbon fibers (ACFs) with ultrahigh surface areas, over 3000 m(2) g(-1) , and pore volumes exceeding 1.50 cm(3) g(-1) , keeping intact the fibrous morphology. The porous structure and the surface chemical properties could easily be controlled through the conditions of activation. The PMIA-derived ACFs were tested in two types of energy storage applications. At -196 °C and 1 bar, H2 uptake values of approximately 3 t% were obtained, which, in combination with the textural properties, rendered it a good candidate for H2 adsorption at high pressure and temperature. The performance of the ACFs as electrodes for electrochemical supercapacitors was also investigated. Specific capacitance values between 297 and 531 g(-1) at 50 mA g(-1) were obtained in aqueous electrolyte (1 H2 SO4 ), showing different behaviors depending on the surface chemical properties.

  13. Present status of and subjects on the industrial utilization of polymer separation membranes. Japan`s first largest sea water desalination plant by RO; Kobunshi bunrimaku no sangyo riyo no genjo to kadai. Zosui bun`ya ni okeru maku riyo

    Energy Technology Data Exchange (ETDEWEB)

    Furuichi, M. [Kurita Water Industries Ltd., Tokyo (Japan)


    The utilization in Japan and abroad is discussed of desalination methods using evaporation, reverse osmosis (RO) membranes, and electrodialysis membranes, out of various desalination techniques for seawater and others containing more salt. A new seawater desalination plant built in Okinawa, Japan, is outlined, and the future trend of Japan`s efforts for desalination is predicted. The said plant in Okinawa is the largest ever built in this country, and occupies 4th or 5th place in terms of capacity among similar facilities across the world. It was completed in April, 1997, and produces pure water at a rate of 40,000m{sup 3}/day. This plant, operating on RO, comprises eight RO membrane units each capable of 5131{sup 3}/day. The membranes are of the spiral type, consisting of Toray`s crosslinked aramid-base composite membranes and Nitto Denko`s membranes composed totally of crosslinked aromatic polyamide. The greatest of the pending tasks is to reduce the desalination cost. As for the operating cost of the desalination facility at the current stage, it costs 120-130 yen/m{sup 3} on the 40,000m{sup 3}/day scale, and the power cost occupies approximately 60% of the total operating cost. It is concluded that the consumption of electric power and chemicals per pure water produced have to be reduced. 8 refs., 5 figs., 5 tabs.

  14. 纤维增强复合材料三明治板的破片穿甲实验%Armor-piercing experiment on fragment against sandwich plate with fiber reinforced composite cores

    Institute of Scientific and Technical Information of China (English)

    徐豫新; 王树山; 严文康; 虢忠仁


    研究了钢板一纤维增强复合材料板一钢板构成的三明治结构对破片的防护性能。通过破片模拟弹丸(FSP)高速撞击不同结构三明治板实验,获得FSP弹丸贯穿16种三明治板的弹道极限,分析结构特征对纤维增强复合材料三明治板比吸收能的影响。结果表明,叠层芳纶、玻纤基三明治板较单层结构三明治板比吸收能分别提高了8.31%和16.09%,8mm面板+8mm夹层+6mm背板芳纶、玻纤基三明治板较4mm面板+8mm夹层+10mm背板的芳纶、玻纤基三明治板比吸收能分别提高了37.72%和25.35%;芳纶、玻纤基三明治板的比吸收能均随复合材料夹层厚度的增加呈指数递增,夹层基板的抗拉性能是影响三明治板比吸收能的重要因素;同面密度下,厚面板、薄背板及多层叠合夹层结构的三明治板具有更高的比吸收能。%The defense performance of sandwich structure of steel plate - fiber composite material plate - steel plate structure against fragment was investigated. By the experiment on the fragment simulation projectile (FSP), impacted to different kinds of sandwich plate with high velocity, the ballistic limits of fragment pierced 16 kinds of sandwich plates were obtained, and the influence of structure characteristic on the speeifie energy absorption of the sandwich plate was analyzed. The results show that the specific energy absorption of laminated sandwich structure on aramid and glass fiber is 8. 31% and 16.09% higher than that of a single-layer structure, respectively. The specific energy absorption of the sandwich structure with 8 mm front+ 8mm core+ 6 mm back on aramid and glass fiber is 37.72% and 25. 35% higher than the one with 4 mm frontq-8 mm core+10 mm back, respectively. The speeific energy absorption of sandwich plate exponentially increases with the thickness of fiber composite sandwich. The tensile properties of middle layer plate is an

  15. 新合成纤维与分散染料染色%Novel synthetic fibers and disperse dye dyeing

    Institute of Scientific and Technical Information of China (English)



    Synthetic fibers was studied and developed in about World War II. With the oil industry expanding, the real industrialization of synthetic fibers began in the 1950s'. One of the fastest growing synthetic fibers is the polyester fiber. The world output reached 36 413 000 t in 2010, accounting for 84.7% of total synthetic fibers. Nowadays the new polyester fibers such as PTT, PLA, aramid fiber and polysulfonamide fiber with high performance are developing, whose production is rising gradually. These new fibers are all dyed with disperse dyes. The difference is PTT fibers can be dyed with traditional disperse dyes applied in PET fibers, aramid fibers and polysulfonamide fibers must be dyed with carrier in the presence of special additive. The carrier is required to be non-toxic, tasteless, easy washing, high color value and does not affect the color fastness. PLA is fatty polyester and different from PET and PTT aromatic polyester. Due to the large difference in molecular structure, the dielectric constant, polarity and dye forces of different polyester fibers are different, which brings about the differences in levelness, hue and color fastness. The solubility parameters or inorganic values/organic values were applied in selecting or designing the special molecular structure of disperse dye from the traditional disperse dyes.%合成纤维于二战前后开始研究和开发,随着石油工业的壮大,真正的工业化始于20世纪50年代,其中发展最快的当推聚酯纤维,2010年世界产量已达3 641.3万t,占合纤总量的84.7%.如今发展的是新聚酯纤维(如PTT、PLA纤维)和芳纶、芳砜纶高性能纤维,产量正逐步上升.这些新纤维都用分散染料染色,所不同的是PTT纤维可用PET纤维适用的传统分散染料,芳纶和芳砜纶则需使用特殊添加剂存在下的载体染色,要求载体无毒、无味、易洗除、给色量高、不影响色牢度.而PLA是脂肪类聚酯,与PET、PTT芳香族聚酯性能有所

  16. Macroscopic fibres of CNTs as electrodes for multifunctional electric double layer capacitors: from quantum capacitance to device performance (United States)

    Senokos, E.; Reguero, V.; Palma, J.; Vilatela, J. J.; Marcilla, Rebeca


    In this work we present a combined electrochemical and mechanical study of mesoporous electrodes based on CNT fibres in the context of electric double layer capacitors. We show that through control of the synthetic and assembly processes of the fibres, it is possible to obtain an active material that combines a surface area of 250 m2 g-1, high electrical conductivity (3.5 × 105 S m-1) and mechanical properties in the high-performance range including toughness (35 J g-1) comparable to that of aramid fibre (e.g. Kevlar). These properties are a consequence of the predominant orientation of the CNTs, observed by wide- and small-angle X-ray diffraction, and to the exceptionally long CNT length on the millimetre scale. Cyclic voltammetry measurements in a three-electrode configuration and using 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PYR14TFSI) ionic liquid electrolyte, show that the CNT fibres have a large quantum capacitance, evidenced by the near linear dependence of geometric capacitance (and conductivity) on potential bias. This reflects the low dimensionality of the CNT building blocks, which were purposely synthesised to have 1-5 layers and a high degree of graphitization. From the charge-discharge measurements of supercapacitor devices with symmetric CNT fibre electrodes we obtain power and energy densities as high as 58 kW kg-1 and 14 Wh kg-1, respectively. These record-high values for CNT fibre-based supercapacitors, are a consequence of the low equivalent series resistance due to the high conductivity of the fibres, the large contribution from quantum capacitance, and the wide stability window of the ionic liquid (3.5 V). Cycle life experiments demonstrate stable capacitance and energy retention over 10 000 cycles of charge-discharge at 3.5 V.In this work we present a combined electrochemical and mechanical study of mesoporous electrodes based on CNT fibres in the context of electric double layer capacitors. We show that through

  17. Avaliação da temperatura de transição vítrea de compósitos poliméricos reparados de uso aeronáutico Evaluation of glass transition temperature of the repaired polymeric composites of aeronautical use

    Directory of Open Access Journals (Sweden)

    Jane M. F. de Paiva


    Full Text Available Este trabalho mostra a avaliação da temperatura de transição vítrea (Tg, por DMTA, de três famílias de compósitos poliméricos reparados, tendo como laminados base tecidos de fibras de carbono/resina epóxi modificada com elastômero (F584, vidro/resina epóxi (F161 e aramida/resina epóxi (F161. Os compósitos foram laminados manualmente por processo convencional e curados em autoclave de indústria aeronáutica. Posteriormente, danos foram simulados sendo, em seguida, reparados adotando-se a técnica de sobreposição de camadas de pré-impregnados de resina epóxi (F155, com adição de filme adesivo de epóxi (FM 73. As curvas DMTA mostram os efeitos da combinação de diferentes sistemas de resinas na Tg e, conseqüentemente, na temperatura de serviço do componente reparado. O material de reparo utilizado, baseado em pré-impregnados com resina epóxi F155 e filme adesivo de epóxi, provocou a redução da Tg dos compósitos reparados. Para os laminados base com tecido de fibras de carbono e vidro foram verificadas reduções de aproximadamente 30 °C na Tg. Este efeito foi mais pronunciado (redução de aproximadamente 40 °C quando o laminado reparado de aramida foi submetido a condicionamento higrotérmico a temperatura e umidade elevadas. Esta redução na Tg dos laminados reparados é atribuída à migração do adesivo para o pré-impregnado de resina epóxi F155 utilizado no reparo, durante o processo de cura, e à plasticização do sistema polimérico pela água, durante o condicionamento higrotérmico. A redução da Tg leva a uma conseqüente redução da temperatura de serviço do compósito polimérico reparado.This work shows the evaluation of the glass transition temperature (Tg by DMTA of three different families of repaired polymeric composites, manufactured with carbon fiber fabric/epoxy F584, glass fabric/epoxy F161 and aramide fabric/epoxy F161, respectively. The composites were laminated by conventional hand

  18. Damage Tolerance Testing of a NASA TransHab Derivative Woven Inflatable Module (United States)

    Edgecombe, John; delaFuente, Horacio; Valle, Gerard


    Current options for Lunar habitat architecture include inflatable habitats and airlocks. Inflatable structures can have mass and volume advantages over conventional structures. However, inflatable structures carry different inherent risks and are at a lower Technical Readiness Level (TRL) than more conventional metallic structures. One of the risks associated with inflatable structures is in understanding the tolerance to induced damage. The Damage Tolerance Test (DTT) is designed to study the structural integrity of an expandable structure. TransHab (Figure 1) was an experimental inflatable module developed at the NASA/Johnson Space Center in the 1990 s. The TransHab design was originally envisioned for use in Mars Transits but was also studied as a potential habitat for the International Space Station (ISS). The design of the TransHab module was based on a woven design using an Aramid fabric. Testing of this design demonstrated a high level of predictability and repeatability with analytical predictions of stresses and deflections. Based on JSC s experience with the design and analysis of woven inflatable structures, the Damage Tolerance Test article was designed and fabricated using a woven design. The DTT article was inflated to 45 psig, representing 25% of the ultimate burst pressure, and one of the one-inch wide longitudinal structural members was severed by initiating a Linear Shaped Charge (LSC). Strain gage measurements, at the interface between the expandable elements (straps) and the nonexpandable metallic elements for pre-selected longitudinal straps, were taken throughout pressurization of the module and strap separation. Strain gage measurements show no change in longitudinal strap loading at the bulkhead interface after strap separation indicating loads in the restraint layer were re-distributed local to the damaged area due to the effects of friction under high internal pressure loading. The test completed all primary objectives with better than

  19. Composite molding of SPECTRA{reg_sign} extended chain polyethylene fibers in a flexible rubber matrix

    Energy Technology Data Exchange (ETDEWEB)

    McKeehan, K.


    THETA Technologies, Inc. is a multidisciplinary research and development firm involved in the design and development of affordable, lightweight, high ballistic protection modular body armor ensemble for future military, law enforcement, and specialized commercial market applications. In the course of their research, THETA Technologies, Inc. identified that current state-of-the-art in ballistic protection and overall composite reinforcement is a high density extended chain polyethylene (HDECPE) fiber known as SPECTRA{reg_sign}, a product of AlliedSignal Fibers, Petersburg, VA. SPECTRA{reg_sign} is ten times stronger than steel of equal weight. As a non-aramid polyethylene, it offers highly desirable properties in areas of resistance to chemical degradation, virtual neutral buoyancy (0.97), and increased capacity for composite bonding over competing nylon-based fibers, such as KEVLAR{reg_sign}. SPECTRA Shield{trademark}, a woven ballistic-resistant fabric using the SPECTRA{reg_sign} fiber, is presently the most effective ballistic-resistant component for both flexible and hard plate composite armors. THETA Technologies, Inc. identified a market need for a boot sole design that would measurably increase protection to the wearer without significantly degrading performance in other areas, such as flexibility and overall weight. THETA Technologies, Inc. proposed a nitrile rubber and SPECTRA{reg_sign} fiber matrix to produce an optimal boot sole. The objective of this CRADA effort was to develop and test a process for combining the SPECTRA{reg_sign} fiber, in both chopped fiber and SPECTRA Shield{trademark} form, within a semiflexible nitrile composite having desirable and marketable properties in areas of resistance to penetration and mechanical stress.

  20. Molecular Self-Assembly of Short Aromatic Peptides: From Biology to Nanotechnology and Material Science (United States)

    Gazit, Ehud


    The formation of ordered amyloid fibrils is the hallmark of several diseases of unrelated origin. In spite of grave clinical consequence, the mechanism of amyloid formation is not fully understood. We have suggested, based on experimental and bioinformatic analysis, that aromatic interactions may provide energetic contribution as well as order and directionality in the molecular-recognition and self-association processes that lead to the formation of these assemblies. This is in line with the well-known central role of aromatic-stacking interactions in self-assembly processes. Our works on the mechanism of aromatic peptide self-assembly, lead to the discovery that the diphenylalanine recognition motif self-assembles into peptide nanotubes with a remarkable persistence length. Other aromatic homodipeptides could self-assemble in nano-spheres, nano-plates, nano-fibrils and hydrogels with nano-scale order. We demonstrated that the peptide nanostructures have unique chemical, physical and mechanical properties including ultra-rigidity as aramides, semi-conductive, piezoelectric and non-linear optic properties. We also demonstrated the ability to use these peptide nanostructures as casting mold for the fabrication of metallic nano-wires and coaxial nano-cables. The application of the nanostructures was demonstrated in various fields including electrochemical biosensors, tissue engineering, and molecular imaging. Finally, we had developed ways for depositing of the peptide nanostructures and their organization. We had use inkjet technology as well as vapour deposition methods to coat surface and from the peptide ``nano-forests''. We recently demonstrated that even a single phenylalanine amino-acid can form well-ordered fibrilar assemblies.

  1. [Production technology and use of composite materials in the aeronautics industry, risks and pathology in the manufacturing workers]. (United States)

    Franco, G; Candura, F


    The type and applications of composite materials have increased greatly during the last forty years, particularly in the aircraft and aerospace industries. The foreseeable increase of the employment of composite materials in future needs an adequate engagement in finding out health risks involved with technological processes. Composite materials - considered as a close union between a continuous glass, aramid or carbon reinforcing fibre and a epoxy matrix - present several advantages over traditional materials. Structural epoxy adhesives are defined as complex formulated systems. By mixing a large number of ingredients a formulated resin is obtained, which represents the start of the production process for adhesive manufacture. The most important ingredients such as catalysts, accelerators, the groups of epoxy monomers and oligomers, additives most used and their role into the epoxy matrices are illustrated. Of the various technologies existing for the fabrication of aircraft structures the one so called "vacuum bag" is described. The knowledge of the chemical composition of the substances used in the production of composite materials and epoxy adhesives allows to verify the possible existence of hazard for workers health. Among the potentially dangerous chemicals, epoxy monomers and oligomers, catalysts, accelerators are to be considered. The metabolism and the mechanisms of toxicity of epoxides are summarized. However the toxic effects of most epoxides are far from being wholly investigated. In man epoxides ingestion, inhalation or absorption through the skin can lead to several toxic effects: irritation and sensitisation, alterations of liver and nervous function. Finally some epoxides are considered to be carcinogenic in animals and in man; however for many compounds, the results are not yet conclusive. From what it is said above come out the necessity of a careful sanitary control of the workers exposed to these hazards, control that is made difficult by the

  2. Bag filters at biofuelled plants, reliability and economy of operation; Slangfilter vid bioeldade anlaeggningar, tillfoerlitlighet och driftsekonomi

    Energy Technology Data Exchange (ETDEWEB)

    Lindau, Leif [SYCON Energikonsult, Malmoe (Sweden)


    The background to this work is the increased requirements on dust emission control for smaller (2-50 MW) biofuel plants in Sweden, where established technology consisting of multi cyclones cannot meet the emission demands, and where the specific cost of the large scale established technology (electrostatic precipitators) quickly increases with decreased plant size. Operational experience of bag filters on Swedish biofuel plants down to a size of 2 MW has been collected. The operational experience is remarkably uniform and positive and availability is high. Bag life, being the most important operational cost factor, is between two and eleven years. Most frequent material used is aramide, but also PPS is employed and the experience of both materials is good. The cost relation between bag filter (including an upstream skimmer) and electrostatic precipitator has been studied based on supplier quotations. Bag filter always has the lowest first cost. At one year bag life, the total cost of a bag filter is less than that for an electrostatic precipitator for plants smaller than 15 MW, and at more than one year's bag life, the bag filter has the lowest total cost for plants up to 50 MW. For plants smaller than 5-10 MW, the difference in total cost is very high. With some simple means for quality assurance of new bags, premature failure rate can be reduced. Following up cleaning interval and/or emission during operation time, gives information about the development of bag condition and necessary bag change can be foreseen. Since bag filters are more prone to damage by fire than electrostatic precipitators, the process of damage due to entrained sparks has been analysed based on practical observations and a thermal calculation. This consideration shows that this damage mode can be eliminated by an upstream skimmer having moderate but reliable performance. The result is well in coherence with the practical operational experience found that with an adequate skimmer

  3. Multiscale modeling of interwoven Kevlar fibers based on random walk to predict yarn structural response (United States)

    Recchia, Stephen

    Kevlar is the most common high-end plastic filament yarn used in body armor, tire reinforcement, and wear resistant applications. Kevlar is a trade name for an aramid fiber. These are fibers in which the chain molecules are highly oriented along the fiber axis, so the strength of the chemical bond can be exploited. The bulk material is extruded into filaments that are bound together into yarn, which may be chorded with other materials as in car tires, woven into a fabric, or layered in an epoxy to make composite panels. The high tensile strength to low weight ratio makes this material ideal for designs that decrease weight and inertia, such as automobile tires, body panels, and body armor. For designs that use Kevlar, increasing the strength, or tenacity, to weight ratio would improve performance or reduce cost of all products that are based on this material. This thesis computationally and experimentally investigates the tenacity and stiffness of Kevlar yarns with varying twist ratios. The test boundary conditions were replicated with a geometrically accurate finite element model, resulting in a customized code that can reproduce tortuous filaments in a yarn was developed. The solid model geometry capturing filament tortuosity was implemented through a random walk method of axial geometry creation. A finite element analysis successfully recreated the yarn strength and stiffness dependency observed during the tests. The physics applied in the finite element model was reproduced in an analytical equation that was able to predict the failure strength and strain dependency of twist ratio. The analytical solution can be employed to optimize yarn design for high strength applications.

  4. Review on advanced composite materials boring mechanism and tools (United States)

    Shi, Runping; Wang, Chengyong


    With the rapid development of aviation and aerospace manufacturing technology, advanced composite materials represented by carbon fibre reinforced plastics (CFRP) and super hybrid composites (fibre/metal plates) are more and more widely applied. The fibres are mainly carbon fibre, boron fibre, Aramid fiber and Sic fibre. The matrixes are resin matrix, metal matrix and ceramic matrix. Advanced composite materials have higher specific strength and higher specific modulus than glass fibre reinforced resin composites of the 1st generation. They are widely used in aviation and aerospace industry due to their high specific strength, high specific modulus, excellent ductility, anticorrosion, heat-insulation, sound-insulation, shock absorption and high&low temperature resistance. They are used for radomes, inlets, airfoils(fuel tank included), flap, aileron, vertical tail, horizontal tail, air brake, skin, baseboards and tails, etc. Its hardness is up to 62~65HRC. The holes are greatly affected by the fibre laminates direction of carbon fibre reinforced composite material due to its anisotropy when drilling in unidirectional laminates. There are burrs, splits at the exit because of stress concentration. Besides there is delamination and the hole is prone to be smaller. Burrs are caused by poor sharpness of cutting edge, delamination, tearing, splitting are caused by the great stress caused by high thrust force. Poorer sharpness of cutting edge leads to lower cutting performance and higher drilling force at the same time. The present research focuses on the interrelation between rotation speed, feed, drill's geometry, drill life, cutting mode, tools material etc. and thrust force. At the same time, holes quantity and holes making difficulty of composites have also increased. It requires high performance drills which won't bring out defects and have long tool life. It has become a trend to develop super hard material tools and tools with special geometry for drilling

  5. Ultrasonic Assessment of Impact-Induced Damage and Microcracking in Polymer Matrix Composites (United States)

    Gyekanyesi, John (Technical Monitor); Liaw, Benjamin; Villars, Esther; Delmont, Frantz


    The main objective of this NASA Faculty Awards for Research (FAR) project is to conduct ultrasonic assessment of impact-induced damage and microcracking in fiber-metal laminated (FML) composites at various temperatures. It is believed that the proposed study of impact damage assessment on FML composites will benefit several NASA's missions and current interests, such as ballistic impact testing of composite fan containment and high strain rate deformation modeling of polymer matrix composites. Impact-induced damage mechanisms in GLARE and ARALL fiber-metal laminates subject to instrumented drop-weight impacts at various temperatures were studied. GLARE and ARALL are hybrid composites made of alternating layers of aluminum and glass- (for GLARE) and aramid- (for ARALL) fiber reinforced epoxy. Damage in pure aluminum panels impacted by foreign objects was mainly characterized by large plastic deformation surrounding a deep penetration dent. On the other hand, plastic deformation in fiber-metal laminates was often not as severe although the penetration dent was still produced. The more stiff fiber-reinforced epoxy layers provided better bending rigidity; thus, enhancing impact damage tolerance. Severe cracking, however, occurred due to the use of these more brittle fiber-reinforced epoxy layers. Fracture patterns, e.g., crack length and delamination size, were greatly affected by the lay-up configuration rather than by the number of layers, which implies that thickness effect was not significant for the panels tested in this study. Immersion ultrasound techniques were then used to assess damages generated by instrumented drop-weight impacts onto these fiber-metal laminate panels as well as 2024-T3 aluminum/cast acrylic sandwich plates adhered by epoxy. Depending on several parameters, such as impact velocity, mass, temperature, laminate configuration, sandwich construction, etc., various types of impact damage were observed, including plastic deformation, radiating

  6. Study of mechanical properties and fracture mechanisms of synthetic fibers nylon-and-polyester type, used in engineering products; Estudo das propriedades mecanicas e dos mecanismos de fratura de fibras sinteticas do tipo nailon e poliester em tecidos de engenharia

    Energy Technology Data Exchange (ETDEWEB)

    Cardoso, Sergio Gomes


    Fibers are groups formed by molecular-chain-oriented filaments. Fibers play a fundamental role in human being's daily life and they can be found in several forms and geometries, such as filaments, yarns, beams, rope, fabric, composite, coatings, others. They are used in various segments such as civil, mechanical, electrical, electronics, military, naval, nautical, aviation, health, medicine, environment, communications, safety, space, others. Fibers are divided into two distinct classes: natural and chemical ones, which cover synthetic and man-made sub-classes. They can be produced from several materials, such as wool, cotton, rayon, flax, silk, rock, nylon, polyester, polyethylene, poly-propylene, aramid, glass, carbon, steel, ceramic, others. Globally, the participation of chemical fibers corresponds to approximately 59,9%, and the synthetic fiber polyester, the most used one, represents approximately 63% of the world market. Vital needs have led to the development of multi-function fibers and the focus has changed in the last 10 years with the use of nano technology for environmental responsibility and smart fibers. The study of mechanical properties and fracture mechanisms of fibers is of great relevance for characterization and understanding of causes as consequence of failures. For such reason, it was selected technical fabrics made of high performance synthetic fiber nylon-and-polyester type, used in engineered products such as tires, belts, hoses and pneumatic springs, which have been analyzed in each processing phase. Fiber samples were extracted after each processing phase to be analyzed, by traction destructive tests and scanning electron microscopy. The results of analysis of mechanical properties showed loss of resistance to temperature and multi axial stress during fiber processing phase. Through microscopy tests, it was possible to find contamination, surface stains, plastic deformations, scaling, variations in the fracture faces of the

  7. New situation & innovative thinking of high performance ifbers and composite materials%高性能纤维及其复合材料的新形势与创新思路

    Institute of Scientific and Technical Information of China (English)

    罗益锋; 罗晰旻


    高性能纤维及其复合材料的技术创新和节能环保法律的强化,助推了新市场的开发、生产规模化、高效化和低成本化。工艺技术的重大突破,使产品性能达到了前所未有的高水平,实现下游制品的高端化、轻量化和节能环保。具体介绍和分析了PA N基碳纤维、碳化硅纤维、碳化硅纤维、对位芳酰胺纤维、超高相对分子质量聚乙烯纤维和聚芳酯纤维及其先进复合材料,以及碳纳米管纤维和石墨烯纤维的最新创新技术和发展动向。%New market development, large scaling production line in low cost and more efficiency of high per-formance fibers and their composites were promoted by technical innovations and strengthen of energy saving & environ mental protection lows. The mechanical properties reached the highest level which never before due to the important breakthrough in technologies. The newest innovative technologies and development trends were illustrated for PAN-based carbon fiber, SiC fiber, para-Aramid fiber, ultra high molecular weight poly ethylene fiber, liquid fiber, CNT fiber and graphene fiber.

  8. Permeability and flammability study of composite sandwich structures for cryogenic applications (United States)

    Bubacz, Monika

    Fiber reinforced plastics offer advantageous specific strength and stiffness compared to metals and has been identified as candidates for the reusable space transportation systems primary structures including cryogenic tanks. A number of carbon and aramid fiber reinforced plastics have been considered for the liquid hydrogen tanks. Materials selection is based upon mechanical properties and containment performance (long and short term) and upon manufacturing considerations. The liquid hydrogen tank carries shear, torque, end load, and bending moment due to gusts, maneuver, take-off, landing, lift, drag, and fuel sloshing. The tank is pressurized to about 1.5 atmosphere (14.6psi or 0.1 MPa) differential pressure and on ascent maintains the liquid hydrogen at a temperature of 20K. The objective of the research effort into lay the foundation for developing the technology required for reliable prediction of the effects of various design, manufacturing, and service parameters on the susceptibility of composite tanks to develop excessive permeability to cryogenic fuels. Efforts will be expended on developing the materials and structural concepts for the cryogenic tanks that can meet the functional requirements. This will include consideration for double wall composite sandwich structures, with inner wall to meet the cryogenic requirements. The structure will incorporate nanoparticles for properties modifications and developing barriers. The main effort will be extended to tank wall's internal skin design. The main requirements for internal composite stack are: (1) introduction of barrier film (e.g. honeycomb material paper sheet) to reduce the wall permeability to hydrogen, (2) introduction of nanoparticles into laminate resin to prevent micro-cracking or crack propagation. There is a need to characterize and analyze composite sandwich structural damage due to burning and explosion. Better understanding of the flammability and blast resistance of the composite structures

  9. Strength Evaluation of Steel-Nylon Hybrid Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Maniram Kumar


    Full Text Available When fibres like steel, glass, polypropylene, nylon, carbon, aramid, polyester, jute, etc are mixed with concrete known as fibre reinforced concrete. To overcome the deficiencies of concrete; fibres are added to improve the performance of concrete. In this research hybrid reinforced concrete is made by using steel and nylon 6 fibres. The inclusion of both steel and nylon 6 fibres are used in order to combine the benefits of both fibers; structural improvements provided by steel fibers and the resistance to plastic shrinkage improvements provided by nylon fibers. So the aim of this project is to investigate the mechanical properties (compressive strength, flexure strength and split tensile strength of hybrid fiber reinforced concrete under compression, flexure & tension. The total volume of fibre was taken 0.75 % of total volume of concrete. In this experimental work, four different concrete mix proportions were casted with fibres and one mix without fibres. Four different mix combinations of steel- nylon 6 fibres were 100-00%, 75-25%, 50-50% and 25-75%. Superplasticizer was used in all mixes to make concrete more workable. The results shown that compressive, split tensile and flexural strength of hybrid fibre reinforced concrete increase by increasing quantity of steel and nylon 6 fibres. The increase in compressive and tensile strength due to incorporation of steel fibre is greater than that of using nylon fibre. For the nylon 6 fibres, adding more fibres into the concrete has a limited improvement on splitting tensile strength. Inclusion of nylon 6 fibres along with steel fibres results in considerable improvement in flexural strength as compared to solo steel fibre.

  10. A photovoltaic catenary-tent array for the Martian surface (United States)

    Crutchik, M.; Colozza, Anthony J.; Appelbaum, J.


    To provide electrical power during an exploration mission to Mars, a deployable tent-shaped structure with a flexible photovoltaic (PV) blanket is proposed. The array is designed with a self-deploying mechanism utilizing pressurized gas expansion. The structural design for the array uses a combination of cables, beams, and columns to support and deploy the PV blanket. Under the force of gravity a cable carrying a uniform load will take the shape of a catenary curve. A catenary-tent collector is self shadowing which must be taken into account in the solar radiation calculation. The shape and the area of the shadow on the array was calculated and used in the determination of the global radiation on the array. The PV blanket shape and structure dimension were optimized to achieve a configuration which maximizes the specific power (W/kg). The optimization was performed for four types of PV blankets (Si, GaAs/Ge, GaAs CLEFT, and amorphous Si) and four types of structure materials (Carbon composite, Aramid Fiber composite, Aluminum, and Magnesium). The results show that the catenary shape of the PV blanket, which produces the highest specific power, corresponds to zero end angle at the base with respect to the horizontal. The tent angle is determined by the combined effect of the array structure specific mass and the PV blanket output power. The combination of carbon composite structural material and GaAs CLEFT solar cells produce the highest specific power. The study was carried out for two sites on Mars corresponding to the Viking Lander locations. The designs were also compared for summer, winter, and yearly operation.

  11. On the role of CFRP reinforcement for wood beams stiffness (United States)

    Ianasi, A. C.


    In recent years, carbon fiber composites have been increasingly used in different ways in reinforcing structural elements. Specifically, the use of composite materials as a reinforcement for wood beams under bending loads requires paying attention to several aspects of the problem such as the number of the composite layers applied on the wood beams. Study consolidation of composites revealed that they are made by bonding fibrous material impregnated with resin on the surface of various elements, to restore or increase the load carrying capacity (bending, cutting, compression or torque) without significant damage of their rigidity. Fibers used in building applications can be fiberglass, aramid or carbon. Items that can be strengthened are concrete, brick, wood, steel and stone, and in terms of structural beams, walls, columns and floors. This paper describes an experimental study which was designed to evaluate the effect of composite material on the stiffness of the wood beams. It proposes a summary of the fundamental principles of analysis of composite materials and the design and use. The type of reinforcement used on the beams is the carbon fiber reinforced polymer (CFRP) sheet and plates and also an epoxy resin for bonding all the elements. Structural epoxy resins remain the primary choice of adhesive to form the bond to fiber-reinforced plastics and are the generally accepted adhesives in bonded CFRP-wood connections. The advantages of using epoxy resin in comparison to common wood-laminating adhesives are their gap-filling qualities and the low clamping pressures that are required to form the bond between carbon fiber plates or sheets and the wood beams. Mechanical tests performed on the reinforced wood beams showed that CFRP materials may produce flexural displacement and lifting increases of the beams. Observations of the experimental load-displacement relationships showed that bending strength increased for wood beams reinforced with CFRP composite plates

  12. Improved, Low-Stress Economical Submerged Pipeline (United States)

    Jones, Jack A.; Chao, Yi


    A preliminary study has shown that the use of a high-strength composite fiber cloth material may greatly reduce fabrication and deployment costs of a subsea offshore pipeline. The problem is to develop an inexpensive submerged pipeline that can safely and economically transport large quantities of fresh water, oil, and natural gas underwater for long distances. Above-water pipelines are often not feasible due to safety, cost, and environmental problems, and present, fixed-wall, submerged pipelines are often very expensive. The solution is to have a submerged, compliant-walled tube that when filled, is lighter than the surrounding medium. Some examples include compliant tubes for transporting fresh water under the ocean, for transporting crude oil underneath salt or fresh water, and for transporting high-pressure natural gas from offshore to onshore. In each case, the fluid transported is lighter than its surrounding fluid, and thus the flexible tube will tend to float. The tube should be ballasted to the ocean floor so as to limit the motion of the tube in the horizontal and vertical directions. The tube should be placed below 100-m depth to minimize biofouling and turbulence from surface storms. The tube may also have periodic pumps to maintain flow without over-pressurizing, or it can have a single pump at the beginning. The tube may have periodic valves that allow sections of the tube to be repaired or maintained. Some examples of tube materials that may be particularly suited for these applications are non-porous composite tubes made of high-performance fibers such as Kevlar, Spectra, PBO, Aramid, carbon fibers, or high-strength glass. Above-ground pipes for transporting water, oil, and natural gas have typically been fabricated from fiber-reinforced plastic or from more costly high-strength steel. Also, previous suggested subsea pipeline designs have only included heavy fixed-wall pipes that can be very expensive initially, and can be difficult and expensive

  13. Modeling and Experiments on Ballistic Impact into UHMWPE Yarns Using Flat and Saddle-Nosed Projectiles

    Directory of Open Access Journals (Sweden)

    Stuart Leigh Phoenix


    -tension stress resulted in apparent yarn strengths much lower than 3.4 GPa from quasi-static tension tests, although a plot of critical velocity versus initial tension did project to 3.4 GPa at zero velocity. This strength reduction (occurring also in aramid fibers suggested that transverse fiber distortion and yarn compaction from a compressive shock wave under the projectile results in fiber-on-fiber interference in the emerging transverse wave front, causing a gradient in fiber tensile strains with depth, and strain concentration in fibers nearest the projectile face. A model was developed to illustrate the phenomenon.

  14. Hybrid Composite Cryogenic Tank Structure (United States)

    DeLay, Thomas


    A hybrid lightweight composite tank has been created using specially designed materials and manufacturing processes. The tank is produced by using a hybrid structure consisting of at least two reinforced composite material systems. The inner composite layer comprises a distinct fiber and resin matrix suitable for cryogenic use that is a braided-sleeve (and/or a filamentwound layer) aramid fiber preform that is placed on a removable mandrel (outfitted with metallic end fittings) and is infused (vacuum-assisted resin transfer molded) with a polyurethane resin matrix with a high ductility at low temperatures. This inner layer is allowed to cure and is encapsulated with a filamentwound outer composite layer of a distinct fiber resin system. Both inner and outer layer are in intimate contact, and can also be cured at the same time. The outer layer is a material that performs well for low temperature pressure vessels, and it can rely on the inner layer to act as a liner to contain the fluids. The outer layer can be a variety of materials, but the best embodiment may be the use of a continuous tow of carbon fiber (T-1000 carbon, or others), or other high-strength fibers combined with a high ductility epoxy resin matrix, or a polyurethane matrix, which performs well at low temperatures. After curing, the mandrel can be removed from the outer layer. While the hybrid structure is not limited to two particular materials, a preferred version of the tank has been demonstrated on an actual test tank article cycled at high pressures with liquid nitrogen and liquid hydrogen, and the best version is an inner layer of PBO (poly-pphenylenebenzobisoxazole) fibers with a polyurethane matrix and an outer layer of T-1000 carbon with a high elongation epoxy matrix suitable for cryogenic temperatures. A polyurethane matrix has also been used for the outer layer. The construction method is ideal because the fiber and resin of the inner layer has a high strain to failure at cryogenic


    Institute of Scientific and Technical Information of China (English)

    陈晓丽; 谭云; 姜一鸣; 丰杰


    By using high strength aramid fibre Ⅱ and kevlar - 49 fibre and stainlesssteel liner, one small spherical epoxy resin matrix fibre composite pressure vessel is developed. The structure material, design and testing methods of the vessel are introduced. Through pressure tests and hydrostatic pressure blast tests of the composite vessel before storage and after storage, the results show that design of the vessel is successful, and it can meet the requirement for use in a certain product. The weight of the composite vessel is over 60% lighter than that of the same kind of steel pressure vessel when the inner and outer diameter, work pressure and safety coefficient are same. The veak rate is lower than 1 × 10~(-8) Pa·m /s. After three years' storage of definite environment, the blast pressure goes a little higher instead of decreasing.%采用高强芳纶Ⅱ和凯芙拉-49纤维及不锈钢内衬,研制出小型球形环氧树脂基纤维复合材料压力容器.主要介绍了容器的结构材料、设计、试验方法.通过容器的密封性检验及贮存前后的液压爆破试验,结果表明,容器的设计是成功的,满足了设计使用要求.与同类钢制压力容器相比,在内径、外径、工作压力、安全系数相同情况下,该复合材料容器质量可减轻60%以上,漏率小于1×10~(-8) Pa·m3/s,且贮存3年后爆破压力不会下降并略有提高.

  16. Combination of natural fiber Boehmeria nivea (ramie) with matrix epoxide for bullet proof vest body armor (United States)

    Anggoro, Didi Dwi; Kristiana, Nunung


    Ballistic protection equipment, such as a bulletproof vest, is a soldier's most important means of preserving life and survivability in extreme combat conditions. The bulletproof vests are designed to protect the user's chest from injury without disturbing the ability to perform his duties. Aromatic polyamide or aramid fibers known under the trade name Kevlar, Trawon and so is synthetic fiber materials commonly used in the manufacture of bulletproof vests. This synthetic fibers have high tensile strength and ductility. Kevlar is expensive and imported material. In this study, will introduce local natural raw materials, ramie fiber (Boehmeria nivea) which is cheaper and environmentally friendly. It has enough tenacity and tensile strength as a bulletproof vest. This experiment uses two panels, there are Panel A as front surface of Panel B. Panel A is a combination of ramie and epoxide matrix, while panel B is only ramie. From several variations of experimental combinations between Panel A and Panel B, optimal combination obtained with 16 layers of panel A and 31-34 layers of panel B which is able to protect againts cal. 7.65 mm × 17 mm (.32 ACP) bullet fired through pistol .32 Pindad from a distance of 20 meters. Panel with a size of 20 cm × 20 cm has a total thickness between 12,922 to13,745 mm and a total weight between 506,26 to 520,926gram. Scanning electron microscopy (SEM) observations indicated that the porosity and surface area of the ramie fiber is smooth, fiber surfaces showed topography with micropores. SEM also showed well-arranged structure of fibers bonding. Energy Dispersive X-ray (EDX) analysis indicated 100 % carbon contents in ramie fiber. Test result indicates that panel from composite ramie-epoxide can reach the level 1of International Standard of NIJ - 010104. Compared to panel from polyester fiber, the panel from composite ramie-epoxide (0,50-0,52 kg) is lighter weight than panel polyester fiber (1,642 kg).

  17. A Binder Viscosity Effect on the Wet-Wounded Composite Porosity in the Impregnating Bath

    Directory of Open Access Journals (Sweden)

    M. A. Komkov


    Full Text Available The aim of this work is to define experimentally an impregnation rate of VM-1 glass fibers and CBM aramid bundles with the epoxy binder EDB-10 using wet method of winding. During the impregnation process of the fibrous fillers by the liquid binder, air is displaced from the interfiber space of fiber and bundle. With the composite product winding a fiber impregnation process is short. That is why gas inclusions or pores are formed in the polymer-fiber compositeThe impregnation rate or porosity of wound material will depend directly on the binder viscosity. To reduce an epoxy binder viscosity temporarily is possible by two ways. The first is to heat a liquid epoxy composition EDB-10 to the maximum possible temperature during the winding process of the product. The second method is to dilute the binder by a solvent, such as acetone or alcohol. However, the solvent reduces its strength.The paper presents experimental data to show the volumetric content of pores in the wound composite affected only by the viscosity of the epoxy binder. Heating a binder allowed us to regulate a changing conditional viscosity of the binder in the impregnating bath for the normal conditions of impregnation. Other impacts on the impregnation and filament-winding processes, such as filler kinks, squeeze, vacuuming binder, highly tensioned winding, and others were not used.Experimentally obtained dependences of the porosity value of wound composite on the conditional viscosity of binder are nonlinear and can be used to design heaters for impregnating devices of winders. The research technique and results can be used in development of technological processes to manufacture composite structures by winding from the other reinforcing fibrous fillers and thermo-active binders.The results show that the volumetric content of pores can significantly vary within 8 - 14 % of material volume. Therefore, to reduce the number of pores in the wound composite to 1-2 %, auxiliary

  18. Combination of natural fiber Boehmeria nivea (ramie) with matrix epoxide for bullet proof vest body armor

    Energy Technology Data Exchange (ETDEWEB)

    Anggoro, Didi Dwi, E-mail:; Kristiana, Nunung, E-mail: [Master of Chemical Engineering, Faculty of Engineering, Diponegoro University Jln. Prof. Sudharto, Tembalang, Semarang, 50239 (Indonesia)


    Ballistic protection equipment, such as a bulletproof vest, is a soldier’s most important means of preserving life and survivability in extreme combat conditions. The bulletproof vests are designed to protect the user’s chest from injury without disturbing the ability to perform his duties. Aromatic polyamide or aramid fibers known under the trade name Kevlar, Trawon and so is synthetic fiber materials commonly used in the manufacture of bulletproof vests. This synthetic fibers have high tensile strength and ductility. Kevlar is expensive and imported material. In this study, will introduce local natural raw materials, ramie fiber (Boehmeria nivea) which is cheaper and environmentally friendly. It has enough tenacity and tensile strength as a bulletproof vest. This experiment uses two panels, there are Panel A as front surface of Panel B. Panel A is a combination of ramie and epoxide matrix, while panel B is only ramie. From several variations of experimental combinations between Panel A and Panel B, optimal combination obtained with 16 layers of panel A and 31-34 layers of panel B which is able to protect againts cal. 7.65 mm × 17 mm (.32 ACP) bullet fired through pistol .32 Pindad from a distance of 20 meters. Panel with a size of 20 cm × 20 cm has a total thickness between 12,922 to13,745 mm and a total weight between 506,26 to 520,926gram. Scanning electron microscopy (SEM) observations indicated that the porosity and surface area of the ramie fiber is smooth, fiber surfaces showed topography with micropores. SEM also showed well-arranged structure of fibers bonding. Energy Dispersive X-ray (EDX) analysis indicated 100 % carbon contents in ramie fiber. Test result indicates that panel from composite ramie-epoxide can reach the level 1of International Standard of NIJ - 010104. Compared to panel from polyester fiber, the panel from composite ramie-epoxide (0,50-0,52 kg) is lighter weight than panel polyester fiber (1,642 kg)

  19. Fram-2014/2015: A 400 Day Investigation of the Arctic's Oldest Sediments over the Alpha Ridge with a Research Hovercraft (United States)

    Hall, J. K.; Kristoffersen, Y.


    The thickest multi-year ice in the Arctic covers a secret. Four short cores raised from the Alpha Ridge in the 1970s and 1980s from drift stations T-3 and CESAR showed ages between 45 and 76 my. The reason for these old ages became clear when examination of legacy seismic data from T-3 showed that in some places up to 500 m of sediments had been removed within an area of some 200 by 600 km, presumably by an impact of asteroid fragments. To investigate the impact area, the authors conceived an innovative research platform in 2007. Named the R/H SABVABAA, this 12m by 6m hovercraft has been home-based in Svalbard since June 2008. During the following 6 years the craft and its evolving innovative light-weight equipment have made 18 trips to the summer ice pack, traveling some 4410 km over ice during some six months of scientific investigations. An opportunity to get a lift to this area, some 1500 km from Svalbard, came in a 2011 invitation to join AWI's icebreaker POLARSTERN in its ARK-XXVIII/4 expedition departing Tromsö August 5, 2014. The 400 day drift will be the first wintering over, ever, of a mobile research platform with geophysical, geological, and oceanographic capabilities. The Arctic ice pack continually moves due to winds and currents. While at the main camp, observations will consist of marine geophysics (seismic profiling with four element CHIRP, a 20 in³ airgun with single hydrophone, as well as 12 kHz bathymetry and 200 kHz sounding of the deep scattering layer), marine geology (coring with a hydrostatically-boosted 3 or 6 m corer; bottom photography; and two rock dredges), and oceanography. Deployed away from the camp, four sonobuoys will allow 3-D seismic acquisition. Access to the depths below the ice is via a hydraulic capstan winch, with 6500 m of Kevlar aramid fiber rope with 2.8 ton breaking strength. Ice thickness monitoring of the local 100 km² will be made with the craft's EM-31 probe when away from the camp, moving to choice locations for

  20. Structural Behavior of Concrete Beams Reinforced with Basalt Fiber Reinforced Polymer (BFRP) Bars (United States)

    Ovitigala, Thilan

    The main challenge for civil engineers is to provide sustainable, environmentally friendly and financially feasible structures to the society. Finding new materials such as fiber reinforced polymer (FRP) material that can fulfill the above requirements is a must. FRP material was expensive and it was limited to niche markets such as space shuttles and air industry in the 1960s. Over the time, it became cheaper and spread to other industries such as sporting goods in the 1980-1990, and then towards the infrastructure industry. Design and construction guidelines are available for carbon fiber reinforced polymer (CFRP), aramid fiber reinforced polymer (AFRP) and glass fiber reinforced polymer (GFRP) and they are currently used in structural applications. Since FRP is linear elastic brittle material, design guidelines for the steel reinforcement are not valid for FRP materials. Corrosion of steel reinforcement affects the durability of the concrete structures. FRP reinforcement is identified as an alternative to steel reinforcement in corrosive environments. Although basalt fiber reinforced polymer (BFRP) has many advantages over other FRP materials, but limited studies have been done. These studies didn't include larger BFRP bar diameters that are mostly used in practice. Therefore, larger beam sizes with larger BFRP reinforcement bar diameters are needed to investigate the flexural and shear behavior of BFRP reinforced concrete beams. Also, shear behavior of BFRP reinforced concrete beams was not yet studied. Experimental testing of mechanical properties and bond strength of BFRP bars and flexural and shear behavior of BFRP reinforced concrete beams are needed to include BFRP reinforcement bars in the design codes. This study mainly focuses on the use of BFRP bars as internal reinforcement. The test results of the mechanical properties of BFRP reinforcement bars, the bond strength of BFRP reinforcement bars, and the flexural and shear behavior of concrete beams

  1. Behavior of composite and polycarbonate plate under impact

    Directory of Open Access Journals (Sweden)

    Viot P.


    for filled polycarbonate because of an extension due to the addition of silicon. b Damage like fiber failure, decohesion, delamination and matrix failure are expected for composite material to dissipate energy [5]. Carbon fiber was chosen with thermoplastic matrix (Polyamide and Polyurethane to dissipate energy by plasticity and damage. This means that a higher tensile strain is expected. c Aramid fibers were chosen because of their high tensile strain (εr = 4.5%. Consequently a larger affected zone is expected to dissipate as much as possible energy. An epoxy matrix was loaded with carbon nanotubes in order to increase branching and micro-cracking and also increase dissipated energy.

  2. 煤矿井下车载液压绞车的设计与实验研究%Design and experimental research of vehicle-mounted hydraulic winch in underground coal mine

    Institute of Scientific and Technical Information of China (English)



    According to the structure and performance characteristics of the underground shovel plate carrier used in the coal mine, a U-shaped arrangement of vehicle-mounted hydraulic winch was designed. Under the control of the driving unit integrated by the rotary reducer and the POSI-STOP type anti-drag locking device, the vehicle hydraulic winch driven by the underground shovel plate carrier's hydraulic system could transfer power to the lateral arrangement transmission reducer. Meanwhile, through the application of a new type material rope made from ultra-high molecular weight polyethylene (UHMWPE) and aramid fiber, the inapplicability and the insecurity problems of steel wire rope used in the situation of small curvature radius roller were solved fundamentally. To acquire technical parameters of the vehicle hydraulic winch, the dynamometer tests under various sustained load were carried out with hydraulic test bed and transmission test bed. As a result, the structural correctness of the hydraulic winch's design and the thermal equilibrium of each element were proved.%针对煤矿井下铲板式搬运车的结构和性能特点设计了一种U型布置方式的车载液压绞车,该绞车以铲板式搬运车液压系统为动力源,通过集成了回转减速器、 P OSI-STOP 型反拖自锁装置为一体的驱动控制单元将动力传递给侧向布置传动减速箱,在经过小半径滚筒卷扬超高分子量聚乙烯+芳纶材料的缆绳代替传统钢丝绳实现工作输出,解决了钢丝绳不能应用于较小曲力半径滚筒上的问题和使用安全性问题。通过液压试验台和传动试验台对该绞车进行各种持续负载工况的测功平台试验,以获得绞车的各种技术参数,从而验证绞车结构、设计的合理性和绞车各部位的热平衡。

  3. Adhesion of PBO Fiber in Epoxy Composites

    Institute of Scientific and Technical Information of China (English)


    The high mechanical and thermal performance of poly p-phenylene- 2, 6-benzobisoxazole ( PBO ) fiber provides great potential applications as reinforcement fibers for composites. A composite of PBO fiber and epoxy resin has excellent electrical insulation properties, therefore, it is considered to be the best choice for the reinforcement in high magnetic field coils for pulsed magnetic fields up to 100 T.However, poor adhesion between PBO fiber and matrix is found because of the chemically inactive and/or relatively smooth surface of the reinforcement fiber preventing efficient chemical bonding in the interface, which is a challenging issue to improve mechanical properties. Here, we report the surface modification of PBO fibers by ultraviolet (UV)irradiation, O2 and NH3 plasma, as well as acidic treatments. The interfacial adhesion strength values of all the treatments show the similar level as determined for aramid fibers by pull-out tests, a significant impact on fibermatrix-adhesion was not achieved. The surface free energy and roughness are increased for both sized and extracted fibers after plasma treatments together with maleic anhydride grafting. The sized fiber shows marginal improvement in adhesion strength and no change in fiber tensile strength because of the barrier effect of the finish.For the extracted fiber, different surface treatments either show no apparent effect or cause reduction in adhesion strength. Atomic force microscopy (AFM) topography analysis of the fracture surfaces proved adhesive failure at the fiber surface. The fiber surface roughness is increased and more surface flaws are induced, which could result in coarse interface structures when the treated fiber surface has no adequate wetting and functional groups. The adhesion failure is further confirmed by similar adhesion strength and compression shear strength values when the fiber was embedded in various epoxy resins with different temperature behavior. The tensile strength of fiber

  4. 纤维增强复合材料三明治板破片穿甲数值仿真%Numerical simulation on fragment armor-piercing against sandwich plate with fiber reinforced composite cores

    Institute of Scientific and Technical Information of China (English)

    徐豫新; 戴文喜; 王树山; 赵晓旭


    The energy transform in the process of fragment armor-piercing against a sandwich plate with fiber reinforced composite cores (made up of superimposed steel plate,composite material plate and steel plate laminated)was considered .The fragment simulation projectile (FSP)penetrating into different kinds of sandwich plates with high velocity were numerically simulated and the ballistic limits of fragment piercing 16 kinds of sandwich plates were obtained.The credibility of the numerical simulation method was verified by comparing its results with the experimental ones.Under critical fragment perforation,the correlation between the energy absorption ratio of the each part of the sandwich plate and the structural size was studied by analyzing the numerical simulation results.The results show that the energy absorption ratio is constant for different thickness core plate(for aramid fiber core,10.41%,for glass fiber core,2.68%),the internal energy in core plate is quadratically increased with the increase of its thickness.On this basis,the calculation method for ballistic limit velocity of fragment penetrating into sandwich plate with fiber reinforced composite cores was obtained.%研究破片对(由钢板、纤维增强复合材料板及钢板叠合而成)纤维增强复合材料三明治板穿甲过程中能量转化规律。进行破片模拟弹丸(FSP)对不同结构三明治板高速穿甲数值仿真,获得FSP弹丸对16种三明治板的弹道极限,并与实验结果对比验证数值仿真的可信度。通过分析数值仿真结果,进一步研究破片临界贯穿条件下纤维增强复合材料三明治板各组成部分吸能比率与结构尺寸相关性。结果表明,不同厚度夹层板的吸能比率恒定(芳纶纤维10.41%,玻璃纤维2.68%),夹层板内能随厚度的增加呈二次函数增加。由此获得破片对纤维增强复合材料三明治板弹道极限速度计算方法。

  5. 预应力与非预应力AFRP加固腐蚀钢筋混凝土梁疲劳性能研究%Experimental study on fatigue performance corroded reinforced concrete beams strengthened with prestressed AFRP sheets

    Institute of Scientific and Technical Information of China (English)

    邓宗才; 李凯


    对非预应力芳纶布(AFRP)加固和带永久锚具的预应力AFRP加固锈蚀钢筋混凝土梁的疲劳性能进行研究.通过疲劳试验,探讨预应力水平和钢筋锈蚀程度对加固梁疲劳破坏机制、疲劳寿命、挠度等的影响.试验结果表明:预应力AFRP与非预应力加固梁的疲劳破坏机制相同,都为纵筋的疲劳断裂;预应力AFRP加固锈蚀混凝土梁的抗疲劳特性明显优于非预应力加固梁;预应力水平越高,中度腐蚀梁加固后疲劳寿命越高;锈蚀率越高,梁的疲劳寿命越低,重度锈蚀梁疲劳寿命的降低幅度比中度锈蚀梁更明显.通过与光面钢筋对比,获得锈蚀纵筋的等效疲劳切口系数Kf.结果表明,钢筋锈蚀率的增加会导致Kf增大,从而导致锈蚀梁疲劳寿命明显降低.基于试验结果,建立了预应力AFRP加固中度腐蚀钢筋混凝土梁疲劳寿命的计算公式,供桥梁加固设计参考.%A study was carried out for the fatigue behavior of corroded RC beams strengthened by non-prestressed aramid fiber reinforced polymer ( AFRP) sheets and prestressed AFRP sheets with permanent anchors. Based on the fatigue test results, the effects of different pre-stress levels of AFRP sheets under different corrosion ratios ( moderately corroded; reinforcement mass loss 6. 0% , severely corroded; reinforcement mass loss 12%) on the properties of the fatigue failure, fatigue life and mid-span deflection were analyzed. The major cause of the fatigue of the corroded RC beams strengthened with AFRP sheets is the fatigue fracture of the steel bars. The fatigue life of the beams strengthened with prestressed AFRP sheets was longer than that of those beams with non-prestressed AFRP sheets. The fatigue life of the moderately corroded RC beams increased with the pre-stress levels of AFRP sheets, and the fatigue life of the corroded RC beams decrease with the ratio of corrosion. The fatigue results were compared to the fatigue data of smooth bars

  6. 不同性能掺炭纤维脱除燃煤烟气中Hg0的试验研究%Experimental Studies on Adsorption Capability of Different Properties of Carbon-containing Fiber for Hg~ Removal in Coal-fired Flue Gases

    Institute of Scientific and Technical Information of China (English)

    刁永发; 郝卫辉; 邹钺


    Absorption of gas-phase mercury (Hg0) in coal-fired flue gases by activated carbon fiber(ACF) cooperated with the filter bag with Polyimide (P84) and aramid 1313(NOMEX) polyphenylene sulfide (PPS), glass fiber, polysulfonamide (PSA) and polytetrafluoroethene (PTFE)fiber were investigated in the fixed bed system. The ACF+PPS doped fibers were modified respectively by adding 5%, 10%, 15% potassium bromide (KBr) and Potassium iodide (KI) solution. The results show that mercury removal efficiency of different properties of ACF-doped fibers vary widely, and the removal rate is between 39% and 71%, and adsorption efficiency of mercury (Hg0) by modified ACF+PPS doped fibers with KBr and KI is above 80% and 90% separately when the inlet concentration of mercury is 30μg/m3 and the adsorption temperature is 160℃. The highest efficiency by non-modified ACF+PPS doped fibers is just 70%. The results also indicated that ACF+PPS doped fibers modified by KI had a better adsorption efficiency than doped fibers modified by KBr with the same mass fraction. And the higher the mass fraction of KI is, the better the adsorption efficiency of the Hg0 vapor. The adsorption efficiency is above 98% especially when using modified ACF+PPS doped fibers by 15% KI after a certain time. So modified ACF+PPS doped fibers can keep high Hg0 removal rate.%通过固定床实验系统的烟气脱除零价汞实验,研究了活性炭纤维协同滤袋用聚酰亚胺、芳纶1313、聚苯硫醚、玻璃纤维、芳砜纶以及聚四氟乙烯等常用纤维,对烟气中零价汞的脱除效果。研究了改性前不同性能掺炭纤维,以及用质量分数分别为5%、10%、15%的溴化钾、碘化钾溶液改性后的活性炭纤维(activatedcarbonfiber,ACF)和聚苯硫醚(polyphenylenesulfide,PPS)形成的掺炭纤维,对模拟燃煤烟气中零价汞(Hg0)的吸附性能。结果表明:在汞蒸气入口浓度为30

  7. Reaction Mechanism of Terephthaloyl Chloride/N-Methyl-2-pyrrolidone and the Effect on Poly(p-phenylene terephthalamide) Polymerization%对苯二甲酰氯与N-甲基吡咯烷酮反应机理以及对聚对苯二甲酰对苯二胺聚合的影响

    Institute of Scientific and Technical Information of China (English)

    郭澄龙; 许甲; 王力慧; 庹新林; 王罗新


    Stable synthesis of high molecular weight of poly(p-phenylene terephthalamide) (PPTA) resin is the basis for the production of high-performance aramid fibers. In PPTA polymerization process, the feeding method of the monomer terephthaloyl chloride (TPC) has important influence on the molecular weight. In theory, using TPC/N-methyl-2-pyrrolidone (NMP) solution and monomer p-phenylene diamine (PPD)/NMP solution for solution polycondensation is the most ideal and effective way, but in real polymerization process, it is difficult to synthesize high molecular weight PPTA due to some un-known interaction between TPC and NMP. This article combines experiments and molecular stimulation together, using Fron-tier infrared spectroscopy (FTIR), 1H NMR, the time of flight mass spectrometer (TOF-MS) and differential scanning calo-rimetric analysis (DSC), analyzing the reaction between TPC and NMP, and verified that TPC and NMP has obvious reaction similar to Vilsmeier-Haack reaction through molecular stimulation, which may cause the chloride group on the TPC deactivat-ing, and seriously influence its reactivity. And the conclusion is verified through PPTA polymerization experiments, and the longer TPC/NMP solution is prepared, the worse of the polymerization effect is. These observations and experiments suggest that it is not feasible to synthesize high molecular weight PPTA in industry using TPC/NMP solution feeding method.%稳定合成高分子量聚对苯二甲酰对苯二胺(PPTA)树脂是生产高性能芳纶纤维的基础。在 PPTA 聚合过程中,以单体对苯二甲酰氯(TPC)/N-甲基吡咯烷酮(NMP)溶液与单体对苯二胺(PPD)/NMP 溶液进行溶液缩聚反应是最理想高效的方式,但是因为TPC/NMP间未知的相互作用导致这种聚合方式难以实现。通过实验与计算模拟相结合的方式,利用红外光谱(FTIR)、核磁共振(1H NMR)、飞行时间质谱及示差扫描量热分析对TPC/NMP间的反应进行了分析,并通

  8. Development and characterization of a portable high-temperature PEM fuel cell system; Entwicklung und Charakterisierung eines portablen Hochtemperatur-PEM-Brennstoffzellensystems

    Energy Technology Data Exchange (ETDEWEB)

    Kurz, Timo


    In this thesis, the development of a High Temperature Polymer Electrolyte Membrane Fuel Cell (HT-PEMFC) system prototype is presented. In order to identify appropriate operating conditions and design factors, the development is supported by characterisation and modelling of HT-PEM single cells. The specific properties of this fuel cell type, together with the modelling and characterisation results, are used to achieve a compact and portable system design. Two non-isothermal 2D models are developed and coupled to each other in order to obtain fast and precise calculations in all dimensions in the cell. The models account for the conservation of mass, momentum, species, charge and energy. Additionally, the CO tolerance is investigated in detail. This is achieved by calculating catalyst coverage with four different species on the anode catalyst layer. The modelling results are validated using experimental data over a wide operating range. With the two coupled models, variations caused by different channel-rib structures, both parallel and perpendicular to the channel are investigated and optimal channel-rib ratios are identified. Based on the modelling and experimental results, the design of a compact and portable HT-PEMFC stack module is presented. The aim of the prototype development is to construct a modular system with high power density that meets the specific demands of HT-PEMFC operation. In order to reach this goal, innovative constructive details are developed: Stack compression is achieved with an aramid fibre coil to reduce weight and volume compared to threaded bolts. The development of this compression design is supported by experimental and modelling work. The principle of an open cathode is applied to combine the cathode-fed stream with the air cooling by only one channel, reducing the balance of plant. The air channel configuration is designed with the aid of Computational Fluid Dynamics. The developed channel design helps to maintain a small pressure

  9. Strengthening of monolithic floor slabs of residential buildings that have wall design sustems УСИЛЕНИЕ МОНОЛИТНЫХ ПЛИТ ПЕРЕКРЫТИЙ ЖИЛЫХ ЗДАНИЙ СТЕНОВОЙ КОНСТРУКТИВНОЙ СИСТЕМЫ

    Directory of Open Access Journals (Sweden)

    Malakhova Anna Nikolaevna


    Full Text Available The author proposes several structural solutions aimed at the reinforcement of monolithic floor slabs by means of fastening metal stripes onto the surface of slabs, laying supplementary reinforcement rods inside indents and attaching them by dowels. The author describes a force redistribution pattern identified in the course of analysis of monolithic floor slabs of buildings that have a wall design system. The author provides recommendations concerning the method of trial loading designated for the assessment of the true bearing capacity of floor slabs of residential buildings. The monolithic nature of reinforced slabs is attained by supplementary dowel connections. The dowel joint of old and new concrete elements takes the transverse shearing force in the event of bending to assure the monolithic behaviour of elements. Efficient behaviour of a monolithic slab is attained by means of a reliable connection between supplementary reinforcement rods and reinforcement rods inside slabs. Elements made of composite materials have been recently applied to strengthen reinforced concrete structures. These materials are basically composed of polymer tars and reinforcement materials (glass fiber, carbon and aramid fibers. Polymer sheets, stripes and fabric replace metal sheets, stripes and reinforcing meshes.Предложены конструктивные решения по усилению монолитных плит перекрытия: путем закрепления к поверхности плиты металлических полос и путем прокладки дополнительных арматурных стержней в штрабах со шпонками. Показано использование механизма перераспределения усилий при расчете монолитных плит перекрытия в зданиях стеновой конструктивной системы.

  10. 汽车轻量节能和低成本环保的创新解决方案%The innovation solution of light weight, energy saving and low cost environmental cars

    Institute of Scientific and Technical Information of China (English)

    罗益锋; 罗晰旻


    innovative solutions should be put forward as counter measure:The high efficient and low cost large tow PAN-based carbon fiber production line, which could be increased the production efficiency by 5 times, should be imported from abroad, the R&D of above black PAN precursor should be carried on at the same time; A low cost high speed new forming curing agent for CFRP should be imported from abroad; Add the low price hollow micro-and nano-ceramic powder into car using engineering plastics and CFRP parts in order to decrease the cost to large extent, increase the compre-hensive properties and add some functions; Using para-aramid fiber tire instead of stainless steel filament tire; Speed up the pilot experiment and in dustrialization of solid vanadium battery, its theoretical energy density per weight is more than 10 times compared with lithium ion battery, now 400~600 kWh/kg have reached for solid vanadium battery in laboratory, the smaller volume and lighter weight of vanadium battery the longer last run distance for electric car due to it’s entirely new design concept, the battery need bot charge with electricity, no any safety problems, the reactant can be regenerated and reused; Using plastic light transmitting fiber for dis-play system in the car etc. these could make Chinese automobile industry striding toward worlds’ advanced or leading levels.

  11. 玄武岩纤维布/不饱和聚酯复合材料耐老化性能%Aging-resistant performance of basalt fabrics/unsaturated polyester resin composites

    Institute of Scientific and Technical Information of China (English)

    杨越飞; 杨文斌; 徐建锋; 赖佳佳; 宋剑斌; 张欣向


    为探明玄武岩纤维/不饱和聚酯(UP,unsaturated polyester resin)复合材料的耐候性和力学性能,通过人工模拟加速气候箱对复合材料进行紫外光和冷凝处理,并测试、分析老化前后复合材料的力学性能、微观结构及化学结构的变化。力学性能测试发现,老化后的复合材料力学性能下降明显,拉伸强度、断裂伸长率、弯曲强度和弹性模量与未老化相比分别下降了35%、20%、60%和52%。扫描电子显微镜(SEM,scan electron microscope)观察老化前后的复合材料,发现包裹在纤维周围的树脂逐渐脱落,基体降解并产生碎片和横向裂纹并不断扩展形成多级开裂。傅立叶红外光谱分析(FTIR,Fourier transform infrared spectrum)测试发现,老化后的复合材料在1725 cm-1处的酯羰基吸收峰减弱,1280和1130 cm-1处酯基消失;同时,在747和702 cm-1处的邻苯型1,2-二取代吸收峰也消失。研究结果表明,不饱和聚酯上的羰基与双键或苯环上的羰基共轭体系发生变化,使酯羰基分解产生 CO;同时,聚酯发生链断裂、自由基终止等交联反应。玄武岩纤维/UP 复合材料的耐老化研究有利于延长该产品的使用寿命,对下一阶段制备玄武岩纤维/亚麻纤维混杂复合材料的耐候性和力学性能提供参考依据。%Fiber-reinforced composites made up of unsaturated polyester resin (UP) matrices reinforced with glass, carbon and aramid fibers were commonly standard structural materials in engineering fields. In recent years, basalt fibers, have recently gained an increasing attention as possible replacement of the conventional glass or carbon fibers due to their advantages in terms of environmental-friendly, cost-effective, high chemical and physical properties. In order to verify the mechanical properties of basalt fiber fabrics/UP composites, the author used the artificial simulating climate box (UV and

  12. PREFACE Proceedings of the XIV International Conference on Small-Angle Scattering, SAS-2009 (United States)

    King, Stephen; Terrill, Nicholas


    nine awards were presented at the conference. The Lifetime Achievement, or 'Andre Guinier', Award, given to those who have made a sustained and recognised contribution to the development or application of Small-Angle Scattering, went to Vittorio Luzzati, Emeritus Research Scientist at the Centre de Génétique Moléculaire du CNRS, France. Dr Luzzati has had a long and distinguished career in X-ray scattering publishing over 170 research papers - 10 in Nature - which have so far accumulated over 3500 citations. The award for 'Excellence in SAS Technical/Instrumental Development' went to J Polte, BAM, Germany, for 'New insights into nucleation and growth processes of gold nanoparticles derived via coupled in-situ methods'. That for 'Excellence in the Theoretical Development of SAS' went to C Gommes, Liege, Belgium, for 'SAXS Data Analysis of Ordered and Disordered Morphologies with Gaussian Random Field Models'. B Pauw, Technical University, Denmark, received the award for 'Excellence in the Application of SAS' for work on 'Strain-induced Internal Fibrillation of Aramid Filaments'. And the award for 'Excellence in the Communication of SAS Science' went to J G Grossmann, Liverpool, UK, for his talk on 'Probing the Structure of Biological Macromolecules in the Gas Phase'. A Hexemer, LBNL, USA, won the prize for the 'Best Poster in Technical/Instrumental Development' for 'SAXS/WAXS using a Multilayer Monochromator'. The prize for 'Best Poster in Theoretical Development' went to S Haas, Helmholtz Centre Berlin, Germany, for 'Simultaneous structure and chemical nano-analysis of an efficient frequency upconversion glass-ceramic by ASAXS'. And in a remarkable 'double', the prizes for 'Best Poster for Application in Life Sciences' and 'Best Poster for Application in Physical Sciences' went to A Maerten and J Prass, respectively, both from MPI Golm, Germany, for their work on 'SAXS studies of human tooth dentine: analysis of a spatially inhomogeneous and varying bio