WorldWideScience

Sample records for carbon fibre composite

  1. Applications for carbon fibre recovered from composites

    Science.gov (United States)

    Pickering; Liu, Z.; Turner, TA; Wong, KH

    2016-07-01

    Commercial operations to recover carbon fibre from waste composites are now developing and as more recovered fibre becomes available new applications for recovered fibre are required. Opportunities to use recovered carbon fibre as a structural reinforcement are considered involving the use of wet lay processes to produce nonwoven mats. Mats with random in-plane fibre orientation can readily be produced using existing commercial processes. However, the fibre volume fraction, and hence the mechanical properties that can be achieved, result in composites with limited mechanical properties. Fibre volume fractions of 40% can be achieved with high moulding pressures of over 100 bar, however, moulding at these pressures results in substantial fibre breakage which reduces the mean fibre length and the properties of the composite manufactured. Nonwoven mats made from aligned, short carbon fibres can achieve higher fibre volume fractions with lower fibre breakage even at high moulding pressure. A process for aligning short fibres is described and a composite of over 60% fibre volume fraction has been manufactured at a pressures up to 100 bar with low fibre breakage. Further developments of the alignment process have been undertaken and a composite of 46% fibre volume fraction has been produced moulded at a pressure of 7 bar in an autoclave, exhibiting good mechanical properties that compete with higher grade materials. This demonstrates the potential for high value applications for recovered carbon fibre by fibre alignment.

  2. Multifunctional Carbon Fibre Tapes for Automotive Composites

    Science.gov (United States)

    Koncherry, V.; Potluri, P.; Fernando, A.

    2016-11-01

    Cabon fibre composites are used where mechanical performance such as strength, stiffness and impact properties at low density is a critical parameter for engineering applications. Carbon fibre flat tape is one material which is traditionally used to manufacture three-dimensional composites in this area. Modifying the carbon fibre tape to incorporate other functions such as stealth, electromagnetic interference, shielding, de-icing, self-repair, energy storage, allows us to create multi-functional carbon fibre tape. Researchers have been developing such material and the technology for their manufacture in order to produce multifunctional carbon fibre based components more economically and efficiently. This paper presents the manufacturing process of a metallised carbon fibre material for a chopped fibre preforming process that uses electromagnets for preforming instead of traditional suction airflow fibre deposition. In addition, the paper further presents mechanical and magneto-static modelling that is carried out to investigate the bending properties of the material produced and its suitability for creating 3D preforms.

  3. Radiation curing of carbon fibre composites

    Science.gov (United States)

    Spadaro, G.; Alessi, S.; Dispenza, C.; Sabatino, M. A.; Pitarresi, G.; Tumino, D.; Przbytniak, G.

    2014-01-01

    Epoxy/carbon fibre reinforced composites were produced by means of e-beam irradiation through a pulsed 10 MeV electron beam accelerator. The matrix consisted of a difunctional epoxy monomer (DGEBA) and an initiator of cationic polymerisation, while the reinforcement was a unidirectional high modulus carbon fibre fabric. Dynamic mechanical thermal analysis was carried out in order to determine the cross-linking degree. The analysis pointed out a nonuniformity in the cross-linking degree of the e-beam cured panels, with the formation of clusters at low Tg (glass transition temperature) and clusters at high Tg. An out-of-mould post irradiation thermal treatment on e-beam cured samples provides a higher uniformity in the network although some slight degradation effects. Mode I delamination fracture toughness and Interlaminar Shear Strength (ISS) were also investigated by means of Double Cantilever Beam (DCB) and Short Beam Shear tests, respectively. Results from this mechanical characterisation allowed to correlate fracture toughness of the bulk matrix resin, cross-linking density and fibre/matrix interaction to the delamination fracture behaviour of the fibre reinforced material.

  4. Microwave absorbing properties of activated carbon fibre polymer composites

    Indian Academy of Sciences (India)

    Tianchun Zou; Naiqin Zhao; Chunsheng Shi; Jiajun Li

    2011-02-01

    Microwave absorption of composites containing activated carbon fibres (ACFs) was investigated. The results show that the absorptivity greatly depends on increasing ACF content in the absorbing layer, first increasing and then decreasing. When the content is 0.76 wt.%, the bandwidth below −10dB is 12.2 GHz. Comparing the absorption characteristics of the ACF composite with one containing unactivated fibres, it is found that carbon fibre activation increases the absorption of the composite.

  5. Fatigue properties of unidirectional carbon fibre composites at cryogenic temperatures

    Science.gov (United States)

    Pannkoke, K.; Wagner, H.-J.

    Design engineers working with composite materials are still confronted with uncertainties as to their fatigue behaviour, especially for cryogenic applications. In the course of cooling, different thermal contraction of the fibre and matrix gives rise to thermal stresses and strains which influence most of the mechanical properties. In this paper, the fatigue behaviour of unidirectional (UD) composites with different fibres and matrices will be described. A first step in understanding the failure mechanism under cyclic loading will be presented. In earlier tests excellent fatigue properties were found for carbon fibre UD composites made of T300 carbon fibres and an epoxy matrix 1,2. However, the applied epoxy resin was brittle, especially at low temperatures. Therefore the brittle resin was substituted by polycarbonate (PC), a tough thermoplastic polymer 3,4. Nevertheless, for a composite with that matrix the fatigue endurance limit, normalized to the static strength, was found to be much lower (43%). SEM studies illustrated a poor fibre - matrix bond. To determine the bond's influence on fatigue properties, another tough matrix system was tested. The polymer PEEK is known to build a strong bond to carbon fibres, initiated by crystal growth onto the fibre surface 4,5. However, investigations on the fatigue behaviour of this composite at 77 K yielded the same low fatigue endurance limit as was found for the carbon fibre - PC system 4. At this point it can be concluded that the poor fatigue behaviour is not necessarily due to a strong or poor fibre - matrix bond. It is the purpose of this work to examine whether this different fatigue behaviour is due to matrix failure.

  6. Effects of fibre content on mechanical properties and fracture behaviour of short carbon fibre reinforced geopolymer matrix composites

    Indian Academy of Sciences (India)

    Tiesong Lin; Dechang Jia; Meirong Wang; Peigang He; Defu Liang

    2009-02-01

    Geopolymer matrix composites reinforced with different volume fractions of short carbon fibres (Cf/geopolymer composites) were prepared and the mechanical properties, fracture behaviour and microstructure of as-prepared composites were studied and correlated with fibre content. The results show that short carbon fibres have a great strengthening and toughening effect at low volume percentages of fibres (3.5 and 4.5 vol.%). With the increase of fibre content, the strengthening and toughening effect of short carbon fibres reduce, possibly due to fibre damage, formation of high shear stresses at intersect between fibres and strong interface cohesion of fibre/matrix under higher forming pressure. The property improvements are primarily based on the network structure of short carbon fibre preform and the predominant strengthening and toughening mechanisms are attributed to the apparent fibre bridging and pulling-out effect.

  7. Transport properties of polymer-vapour grown carbon fibre composites

    Science.gov (United States)

    Gordeyev, S. A.; Macedo, F. J.; Ferreira, J. A.; van Hattum, F. W. J.; Bernardo, C. A.

    2000-04-01

    DC electrical resistivity and thermal conductivity of polypropylene (PP) filled with vapour grown carbon fibre (VGCF) was studied. This was done for a wide range of fibre content and compared to systems produced under the same conditions in which a conventional carbon fibre was used as filler. The composites studied exhibit characteristic percolating behaviour. Because of the low degree of graphite perfection in the VGCF used in this work, the fraction of VGCF required to achieve percolation was higher than expected. Non-linear I- V characteristics and time dependent electrical resistivity effects are only observed in PP filled with VGCF. Several mechanisms must be called upon to explain the observed electrical behaviour of the PP/VGCF composite. The thermal conductivity of the composites is in agreement with the effective medium theories.

  8. GROWTH OF CARBON NANOTUBES ON CARBON FIBRES AND THE TENSILE PROPERTIES OF RESULTING CARBON FIBRE REINFORCED POLYPROPYLENE COMPOSITES

    Directory of Open Access Journals (Sweden)

    A.R. SURAYA

    2009-12-01

    Full Text Available Carbon nanotubes were grown directly on carbon fibres using the chemical vapor deposition technique. The effects of reaction temperature (800-900oC and hydrogen gas flowrate (100-300 ml/min on the morphology of the carbon nanotube coating were investigated. Carbon nanotubes produced were characterized using scanning electron microscope and transmission electron microscope. The resulting fibres were compounded with polypropylene to produce carbon fibre reinforced polypropylene composites. The tensile properties of these composites were determined to investigate the effects of the carbon nanotubes on the overall performance of the composites. The optimum treatment condition that produced the thickest coating of carbon nanotubes was obtained at 800oC and 300 ml/min hydrogen gas flowrate. The composite sample obtained under these conditions demonstrated remarkable enhancement in tensile properties compared to composites made from as-received carbon fibres, whereby an increment of up to 52% and 133% was observed for the tensile strength and modulus respectively.

  9. Analysis of composition and microstructural uniformity of hybrid glass/carbon fibre composites

    DEFF Research Database (Denmark)

    Beauson, Justine; Markussen, Christen Malte; Madsen, Bo

    2013-01-01

    In hybrid fibre composites, the intermixing of the two types of fibres imposes challenges to obtain materials with a well-defined and uniform microstructure. In the present paper, the composition and the microstructural uniformity of hybrid glass/carbon fibre composites mixed at the fibre bundle...... fibre volume fractions are determined using volumetric calculations. A model is presented to predict the interrelation of volume fractions in hybrid fibre composites. The microstructural uniformity of the composites is analysed by the determined variation in composite volume fractions. Two analytical...... level are investigated. The different levels of compositions in the composites are defined and experimentally determined. The composite volume fractions are determined using an image analysis based procedure. The global fibre volume fractions are determined using a gravimetrical based method. The local...

  10. Toughened carbon fibre fabric-reinforced thermoplastic composites

    OpenAIRE

    Abt, Tobias Martin; Sánchez Soto, Miguel; Maspoch Rulduà, Mª Lluïsa; Velasco Perero, José Ignacio

    2014-01-01

    Toughened carbon fibre fabric-reinforced composites were obtained by compression moulding of powder prepregs, using a modified cyclic butylene terephthalate (pCBT) matrix and a bi-directional [0°/90°] carbon fibre fabric. Modification of the pCBT matrix was done by adding small amounts of epoxy resin or isocyanates, acting as toughening agents. Homogeneous CBT/epoxy and CBT/isocyanate blends were obtained by melt blending in a lab-scale batch mixer by applying low temperatures and short proce...

  11. A carbon fibre composite (CFC) Byelorussian peat corer

    OpenAIRE

    2009-01-01

    The design specification, development and manufacture of a Byelorussian (Russian) peat corer constructed from carbon fibre composite (CFC) are described. The availability of this new composite material introduces new possibilities for constructing field instruments that are as strong as, or stronger than, equipment made from steel and other metals. One advantage is a significant weight reduction. A 10.5 metre coring set in standard stainless and soft steel weighs around 16 kg, whereas the tot...

  12. Carbon fibre composite for ventilation air methane (VAM) capture

    Energy Technology Data Exchange (ETDEWEB)

    Thiruvenkatachari, Ramesh [Commonwealth Scientific and Industrial Research Organisation (CSIRO), PO Box 883, Kenmore, Queensland 4069 (Australia); Su Shi, E-mail: Shi.Su@csiro.au [Commonwealth Scientific and Industrial Research Organisation (CSIRO), PO Box 883, Kenmore, Queensland 4069 (Australia); Yu Xinxiang [Commonwealth Scientific and Industrial Research Organisation (CSIRO), PO Box 883, Kenmore, Queensland 4069 (Australia)

    2009-12-30

    Coal mine methane (CMM) is not only a hazardous greenhouse gas but is also a wasted energy resource, if not utilised. This paper evaluates a novel adsorbent material developed for capturing methane from ventilation air methane (VAM) gas in underground coal mines. The adsorbent material is a honeycomb monolithic carbon fibre composite (HMCFC) consisting of multiple parallel flow-through channels and the material exhibits unique features including low pressure drop, good mechanical properties, ability to handle dust-containing gas streams, good thermal and electrical conductivity and selective adsorption of gases. During this study, a series of HMCFC adsorbents (using different types of carbon fibres) were successfully fabricated. Experimental data demonstrated the proof-of-concept of using the HMCFC adsorbent to capture methane from VAM gas. The adsorption capacity of the HMCFC adsorbent was twice that of commercial activated carbon. Methane concentration of 0.56% in the inlet VAM gas stream is reduced to about 0.011% after it passes through the novel carbon fibre composite adsorbent material at ambient temperature and atmospheric pressure. This amounts to a maximum capture efficiency of 98%. These encouraging laboratory scale studies have prompted further large scale trials and economic assessment.

  13. Carbon fibre composite for ventilation air methane (VAM) capture.

    Science.gov (United States)

    Thiruvenkatachari, Ramesh; Su, Shi; Yu, Xin Xiang

    2009-12-30

    Coal mine methane (CMM) is not only a hazardous greenhouse gas but is also a wasted energy resource, if not utilised. This paper evaluates a novel adsorbent material developed for capturing methane from ventilation air methane (VAM) gas in underground coal mines. The adsorbent material is a honeycomb monolithic carbon fibre composite (HMCFC) consisting of multiple parallel flow-through channels and the material exhibits unique features including low pressure drop, good mechanical properties, ability to handle dust-containing gas streams, good thermal and electrical conductivity and selective adsorption of gases. During this study, a series of HMCFC adsorbents (using different types of carbon fibres) were successfully fabricated. Experimental data demonstrated the proof-of-concept of using the HMCFC adsorbent to capture methane from VAM gas. The adsorption capacity of the HMCFC adsorbent was twice that of commercial activated carbon. Methane concentration of 0.56% in the inlet VAM gas stream is reduced to about 0.011% after it passes through the novel carbon fibre composite adsorbent material at ambient temperature and atmospheric pressure. This amounts to a maximum capture efficiency of 98%. These encouraging laboratory scale studies have prompted further large scale trials and economic assessment.

  14. Tribological behaviour of unidirectional carbon fibre-reinforced epoxy composites

    Science.gov (United States)

    Şahin, Y.; De Baets, P.

    2017-02-01

    Tribological behaviour of unidirectional carbon fibre-reinforced epoxy composites containing 42wt.% (CU42) and 52wt.% (CU52) carbon fibres fabricated by moulding technique was investigated on a pin-on-flat plate configuration. It is the first time to measure static and dynamic coefficient of frictions and wear rates of epoxy composites under heavy loading conditions. Microstructures of composites were examined by scanning electron microscopy (SEM). The experimental results indicated the carbon fiber improved the tribological properties of thermoset epoxy by reducing wear rate, but increased the coefficient of friction. At higher load, average wear rates were about 10.8x10-5 mm3/N.m for composites while it was about 38.20x10-5 mm3/N.m for epoxy resin. The wear rate decreased with decreasing load while friction coefficient increased with decreasing load. Moreover, friction coefficient of composites of CU42 tested at 90 N load was measured to be in the range 0.35 and 0.13 for static and dynamic component, respectively.

  15. Synthesis of unsaturated polyesters for improved interfacial strength in carbon fibre composites

    DEFF Research Database (Denmark)

    Gamstedt, E.K.; Skrifvars, M.; Jacobsen, T. K.

    2002-01-01

    Carbon fibres are gaining use as reinforcement in glass fibre/polyester composites for increased stiffness as a hybrid composite. The mechanics and chemistry of the carbon fibre–polyester interface should be addressed to achieve an improvement also in fatigue performance and off-axis strength....... To make better use of the versatility of unsaturated polyesters in a carbon fibre composite, a set of unsaturated polyester resins have been synthesized with different ratios of maleic anhydride, o-phthalic anhydride and 1,2-propylene glycol as precursors. The effective interfacial strength was determined...... by micro-Raman spectroscopy of a single-fibre composite tested in tension. The interfacial shear strength with untreated carbon fibres increased with increasing degree of unsaturation of the polyester, which is controlled by the relative amount of maleic anhydride. This can be explained by a contribution...

  16. A carbon fibre composite (CFC Byelorussian peat corer

    Directory of Open Access Journals (Sweden)

    L.G. Franzén

    2009-01-01

    Full Text Available The design specification, development and manufacture of a Byelorussian (Russian peat corer constructed from carbon fibre composite (CFC are described. The availability of this new composite material introduces new possibilities for constructing field instruments that are as strong as, or stronger than, equipment made from steel and other metals. One advantage is a significant weight reduction. A 10.5 metre coring set in standard stainless and soft steel weighs around 16 kg, whereas the total weight of a similar CFC set is 5.2 kg, giving a weight reduction of almost 70%. The CFC sample chamber is 500 mm long with internal diameter 65 mm, and so contains almost twice the volume of peat that can be collected with a standard 45 mm diameter steel corer. The diameter of the rods is 30 mm, which improves ergonomics, and the CFC has better thermic properties for winter use. Another advantage is that the contamination of samples (notably by chromium and nickel associated with the use of steel corers is eliminated. The CFC sampler works well in soft peats such as Sphagnum and Carex types. It is less suitable for little-decomposed fibrous and forest peats (e.g. Polytrichum type and those containing hardwood remains, especially in the more compacted bottom layers. It should be totally satisfactory for organic lake sediments, but probably not for stiff and coarse mineral deposits.

  17. Investigations on d.c. conductivity behaviour of milled carbon fibre reinforced epoxy graded composites

    Indian Academy of Sciences (India)

    Navin Chand; Archana Nigrawal

    2008-08-01

    This paper reports the d.c. conductivity behaviour of milled carbon fibre reinforced polysulphide modified epoxy gradient composites. Milled carbon fibre reinforced composites having 3 vol. % of milled carbon fibre and poly sulphide modified epoxy resin have been developed. D.C. conductivity measurements are conducted on the graded composites by using an Electrometer in the temperature range from 26°C to 150°C. D.C. conductivity increases with the increase of distance in the direction of centrifugal force, which shows the formation of graded structure with the composites. D.C. conductivity increases on increase of milled carbon fibre content from 0.45 to 1.66 vol.%. At 50°C, d.c. conductivity values were 1.85 × 10-11, 1.08 × 10-11 and 2.16 × 10-12 for samples 1, 2 and 3, respectively. The activation energy values for different composite samples 1, 2 and 3 are 0.489, 0.565 and 0.654 eV, respectively which shows decrease in activation energy with increase of fibre content.

  18. Development of textile-reinforced carbon fibre aluminium composites manufactured with gas pressure infiltration methods

    Directory of Open Access Journals (Sweden)

    W. Hufenbach

    2009-08-01

    Full Text Available Purpose: The aim of his paper is to show potential of textile-reinforced carbon fibre aluminium composite with advantage of the lightweight construction of structural components subjected to thermo-mechanical stress.Design/methodology/approach: The manufacture of specimens of the carbon fibre-reinforced aluminium was realised with the aid of an advanced differential gas pressure infiltration technique, which was developed at ILK, TU Dresden.Findings: The gas pressure infiltration technology enables to fabricate complex carbon aluminium composites with fibre or textile reinforcement using moulds of graphite, but in future development the optimization of infiltration process is required. The load-adapted combination of 3D reinforced semi-finished fibre products (textile preforms made from carbon fibres (CF with aluminium light metal alloys (Al offers a considerable lightweight construction potential, which up to now has not been exploited.Research limitations/implications: Gas pressure infiltration technology enables to fabricate complex carbon aluminium composites with fibre or textile reinforcement using precision moulds of graphite, but in future development the optimization of infiltration process is required.Practical implications: Load-adapted CF/Al-MMC, due to the relatively high stiffness and strength of the metal matrix, allow the introduction of extremely high forces, thereby enabling a much better exploitation of the existing lightweight construction potential of this material in comparison to other composite materials.Originality/value: Constantly rising demands on extremely stressed lightweight structures, particularly in traffic engineering as well as in machine building and plant engineering, increasingly require the use of endless fibre-reinforced composite materials which, due to their selectively adaptable characteristics profiles, are clearly superior to conventional monolithic materials.

  19. Processing, structure and flexural strength of CNT and carbon fibre reinforced, epoxy-matrix hybrid composite

    Indian Academy of Sciences (India)

    K Chandra Shekar; M Sai Priya; P K Subramanian; Anil Kumar; B Anjaneya Prasad; N Eswara Prasad

    2014-05-01

    Advanced materials such as continuous fibre-reinforced polymer matrix composites offer significant enhancements in variety of properties, as compared to their bulk, monolithic counterparts. These properties include primarily the tensile stress, flexural stress and fracture parameters. However, till date, there are hardly any scientific studies reported on carbon fibre (Cf) and carbon nanotube (CNT) reinforced hybrid epoxy matrix composites (unidirectional). The present work is an attempt to bring out the flexural strength properties along with a detailed investigation in the synthesis of reinforced hybrid composite. In this present study, the importance of alignment of fibre is comprehensively evaluated and reported. The results obtained are discussed in terms of material characteristics, microstructure and mode of failure under flexural (3-point bend) loading. The study reveals the material exhibiting exceptionally high strength values and declaring itself as a material with high strength to weight ratio when compared to other competing polymer matrix composites (PMCs); as a novel structural material for aeronautical and aerospace applications.

  20. Effect of emulsifier content of sizing agent on the surface of carbon fibres and interface of its composites

    Science.gov (United States)

    Zhang, R. L.; Huang, Y. D.; Liu, L.; Tang, Y. R.; Su, D.; Xu, L. W.

    2011-02-01

    In this work, carbon fibres were sized with different emulsifier content sizing agent in order to improve the performances of carbon fibres and the interface of carbon fibres composites. The surface characteristic changing after modification was investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM). Wetting and surface energy along with contact angles were determined by the dynamic contact angle analysis test (DCAT). At the same time, the single fibre strengths and weibull distributions were also studied in order to understand the effect of the emulsifier content of sizing agent on the carbon fibres. The interfacial shear strength and hygrothermal ageing of the composites were measured which showed a different enhancement, respectively. The results revealed that sizing agent E-3 showed better interface adhesion between fibres and matrix and sizing agent E-2 sized carbon fibre has better ageing resistant properties.

  1. INFLUENCE OF THERMAL CYCLING ON MICROSTRUCTURE AND THERMAL EXPANSION OF CARBON FIBRES/COPPER COMPOSITES

    Directory of Open Access Journals (Sweden)

    Pavol Štefánik

    2009-06-01

    Full Text Available The preparation of copper matrix reinforced by high modulus carbon fibres (Thornel K1100 as well as the microstructure and dilatation changes during thermocycling is presented.Unidirectional composites with two types of matrix - pure copper and/or copper alloy with 0.2 wt. % of chromium - were thermally cycled between 30-600 °C three times.The composite with pure Cu exhibited larger voids and weak interfacial bonding. Due to the chemical reaction with K1100 fibres a reactive interfacial bonding has been formed. During thermocycling the hysteresis, but no large disintegration was observed. The coefficients of thermal expansion (CTEs strongly depend on fibre orientation. In direction parallel to the fibre orientation in the temperature range of 220-500°C CTEs were very low (0.7-1.0x10-6/K, but in perpendicular direction the CTEs were higher than that of pure copper.

  2. The Influence of Nanofillers on the Mechanical Properties of Carbon Fibre Reinforced Methyl Methacrylate Composite

    Directory of Open Access Journals (Sweden)

    Tomas ŽUKAS

    2012-09-01

    Full Text Available The influence of different types of nanofillers – carbon nanotubes (CNT and organically modified nanoclay – on the flexural properties and nail penetration resistance of carbon fiber reinforced methyl methacrylate (MMA composite have been investigated. An ultrasonic mixing was used to distribute various content of nanofillers (0.7 wt.% – 3.0 wt.% in MMA resin. Scanning electron microscopy and X-ray diffraction analyses confirmed formation of intercalated MMA clay nanocomposites. Two different stacking sequences, [0/90]3 or [0/90/45]2, and two types of carbon fibre, with or without epoxy binder, were used for composites preparation. The composites with stacking sequence of [0/90]3 show higher resistance to the mechanical loading. Epoxy binder increases fibre adhesion interaction with MMA resin, however, almost does not influences on the fibre reinforced composite strength properties. The results demonstrated that only low content (up to 1 wt.% of organically modified nanoclay Cloisite 10A increases the carbon fibre reinforced composites resistance to flexure and nail penetration. The low content of CNT also increases flexural stress and modulus, but decreases resistance to the nail penetration.DOI: http://dx.doi.org/10.5755/j01.ms.18.3.2434

  3. The Dependance of Damage Accumulation in Carbon Fibre Reinforced Epoxy Composites on Matrix Properties.

    Science.gov (United States)

    1985-12-01

    Diguuibutiofl Unlimited 0- Contract U.S. AIR FORCE/ARMINES- Centre des Matdriaux No A.F.O.S.R. 84-0397 - Final Report December 1985 THE DEPENDANCE OF DAMAGE...61102F 2301 D1 185 11 TITLE (include Security Classification) THE DEPENDANCE OF DAMAGE ACCUMULATION IN CARBON FIBRE REINFORCED EPOXY COMPOSITES ON...ATN OF: LTS/Autovon 235-4299 26 March 1986 SUBJECT: EOARD-TR-86-04, Final Scientific Report, "The Dependance of Damage Accumu- lation in Carbon Fibre

  4. Multi-Functional Carbon Fibre Composites using Carbon Nanotubes as an Alternative to Polymer Sizing

    Science.gov (United States)

    Pozegic, T. R.; Anguita, J. V.; Hamerton, I.; Jayawardena, K. D. G. I.; Chen, J.-S.; Stolojan, V.; Ballocchi, P.; Walsh, R.; Silva, S. R. P.

    2016-11-01

    Carbon fibre reinforced polymers (CFRP) were introduced to the aerospace, automobile and civil engineering industries for their high strength and low weight. A key feature of CFRP is the polymer sizing - a coating applied to the surface of the carbon fibres to assist handling, improve the interfacial adhesion between fibre and polymer matrix and allow this matrix to wet-out the carbon fibres. In this paper, we introduce an alternative material to the polymer sizing, namely carbon nanotubes (CNTs) on the carbon fibres, which in addition imparts electrical and thermal functionality. High quality CNTs are grown at a high density as a result of a 35 nm aluminium interlayer which has previously been shown to minimise diffusion of the catalyst in the carbon fibre substrate. A CNT modified-CFRP show 300%, 450% and 230% improvements in the electrical conductivity on the ‘surface’, ‘through-thickness’ and ‘volume’ directions, respectively. Furthermore, through-thickness thermal conductivity calculations reveal a 107% increase. These improvements suggest the potential of a direct replacement for lightning strike solutions and to enhance the efficiency of current de-icing solutions employed in the aerospace industry.

  5. Investigation of Effect of Carbon Fibres on the Mechanical Properties of the Hybrid Composite Laminate

    Directory of Open Access Journals (Sweden)

    Vidyashankar B V

    2014-06-01

    Full Text Available In this work Fabric made of woven carbon, glass along with epoxy resins are used to make composite laminate. Average resin fraction on weight basis after curing was 45%. The different types of specimens are prepared with variable percentage of carbon fibres. The mechanical tests such as Tensile test, compression test, flexural test and impact tests are conducted over the specimens and the results are evaluated which indicates that the increase in carbon content increases the mechanical properties of the composite laminate .

  6. Impact fatigue behaviour of carbon fibre-reinforced vinylester resin composites

    Indian Academy of Sciences (India)

    Rita Roy; B K Sarkar; A K Rana; N R Bose

    2001-02-01

    Two types of unidirectional carbon fibre, one of high strength (DHMS) and another of medium strength (VLMS) reinforced vinylester resin composites have been examined for their impact fatigue behaviour over 104 impact cycles for the first time. The study was conducted using a pendulum type repeated impact apparatus specially designed and constructed for the purpose. A well-defined impact fatigue behaviour (S–N type curve) curve has been demonstrated. It showed a plateau region of 10–102 cycles immediately below the single cycle impact strength, followed by progressive endurance with decreasing impact loads, culminating in an endurance limit at about 71% and 85% of the single impact strength for DHMS-48 and VLMS-48, respectively. Analysis of the fractured surfaces revealed primary debonding, fibre breakage and pull-out at the tensile zone of the samples and a shear mode of fracture with breakage of fibre bundles at the compressive zone of the samples. The occurrence of a few major macrocracks in the matrix with fibre breakage at the high load–low endurance region and development of multiple microcracks in the matrix, coalescing and fibre breakage at the low-load–high endurance region have been inferred to explain the fatigue behaviour of the composites examined.

  7. Fibre composite in driveline

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, W.

    1989-03-01

    Apart from the geometric degrees of freedom of classical material, fibre composites as material for cardan shafts offer two further free parameters to the design engineer: The fiberment winding angle and the ratio of carbon and glass fibres. This results in a large scope of characteristics in terms of flexibility and torsion. In many cases it is therefore possible to use a one-piece shaft instead of a two-piece shaft, and a specific harmonization of the vibration characteristics of the driveline can be realized. In comparison with shafts made out of steel, mass is reduced by 40-50%, the moment of inertia of the mass by 35-40%. The Composite shaft fulfils the requirements of the performance specifications typical of the components concerned both in terms of engineering and efficiency.

  8. Influence of Fabric Parameters on Microstructure, Mechanical Properties and Failure Mechanisms in Carbon-Fibre Reinforced Composites

    Institute of Scientific and Technical Information of China (English)

    B.Wielage; D.Richter; H.Mucha; Th.Lampke

    2008-01-01

    The effects of fibre/matrix bonding,fabric density,fibre volume fraction and bundle size on microstructure,mechanical properties and failure mechanisms in carbon fibre reinforced composites (plastic and carbon matrix) have been investigated.The microstructure of unloaded and cracked samples was studied by optical microscopy and scanning electron microscopy (SEM),respectively whereas the mechanical behaviour was examined by 3-point bending experiments.Exclusively one type of experimental resole type phenolic resin was applied.A strong fibre/matrix bonding,which is needed for high strength of carbon fibre reinforced plastic (CFRP) materials leads to severe composite damages during the pyrolysis resulting in low strength,brittle failure and a very low utilisation of the fibres strain to failure in C/C composites.Inherent fabric parameters such as an increasing fabric density or bundle size or a reduced fibre volume fraction introduce inhomogenities to the CFRP's microstructure.Results are lower strength and stiffness whereas the strain to failure increases or remains unchanged.Toughness is almost not affected.In C/C composites inhomogenities due to a reduced bundle size reduce strain to failure,strength,stiffness and toughness.Vice versa a declining fibre volume fraction leads to exactly the opposite behaviour.Increasing the fabric density (weight per unit area) causes similar effects as in CFRPs.

  9. High-power picosecond laser drilling/machining of carbon fibre-reinforced polymer (CFRP) composites

    Science.gov (United States)

    Salama, A.; Li, L.; Mativenga, P.; Sabli, A.

    2016-02-01

    The large differences in physical and thermal properties of the carbon fibre-reinforced polymer (CFRP) composite constituents make laser machining of this material challenging. An extended heat-affected zone (HAZ) often occurs. The availability of ultrashort laser pulse sources such as picosecond lasers makes it possible to improve the laser machining quality of these materials. This paper reports an investigation on the drilling and machining of CFRP composites using a state-of-the-art 400 W picosecond laser system. Small HAZs (laser processing parameters such as laser power, scanning speed and repetition rate on HAZ sizes and ablation depth was investigated.

  10. Analysis of mechanical properties anisotropy of nanomodified carbon fibre-reinforced woven composites

    Science.gov (United States)

    Ruslantsev, A. N.; Portnova, Ya M.; Tairova, L. P.; Dumansky, A. M.

    2016-10-01

    The polymer binder cracking problem arises while designing and maintaining polymer composite-based aircraft load-bearing members. Some technological methods are used to solve this problem. In particular the injection of nanoagents can block the initiation and growth of microscopic cracks. Crack propagation can also be blocked if the strain energy release is not related with fracturing. One of the possible ways for such energy release is creep. Testing of the anisotropy of the woven carbon fibre reinforced plastic elastic characteristics and creep have been conducted. The samples with different layouts have been made of woven carbon fibre laminate BMI-3/3692 with nanomodified bismaleimide matrix. This matrix has a higher glass transition temperature and improved mechanical properties. The deformation regularities have been analyzed, layer elastic characteristics have been determined. The constitutive equations describing composite material creep have been obtained and its parameters have been defined. Experimental and calculated creep curves have been plotted. It was found that the effects of rheology arise as the direction of load does not match the direction of reinforcing fibres of the material.

  11. Mapping local microstructure and mechanical performance around carbon nanotube grafted silica fibres: Methodologies for hierarchical composites

    Science.gov (United States)

    Qian, Hui; Kalinka, Gerhard; Chan, K. L. Andrew; Kazarian, Sergei G.; Greenhalgh, Emile S.; Bismarck, Alexander; Shaffer, Milo S. P.

    2011-11-01

    The introduction of carbon nanotubes (CNTs) modifies bulk polymer properties, depending on intrinsic quality, dispersion, alignment, interfacial chemistry and mechanical properties of the nanofiller. These effects can be exploited to enhance the matrices of conventional microscale fibre-reinforced polymer composites, by using primary reinforcing fibres grafted with CNTs. This paper presents a methodology that combines atomic force microscopy, polarised Raman spectroscopy, and nanoindentation techniques, to study the distribution, alignment and orientation of CNTs in the vicinity of epoxy-embedded micrometre-scale silica fibres, as well as, the resulting local mechanical properties of the matrix. Raman maps of key features in the CNT spectra clearly show the CNT distribution and orientation, including a `parted' morphology associated with long grafted CNTs. The hardness and indentation modulus of the epoxy matrix were improved locally by 28% and 24%, respectively, due to the reinforcing effects of CNTs. Moreover, a slower stress relaxation was observed in the epoxy region containing CNTs, which may be due to restricted molecular mobility of the matrix. The proposed methodology is likely to be relevant to further studies of nanocomposites and hierarchical composites.The introduction of carbon nanotubes (CNTs) modifies bulk polymer properties, depending on intrinsic quality, dispersion, alignment, interfacial chemistry and mechanical properties of the nanofiller. These effects can be exploited to enhance the matrices of conventional microscale fibre-reinforced polymer composites, by using primary reinforcing fibres grafted with CNTs. This paper presents a methodology that combines atomic force microscopy, polarised Raman spectroscopy, and nanoindentation techniques, to study the distribution, alignment and orientation of CNTs in the vicinity of epoxy-embedded micrometre-scale silica fibres, as well as, the resulting local mechanical properties of the matrix. Raman

  12. Exposure Assessment of Particulate Matter from Abrasive Treatment of Carbon and Glass Fibre-Reinforced Epoxy-Composites

    DEFF Research Database (Denmark)

    Jensen, Alexander C. Ø.; Levin, Marcus; Koivisto, Antti J.

    2015-01-01

    The use of composites is ever increasing due to their important structural and chemical features. The composite component production often involves high energy grinding and sanding processes to which emissions workers are potentially exposed. In this study we investigated the machining of carbon...... and glass fibre-reinforced epoxy composite materials at two facilities. We measured particle number concentrations and size distributions of the released material in near field and far field during sanding of glass-and carbon fibre-reinforced composites. We assessed the means of reducing exposure during...

  13. Mapping local microstructure and mechanical performance around carbon nanotube grafted silica fibres: methodologies for hierarchical composites.

    Science.gov (United States)

    Qian, Hui; Kalinka, Gerhard; Chan, K L Andrew; Kazarian, Sergei G; Greenhalgh, Emile S; Bismarck, Alexander; Shaffer, Milo S P

    2011-11-01

    The introduction of carbon nanotubes (CNTs) modifies bulk polymer properties, depending on intrinsic quality, dispersion, alignment, interfacial chemistry and mechanical properties of the nanofiller. These effects can be exploited to enhance the matrices of conventional microscale fibre-reinforced polymer composites, by using primary reinforcing fibres grafted with CNTs. This paper presents a methodology that combines atomic force microscopy, polarised Raman spectroscopy, and nanoindentation techniques, to study the distribution, alignment and orientation of CNTs in the vicinity of epoxy-embedded micrometre-scale silica fibres, as well as, the resulting local mechanical properties of the matrix. Raman maps of key features in the CNT spectra clearly show the CNT distribution and orientation, including a 'parted' morphology associated with long grafted CNTs. The hardness and indentation modulus of the epoxy matrix were improved locally by 28% and 24%, respectively, due to the reinforcing effects of CNTs. Moreover, a slower stress relaxation was observed in the epoxy region containing CNTs, which may be due to restricted molecular mobility of the matrix. The proposed methodology is likely to be relevant to further studies of nanocomposites and hierarchical composites.

  14. Strengthening of steel–concrete composite girders using carbon fibre reinforced polymer (CFRP) plates

    Indian Academy of Sciences (India)

    S M Mosavi; A Sadeghi Nik

    2015-02-01

    Applying composites in order to strengthen and renew the infrastructures has globally been accepted. Traditional methods to strengthen the out-of-standard structures are costly, time consuming and requires a lot of labour. Today, new techniques are hired using light and strong substances which also resist against corrosion, known as Carbon Fibre Reinforced Polymer (CFRP) plates. Regarding the high tensile strength and proper module of elasticity, CFRP plates are considered as a suitable alternative to strengthen girders. The behaviour of steel–concrete composite girders being statically loaded and strengthened by CFRP plates in this study. The CFRP plates used in this study have been stuck, with epoxy adhesive, under the tensile sections of three steel girders. The results accompanied with analytical study of moment–curvature and numerical analysis done with ANSYS, show that CFRP plates with epoxy adhesive increases the ultimate loading capacity of steel–concrete composite girder. Plastic stiffness of the girders was also increased.

  15. Repeated self-healing of microvascular carbon fibre reinforced polymer composites

    Science.gov (United States)

    Coope, T. S.; Wass, D. F.; Trask, R. S.; Bond, I. P.

    2014-11-01

    A self-healing, high performance, carbon fibre reinforced polymer (CFRP) composite is demonstrated by embedding a Lewis-acid catalytic curing agent within a laminate, manufactured using out of autoclave (OOA) composite manufacturing methods. Two configurations of healing agent delivery, pre-mixed and autonomous mixing, are investigated via injection of a healing agent through bio-inspired microvascular channels exposed on Mode I fractured crack planes. Healing is effected when an epoxy resin-solvent healing agent mixture reaches the boundary of embedded solid-state scandium(III) triflate (Sc(OTf)3) catalyst, located on the crack plane, to initiate the ring-opening polymerisation (ROP) of epoxides. Tailored self-healing agents confer high healing efficiency values after multiple healing cycles (69-108%) to successfully mitigate against crack propagation within the composite microstructure.

  16. The influence of carbon fibre content on the tribological properties of polyarylate based composites materials

    Institute of Scientific and Technical Information of China (English)

    Burya; A.I.; Chigvintseva; O.P

    2001-01-01

    The analysis of scientific-technical literature has shown the prospectiveness of applyinghigh-temperature thermoplastic polymers - among which there are complex aromatic polyesters -as constructive materials. Mixed polyarylates of DV mark based on diphenilolpropane and themixture of iso- and terephtale acid are mentioned to make the most valuable practical interest. Forimproving technological and exploitation properties the authors of the article have suggested toreinforce the polymer linking element with uglen-9 mark. Combination of the composition compo-nents was realized within the rotating electromagnetic field with the help of non-equiaxial ferro-magnetic elements. The study of tribotechnical characteristics (coefficient of friction, intensity oflinear wear, temperature in the contact zone "polymer specimen - counterbody" of elaborated car-bon plastics) has been made at the disc machine of friction. Investigation of exploitation regimes’(specific pressure and slip velocity) influence on the mentioned properties of the initial polymer hasshown that polyarylate can be recommended for work at values of PV criterion not greater than 1.2MPa · m/s. Hardening the exploitation regimes is accompanied by the catastrophic wear of plastic.Reinforcement of polyarylate with carbon fibre is noted to enable significant improvement (to de-crease the coefficient of friction, to increase resistance to wear) of tribotechnical characteristics ofcarbon plastics. The most optimal is the content of carbon fibre in polyarylate in amount of 25mass.%.

  17. A methodology for the control of the residual lifetimes of carbon fibre reinforced composite pressure vessels

    OpenAIRE

    Bunsell, Anthony R.; Blassiau, Sébastien; Thionnet, Alain

    2005-01-01

    International audience; Pressure vessels must be periodically proof tested. Traditional techniques for metal vessels are inapplicable for composite vessels as the latter do not break by crack propagation so that the reasoning behind the traditional testing procedures is not appropriate. Damage accumulation leading to the degradation of a composite vessel is by fibre failure. Fibres show a wide distribution in strengths and loading a composite inevitably breaks some. The method which has been ...

  18. Shape memory performance of asymmetrically reinforced epoxy/carbon fibre fabric composites in flexure

    Directory of Open Access Journals (Sweden)

    M. Fejos

    2013-06-01

    Full Text Available In this study asymmetrically reinforced epoxy (EP/carbon fibre (CF fabric composites were prepared and their shape memory properties were quantified in both unconstrained and fully constrained flexural tests performed in a dynamic mechanical analyser (DMA. Asymmetric layering was achieved by incorporating two and four CF fabric layers whereby setting a resin- and reinforcement-rich layer ratio of 1/4 and 1/2, respectively. The recovery stress was markedly increased with increasing CF content. The related stress was always higher when the CF-rich layer experienced tension load locally. Specimens with CF-rich layers on the tension side yielded better shape fixity ratio, than those with reinforcement layering on the compression side. Cyclic unconstrained shape memory tests were also run up to five cycles on specimens having the CF-rich layer under local tension. This resulted in marginal changes in the shape fixity and recovery ratios.

  19. Synergistic toughening of composite fibres by self-alignment of reduced graphene oxide and carbon nanotubes

    Science.gov (United States)

    Shin, Min Kyoon; Lee, Bommy; Kim, Shi Hyeong; Lee, Jae Ah; Spinks, Geoffrey M.; Gambhir, Sanjeev; Wallace, Gordon G.; Kozlov, Mikhail E.; Baughman, Ray H.; Kim, Seon Jeong

    2012-01-01

    The extraordinary properties of graphene and carbon nanotubes motivate the development of methods for their use in producing continuous, strong, tough fibres. Previous work has shown that the toughness of the carbon nanotube-reinforced polymer fibres exceeds that of previously known materials. Here we show that further increased toughness results from combining carbon nanotubes and reduced graphene oxide flakes in solution-spun polymer fibres. The gravimetric toughness approaches 1,000 J g-1, far exceeding spider dragline silk (165 J g-1) and Kevlar (78 J g-1). This toughness enhancement is consistent with the observed formation of an interconnected network of partially aligned reduced graphene oxide flakes and carbon nanotubes during solution spinning, which act to deflect cracks and allow energy-consuming polymer deformation. Toughness is sensitive to the volume ratio of the reduced graphene oxide flakes to the carbon nanotubes in the spinning solution and the degree of graphene oxidation. The hybrid fibres were sewable and weavable, and could be shaped into high-modulus helical springs.

  20. Vibration-based monitoring of a 10-meter span composite UHPFRC-carbon fibre-timber bridge mockup

    OpenAIRE

    SIEGERT, D; BEN MEKKI, O; Toutlemonde, F.

    2008-01-01

    This paper deals with the vibration-based damage detection of a 10-meter span composite UHPFRC carbon fibre-timber bridge mockup loaded up to the serviceability limit state (SLS). The effectiveness of the vibration-based monitoring depends on the sensitivity of the modal parameters to local changes in the stiffness of the structure and on the accuracy of the modal parameters estimates. Output-only modal analysis of the transient acceleration signals was carried out using a subspace covariance...

  1. Bolted Joints in Three Axially Braided Carbon Fibre/Epoxy Textile Composites with Moulded-in and Drilled Fastener Holes

    Science.gov (United States)

    Ataş, Akın; Gautam, Mayank; Soutis, Constantinos; Potluri, Prasad

    2016-10-01

    Experimental behaviour of bolted joints in triaxial braided (0°/±45°) carbon fibre/epoxy composite laminates with drilled and moulded-in fastener holes has been investigated in this paper. Braided laminates were manufactured by vacuum infusion process using 12 K T700S carbon fibres (for bias and axial tows) and Araldite LY-564 epoxy resin. Moulded-in fastener holes were formed using guide pins which were inserted in the braided structure prior to the vacuum infusion process. The damage mechanism of the specimens was investigated using ultrasonic C-Scan technique. The specimens were dimensioned to obtain a bearing mode of failure. The bearing strength of the specimens with moulded-in hole was reduced in comparison to the specimens with drilled hole, due to the increased fibre misalignment angle following the pin insertion procedure. An improvement on the bearing strength of moulded-in hole specimens might be developed if the specimen dimensions would be prepared for a net-tension mode of failure where the fibre misalignment would not have an effect as significant as in the case of bearing failure mode, but this mode should be avoided since it leads to sudden catastrophic failures.

  2. Mechanical properties of reactively flame retarded cyanate ester/epoxy resin blends and their carbon fibre reinforced composites

    Directory of Open Access Journals (Sweden)

    A. Toldy

    2016-12-01

    Full Text Available Cyanate ester/epoxy resin (CE/EP carbon fibre reinforced composites consisting of diglycidyl ether of bisphenol A (DGEBA and novolac type cyanate ester (CE were prepared and reactively flame retarded using epoxy functional adduct of DGEBA and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO. Effect of cyanate ester and flame retardant (FR ratio was determined on matrix viscosity, matrix and composite glass transition temperature (Tg, as well as composite mechanical properties including storage modulus, tensile, bending, interlaminar shear and Charpy impact properties. Although the epoxy resin (EP and FR decreased the Tg, even the flame retarded CE/EP blends had at least 22 °C higher Tg than the benchmark DGEBA composite. As for the mechanical properties, as a result of higher interlaminar shear strength suggesting better fibre-matrix adhesion, the CE/EP blends managed to over-perform the reference CE in most cases: The 2% phosphorus (P-containing CE/EP composite had 25% higher tensile strength than the CE reference. The bending strength of the blends remained in the same range as the reference, while the impact resistance significantly increased in comparison to CE, especially in flame retarded composites.

  3. Resistance welding of carbon fibre reinforced polyetheretherketone composites using metal mesh and PEI film

    Institute of Scientific and Technical Information of China (English)

    闫久春; 王晓林; 秦明; 赵新英; 杨士勤

    2004-01-01

    Weldability of polyetheretherketone(PEEK) with polyetherimide(PEI) is tested. And carbon fiber reinforced PEEK laminates are resistance welded using stainless steel mesh heating element. The effects of the welding time and welding pressure on the lap shear strength of joints are investigated. Results show that PEEK can heal with PEI well in welding condition and the lap shear strength of PEEK/CF(carbon fibre) joint increases linearly with welding time, but reaches a maximum value when welding pressure ranging from 0.3MPa to 0.5MPa with constant welding time. The fracture characteristics of surface are analyzed by SEM techniques, and four types of fracture modes of lap shear joints are suggested.

  4. Characterization and analysis of carbon fibre-reinforced polymer composite laminates with embedded circular vasculature.

    Science.gov (United States)

    Huang, C-Y; Trask, R S; Bond, I P

    2010-08-06

    A study of the influence of embedded circular hollow vascules on structural performance of a fibre-reinforced polymer (FRP) composite laminate is presented. Incorporating such vascules will lead to multi-functional composites by bestowing functions such as self-healing and active thermal management. However, the presence of off-axis vascules leads to localized disruption to the fibre architecture, i.e. resin-rich pockets, which are regarded as internal defects and may cause stress concentrations within the structure. Engineering approaches for creating these simple vascule geometries in conventional FRP laminates are proposed and demonstrated. This study includes development of a manufacturing method for forming vascules, microscopic characterization of their effect on the laminate, finite element (FE) analysis of crack initiation and failure under load, and validation of the FE results via mechanical testing observed using high-speed photography. The failure behaviour predicted by FE modelling is in good agreement with experimental results. The reduction in compressive strength owing to the embedding of circular vascules ranges from 13 to 70 per cent, which correlates with vascule dimension.

  5. Carbon/Carbon Nanotubes (CNTs) Composites from Green Pellets Contain CNTs and Self-adhesive Carbon Grains from Fibres of Oil Palm Empty Fruit Bunch

    Science.gov (United States)

    Deraman, Mohamad; Saad, Siti Khatijah Md.; Ishak, Maria M.; Awitdrus, Taer, Erman; Talib, Ibrahim; Omar, Ramli; Jumali, Mohammad Hafizuddin Hj.

    2010-10-01

    Nano composites green pellets (GPs) were prepared from the mixtures of carbon nanotubes (CNTs) at varying percentage (0, 2, 4, 6, 8 and 10%) and self-adhesive carbon grains (SACG) from fibres of oil palm empty fruit bunch. These GPs were carbonized and CO2 activated to produce activated carbon/CNTs composites in the form of pellets (ACPs). It was found that the density (ρ) and electrical conductivity (σ) of the ACPs varied nonlinearly with CNTs content; as for the CNTs content of 3-5%, we observed the peak values of ρ and σ at 1.3781 gcm-3 and 3.4146 (Ωcm)-1 respectively. The presence of the agglomerated and individual particles of CNTs in the pores of the ACPs was clearly shown by the micrograph of the Field Emission Scanning Electron Microscope (FESEM). The nitrogen adsorption isotherm data showed the decrease in surface area, volume and diameter of pores due to the effect of CNTs. The effect of CNTs on the electrochemical behavior of the ACPs were investigated from the supercapacitor cells fabricated using the ACPs as composite electrodes. It was found that the specific capacitance, energy density and power density of the supercapacitor with electrodes containing 10% CNTs were lower than that with electrodes without CNTs. This result is consistent with the change of pores characteristic due to the presence of CNTs in the ACPs, suggesting the need to optimize the pore characteristic for improving the supercapacitor performance.

  6. Deformation behavior of release agent coated glass fibre / epoxy composite using carbon nanotubes as strain sensors

    Directory of Open Access Journals (Sweden)

    Paweena Sureeyatanapas

    2013-02-01

    Full Text Available The deformation behavior of model glass fiber in epoxy composites has been studied using Raman spectroscopyproperties. Single walled carbon nanotubes (SWNTs were introduced at the glass fiber/epoxy interface as strain sensors,which can be detected by Raman Spectroscopy, to sense the strain profile of the fiber under deformation. The release agentwas applied on the fiber surface before composite fabrication. It was found that at high strain level, the behavior of a singlefiber in a composite did not follow a classical shear-lag model as shown in the fragmentation study. This is due to the interfacial failure caused by the release agent. The strain mapping result can be compared to that without release agent coating.The finding confirmed the application of SWNTs as strain sensors at the fiber/composite interface.

  7. Aligned flax fibre/polylactate composites

    DEFF Research Database (Denmark)

    Madsen, Bo; Lilholt, Hans; Thygesen, Anders;

    2008-01-01

    The potential of biocomposites in engineering applications is demonstrated by using aligned flax fibre/polylactate composites as a materials model system. The failure stress of flax fibres is measured by tensile testing of single fibres and fibre bundles. For both fibre configurations, it is found...... that failure stress is decreased by increasing the tested fibre volume. Based on two types of flax fibre preforms: carded sliver and unidirectional non-crimp fabric, aligned flax fibre/polylactate composites were fabricated with variable fibre content. The volumetric composition and tensile properties...... of the composite were measured. For composites with a fibre content of 37 % by volume, stiffness is about 20 GPa and failure stress is about 180 MPa. The tensile properties of the composites are analysed with a modified rule of mixtures model, which includes the effect of porosity. The experimental results...

  8. Carbon Carbon Composites: An Overview .

    Directory of Open Access Journals (Sweden)

    G. Rohini Devi

    1993-10-01

    Full Text Available Carbon carbon composites are a new class of engineering materials that are ceramic in nature but exhibit brittle to pseudoplastic behaviour. Carbon-carbon is a unique all-carbon composite with carbon fibre embeded in carbon matrix and is known as an inverse composite. Due to their excellent thermo-structural properties, carbon-carbon composites are used in specialised application like re-entry nose-tips, leading edges, rocket nozzles, and aircraft brake discs apart from several industrial and biomedical applications. The multidirectional carbon-carbon product technology is versatile and offers design flexibility. This paper describes the multidirectional preform and carbon-carbon process technology and research and development activities within the country. Carbon-carbon product experience at DRDL has also been discussed. Development of carbon-carbon brake discs process technology using the liquid impregnation process is described. Further the test results on material characterisation, thermal, mechanical and tribological properties are presented.

  9. Influence of the Testing Gage Length on the Strength, Young's Modulus and Weibull Modulus of Carbon Fibres and Glass Fibres

    Directory of Open Access Journals (Sweden)

    Luiz Claudio Pardini

    2002-10-01

    Full Text Available Carbon fibres and glass fibres are reinforcements for advanced composites and the fiber strength is the most influential factor on the strength of the composites. They are essentially brittle and fail with very little reduction in cross section. Composites made with these fibres are characterized by a high strength/density ratio and their properties are intrisically related to their microstructure, i.e., amount and orientation of the fibres, surface treatment, among other factors. Processing parameters have an important role in the fibre mechanical behaviour (strength and modulus. Cracks, voids and impurities in the case of glass fibres and fibrillar misalignments in the case of carbon fibres are created during processing. Such inhomogeneities give rise to an appreciable scatter in properties. The most used statistical tool that deals with this characteristic variability in properties is the Weibull distribution. The present work investigates the influence of the testing gage length on the strength, Young's modulus and Weibull modulus of carbon fibres and glass fibres. The Young's modulus is calculated by two methods: (i ASTM D 3379M, and (ii interaction between testing equipment/specimen The first method resulted in a Young modulus of 183 GPa for carbon fibre, and 76 GPa for glass fibre. The second method gave a Young modulus of 250 GPa for carbon fibre and 50 GPa for glass fibre. These differences revelead differences on how the interaction specimen/testing machine can interfere in the Young modulus calculations. Weibull modulus can be a tool to evaluate the fibre's homogeneity in terms of properties and it is a good quality control parameter during processing. In the range of specimen gage length tested the Weibull modulus for carbon fibre is ~ 3.30 and for glass fibres is ~ 5.65, which indicates that for the batch of fibres tested, the glass fibre is more uniform in properties.

  10. Contrast Enhancement of MicroCT Scans to Aid 3D Modelling of Carbon Fibre Fabric Composites

    Science.gov (United States)

    Djukic, Luke P.; Pearce, Garth M.; Herszberg, Israel; Bannister, Michael K.; Mollenhauer, David H.

    2013-12-01

    This paper presents a methodology for volume capture and rendering of plain weave and multi-layer fabric meso-architectures within a consolidated, cured laminate. Micro X-ray Computed Tomography (MicroCT) is an excellent tool for the non-destructive visualisation of material microstructures however the contrast between tows and resin is poor for carbon fibre composites. Firstly, this paper demonstrates techniques to improve the contrast of the microCT images by introducing higher density materials such as gold, iodine and glass into the fabric. Two approaches were demonstrated to be effective for enhancing the differentiation between the tows in the reconstructed microCT visualisations. Secondly, a method of generating three-dimensional volume models of woven composites using microCT scan data is discussed. The process of generating a model is explained from initial manufacture with the aid of an example plain weave fabric. These methods are to be used in the finite element modelling of three-dimensional fabric preforms in future work.

  11. Flat nose low velocity drop-weight impact response of carbon fibre composites using non-destructive damage detection techniques

    Science.gov (United States)

    Farooq, Umar; Myler, Peter

    2015-03-01

    This work is mainly concerned with the nondestructive post-impact damage evaluation of carbon fibre reinforced laminated composite panels subject to low velocity drop-weight impact by flat and round nose impactors. Quasi-isotropic laminates consisting of eight-, sixteen-, and twenty-four plies were impacted by flat and round nose impactors at different velocity levels. Load-time history data were recorded and plotted to correlate loaddrop as damage level to the impactor nose profiles. Test produced data, non-destructive damage detection techniques: visual, ultrasonic, and eddy- current, and computer simulations were utilised to identify and quantify status of the impact induced damage. To evaluate damage in relatively thick laminates (consisting of 24-Ply), the damage ratios and deflection quantities were correlated to the corresponding impactor nose profiles. Damage induced by the flat nose impactor to thick laminates was compared against the data produced by the round nose impactor. Results show that relatively thin laminates were largely affected by the impactor nose. Reasonable difference was observed in damage caused by flat and round impactor nose profiles to thick laminates impacted at relatively higher velocity impacts. Resultswere compared and validated against simulation produced data.

  12. Damage prediction of carbon fibre composite armoured actively cooled plasma-facing components under cycling heat loads

    Energy Technology Data Exchange (ETDEWEB)

    Chevet, G; Schlosser, J; Courtois, X; Escourbiac, F; Missirlian, M [CEA, IRFM, F-13108 Saint Paul Lez Durance (France); Herb, V; Martin, E; Camus, G [LCTS, CNRS UMR 5801, Universite Bordeaux 1, Pessac (France); Braccini, M [SIMaP, CNRS UMR 5266, Grenoble (France)], E-mail: gaelle.chevet@cea.fr

    2009-12-15

    In order to predict the lifetime of carbon fibre composite (CFC) armoured plasma-facing components in magnetic fusion devices, it is necessary to analyse the damage mechanisms and to model the damage propagation under cycling heat loads. At Tore Supra studies have been launched to better understand the damage process of the armoured flat tile elements of the actively cooled toroidal pump limiter, leading to the characterization of the damageable mechanical behaviour of the used N11 CFC material and of the CFC/Cu bond. Up until now the calculations have shown damage developing in the CFC (within the zone submitted to high shear stress) and in the bond (from the free edge of the CFC/Cu interface). Damage is due to manufacturing shear stresses and does not evolve under heat due to stress relaxation. For the ITER divertor, NB31 material has been characterized and the characterization of NB41 is in progress. Finite element calculations show again the development of CFC damage in the high shear stress zones after manufacturing. Stresses also decrease under heat flux so the damage does not evolve. The characterization of the CFC/Cu bond is more complex due to the monoblock geometry, which leads to more scattered stresses. These calculations allow the fabrication difficulties to be better understood and will help to analyse future high heat flux tests on various mock-ups.

  13. The Surface Finish of Thermally Aged Carbon Fibre Reinforced Composites Using E-glass as a Surface Barrier

    Science.gov (United States)

    de Souza, M. L.; Fox, B. L.

    2015-10-01

    This work investigated the effect of woven E-glass mass (25 g/m2, 50 g/m2, 85 g/m2, 135 g/m2) on the painted surface finish of various thermoset (EPIKOTETM RIM935, EPIKOTETM 04434, Ultratec LpTM ES300, Ultratec LpTM SPV6035) carbon fibre composite laminates, before and after aging at 95 °C for 168 h. The as-moulded laminate surfaces were evaluated using surface profilometry techniques and the painted and aged surfaces were evaluated using a wave-scan distinctness of image (DOI) instrument. It was found that the 25 g/m2 E-glass surface layer assisted with reducing the roughness of the as-moulded surfaces and the long-term waviness of the painted surfaces due to the increase in resin-richness at the surface. The EPIKOTETM 04434 resin system that contained diglycidyl ether of bisphenol F (DGEBF) epoxy had the least change in long-term waviness with thermal aging due to the rigid fluorene-based backbone in comparison to the diglycidyl ether of bisphenol A (DGEBA) systems.

  14. Strength and toughness of structural fibres for composite material reinforcement.

    Science.gov (United States)

    Herráez, M; Fernández, A; Lopes, C S; González, C

    2016-07-13

    The characterization of the strength and fracture toughness of three common structural fibres, E-glass, AS4 carbon and Kevlar KM2, is presented in this work. The notched specimens were prepared by means of selective carving of individual fibres by means of the focused ion beam. A straight-fronted edge notch was introduced in a plane perpendicular to the fibre axis, with the relative notch depth being a0/D≈0.1 and the notch radius at the tip approximately 50 nm. The selection of the appropriate beam current during milling operations was performed to avoid to as much as possible any microstructural changes owing to ion impingement. Both notched and un-notched fibres were submitted to uniaxial tensile tests up to failure. The strength of the un-notched fibres was characterized in terms of the Weibull statistics, whereas the residual strength of the notched fibres was used to determine their apparent toughness. To this end, the stress intensity factor of a fronted edge crack was computed by means of the finite-element method for different crack lengths. The experimental results agreed with those reported in the literature for polyacrylonitrile-based carbon fibres obtained by using similar techniques. After mechanical testing, the fracture surface of the fibres was analysed to ascertain the failure mechanisms. It was found that AS4 carbon and E-glass fibres presented the lower toughness with fracture surfaces perpendicular to the fibre axis, emanating from the notch tip. The fractured region of Kevlar KM2 fibres extended along the fibre and showed large permanent deformation, which explains their higher degree of toughness when compared with carbon and glass fibres. This article is part of the themed issue 'Multiscale modelling of the structural integrity of composite materials'.

  15. Carbon nanotubes for ultrafast fibre lasers

    Directory of Open Access Journals (Sweden)

    Chernysheva Maria

    2016-06-01

    Full Text Available Carbon nanotubes (CNTs possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNT-based saturable absorbers (CNT-SA, their integration and operation in fibre laser cavities putting emphasis on state-of-the-art fibre lasers, mode locked using CNT-SA. We discuss new design concepts of high-performance ultrafast operation fibre lasers covering ytterbium (Yb, bismuth (Bi, erbium (Er, thulium (Tm and holmium (Ho-doped fibre lasers.

  16. Carbon nanotubes for ultrafast fibre lasers

    Science.gov (United States)

    Chernysheva, Maria; Rozhin, Aleksey; Fedotov, Yuri; Mou, Chengbo; Arif, Raz; Kobtsev, Sergey M.; Dianov, Evgeny M.; Turitsyn, Sergei K.

    2017-01-01

    Carbon nanotubes (CNTs) possess both remarkable optical properties and high potential for integration in various photonic devices. We overview, here, recent progress in CNT applications in fibre optics putting particular emphasis on fibre lasers. We discuss fabrication and characterisation of different CNTs, development of CNT-based saturable absorbers (CNT-SA), their integration and operation in fibre laser cavities putting emphasis on state-of-the-art fibre lasers, mode locked using CNT-SA. We discuss new design concepts of high-performance ultrafast operation fibre lasers covering ytterbium (Yb), bismuth (Bi), erbium (Er), thulium (Tm) and holmium (Ho)-doped fibre lasers.

  17. A novel method based on selective laser sintering for preparing high-performance carbon fibres/polyamide12/epoxy ternary composites

    Science.gov (United States)

    Zhu, Wei; Yan, Chunze; Shi, Yunsong; Wen, Shifeng; Liu, Jie; Wei, Qingsong; Shi, Yusheng

    2016-01-01

    A novel method based on selective laser sintering (SLS) process is proposed for the first time to prepare complex and high-performance carbon fibres/polyamide12/epoxy (CF/PA12/EP) ternary composites. The procedures are briefly described as follows: prepare polyamide12 (PA12) coated carbon fibre (CF) composite powder; build porous green parts by SLS; infiltrate the green parts with high-performance thermosetting epoxy (EP) resin; and finally cure the resin at high temperature. The obtained composites are a ternary composite system consisting of the matrix of novolac EP resin, the reinforcement of CFs and the transition thin layer of PA12 with a thickness of 595 nm. The SEM images and micro-CT analysis prove that the ternary system is a three-dimensional co-continuous structure and the reinforcement of CFs are well dispersed in the matrix of EP with the volume fraction of 31%. Mechanical tests show that the composites fabricated by this method yield an ultimate tensile strength of 101.03 MPa and a flexural strength of 153.43 MPa, which are higher than those of most of the previously reported SLS materials. Therefore, the process proposed in this paper shows great potential for manufacturing complex, lightweight and high-performance CF reinforced composite components in aerospace, automotive industries and other areas. PMID:27650254

  18. A novel method based on selective laser sintering for preparing high-performance carbon fibres/polyamide12/epoxy ternary composites.

    Science.gov (United States)

    Zhu, Wei; Yan, Chunze; Shi, Yunsong; Wen, Shifeng; Liu, Jie; Wei, Qingsong; Shi, Yusheng

    2016-09-21

    A novel method based on selective laser sintering (SLS) process is proposed for the first time to prepare complex and high-performance carbon fibres/polyamide12/epoxy (CF/PA12/EP) ternary composites. The procedures are briefly described as follows: prepare polyamide12 (PA12) coated carbon fibre (CF) composite powder; build porous green parts by SLS; infiltrate the green parts with high-performance thermosetting epoxy (EP) resin; and finally cure the resin at high temperature. The obtained composites are a ternary composite system consisting of the matrix of novolac EP resin, the reinforcement of CFs and the transition thin layer of PA12 with a thickness of 595 nm. The SEM images and micro-CT analysis prove that the ternary system is a three-dimensional co-continuous structure and the reinforcement of CFs are well dispersed in the matrix of EP with the volume fraction of 31%. Mechanical tests show that the composites fabricated by this method yield an ultimate tensile strength of 101.03 MPa and a flexural strength of 153.43 MPa, which are higher than those of most of the previously reported SLS materials. Therefore, the process proposed in this paper shows great potential for manufacturing complex, lightweight and high-performance CF reinforced composite components in aerospace, automotive industries and other areas.

  19. A novel method based on selective laser sintering for preparing high-performance carbon fibres/polyamide12/epoxy ternary composites

    Science.gov (United States)

    Zhu, Wei; Yan, Chunze; Shi, Yunsong; Wen, Shifeng; Liu, Jie; Wei, Qingsong; Shi, Yusheng

    2016-09-01

    A novel method based on selective laser sintering (SLS) process is proposed for the first time to prepare complex and high-performance carbon fibres/polyamide12/epoxy (CF/PA12/EP) ternary composites. The procedures are briefly described as follows: prepare polyamide12 (PA12) coated carbon fibre (CF) composite powder; build porous green parts by SLS; infiltrate the green parts with high-performance thermosetting epoxy (EP) resin; and finally cure the resin at high temperature. The obtained composites are a ternary composite system consisting of the matrix of novolac EP resin, the reinforcement of CFs and the transition thin layer of PA12 with a thickness of 595 nm. The SEM images and micro-CT analysis prove that the ternary system is a three-dimensional co-continuous structure and the reinforcement of CFs are well dispersed in the matrix of EP with the volume fraction of 31%. Mechanical tests show that the composites fabricated by this method yield an ultimate tensile strength of 101.03 MPa and a flexural strength of 153.43 MPa, which are higher than those of most of the previously reported SLS materials. Therefore, the process proposed in this paper shows great potential for manufacturing complex, lightweight and high-performance CF reinforced composite components in aerospace, automotive industries and other areas.

  20. Characterisation of Natural Fibre Reinforcements and Composites

    Directory of Open Access Journals (Sweden)

    Richard K. Cullen

    2013-01-01

    Full Text Available Recent EU directives (e.g., ELV and WEEE have caused some rethinking of the life cycle implications of fibre reinforced polymer matrix composites. Man-made reinforcement fibres have significant ecological implications. One alternative is the use of natural fibres as reinforcements. The principal candidates are bast (plant stem fibres with flax, hemp, and jute as the current front runners. The work presented here will consider the characterisation of jute fibres and their composites. A novel technique is proposed for the measurement of fibre density. The new rule of mixtures, extended for noncircular cross-section natural fibres, is shown to provide a sensible estimate for the experimentally measured elastic modulus of the composite.

  1. Plasma treatment of carbon fibres and glass-fibre-reinforced polyesters at atmospheric pressure for adhesion improvement

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Løgstrup Andersen, Tom; Toftegaard, Helmuth Langmaack

    2014-01-01

    Atmospheric pressure plasma treatment is useful for adhesion improvement, because cleaning, roughening and addition of polar functional groups can be expected at the surfaces. Its possible applications in the wind energy industry include plasma treatment of fibres and fibre-reinforced polymer...... composites before assembling them to build wind turbine blades. In the present work, unsized carbon fibres are continuously treated using a dielectric barrier discharge plasma in helium at atmospheric pressure, and carbon fibre reinforced epoxy composite plates are manufactured for the mechanical test...

  2. Roughness Influence On Macro- And Micro-Tribology Of Multi-Layered Hard Coatings On Carbon Fibre Polymer Composite

    Directory of Open Access Journals (Sweden)

    Lackner J.M.

    2015-09-01

    Full Text Available Goal of this work is the investigation of roughness influences on the abrasive wear behaviour of magnetron sputtered multi-layered, low-friction coatings on carbon-fibre reinforced polymers (CFRP. Higher coating roughness at similar CFRP quality was realized by higher deposition rates, leading to increased heat flux to the substrates during deposition. Thermal expansion of the epoxy matrix on the micro scale results in a wavy, wrinkled surface topography. Both in scratch and reciprocal sliding testing against alumina, the friction coefficients are lower for the smooth coatings, but their wear rate is higher due to low-cycle fatigue caused abrasion.

  3. High energy flux thermo-mechanical test of 1D-carbon-carbon fibre composite prototypes for the SPIDER diagnostic calorimeter.

    Science.gov (United States)

    De Muri, M; Cavallin, T; Pasqualotto, R; Dalla Palma, M; Cervaro, V; Fasolo, D; Franchin, L; Tollin, M; Greuner, H; Böswirth, B; Serianni, G

    2014-02-01

    Operation of the thermonuclear fusion experiment ITER requires additional heating via injection of neutral beams from accelerated negative ions. In the SPIDER test facility, under construction in Padova, the production of negative ions will be studied and optimised. STRIKE (Short-Time Retractable Instrumented Kalorimeter Experiment) is a diagnostic used to characterise the SPIDER beam during short pulse operation (several seconds) to verify if the beam meets the ITER requirements about the maximum allowed beam non-uniformity (below ±10%). The major components of STRIKE are 16 1D-CFC (Carbon-Carbon Fibre Composite) tiles, observed at the rear side by a thermal camera. This contribution gives an overview of some tests under high energy particle flux, aimed at verifying the thermo-mechanical behaviour of several CFC prototype tiles. The tests were performed in the GLADIS facility at IPP (Max-Plank-Institut für Plasmaphysik), Garching. Dedicated linear and nonlinear simulations were carried out to interpret the experiments and a comparison of the experimental data with the simulation results is presented. The results of some morphological and structural studies on the material after exposure to the GLADIS beam are also given.

  4. High energy flux thermo-mechanical test of 1D-carbon-carbon fibre composite prototypes for the SPIDER diagnostic calorimeter

    Science.gov (United States)

    De Muri, M.; Cavallin, T.; Pasqualotto, R.; Dalla Palma, M.; Cervaro, V.; Fasolo, D.; Franchin, L.; Tollin, M.; Greuner, H.; Böswirth, B.; Serianni, G.

    2014-02-01

    Operation of the thermonuclear fusion experiment ITER requires additional heating via injection of neutral beams from accelerated negative ions. In the SPIDER test facility, under construction in Padova, the production of negative ions will be studied and optimised. STRIKE (Short-Time Retractable Instrumented Kalorimeter Experiment) is a diagnostic used to characterise the SPIDER beam during short pulse operation (several seconds) to verify if the beam meets the ITER requirements about the maximum allowed beam non-uniformity (below ±10%). The major components of STRIKE are 16 1D-CFC (Carbon-Carbon Fibre Composite) tiles, observed at the rear side by a thermal camera. This contribution gives an overview of some tests under high energy particle flux, aimed at verifying the thermo-mechanical behaviour of several CFC prototype tiles. The tests were performed in the GLADIS facility at IPP (Max-Plank-Institut für Plasmaphysik), Garching. Dedicated linear and nonlinear simulations were carried out to interpret the experiments and a comparison of the experimental data with the simulation results is presented. The results of some morphological and structural studies on the material after exposure to the GLADIS beam are also given.

  5. High energy flux thermo-mechanical test of 1D-carbon-carbon fibre composite prototypes for the SPIDER diagnostic calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    De Muri, M., E-mail: michela.demuri@igi.cnr.it; Pasqualotto, R.; Dalla Palma, M.; Cervaro, V.; Fasolo, D.; Franchin, L.; Tollin, M.; Serianni, G. [Consorzio RFX, Euratom-ENEA association, Corso Stati Uniti 4, 35127 Padova (Italy); Cavallin, T. [Istituto per l’Energetica e le Interfasi, Corso Stati Uniti 4, 35127 Padova (Italy); Greuner, H.; Böswirth, B. [Max-Planck-Institut für Plasmaphysik, D-85748 Garching bei München (Germany)

    2014-02-15

    Operation of the thermonuclear fusion experiment ITER requires additional heating via injection of neutral beams from accelerated negative ions. In the SPIDER test facility, under construction in Padova, the production of negative ions will be studied and optimised. STRIKE (Short-Time Retractable Instrumented Kalorimeter Experiment) is a diagnostic used to characterise the SPIDER beam during short pulse operation (several seconds) to verify if the beam meets the ITER requirements about the maximum allowed beam non-uniformity (below ±10%). The major components of STRIKE are 16 1D-CFC (Carbon-Carbon Fibre Composite) tiles, observed at the rear side by a thermal camera. This contribution gives an overview of some tests under high energy particle flux, aimed at verifying the thermo-mechanical behaviour of several CFC prototype tiles. The tests were performed in the GLADIS facility at IPP (Max-Plank-Institut für Plasmaphysik), Garching. Dedicated linear and nonlinear simulations were carried out to interpret the experiments and a comparison of the experimental data with the simulation results is presented. The results of some morphological and structural studies on the material after exposure to the GLADIS beam are also given.

  6. Abaca fibre reinforced PP composites and comparison with jute and flax fibre PP composites

    Directory of Open Access Journals (Sweden)

    2007-11-01

    Full Text Available Abaca fibre reinforced PP composites were fabricated with different fibre loadings (20, 30, 40, 50wt% and in some cases 35 and 45 wt%. Flax and jute fibre reinforced PP composites were also fabricated with 30 wt% fibre loading. The mechanical properties, odour emission and structure properties were investigated for those composites. Tensile, flexural and Charpy impact strengths were found to increase for fibre loadings up to 40 wt% and then decreased. Falling weight impact tests were also carried out and the same tendency was observed. Owing to the addition of coupling agent (maleated polypropylene -MAH-PP, the tensile, flexural and falling weight impact properties were found to increase in between 30 to 80% for different fibre loadings. When comparing jute and flax fibre composites with abaca fibre composites, jute fibre composites provided best tensile properties but abaca fibre polypropylene composites were shown to provide best notch Charpy and falling weight impact properties. Odours released by flax fibre composites were smaller than jute and abaca fibre composites.

  7. Hydrofluoric–nitric–sulphuric-acid surface treatment of tungsten for carbon fibre-reinforced composite hybrids in space applications

    Energy Technology Data Exchange (ETDEWEB)

    Kanerva, M., E-mail: Mikko.Kanerva@aalto.fi [Aalto University, School of Engineering, Department of Applied Mechanics, P.O.B. 14300, FI-00076 Aalto (Finland); Johansson, L.-S.; Campbell, J.M. [Aalto University, School of Chemical Technology, Department of Forest Products Technology, P.O.B. 16300, FI-00076 Aalto (Finland); Revitzer, H. [Aalto University, School of Chemical Technology, Department of Chemistry, P.O.B. 16300, FI-00076 Aalto (Finland); Sarlin, E. [Tampere University of Technology, Department of Materials Science, P.O.B. 589, FI-33101 Tampere (Finland); Brander, T.; Saarela, O. [Aalto University, School of Engineering, Department of Applied Mechanics, P.O.B. 14300, FI-00076 Aalto (Finland)

    2015-02-15

    Highlights: • XPS and AFM analysis of the effect of hydrofluoric–nitric–sulphuric-acid on tungsten. • Dreiling's model established 54.4% thinning of WO{sub 3} due to 67 s treatment. • Strain energy release rate increased ≈8.4 J/m{sup 2} at the interface. • Failure loci analysis expressed the oxide and carbon fibre surfaces as weak points. - Abstract: Hybrid material systems, such as combinations of tungsten foils and carbon fibre-reinforced plastic (CFRP), are replacing metal alloy concepts in spacecraft enclosures. However, a good adhesion between the tungsten oxide scale and the epoxy resin used is required. Here, the effects of a hydrofluoric–nitric–sulphuric-acid (HFNS) treatment on tungsten oxides and subsequent adhesion to CFRP are analysed using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and fracture testing. The work shows that HFNS treatment results in decreased oxygen content, over 50% thinner tungsten trioxide (WO{sub 3}) layer and increased nano-roughness on thin tungsten foils. Fracture testing established a 39% increase in the average critical strain for tungsten–CFRP specimens after HFNS treatment was carried out on tungsten. The effect of the oxide scale modification regarding the critical strain energy release rate was ΔG{sub c}≈ 8.4 J/m{sup 2}.

  8. Hydrofluoric-nitric-sulphuric-acid surface treatment of tungsten for carbon fibre-reinforced composite hybrids in space applications

    Science.gov (United States)

    Kanerva, M.; Johansson, L.-S.; Campbell, J. M.; Revitzer, H.; Sarlin, E.; Brander, T.; Saarela, O.

    2015-02-01

    Hybrid material systems, such as combinations of tungsten foils and carbon fibre-reinforced plastic (CFRP), are replacing metal alloy concepts in spacecraft enclosures. However, a good adhesion between the tungsten oxide scale and the epoxy resin used is required. Here, the effects of a hydrofluoric-nitric-sulphuric-acid (HFNS) treatment on tungsten oxides and subsequent adhesion to CFRP are analysed using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and fracture testing. The work shows that HFNS treatment results in decreased oxygen content, over 50% thinner tungsten trioxide (WO3) layer and increased nano-roughness on thin tungsten foils. Fracture testing established a 39% increase in the average critical strain for tungsten-CFRP specimens after HFNS treatment was carried out on tungsten. The effect of the oxide scale modification regarding the critical strain energy release rate was ΔGc≈ 8.4 J/m2.

  9. Winding of fibre composites; Vikling af fiberkompositter

    Energy Technology Data Exchange (ETDEWEB)

    Lystrup, Aage

    2006-01-01

    Within the project 'Storage of hydrogen in advanced high pressure vessels' under the PSO-R AND D 2005 program one of the tasks is to describe the technology, which is used for manufacturing of fibre reinforced pressure vessels. Fibre reinforced pressure vessels for high pressures are manufactured by winding structural load bearing fibres around a mandrel or an internal liner. There are two different types of cylindrical pressure vessels: 1) Cylinders with thick metal liner, where only the cylindrical part is over wrapped with hoop windings, and 2) cylinders with a thin metal or polymer liner, where both the cylindrical part and the end domes are over wrapped with more layers with different fibre orientations (helical and hoop windings). This report describes the fundamental principles for filament winding of fibre reinforced polymer composites. After a short introduction to the advanced fibre composites, their properties and semi-raw materials used for fibre composites, the focus is on the process parameters, which have influence on the material quality of filament wound components. The report is both covering winding of fibre reinforced thermo-setting polymers as well as thermoplastic polymers, and there are references to vendors of filament winding machines, accessory equipment and computer software for design and manufacturing of filament wound components. (au)

  10. Plant fibre composites - porosity and stiffness

    DEFF Research Database (Denmark)

    Madsen, Bo; Thygesen, Anders; Lilholt, Hans

    2009-01-01

    Plant fibre composites contain typically a relatively large amount of porosity which influences their performance. A model, based on a modified rule of mixtures, is presented to include the influence of porosity on the composite stiffness. The model integrates the volumetric composition of the co......Plant fibre composites contain typically a relatively large amount of porosity which influences their performance. A model, based on a modified rule of mixtures, is presented to include the influence of porosity on the composite stiffness. The model integrates the volumetric composition...... of the composites with their mechanical properties. The fibre weight fraction is used as an independent parameter to calculate the complete volumetric composition. A maximum obtainable stiffness of the composites is calculated at a certain transition fibre weight fraction, which is characterised by a best possible...... combination of high fibre volume fraction and low porosity. The model is validated with experimental data from the literature on several types of composites. A stiffness diagram is presented to demonstrate that the calculations can be used for tailoring and design of composites with a given profile...

  11. Natural Composites: Cellulose Fibres and the related Performance of Composites

    DEFF Research Database (Denmark)

    Lilholt, Hans; Madsen, Bo

    2014-01-01

    Biobased materials are becoming of increasing interest as potential structural materials for the future. A useful concept in this context is the fibre reinforcement of materials by stiff and strong fibres. The biobased resources can contribute with cellulose fibres and biopolymers. This offers...... the potential for stiff and strong biocomposite materials, but these have some limitations and obstacles to full performance. The focus will be on the ultra-structure, and the strength and stiffness of cellulose fibres, on the (unavoidable) defects causing large reductions in strength and moderate reductions...... in stiffness, on the packing ability of cellulose fibres and the related maximum fibre volume fraction in composites, on the moisture sorption of cellulose fibres and the related mass increase and (large) hygral strains induced, and on the mechanical performance of composites....

  12. Hybrid filler composition optimization for tensile strength of jute fibre-reinforced polymer composite

    Indian Academy of Sciences (India)

    ANURAG GUPTA; HARI SINGH; R SWALIA

    2016-09-01

    In present research work, pultrusion process is used to develop jute fibre-reinforced polyester (GFRP) composite and experiments have been performed on an indigenously developed pultrusion experimental setup. The developed composite consists of natural jute fibre as reinforcement and unsaturated polyester resin as matrix with hybrid filler containing bagasse fibre, carbon black and calcium carbonate (CaCO$_3$). The effect of weight content of bagasse fibre, carbon black and calcium carbonate on tensile strength of pultruded GFRP composite is evaluated and the optimum hybrid filler composition for maximizing the tensile strength is determined. Different compositions of hybrid filler are prepared by mixing three fillers using Taguchi L$_9$ orthogonal array. Fifteen percent of hybrid filler of different composition by weight was mixed in the unsaturated polyester resin matrix. Taguchi L$_9$ orthogonal array (OA) has been used to plan the experiments and ANOVA is used for analysing tensile strength. A regression model has also been proposed to evaluate the tensile strength of the composite within 7% error by varying the abovefillers weight. A confirmation experiment was performed which gives 73.14 MPa tensile strength of pultruded jute fibre polymer composite at the optimum composition of hybrid filler.

  13. Microwave-synthesized freestanding iron-carbon nanotubes on polyester composites of woven Kevlar fibre and silver nanoparticle-decorated graphene

    Science.gov (United States)

    Hazarika, Ankita; Deka, Biplab K.; Kim, DoYoung; Kong, Kyungil; Park, Young-Bin; Park, Hyung Wook

    2017-01-01

    We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from graphite nanoplatelets and silver nitrate through 90–100 s of microwave exposure, without the use of any mineral acids or harsh reducing agents. Fe nanoparticle-decorated carbon nanotubes (Fe-CNTs) were grown on polypyrrole (PPy) deposited on woven Kevlar fibre (WKF), using ferrocene as a catalyst, under microwave irradiation. Fe-CNTs grown on WKF and Ag-graphene dispersed in polyester resin (PES) were combined to fabricate Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites by vacuum-assisted resin transfer moulding. The combined effect of Fe-CNTs and Ag-graphene in the resulting composites resulted in a remarkable enhancement of tensile properties (a 192.56% increase in strength and 100.64% increase in modulus) as well as impact resistance (a 116.33% increase). The electrical conductivity significantly increased for Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites. The effectiveness of electromagnetic interference shielding, which relies strongly on the Ag-graphene content in the composites, was 25 times higher in Ag-graphene/Fe-CNT/PPy-coated WKF/PES than in neat WKF/PES composites. The current work offers a novel route for fabricating highly promising, cost effective WKF/PES composites through microwave-assisted synthesis of Fe-CNTs and Ag-graphene. PMID:28074877

  14. Microwave-synthesized freestanding iron-carbon nanotubes on polyester composites of woven Kevlar fibre and silver nanoparticle-decorated graphene

    Science.gov (United States)

    Hazarika, Ankita; Deka, Biplab K.; Kim, Doyoung; Kong, Kyungil; Park, Young-Bin; Park, Hyung Wook

    2017-01-01

    We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from graphite nanoplatelets and silver nitrate through 90–100 s of microwave exposure, without the use of any mineral acids or harsh reducing agents. Fe nanoparticle-decorated carbon nanotubes (Fe-CNTs) were grown on polypyrrole (PPy) deposited on woven Kevlar fibre (WKF), using ferrocene as a catalyst, under microwave irradiation. Fe-CNTs grown on WKF and Ag-graphene dispersed in polyester resin (PES) were combined to fabricate Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites by vacuum-assisted resin transfer moulding. The combined effect of Fe-CNTs and Ag-graphene in the resulting composites resulted in a remarkable enhancement of tensile properties (a 192.56% increase in strength and 100.64% increase in modulus) as well as impact resistance (a 116.33% increase). The electrical conductivity significantly increased for Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites. The effectiveness of electromagnetic interference shielding, which relies strongly on the Ag-graphene content in the composites, was 25 times higher in Ag-graphene/Fe-CNT/PPy-coated WKF/PES than in neat WKF/PES composites. The current work offers a novel route for fabricating highly promising, cost effective WKF/PES composites through microwave-assisted synthesis of Fe-CNTs and Ag-graphene.

  15. Microwave-synthesized freestanding iron-carbon nanotubes on polyester composites of woven Kevlar fibre and silver nanoparticle-decorated graphene.

    Science.gov (United States)

    Hazarika, Ankita; Deka, Biplab K; Kim, DoYoung; Kong, Kyungil; Park, Young-Bin; Park, Hyung Wook

    2017-01-11

    We synthesized Ag nanoparticle-decorated multilayered graphene nanosheets (Ag-graphene) from graphite nanoplatelets and silver nitrate through 90-100 s of microwave exposure, without the use of any mineral acids or harsh reducing agents. Fe nanoparticle-decorated carbon nanotubes (Fe-CNTs) were grown on polypyrrole (PPy) deposited on woven Kevlar fibre (WKF), using ferrocene as a catalyst, under microwave irradiation. Fe-CNTs grown on WKF and Ag-graphene dispersed in polyester resin (PES) were combined to fabricate Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites by vacuum-assisted resin transfer moulding. The combined effect of Fe-CNTs and Ag-graphene in the resulting composites resulted in a remarkable enhancement of tensile properties (a 192.56% increase in strength and 100.64% increase in modulus) as well as impact resistance (a 116.33% increase). The electrical conductivity significantly increased for Ag-graphene/Fe-CNT/PPy-coated WKF/PES composites. The effectiveness of electromagnetic interference shielding, which relies strongly on the Ag-graphene content in the composites, was 25 times higher in Ag-graphene/Fe-CNT/PPy-coated WKF/PES than in neat WKF/PES composites. The current work offers a novel route for fabricating highly promising, cost effective WKF/PES composites through microwave-assisted synthesis of Fe-CNTs and Ag-graphene.

  16. 碳纤维复合材料强度的有限元模拟%FINITE ELEMENT SIMULATION FOR THE STRENGTH OF CARBON FIBRE COMPOSITE MATERIAL

    Institute of Scientific and Technical Information of China (English)

    李玮; 段成红; 吴祥

    2011-01-01

    Carbon fibre composite materials are more and more used in industries, but the research on the properties is not deep enough. To save test cost, it is necessary to carry out theoretical simulation for the materials while performing experimental investigation. In this paper, ultimate strength of a carbon fibre composite material with a standard testing NOL-ring was calculated numerically by using ANSYS software with two simulation methods,namely node coupling and contacting. Circumferential stresses along the NOL-ring were given. Results show that errors between the two simulations and the test results are 23.6% and 5.6% respectively, indicating that using contacting method is more precise.%碳纤维复合材料在工业上的应用越来越广,但对其材料性质的研究还远不充分.为了节省试验经费,应在进行必要试验的同时对碳纤维复合材料的性质进行模拟计算.本文针对一标准试验,利用ANSYS软件的节点耦合技术和接触分析技术分别对某碳纤维复合材料制成的NOL环进行了拉伸破坏载荷下的强度计算,给出NOL环上各点的周向应力.结果发现,这两种模拟方法与试验值的误差分别为23.6%和5.6%,表明接触分析技术比较精确.

  17. A multi-purpose optical fibre sensor design for fibre reinforced composite materials

    Science.gov (United States)

    Fernando, G. F.; Liu, T.; Crosby, P.; Doyle, C.; Martin, A.; Brooks, D.; Ralph, B.; Badcock, R.

    1997-10-01

    This paper reports on the evaluation of a multi-functional extrinsic Fabry - Pérot optical fibre-based sensor design. The sensor was constructed using multimode and single mode optical fibres and a precision bore capillary tube. Fusion joints were used to secure the optical fibres into the capillary tube. The separation between the cleaved end-faces of the optical fibres defined the cavity length for the Fabry - Pérot sensor and the distance between the fusion joints defined the gauge length for this strain and temperature sensor. The sensor design was modified to: (i) monitor the progress of cure in an epoxy/amine resin system; (ii) detect the ingress of moisture in a cured epoxy/amine resin system; (iii) monitor the vibration characteristics of a pre- and post-impact damaged carbon fibre reinforced epoxy panel; and (iv) discriminate between strain and temperature measurements. The feasibility of using this type of sensor for cure monitoring, strain, temperature, residual stress measurements and damage detection in advanced fibre reinforced composites is demonstrated.

  18. Fatigue damage propagation in unidirectional glass fibre reinforced composites

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Alzamora Guzman, Vladimir Joel; Østergaard, R.C.

    2012-01-01

    Damage progression in unidirectional glass fibre reinforced composites exposed to tension fatigue is investigated, and a quantitative explanation is given for the observed stiffness loss. The stiffness degradation during fatigue is directly related to fibre breaks in the load-carrying axial fibre...... needs further attention and understanding in order to improve the fatigue life-time of glass fibre reinforced composites....

  19. Hybrid Composite Structures: Multifunctionality through Metal Fibres

    NARCIS (Netherlands)

    Ahmed, T.

    2009-01-01

    The introduction of fibre reinforced polymer composites into the wings and fuselages of the newest aircraft are changing the design and manufacturing approach. Composites provide greater freedom to designers who want to improve aircraft performance in an affordable way. In this quest, researchers ar

  20. Preparation & characterization of SiO{sub 2} interface layer by dip coating technique on carbon fibre for C{sub f}/SiC composites

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Kundan, E-mail: kundanemails@gmail.com [Fusion Reactor Material Development & Characterization Division, Institute for Plasma Research, GIDC Electronics Estate, Sector-25, Gandhinagar-382016 (India); Centre for Nanotechnology, Central University of Jharkhand, Ratu-Lohardaga Road, Brambe, Ranchi-835205 INDIA (India); Jariwala, C., E-mail: chetan@ipr.res.in; Pillai, R.; Chauhan, N.; Raole, P. M. [Fusion Reactor Material Development & Characterization Division, Institute for Plasma Research, GIDC Electronics Estate, Sector-25, Gandhinagar-382016 (India)

    2015-08-28

    Carbon fibres (C{sub f}) are one of the most important reinforced materials for ceramic matrix composites such as C{sub f} - SiC composites and they are generally sought for high temperature applications in as space application, nuclear reactor and automobile industries. But the major problem arise when C{sub f} reinforced composites exposed to high temperature in an oxidizing environment, C{sub f} react with oxygen and burnt away. In present work, we have studied the effect of silica (SiO{sub 2}) coating as a protective coating on C{sub f} for the C{sub f} / SiC composites. The silica solution prepared by the sol-gel process and coating on C{sub f} is done by dip coating technique with varying the withdrawing speed i.e. 2, 5, 8 mm/s with fixed dipping cycle (3 Nos.). The uniform silica coating on the C{sub f} is shown by the Scanning Electron Microscope (SEM) analysis. The tensile test shows the increase in tensile strength with respect to increase in withdrawing speed. The isothermal oxidation analysis confirmed enhancement of oxidation resistance of silica coated C{sub f} as compared tothe uncoated C{sub f}.

  1. Preparation & characterization of SiO2 interface layer by dip coating technique on carbon fibre for Cf/SiC composites

    Science.gov (United States)

    Kumar, Kundan; Jariwala, C.; Pillai, R.; Chauhan, N.; Raole, P. M.

    2015-08-01

    Carbon fibres (Cf) are one of the most important reinforced materials for ceramic matrix composites such as Cf - SiC composites and they are generally sought for high temperature applications in as space application, nuclear reactor and automobile industries. But the major problem arise when Cf reinforced composites exposed to high temperature in an oxidizing environment, Cf react with oxygen and burnt away. In present work, we have studied the effect of silica (SiO2) coating as a protective coating on Cf for the Cf / SiC composites. The silica solution prepared by the sol-gel process and coating on Cf is done by dip coating technique with varying the withdrawing speed i.e. 2, 5, 8 mm/s with fixed dipping cycle (3 Nos.). The uniform silica coating on the Cf is shown by the Scanning Electron Microscope (SEM) analysis. The tensile test shows the increase in tensile strength with respect to increase in withdrawing speed. The isothermal oxidation analysis confirmed enhancement of oxidation resistance of silica coated Cf as compared tothe uncoated Cf.

  2. Voronoi cells, fractal dimensions and fibre composites.

    Science.gov (United States)

    Summerscales, J.; Guild, F. J.; Pearce, N. R. L.; Russell, P. M.

    2001-02-01

    The use of fibre-reinforced polymer matrix composite materials is growing at a faster rate than the gross domestic product (GDP) in many countries. An improved understanding of their processing and mechanical behaviour would extend the potential applications of these materials. For unidirectional composites, it is predicted that localized absence of fibres is related to longitudinal compression failure. The use of woven reinforcements permits more effective manufacture than for unidirectional fibres. It has been demonstrated experimentally that compression strengths of woven composites are reduced when fibres are clustered. Summerscales predicted that clustering of fibres would increase the permeability of the reinforcement and hence expedite the processing of these materials. Commercial fabrics are available which employ this concept using flow-enhancing bound tows. The net effect of clustering fibres is to enhance processability whilst reducing the mechanical properties. The effects reported above were qualitative correlations. To improve the design tools for reinforcement fabrics we have sought to quantify the changes in the micro/meso-structure of woven reinforcement fabrics. Gross differences in the appearance of laminate sections are apparent for different weave styles. The use of automated image analysis is essential for the quantification of subtle changes in fabric architecture. This paper considers Voronoi tessellation and fractal dimensions for the quantification of the microstructures of woven fibre-reinforced composites. It reviews our studies in the last decade of the process-property-structure relationships for commercial and experimental fabric reinforcements in an attempt to resolve the processing vs. properties dilemma. A new flow-enhancement concept has been developed which has a reduced impact on laminate mechanical properties.

  3. Characterisation of Flax Fibres and Flax Fibre Composites. Being cellulose based sources of materials

    DEFF Research Database (Denmark)

    Aslan, Mustafa

    that currently have the largest market share for composite applications. However, the most critical limitation in the use of cellulosic fibre composites for structural applications is the lack of well described fibre properties, in particular, the tensile strength. This is due to variations in fibre morphology...... of the internal cell wall structures. This is in contrast to the crack growth in brittle ceramic and glass fibres. Moreover, two typical stress-strain curves (linear and non-linear) measured for the flax fibres were found to be correlated with the amount of defected region in the fibres. The defects are induced...... a similar microstructure at low fibre weight fractions. However, when the fibre content is increased, a difference in porosity content can be observed from the composite cross sections. The nominal tensile strength of the unidirectional flax fibre/LPET composites is measured in the range 180 to 340 MPa...

  4. Microstructure characterization of advanced protective Cr/CrN+a-C:H/a-C:H:Cr multilayer coatings on carbon fibre composite (CFC).

    Science.gov (United States)

    Major, L; Janusz, M; Lackner, J M; Kot, M; Major, B

    2016-06-01

    Studies of advanced protective chromium-based coatings on the carbon fibre composite (CFC) were performed. Multidisciplinary examinations were carried out comprising: microstructure transmission electron microscopy (TEM, HREM) studies, micromechanical analysis and wear resistance. Coatings were prepared using a magnetron sputtering technique with application of high-purity chromium and carbon (graphite) targets deposited on the CFC substrate. Selection of the CFC for surface modification in respect to irregularities on the surface making the CFC surface more smooth was performed. Deposited coatings consisted of two parts. The inner part was responsible for the residual stress compensation and cracking initiation as well as resistance at elevated temperatures occurring namely during surgical tools sterilization process. The outer part was responsible for wear resistance properties and biocompatibility. Experimental studies revealed that irregularities on the substrate surface had a negative influence on the crystallites growth direction. Chromium implanted into the a-C:H structure reacted with carbon forming the cubic nanocrystal chromium carbides of the Cr23 C6 type. The cracking was initiated at the coating/substrate interface and the energy of brittle cracking was reduced because of the plastic deformation at each Cr interlayer interface. The wear mechanism and cracking process was described in micro- and nanoscale by means of transmission electron microscope studies. Examined materials of coated CFC type would find applications in advanced surgical tools.

  5. Electron processing of fibre-reinforced advanced composites

    Science.gov (United States)

    Singh, Ajit; Saunders, Chris B.; Barnard, John W.; Lopata, Vince J.; Kremers, Walter; McDougall, Tom E.; Chung, Minda; Tateishi, Miyoko

    1996-08-01

    Advanced composites, such as carbon-fibre-reinforced epoxies, are used in the aircraft, aerospace, sporting goods, and transportation industries. Though thermal curing is the dominant industrial process for advanced composites, electron curing of similar composites containing acrylated epoxy matrices has been demonstrated by our work. The main attraction of electron processing technology over thermal technology is the advantages it offers which include ambient temperature curing, reduced curing times, reduced volatile emissions, better material handling, and reduced costs. Electron curing technology allows for the curing of many types of products, such as complex shaped, those containing different types of fibres, and up to 15 cm thick. Our work has been done principally with the AECL's 10 MeV, 1 kW electron accelerator; we have also done some comparative work with an AECL Gammacell 220. In this paper we briefly review our work on the various aspects of electron curing of advanced composites and their properties.

  6. Methodology for characterisation of glass fibre composite architecture

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Larsen, J.B.; Østergaard, R.C.

    2012-01-01

    of the fibres. The information is used for different analyses to investigate and characterise the fibre architecture. As an example, the methodology is applied to glass fibre reinforced composites with varying fibre contents. The different fibre volume fractions (FVFs) affect the number of contact points per......The present study outlines a methodology for microstructural characterisation of fibre reinforced composites containing circular fibres. Digital micrographs of polished cross-sections are used as input to a numerical image processing tool that determines spatial mapping and radii detection...... fibre, the communal fibre distance and the local FVF. The fibre diameter distribution and packing pattern remain somewhat similar for the considered materials. The methodology is a step towards a better understanding of the composite microstructure and can be used to evaluate the interconnection between...

  7. Optimization of process parameters for friction stir lap welding of carbon fibre reinforced thermoplastic composites by Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Ahmadi, H.; Arab, N. B. Mostafa; Ghasemi, F. Ashenai [Shahid Rajaee Teacher Training University, Tehran (Iran, Islamic Republic of)

    2014-01-15

    Friction stir welding process parameters such as welding speed, rotational speed and tilt angle affect the strength of the weld joint. For maximizing the weld strength, these process parameters must therefore be properly selected and optimized. This study presents an application of Taguchi method to optimize process parameters like welding speed, rotational speed and tilt angle to maximize lap weld tensile-shear strength in 4 mm thick polypropylene composite sheets with 20 wt% carbon fiber. To this end, a L9 orthogonal array of Taguchi method using three factors at three levels was used. Analysis of variance and confirmation tests were conducted. The results indicated that welding speed, rotational speed and tilt angle are respectively the significant parameters affecting the lap weld strength. Optimization results also showed that tensile-shear strength of 6.06 MPa was obtained when welding speed, rotational speed and tilt angle were 25 mm/min, 1250 rpm and 1 degree, respectively.

  8. Electrospun cerium nitrate/polymer composite fibres:synthesis, characterization and fibre-division model

    Institute of Scientific and Technical Information of China (English)

    Li Meng-Meng; Long Yun-Ze; Yin Hong-Xing; Zhang Zhi-Ming

    2011-01-01

    Cerium (III)nitrate/poly(vinylpyrrolidone)(Ce(NO3)3/PVP)composite fibres have been prepared by electrospinning. After calcining the composite fibres in air at 500℃, CeO2 nanowires were obtained. The characterizations of the as-spun composite fibres and resultant nanowires have been carried out by a scanning electron microscope (SEM),an infrared spectrometer, an x-ray diffractometer and a fluorescence spectrophotometer. Interestingly, some unusual ribbon-like or twin fibres were observed besides the common fibres with circular or elliptic cross sections. We developed a fibre-division model resulting from Coulomb repulsion and solvent vaporization to interpret the formation of the ribbona or twin fibres, which has been confirmed by the SEM studies. Our results also indicate that the formation of the ribbons or twin fibres is less dependent on operation voltage and work distance.

  9. Roughness and fibre reinforcement effect onto wettability of composite surfaces

    Science.gov (United States)

    Bénard, Quentin; Fois, Magali; Grisel, Michel

    2007-03-01

    Wettability of glass/epoxy and carbon/epoxy composites materials has been determined via sessile drop technique. Good-Van Oss approach has been used to evaluate surface free energy parameters of smooth and rough surfaces. Results obtained point out the influence of fibre reinforcement on surface free energy of composite materials. In addition, the interest of surface treatment to increase surface roughness has been discussed in terms of wettability. To sum up, results obtained clearly demonstrate the necessity of considering properties of a given composite surface not only as a polymer but a fibre/polymer couple. The drawn conclusions are of great interest as it may have numerous consequences in applications such as adhesion.

  10. Short Fibre and Particulate-reinforced Rubber Composites

    Directory of Open Access Journals (Sweden)

    Kavita Agarwal

    2002-07-01

    Full Text Available Particulate fillers (carbon black and silica and short fibre (aromatic polyamide, Kevlar have been utilised to produce rubber composites based on acrylonitrile-co-butadiene rubber (NBR. Mechanical properties of these composites have been determined and compared with unfilled rubber vulcanisate. The effect of surface treatment on the improvement of strength, in case of Kevlar, has also been considered. The influence of elevated temperature on tear strength, an important failure criterion, has been evaluated. Scanning electron microscopy has been used as a tool to correlate the topographical features associated with changes in the tear strength of the composites.

  11. Continuous jute fibre reinforced laminated paper composite and reinforcement-fibre free paper laminate

    Indian Academy of Sciences (India)

    B B Verma

    2009-12-01

    Plastic bags create a serious environmental problem. The proposed jute fibre reinforced laminated paper composite and reinforcement-fibre free paper laminate may help to combat the war against this pollutant to certain extent. The paper laminate, without reinforcement fibre, exhibited a few fold superiority in tensile properties than single paper strip. The studies further show that an appreciable improvement in tensile properties can be achieved by introducing continuous jute fibre in paper laminates.

  12. Creep Strength of Discontinuous Fibre Composites

    DEFF Research Database (Denmark)

    Pedersen, Ole Bøcker

    1974-01-01

    relation between stress and strain rate. Expressions for the interface stress, the creep velocity profile adjacent to the fibres and the creep strength of the composite are derived. Previous results for the creep strength, sc = aVfs0 ( \\frac[( Î )\\dot] [( Î )\\dot] 0 )1/nr1 + 1/n c=Vf001n1+1n in which[( Î...... )\\dot] is the composite creep rate,V f is the fibre volume fraction,sgr 0,epsi 0 andn are the constants in the matrix creep law. The creep strength coefficient agr is found to be very weakly dependent onV f and practically independent ofn whenn is greater than about 6....

  13. Experimental Characterization of Carbon Fibre T700 / Epoxy towpreg for Space Applications

    Directory of Open Access Journals (Sweden)

    S.Sankar Reddy

    2015-12-01

    Full Text Available This document covers detailed experimental characterization of Carbon Fibre T 700/Epoxy towpreg.The experimental characterization of carbon fibre T 700/Epoxy towpreg composite material is necessary required for generation of mechanical properties data for analysis, design, and fabrication of structural components using that material and for quality control of the material. The testing of composite materials offers unique surprises because of the special characteristics of composites. Factors not considered important in metals testing are very important in testing composites. For example, composites are anisotropic, with properties that depend on the direction in which they are tested. Speed must be carefully monitored at the time of testing of specimens and also fiber content, void content, specimen conditioning (drying, storage, etc have important effects on material properties. In order to design composite products, a thorough experimental characterization of carbon fibre T 700 / Epoxy towpreg composite material and its behaviour is necessary.

  14. Fractographic observations of the microstructural characteristics of flax fibre composites

    DEFF Research Database (Denmark)

    Madsen, Bo; Asian, Mustafa; Lilholt, Hans

    2016-01-01

    flax fibre/thermoplastic composites are presented. The findings are presented in relation to the three operational parts in composites: fibres, matrix and fibre/matrix interface. For the flax fibres, the striated structure on the fibre surface is shown to consist of cellulose macrofibrils oriented...... failure followed by longitudinal splitting. For the thermoplastic matrix, concentric rings with different points of origin are observed in the matrix regions of the composite fracture surface. The concentric rings have a microporous structure consisting of nanoscale polymer fibrils. The concentring rings...... form mirror zones with no riverlines, followed by repeated mist and hackle zones with distinct radiating riverlines. For the flax fibre/thermoplastic matrix interface, microscale imprints of whole fibres, and nanoscale imprints of fibre surface structures are observed on the matrix surface...

  15. Characterisation of the mechanical and fracture properties of a uni-weave carbon fibre/epoxy non-crimp fabric composite

    Directory of Open Access Journals (Sweden)

    Thomas Bru

    2016-03-01

    Full Text Available A complete database of the mechanical properties of an epoxy polymer reinforced with uni-weave carbon fibre non-crimp fabric (NCF is established. In-plane and through-the-thickness tests were performed on unidirectional laminates under normal loading and shear loading. The response under cyclic shear loading was also measured. The material has been characterised in terms of stiffness, strength, and failure features for the different loading cases. The critical energy release rates associated with different failure modes in the material were measured from interlaminar and translaminar fracture toughness tests. The stress–strain data of the tensile, compressive, and shear test specimens are included. The load–deflection data for all fracture toughness tests are also included. The database can be used in the development and validation of analytical and numerical models of fibre reinforced plastics (FRPs, in particular FRPs with NCF reinforcements.

  16. Manufacturing Titanium Metal Matrix Composites by Consolidating Matrix Coated Fibres

    Institute of Scientific and Technical Information of China (English)

    Hua-Xin PENG

    2005-01-01

    Titanium metal matrix composites (TiMMCs) reinforced by continuous silicon carbide fibres are being developed for aerospace applications. TiMMCs manufactured by the consolidation of matrix-coated fibre (MCF) method offer optimum properties because of the resulting uniform fibre distribution, minimum fibre damage and fibre volume fraction control. In this paper, the consolidation of Ti-6Al-4V matrix-coated SiC fibres during vacuum hot pressing has been investigated. Experiments were carried out on multi-ply MCFs under vacuum hot pressing (VHP). In contrast to most of existing studies, the fibre arrangement has been carefully controlled either in square or hexagonal arraysthroughout the consolidated sample. This has enabled the dynamic consolidation behaviour of MCFs to be demonstrated by eliminating the fibre re-arrangement during the VHP process. The microstructural evolution of the matrix coating was reported and the deformation mechanisms involved were discussed.

  17. Experimental Investigation and Analysis of Mechanical Properties of Palm fibre reinforced Epoxy composites and Sisal fibre reinforced Polyester composites

    Directory of Open Access Journals (Sweden)

    B. Muthu Chozha Rajan

    2015-12-01

    Full Text Available The objective of this paper was investigated to evaluate tensile, flexural and Impact properties of Palm fibre reinforced Epoxy composites (PFRP and compared with Sisal fibre reinforced Polyester composites (SFRP. Untreated chopped Palmyra Palm fruit fibre was used as reinforcement in Epoxy resin matrix and chopped sisal fibre was used as reinforcement in Polyester resin matrix. The chopped palm fibrereinforced composite were prepared in volume fractions (Vf such as 10 %, 20 % and 30 % of specimens by using Epoxy and the chopped sisalfibre reinforced composite were prepared in volume fractions (Vf such as 10 %, 20 % and 30 % of specimens by using Polyester. The specimens are tested for their mechanical Properties strictly as per ASTM procedures. Static analysis is performed by FEA based software ANSYS R15 with design constraints as Equivalent stress, Shear stress and deflection.The experimental result and analysis shows that the fibre volume fraction increases the tensile, flexural, Impact strength and modulus of the fibre reinforced composites

  18. Atmospheric pressure plasma surface modification of carbon fibres

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Løgstrup Andersen, Tom; Michelsen, Poul

    2008-01-01

    Carbon fibres are continuously treated with dielectric barrier discharge plasma at atmospheric pressure in various gas conditions for adhesion improvement in mind. An x-ray photoelectron spectroscopic analysis indicated that oxygen is effectively introduced onto the carbon fibre surfaces by He, He...

  19. Natural fibre selection for composite eco-design

    DEFF Research Database (Denmark)

    Corona, Andrea; Madsen, Bo; Hauschild, Michael Zwicky;

    2016-01-01

    Natural fibre composites (NFC) are gaining interest in manufacturing because they address some of the environmental problems of traditional composites: use of non-renewable resources, and large impacts related to their production and disposal. Since natural fibres are not yet optimized for compos...

  20. Electroless plating and magnetic properties of Co–Zn–P coating on short carbon fibres

    Indian Academy of Sciences (India)

    Xinghua Su; Chengwen Qiang

    2012-12-01

    A layer of Co–Zn–P alloys was coated on short carbon fibre (CFs) surfaces using electroless plating method. The influence of the concentration of Co2+ and Zn2+ and reaction time on the plating rate were measured by comparing the relative mass gain rate of Co–Zn–P-coated fibres with uncoated carbon fibres prepared under different conditions. The materials characterizations were analysed by field emission scanning electron microscopy, X-ray diffraction and energy dispersive spectroscope. The magnetic properties of Co–Zn–P/CFs composites prepared in different Zn2+ concentration baths were measured by the vibrating sample magnetometer. The best processing parameters of electroless plating of Co–Zn–P coating on short carbon fibres were obtained.

  1. Analysis of Composite Material Blended With Thermoplastics and Jute Fibre

    Directory of Open Access Journals (Sweden)

    Venugopal S

    2015-03-01

    Full Text Available Recently natural fibres have been receiving considerable attention as substitutes for synthetic fibre reinforcements due to their low cost, low density, acceptable specific strength, good thermal insulation properties, reduced tool wear, reduced thermal and respiratory irritation and renewable resources. The aim of this work is to develop chemically treated and chemically untreated fibre reinforced composite material with optimum properties so that it can replace the existing synthetic fibre reinforced composite material for a suitable application. In this work, polyester resin has been reinforced with jute fabric, so as to develop jute fibre reinforced plastic (JFRP with a weight ratio of 10:1:1 Hand lay-up technique was used to manufacture the composites where Methyl Ethyl Ketone Peroxide and cobalt Naphthalene were used as coupling agent and accelerator respectively. The thickness of the composite specimen was obtained by laying up layer of fibre and matrix. The untreated composites have been used and mechanical properties are compared with natural fibre and jute fibre composite by using the Ansys method.

  2. Microstructure and Mechanical Properties of Aligned Natural Fibre Composites

    DEFF Research Database (Denmark)

    Rask, Morten

    . Several challenges have to be addressed and solved, many of which pertain to the fact that the fibres are sourced from a natural resource: 1) Inconsistent properties, depending on plant species, growth and harvest conditions, and fibre extraction techniques. 2) Strength values of composites are lower than...... splitting cracks typically seen at the interfaces of bundles of unseparated fibres, (ii) matrix shear cracks, and (iii) fibre failures typically seen at fibre defects. The three damage mechanisms initiated at about 50, 75 and 90% of the failure stress, respectively. After harvesting the plants, the fibre...... strain gauges. After developing the approach, it was used to determine the fracture toughness of flax/PLA (polymer based on lactic acid) specimens made from yarns with different twisting angles. It was found that a high twisting angle greatly decreases the fracture toughness of the composite...

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

    Directory of Open Access Journals (Sweden)

    S.BENJAMIN LAZARUS

    2014-03-01

    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.

  4. Mechanical properties of pineapple leaf fibre reinforced polypropylene composites

    Energy Technology Data Exchange (ETDEWEB)

    Arib, R.M.N. [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Sapuan, S.M. [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia)]. E-mail: sapuan@eng.upm.edu.my; Ahmad, M.M.H.M. [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Paridah, M.T. [Faculty of Forestry, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Zaman, H.M.D. Khairul [Radiation Processing Technology Division, Malaysian Institute for Nuclear Technology Research (MINT), Bangi 43000 Kajang, Selangor (Malaysia)

    2006-07-01

    Pineapple leaf fibre, which is rich in cellulose, relative inexpensive and abundantly available has the potential for polymer-reinforced composite. The present study investigates the tensile and flexural behaviours of pineapple leaf fibre-polypropylene composites as a function of volume fraction. The tensile modulus and tensile strength of the composites were found to be increasing with fibre content in accordance with the rule of mixtures. The tensile modulus and tensile strength with a volume fraction 10.8% are 687.02 and 37.28 MPa, respectively. The flexural modulus gives higher value at 2.7% volume fraction. The flexural strength of the composites containing 5.4% volume fraction was found to be higher than that of pure polypropylene resin by 5.1%. Scanning electron microscopic studies were carried out to understand the fibre-matrix adhesion and fibre breakage.

  5. Mechanical properties of natural fibre reinforced polymer composites

    Indian Academy of Sciences (India)

    A S Singha; Vijay Kumar Thakur

    2008-10-01

    During the last few years, natural fibres have received much more attention than ever before from the research community all over the world. These natural fibres offer a number of advantages over traditional synthetic fibres. In the present communication, a study on the synthesis and mechanical properties of new series of green composites involving Hibiscus sabdariffa fibre as a reinforcing material in urea–formaldehyde (UF) resin based polymer matrix has been reported. Static mechanical properties of randomly oriented intimately mixed Hibiscus sabdariffa fibre reinforced polymer composites such as tensile, compressive and wear properties were investigated as a function of fibre loading. Initially urea–formaldehyde resin prepared was subjected to evaluation of its optimum mechanical properties. Then reinforcing of the resin with Hibiscus sabdariffa fibre was accomplished in three different forms: particle size, short fibre and long fibre by employing optimized resin. Present work reveals that mechanical properties such as tensile strength, compressive strength and wear resistance etc of the urea–formaldehyde resin increases to considerable extent when reinforced with the fibre. Thermal (TGA/DTA/DTG) and morphological studies (SEM) of the resin and biocomposites have also been carried out.

  6. Fabrication and Sensing Performance of Smart Composite Structures Using Optical Fibre Sensors

    Institute of Scientific and Technical Information of China (English)

    C Y Wei; S W James; C C Ye; R P Tatam; P E lrving

    2000-01-01

    This paper determines the performance of Fibre Bragg Grating (FBG) sensors for strain sensing applications in carbon fibre composite materials. Carbon fibre laminates in either cross-plied or quasiisotropic stacking sequences were fabricated using T300/Hexcel 914 prepregs. The FBG optical sensors were either surface attached, or embedded within laminates. The sensor orientation was aligned either parallel or transverse to the adjacent carbon fibre layers. The composite structures with integrated FBG sensors were subjected to static tensile loading. A scanning fibre Fabry-Perot filter was used to monitor the reflected Bragg wavelengths. The optical sensor embedded between two 90° carbon fibre plies shows a high sensitivity to multi-site cracking formed in the transverse plies. The embedding in 90° plies seems to change the local stress distributions and to become a source of crack initiation. Efficient stress transfer from the host materials to the sensors is dependent upon incorporation methods, the thickness of the adhesive layers, and the location of the sensors.

  7. Multiplexed fibre optic sensors for monitoring resin infusion, flow, and cure in composite material processing

    Science.gov (United States)

    Chehura, Edmon; Jarzebinska, Renata; Da Costa, Elisabete F. R.; Skordos, Alexandros A.; James, Stephen W.; Partridge, Ivana K.; Tatam, Ralph P.

    2013-04-01

    The infusion, flow and cure of RTM6 resin in a carbon fibre reinforced composite preform have been monitored using a variety of multiplexed fibre optic sensors. Optical fibre Fresnel sensors and tilted fibre Bragg grating (TFBG) sensors were configured to monitor resin infusion/flow in-plane of the component. The results obtained from the different sensors were in good agreement with visual observations. The degree of cure was monitored by Fresnel sensors via a measurement of the refractive index of the resin which was converted to degree of cure using a calibration determined from Differential Scanning Calorimetry. Fibre Bragg grating sensors fabricated in highly linearly birefringent fibre were used to monitor the development of transverse strain during the cure process, revealing through-thickness material shrinkage of about 712 μɛ and residual strain of 223 μɛ. An alternative approach to infusion monitoring, based on an array of multiplexed tapered optical fibre sensors interrogated using optical frequency domain reflectometry, was also investigated in a separate carbon fibre preform that was infused with RTM6 resin.

  8. Thermoforming of Continuous Fibre Reinforced Thermoplastic Composites

    Science.gov (United States)

    McCool, Raurí; Murphy, Adrian; Wilson, Ryan; Jiang, Zhenyu; Price, Mark

    2011-05-01

    The introduction of new materials, particularly for aerospace products, is not a simple, quick or cheap task. New materials require extensive and expensive qualification and must meet challenging strength, stiffness, durability, manufacturing, inspection and maintenance requirements. Growth in industry acceptance for fibre reinforced thermoplastic composite systems requires the determination of whole life attributes including both part processing and processed part performance data. For thermoplastic composite materials the interactions between the processing parameters, in-service structural performance and end of life recyclability are potentially interrelated. Given the large number and range of parameters and the complexity of the potential relationships, understanding for whole life design must be developed in a systematic building block approach. To assess and demonstrate such an approach this article documents initial coupon level thermoforming trials for a commercially available fibre reinforced thermoplastic laminate, identifying the key interactions between processing and whole life performance characteristics. To examine the role of the thermoforming process parameters on the whole life performance characteristics of the formed part requires a series of manufacturing trials combined with a series of characterisation tests on the manufacturing trial output. Using a full factorial test programme and considering all possible process parameters over a range of potential magnitudes would result in a very large number of manufacturing trials and accompanying characterisation tests. Such an approach would clearly be expensive and require significant time to complete, therefore failing to address the key requirement for a future design methodology capable of rapidly generating design knowledge for new materials and processes. In this work the role of mould tool temperature and blank forming temperature on the thermoforming of a commercially available

  9. Effects of fibre orientation on mechanical properties of hybrid bamboo/glass fibre polymer composites

    Indian Academy of Sciences (India)

    B Stanly Jones Retnam; M Sivapragash; P Pradeep

    2014-08-01

    The usage of natural fibre as reinforcement in polymer composites have widely increased because of its enhanced properties. The usage of plant fibre cannot alone satisfy all the needs of the composites. Hence, introduction of hybrid plays a vital role in enhancing the mechanical properties of the FRP composites. Fibre orientation contributes significant role in improving the mechanical properties of the FRP composites. In this proposal, hybrid bamboo/glass fibre woven in different orientations such as 0°/90° and ± 45° was used and its effect on mechanical properties were studied. Composites containing hybrid fibres found to possess better mechanical properties, when compared to pure bamboo. In order to justify this, the following mechanical properties such as tensile, flexural, impact and hardness were investigated. SEM analysis shows the bonding between the matrix and reinforcement. All the above test results indicate that the introduction of natural bamboo fibre in glass reduces the overall cost of the composites with no compromise in strength and also attracted several studies covering green technologies.

  10. Infiltrated carbon foam composites

    Science.gov (United States)

    Lucas, Rick D. (Inventor); Danford, Harry E. (Inventor); Plucinski, Janusz W. (Inventor); Merriman, Douglas J. (Inventor); Blacker, Jesse M. (Inventor)

    2012-01-01

    An infiltrated carbon foam composite and method for making the composite is described. The infiltrated carbon foam composite may include a carbonized carbon aerogel in cells of a carbon foam body and a resin is infiltrated into the carbon foam body filling the cells of the carbon foam body and spaces around the carbonized carbon aerogel. The infiltrated carbon foam composites may be useful for mid-density ablative thermal protection systems.

  11. Fabrication and characterization of S. cilliare fibre reinforced polymer composites

    Indian Academy of Sciences (India)

    A S Singha; Vijay Kumar Thakur

    2009-02-01

    In the recent times, there has been an ever-increasing interest in green composite materials for its applications in the field of industries, aerospace, sports, household etc and in many other fields. In this paper, fabrication of Saccharum cilliare fibre reinforced green polymer composites using resorcinol formaldehyde (RF) as a novel matrix has been reported. A systematic approach for processing of polymer is presented. Effect of fibre loading on mechanical properties like flexural, tensile, compressive and wear resistances has also been determined. Reinforcing of the RF resin with Saccharum cilliare (SC) fibre was done in the form of particle size (200 micron). Present work reveals that mechanical properties of the RF resin have been found to increase up to 30% fibre loading and then decreases. Morphological and thermal studies of the resin, fibre and particle reinforced (P-Rnf) green composites have also been studied.

  12. Protocol for Quantification of Defects in Natural Fibres for Composites

    DEFF Research Database (Denmark)

    Mortensen, Ulrich Andreas; Madsen, Bo

    2014-01-01

    Natural bast-type plant fibres are attracting increasing interest for being used for structural composite applications where high quality fibres with good mechanical properties are required. A protocol for the quantification of defects in natural fibres is presented. The protocol is based...... of defect size by width, and it is shown that both definitions can be used to give unbiased findings for the comparison between fibre types. Finally, considerations are given with respect to true measures of defect content, number of determinations, and number of significant figures used for the descriptive...

  13. Service life prediction and fibre reinforced cementitious composites

    DEFF Research Database (Denmark)

    Stoklund Larsen, E.

    The present Ph.D.thesis addresses the service life concept on the fibre reinforced cementitious composites. The advantages and problems of adding fibre to a cementitious matrix and the influence on service life are described. In SBI Report 221, Service life prediction and cementitious somposites......, the factors affecting the pure cementitious composite are described. Different sizes and types of fibre reinforced crmentitious composites have been chosen to illustrate different ageing and deterioration mechanisms. Some ageing mechanisms can be accelerated and others cannot which is demonstrated in a test...

  14. Segmental fibre type composition of the rat iliopsoas muscle.

    Science.gov (United States)

    Vlahovic, Hrvoje; Bazdaric, Ksenija; Marijancic, Verner; Soic-Vranic, Tamara; Malnar, Daniela; Arbanas, Juraj

    2017-01-18

    The iliopsoas of the rat is composed of two muscles - the psoas major muscle and the iliacus muscle. The psoas major muscle arises from all the lumbar vertebrae and the iliacus muscle from the fifth and sixth lumbar vertebrae and ilium. Their common insertion point is the lesser trochanter of the femur, and their common action is the lateral rotation of the femur and flexion of the hip joint. Unlike humans, the rat is a quadruped and only occasionally rises up on its hind legs. Therefore, it is expected that the fibre type composition of the rat iliopsoas muscle will be different than that of humans. The iliopsoas muscle of the rat is generally considered to be a fast muscle. However, previous studies of the fibre type composition of the rat psoas muscle showed different results. Moreover, very little is known about the composition of the rat iliacus muscle. The aim of our study was to examine the fibre type composition of the rat iliopsoas muscle in order to better understand the complex function of the listed muscle. The psoas major muscle was examined segmentally at four different levels of its origin. Type I, IIA, IIB and IIX muscle fibres were typed using monoclonal antibodies for myosin heavy chain identification. The percentage of muscle fibre types and muscle fibre cross-sectional areas were calculated. In our study we showed that in the rat iliopsoas muscle both the iliacus and the psoas major muscles had a predominance of fast muscle fibre types, with the highest percentage of the fastest IIB muscle fibres. Also, the IIB muscle fibres showed the largest cross-sectional area (CSA) in both muscles. As well, the psoas major muscle showed segmental differences of fibre type composition. Our results showed changes in percentages, as well as the CSAs of muscle fibre types in cranio-caudal direction. The most significant changes were visible in type IIB muscle fibres, where there was a decrease of percentages and the CSAs from the cranial towards the caudal part

  15. Frottement des matériaux composites polymères à renfort fibre de carbone : expériences et modélisation

    OpenAIRE

    Smerdova, Olga; Le Bot, Alain; Cayer-Barrioz, Juliette; Sarbaev, Boris

    2011-01-01

    International audience; combinaison de leurs propriétés mécaniques et thermiques avec leur faible masse. Cependant, leurs propriétés tribologiques restent largement méconnues. Dans le cadre de ce travail, l'étude expérimentale du frottement entre deux PRFC composites sous faible charge normale (jusqu'à 20N) a été réalisée. Deux effets ont été soigneusement étudiés pendant l'expérience : la fraction volumique et l'orientation des fibres. En complément de ce travail expérimental, une modélisati...

  16. Carbon nanotube integrated multifunctional multiscale composites

    Energy Technology Data Exchange (ETDEWEB)

    Qiu Jingjing; Zhang, Chuck; Wang, Ben; Liang, Richard [High-Performance Materials Institute, Department of Industrial and Manufacturing Engineering, Florida A and M University-Florida State University College of Engineering, 2525 Pottsdamer Street, Tallahassee, FL 32310-6046 (United States)

    2007-07-11

    Carbon nanotubes (CNTs) demonstrate extraordinary properties and show great promise in enhancing out-of-plane properties of traditional polymer composites and enabling functionality, but current manufacturing challenges hinder the realization of their potential. This paper presents a method to fabricate multifunctional multiscale composites through an effective infiltration-based vacuum-assisted resin transfer moulding (VARTM) process. Multi-walled carbon nanotubes (MWNTs) were infused through and between glass-fibre tows along the through-thickness direction. Both pristine and functionalized MWNTs were used in fabricating multiscale glass-fibre-reinforced epoxy composites. It was demonstrated that the mechanical properties of multiscale composites were remarkably enhanced, especially in the functionalized MWNT multiscale composites. With only 1 wt% loading of functionalized MWNTs, tensile strength was increased by 14% and Young's modulus by 20%, in comparison with conventional fibre-reinforced composites. Moreover, the shear strength and short-beam modulus were increased by 5% and 8%, respectively, indicating the improved inter-laminar properties. The strain-stress tests also suggested noticeable enhancement in toughness. Scanning electron microscopy (SEM) characterization confirmed an enhanced interfacial bonding when functionalized MWNTs were integrated into epoxy/glass-fibre composites. The coefficient thermal expansion (CTE) of functionalized nanocomposites indicated a reduction of 25.2% compared with epoxy/glass-fibre composites. The desired improvement of electrical conductivities was also achieved. The multiscale composites indicated a way to leverage the benefits of CNTs and opened up new opportunities for high-performance multifunctional multiscale composites.

  17. Carbon nanotube integrated multifunctional multiscale composites

    Science.gov (United States)

    Qiu, Jingjing; Zhang, Chuck; Wang, Ben; Liang, Richard

    2007-07-01

    Carbon nanotubes (CNTs) demonstrate extraordinary properties and show great promise in enhancing out-of-plane properties of traditional polymer composites and enabling functionality, but current manufacturing challenges hinder the realization of their potential. This paper presents a method to fabricate multifunctional multiscale composites through an effective infiltration-based vacuum-assisted resin transfer moulding (VARTM) process. Multi-walled carbon nanotubes (MWNTs) were infused through and between glass-fibre tows along the through-thickness direction. Both pristine and functionalized MWNTs were used in fabricating multiscale glass-fibre-reinforced epoxy composites. It was demonstrated that the mechanical properties of multiscale composites were remarkably enhanced, especially in the functionalized MWNT multiscale composites. With only 1 wt% loading of functionalized MWNTs, tensile strength was increased by 14% and Young's modulus by 20%, in comparison with conventional fibre-reinforced composites. Moreover, the shear strength and short-beam modulus were increased by 5% and 8%, respectively, indicating the improved inter-laminar properties. The strain-stress tests also suggested noticeable enhancement in toughness. Scanning electron microscopy (SEM) characterization confirmed an enhanced interfacial bonding when functionalized MWNTs were integrated into epoxy/glass-fibre composites. The coefficient thermal expansion (CTE) of functionalized nanocomposites indicated a reduction of 25.2% compared with epoxy/glass-fibre composites. The desired improvement of electrical conductivities was also achieved. The multiscale composites indicated a way to leverage the benefits of CNTs and opened up new opportunities for high-performance multifunctional multiscale composites.

  18. Influence of the physical structure of flax fibres on the mechanical properties of flax fibre reinforced polypropylene composites

    NARCIS (Netherlands)

    Oever, van den M.J.A.; Bos, H.L.; Kemenade, van M.J.J.M.

    2000-01-01

    This study investigates the influence of the physical structure of flax fibres on the mechanical properties of polypropylene (PP) composites. Due to their composite-like structure, flax fibres have relatively weak lateral bonds which are in particular present in flax fibres that are often used in na

  19. Deflection analysis of reinforced concrete beams strengthened with carbon fibre reinforced polymer under long-term load action

    Institute of Scientific and Technical Information of China (English)

    Mykolas DAUGEVI(C)IUS; Juozas VALIVONIS; Gediminas MAR(C)IUKAITIS

    2012-01-01

    This paper presents the results of an experimental research on reinforced concrete beams strengthened with an external carbon fibre reinforced polymer (CFRP) layer under long-term load action that lasted for 330 d.We describe the characteristics of deflection development of the beams strengthened with different additional anchorages of the external carbon fibre composite layer during the period of interest.The conducted experiments showed that the additional anchorage influences the slip of the extemal layer with respect to the strengthened element.Thus,concrete and carbon fibre composite interface stiffness decreases with a long-term load action.Therefore,the proposed method of analysis based on the built-up-bars theory can be used to estimate concrete and carbon fibre composite interface stiffness in the case of long-term load.

  20. Adsorption of polar probe molecules on plasma-oxidised high-strength carbon fibres

    Energy Technology Data Exchange (ETDEWEB)

    Montes-Moran, M.A.; Martinez-Alonso, A.; Tascon, J.M.D. [Instituto Nacional del Carbon, CSIC, Apartado 73, 33080, Oviedo (Spain)

    2002-06-20

    The objective of this work was to examine the effect of oxygen plasma treatment on the surface chemistry of carbon fibres. Virgin, unsized high-strength carbon fibres were subjected to oxygen plasma treatments with different degrees of severity. Adsorption of probe molecules with different acid-base characteristics (acetone, carbon tetrachloride, trichloromethane, dichloromethane, diethyl ether, nitromethane, tetrahydrofurane) was measured at 303-353 K using inverse gas chromatography (IGC) at infinite dilution. Plasma treatment brings about increases in the specific free energy of adsorption of either acidic, basic or amphoteric probe molecules, indicating creation of surface functionalities with various acid-base strengths. This helps to justify the improvement in interfacial adhesion in polycarbonate matrix composites following plasma treatment of carbon fibres.

  1. UNIFORMITY ASSESSMENT OF CARBON FIBRES DISPERSION IN CEMENT PASTE BY IMPEDANCE MEASUREMENTS

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    An alternating current was applied to measure the impedance of a hardened cement paste with various contents of carbon fibres.When the free water content in the hardened cement paste is 90%-98%,and the measuring frequency 500Hz,an approximate linear relationship was found between fibre content and impedance of the composite.Based on this relationship,a new attempt was made to evaluate the dispersion uniformity of carbon fibres in cement paste by impedance measurement.The standard deviation S and the coefficient of vriation S/(X-)i of impedance of the fibre-cement specimens randomly taken locating in different points were used as main parameters for the uniformity assessment.As a case,four different mixing processes were designed for dispersing carbon fibres into the cement paste.The results demonstrate that the relative longer mixing time increases the dispersion uniformity of carbon fibres in cement paste,and the addition of the water reducer dramatically improves the uniformity due to the change of the fluidity of the paste.The ground fly ash can increase the uniformity to a certain extent.

  2. Control and design of volumetric composition in pultruded hybrid fibre composites

    DEFF Research Database (Denmark)

    Madsen, Bo; Hashemi, Fariborz; Tahir, Paridah

    2016-01-01

    Hybrid composites consist of two of more fibre phases in a common matrix phase. This is a challenge for the control and design of the volumetric composition and microstructural uniformity of such composites. In the present study, a model is presented for the prediction of the complete volumetric...... composition (i.e. volume fractions of fibres, matrix and porosity) in hybrid fibre composites. The model is based on a constant local fibre volume fraction criterion. Good agreement is found between model predictions and experimental data of pultruded hybrid kenaf/glass fibre composites with variable hybrid...... fibre weight mixing ratios. To demonstrate the suitability of the model, simulations are performed for four different cases of volumetric composition in hybrid kenaf/glass composites....

  3. Woven Structures from Natural Fibres for Reinforcing Composites

    OpenAIRE

    Maniņš, M; Bernava, A; Strazds, G.

    2015-01-01

    The increase of production of woven structures from natural fibres for reinforced composites can be noticed in different sectors of economy. This can be explained by limited sources of raw materials and different environmental issues, as well as European Union guidelines for car manufacture [4]. This research produced 2D textile structures of hemp yarn and polypropylene yarn and tested the impact of added glass fibre yarn on the mechanical properties of the woven structures and the composites...

  4. The effect of fibre content, fibre size and alkali treatment to Charpy impact resistance of Oil Palm fibre reinforced composite material

    Science.gov (United States)

    Fitri, Muhamad; Mahzan, Shahruddin

    2016-11-01

    In this research, the effect of fibre content, fibre size and alkali treatment to the impact resistance of the composite material have been investigated, The composite material employs oil palm fibre as the reinforcement material whereas the matrix used for the composite materials are polypropylene. The Oil Palm fibres are prepared for two conditions: alkali treated fibres and untreated fibres. The fibre sizes are varied in three sizes: 5mm, 7mm and 10mm. During the composite material preparation, the fibre contents also have been varied into 3 different percentages: 5%, 7% and 10%. The statistical approach is used to optimise the variation of specimen determined by using Taguchi method. The results were analyzed also by the Taguchi method and shows that the Oil Palm fibre content is significantly affect the impact resistance of the polymer matrix composite. However, the fibre size is moderately affecting the impact resistance, whereas the fibre treatment is insignificant to the impact resistance of the oil palm fibre reinforced polymer matrix composite.

  5. A Review on Pineapple Leaves Fibre and Its Composites

    Directory of Open Access Journals (Sweden)

    M. Asim

    2015-01-01

    Full Text Available Natural fibre based composites are under intensive study due to their ecofriendly nature and peculiar properties. The advantage of natural fibres is their continuous supply, easy and safe handling, and biodegradable nature. Although natural fibres exhibit admirable physical and mechanical properties, it varies with the plant source, species, geography, and so forth. Pineapple leave fibre (PALF is one of the abundantly available wastes materials of Malaysia and has not been studied yet as it is required. A detailed study of chemical, physical, and mechanical properties will bring out logical and reasonable utilization of PALF for various applications. From the socioeconomic prospective, PALF can be a new source of raw material to the industries and can be potential replacement of the expensive and nonrenewable synthetic fibre. However, few studies on PALF have been done describing the interfacial adhesion between fibres and reinforcement compatibility of fibre but a detailed study on PALF properties is not available. In this review, author covered the basic information of PALF and compared the chemical, physical, and mechanical properties with other natural fibres. Furthermore, it summarizes the recent work reported on physical, mechanical, and thermal properties of PALF reinforced polymer composites with its potential applications.

  6. Physical and mechanical properties of unidirectional plant fibre composites

    DEFF Research Database (Denmark)

    Madsen, B.; Lilholt, H.

    2003-01-01

    Unidirectional composites were made from filament wound non-treated flax yarns and polypropylene foils. With increasing composite fibre weight fractions from 0.56 to 0.72, porosity fractions increased from 0.04 to 0.08; a theoretical model was fitted to the data in order to describe the composite...... volumetric interaction between contents of fibre, matrix and porosity. In the model two porosity components were proposed, a process governed component and a structurally governed component. The composite axial stiffness and strength were in the range 27-29 GPa and 251-321 MPa, respectively. A modified...... version of the "rule-of-mixtures", supplemented with parameters of composite porosity content and anisotropy of fibre properties, were developed to improve the prediction of composite tensile properties. (C) 2003 Elsevier Science Ltd. All rights reserved....

  7. Hybrid yarn for thermoplastic fibre composites. Summary of technical results

    Energy Technology Data Exchange (ETDEWEB)

    Lystrup, Aa.

    1998-01-01

    This report is a summary of the technical results obtained within the framework program: `Hybrid Yarn for Thermoplastic Fibre Composites`. The program which started at the 15th of June 1994 and expired at the 31st of December 1997, was a framework program under the Danish Materials Technology Program, MUP2. A new type of hybrid yarn for production of fibre composites with thermoplastic matrix material is developed and tested. A hybrid yarn is a commingled textured yarn consisting of structural fibres and thermoplastic fibres. In a subsequent heating and consolidation process the plastic fibres melt and become the matrix material in the formed fibre composite material. Two types of processing technology are developed and studied: Vacuum consolidation and press consolidation. Vacuum consolidation of hybrid yarn fabrics is suitable for fabrication of larger parts such as wind turbine blades, and press consolidation is a fast process suitable for smaller parts such as automobile body parts. To demonstrate the potential for industrial use of the developed hybrid yarn and process technologies a section of a wind turbine blade, an inspection cover and a car door-post have been produced. An environmental evaluation of the manufacture of hybrid yarn and composites shows that the use of the hybrid yarn is a gain for both the working environment and the external environment, compared to the use of thermosetting polymer composites. (au)

  8. Design and evaluation of carbon fibre-reinforced launch packages with segmented, copper and molybdenum fibre armatures

    NARCIS (Netherlands)

    Koops, M.; Huijser, T.; Karthaus, W.

    1997-01-01

    Fibre armatures have been studied both dynamically and statically to gain insight in their electrothermal and mechanical behaviour. In the first part of this paper, the results of launch experiments with single and multi-segment copper and molybdenum fibre armatures integrated in carbon-fibre reinfo

  9. Effects of fibre-surface morphology on the mechanical properties of Porifera-inspired rubber-matrix composites

    Science.gov (United States)

    Alam, Parvez; Stillfried, Daniela Graf; Celli, Jessika; Toivakka, Martti

    2013-06-01

    In this paper, mineralised organic fibre morphologies, inspired by the structures of Porifera (sponges) are correlated to the mechanical performance of fibre reinforced rubbers. The mineralised structures are rich in calcium carbonate and silica. These compounds nucleate and precipitate on the fibre surfaces yielding different morphologies as a function of mineral ion concentrations. Smaller mineralised precipitates manifestly improve the mechanical performance of composites while thicker precipitates enveloping the fibres give rise to inferior properties. Mechanisms and evidenced reasoning for these differences are reported herein.

  10. Shape memory polymeric composites sensing by optic fibre Bragg gratings: A very first approach

    Science.gov (United States)

    Quadrini, Fabrizio; Santo, Loredana; Ciminello, Monica; Concilio, Antonio; Volponi, Ruggero; Spena, Paola

    2016-05-01

    Shape memory polymer composites (SMPCs) have the potential for many applications in aerospace, spanning from self-repairing of structures to self-deploying of antennas, solar sails, or functional devices (e.g. for grabbing small space debris). In all these cases, it may be essential to have information about their configuration at different stages of shape recovery. In this study, the strain history of a prepreg carbon fibre system, cured with a shape memory polymer (SMP) interlayer, is monitored through a Fibre Bragg Grating (FBG), a fibre optic sensor device. SMPC has been manufactured by using traditional technologies for aerospace. After manufacturing cylindrical shape samples, an external fibre optic system is added to the composite structure; this system is especially suited for high temperatures which are necessary for SMP recovery and composite softening. Sensor functionality is checked before and after each strain history path. Optic fibre arrangement is optimized to avoid unwanted breakings whereas strains are limited by fibre collapsing, i.e. within nominal 2% of deformation. Dynamic information about shape recovery gives fundamental insights about strain evolution during time as well as its spatial distribution.

  11. Quantitative evaluation of iPP nucleation in the presence of carbon fibres: induction time approach

    Directory of Open Access Journals (Sweden)

    ANITA GROZDANOV

    2002-12-01

    Full Text Available Crystallization and nucleation behavior in model composites based on iPP and differently sized carbon fibres have been analyzed in this work. The investigations were performed in the isothermal regime (120–127°C using PLM and DSC. The results were analyzed by applying the Avrami and Muchova-Lednicky methods. It was shown that the carbon fibre surface acts as a nucleating agent during the crystallization of the iPP matrix. The highest effect was obtained with the fibres of PP-compatible size (C-T related to unsized carbon fibres (C-U. The induction time,ti, and half-time of crystallization decreased with increasing carbon fibre content. The energy effect on the thickness of the critical nucleus decreased in the presence of C-fibres, a fact confirmed by a decrease in the nucleation parameter Q and the difference energy parameter Ds(Q decreased from – 4.96 for iPP to –21.32 for C/iPP model composites, and Ds decreased from 6.14×10-7 J/cm2for iPP to 1.63×10-7 J/cm2for model composites. The results of the model composites and their comparison with published data confirmed that the Muchova-Lednicky method could be successfully applied for the quantitative evaluation of the nucleation parameters not only in the temperature range previously suggested (130 – 138°C, but also at lower crystallization temperatures (Tc = 121–127°C.

  12. Shielding effectiveness of non-woven carbon fibre sheets

    OpenAIRE

    Dawson, John F.; Flintoft, Ian Dand; Austin, A. N.; Marvin, Andrew C.

    2016-01-01

    This paper describes work undertaken to understand how the structure of a nonwoven carbon fibre material determines its shielding effectiveness, including the effects of fibre orientation, and contact resistance. In order to facilitate understanding of the material behaviour, software has been written to generate Monte Carlo Models (MCMs) of the material structure. The results of our MCMs are compared with measurements and some empirical expressions.

  13. Investigation of crack paths in natural fibre-reinforced composites

    Directory of Open Access Journals (Sweden)

    S. Keck

    2015-10-01

    Full Text Available Nowadays, fibre-reinforced composite materials are widely used in many fields, e.g. automotive and aerospace. Natural fibres such as flax and hemp provide good density specific mechanical properties. Additionally, the embodied production energy in natural fibres is much smaller than in synthetic ones. Within this paper the fracture mechanical behaviour of flax fibre-reinforced composites is discussed. Especially, this paper focuses on the determination and investigation of crack paths in compact tension specimens with three different fibre directions under a static as well as fatigue load. Differences and similarities in the obtained crack paths under different loading conditions are presented. Due to the pronounced orthotropic behaviour of those materials the crack path is not only governed by the stress state, but practically determined by the fibre direction and fibre volume fraction. Therefore, the well-known stress intensity factor solutions for the standard specimens are not applicable. It is necessary to carry out extensive numerical simulations to evaluate the stress intensity factor evolution along the growing crack in order to be able to determine fatigue crack growth rate curves. Those numerical crack growth simulations are performed with the three-dimensional crack simulation program ADAPCRACK3D to gain energy release rates and in addition stress intensity factors

  14. Influence of an Optimized Fibre Coating on Interfacial and Mechanical Properties of Glass Fibre/Polypropylene Composites

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The influence of pretreatment of fibre on interfacial and mechanical properties of glass fibre/polypropylene composites was investigated. Firstly, the glass fibres were coated with the blends of m-IPP (maleic anhydride grafting isotatic polypropylene) and m-APP (maleic anhydride grafting amorphous polypropylene) in different ratios.Secondly, the interfacial reaction of the coated composites was analysed by FTIR, which shows that the interfacial chemical reaction between m-IPP/m-APP in the fibre coating and the fibre surface-bound coupling agent is in existence.Thirdly, the microstructure of the coated composites was studied by SEM. The results indicate that the coating treatment is effective on improving interfacial adhesion of the fibre-matrix and the right amount of m-APP added to the coat impels the plastic deformation surrounding the point of cracks, which makes cracks turn to region and prevents from further interface debonding. Lastly, the mechanical properties were evaluated by measurement of the flexural strength and impact strength of the composites. It was found that the flexural strength and impact strength of the composites with coating fibre are higher than those of uncoating fibre composite. The results of these investigations draw the conclusion that the pretreatment of fibre with m-IPP/m-APP blends can form an optimize interlayer between the fibre and the PP matrix, which improves both the strength and toughness of the composites.

  15. Thermal recycling and re-manufacturing of glass fibre thermosetting composites

    DEFF Research Database (Denmark)

    Fraisse, Anthony; Beauson, Justine; Brøndsted, Povl

    2016-01-01

    The impact of using thermally recycled glass fibre in re-manufactured composites was investigated. A unidirectional glass fibre thermosetting composite laminate was manufactured. The matrix in one part of the laminate was burnt off to recover the glass fibres. These recycled glass fibres were used...... to manufacture a new composite laminate with the same fibre architecture as the pristine one. The fibres, the matrix and the composite laminates were thoroughly characterised and analysed. The results show that good materials quality was obtained for both laminates. A difference in fibre packing behaviour...... was observed in the composites with the pristine and the recycled fibres, which lead to a lower fibre volume fraction in the latter one. The Young's modulus of the composites was not changed by the recycling process, if the lower fibre volume fraction is taken into account. However, a marked drop...

  16. Self Healing Fibre-reinforced Polymer Composites: an Overview

    Science.gov (United States)

    Bond, Ian P.; Trask, Richard S.; Williams, Hugo R.; Williams, Gareth J.

    Lightweight, high-strength, high-stiffness fibre-reinforced polymer composite materials are leading contenders as component materials to improve the efficiency and sustainability of many forms of transport. For example, their widespread use is critical to the success of advanced engineering applications, such as the Boeing 787 and Airbus A380. Such materials typically comprise complex architectures of fine fibrous reinforcement e.g. carbon or glass, dispersed within a bulk polymer matrix, e.g. epoxy. This can provide exceptionally strong, stiff, and lightweight materials which are inherently anisotropic, as the fibres are usually arranged at a multitude of predetermined angles within discrete stacked 2D layers. The direction orthogonal to the 2D layers is usually without reinforcement to avoid compromising in-plane performance, which results in a vulnerability to damage in the polymer matrix caused by out-of-plane loading, i.e. impact. Their inability to plastically deform leaves only energy absorption via damage creation. This damage often manifests itself internally within the material as intra-ply matrix cracks and inter-ply delaminations, and can thus be difficult to detect visually. Since relatively minor damage can lead to a significant reduction in strength, stiffness and stability, there has been some reticence by designers for their use in safety critical applications, and the adoption of a `no growth' approach (i.e. damage propagation from a defect constitutes failure) is now the mindset of the composites industry. This has led to excessively heavy components, shackling of innovative design, and a need for frequent inspection during service (Richardson 1996; Abrate 1998).

  17. Solution electrospinning of particle-composite fibres

    DEFF Research Database (Denmark)

    Christiansen, Lasse; Fojan, Peter

    2016-01-01

    Electrospinning is a simple and fast way to produce nano- and microfibers. By applying high voltage to a droplet of solution or polymer melt, fibre mats can be produced. These mats are porous in the micrometre domain, and have a high surface area to volume ratio.......Electrospinning is a simple and fast way to produce nano- and microfibers. By applying high voltage to a droplet of solution or polymer melt, fibre mats can be produced. These mats are porous in the micrometre domain, and have a high surface area to volume ratio....

  18. Biodegradable composites based on L-polylactide and jute fibres

    DEFF Research Database (Denmark)

    Plackett, David; Løgstrup Andersen, T.; Batsberg Pedersen, W.;

    2003-01-01

    in the 180-220 degreesC range were significantly higher than those of polylactide alone. Composite samples failed in a brittle fashion under tensile load and showed little sign of fibre pull-out. Examination of composite fracture surfaces using electron microscopy showed voids occurring between the jute...

  19. Development of Diamond-like Carbon Fibre Wheel

    Institute of Scientific and Technical Information of China (English)

    魏源迁; 山口勝美; 洞口巌; 竹内雅之

    2004-01-01

    A unique diamond-like carbon (DLC) grinding wheel was developed, in which the DLC fibres were made by rolling Al sheets coated with DLC films and aligned normally to the grinding wheel surface by laminating Al sheets together with DLC fibres. In this paper, the formation process of DLC fibres and the fabrication process of a DLC fibre wheel were investigated. Many grinding experiments were also carried out on a precision NC plane milling machine using a newly developed DLC wheel. Grinding of specimens of silicon wafers, optical glasses, quartz, granites and hardened die steel SKD11 demonstrated the capabilities of nanometer surface finish. A smooth surface with a roughness value of Ra2.5nm (Ry26nm) was achieved.

  20. Dynamic fracture behaviour in fibre-reinforced cementitious composites

    Science.gov (United States)

    Yu, Rena C.; Cifuentes, Héctor; Rivero, Ignacio; Ruiz, Gonzalo; Zhang, Xiaoxin

    2016-08-01

    The object of this work is to simulate the dynamic fracture propagation in fibre-reinforced cementitious composites, in particular, in steel fibre reinforced concrete (SFRC). Beams loaded in a three-point bend configuration through a drop-weight impact device are considered. A single cohesive crack is assumed to propagate at the middle section; the opening of this crack is governed by a rate-dependent cohesive law; the fibres around the fracture plane are explicitly represented through truss elements. The fibre pull-out behaviour is depicted by an equivalent constitutive law, which is obtained from an analytical load-slip curve. The obtained load-displacement curves and crack propagation velocities are compared with their experimental counterparts. The good agreement with experimental data testifies to the feasibility of the proposed methodology and paves the way to its application in a multi-scale framework.

  1. Myosin heavy-chain isoform distribution, fibre-type composition and fibre size in skeletal muscle of patients on haemodialysis

    DEFF Research Database (Denmark)

    Molsted, Stig; Eidemak, Inge; Sorensen, Helle Tauby;

    2007-01-01

    Objective. Chronic uraemia is associated with abnormalities in skeletal muscles, which can affect their working capacity. It is also well known that the fibre-type composition of skeletal muscles influences endurance, muscle strength and power. In this study we therefore determined the size...... and distribution of muscle fibres and the myosin heavy-chain (MHC) isoform composition in patiens on haemodialysis (HD) in order to establish any differences with values for untrained control subjects. Material and methods. Muscle biopsies were obtained from the vastus lateralis muscle of 14 non-diabetic patients...... determined fibre-type composition of the vastus lateralis muscle. The mean fibre area of type 1 and 2 fibres was 3283±873 and 3594±1483 µm2, respectively. The MHC composition and the size of the type 1 fibres of the patients on HD were significantly different from those of the control subjects. Conclusions...

  2. Cavitation instabilities between fibres in a metal matrix composite

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2016-01-01

    Short fibre reinforced metal matrix composites (MMC) are studied here to investigate the possibility that a cavitation instability can develop in the metal matrix. The high stress levels needed for a cavitation instability may occur in metal–ceramic systems due to the constraint on plastic flow...... of transversely staggered fibres is here modelled by using an axisymmetric cell model analysis. First the critical stress level is determined for a cavitation instability in an infinite solid made of the Al matrix material. By studying composites with different distributions and aspect ratios of the fibres...... induced by bonding to the ceramics that only show elastic deformation. In an MMC the stress state in the metal matrix is highly non-uniform, varying between regions where shear stresses are dominant and regions where hydrostatic tension is strong. An Al–SiC whisker composite with a periodic pattern...

  3. Tribological properties of Al 7075 alloy based composites strengthened with Al2O3 fibres

    Directory of Open Access Journals (Sweden)

    K. Naplocha

    2011-04-01

    Full Text Available Wear resistance of 7075 aluminium alloy based composite materials reinforced with Al2O3 Saffil fibres was investigated. The measurementsof wear were performed applying the pin-on-disc method at dry friction conditions with the gray iron counterpart. The effects ofpressure of composite samples on the counterpart made of gray iron and the orientation of fibers in relation to the friction surface on wear rate were determined. The materials were produced by squeeze casting method where 80-90% porous ceramic preform were infiltrated.After T6 heat treatment hardness increased about 50-60% both for unreinforced alloy and composites containing strengthening Saffilfibres. Wear resistance of composite materials in relation to the unreinforced 7075 alloy was slightly worse at lower pressure of 0.8 MPa. Under higher pressure of 1.2 MPa wear resistance of unreinforced 7075 alloy was even better whereas no effect of orientation of fibers on wear in composite materials was observed. Additionally, significant wear of counterface in the presence of debris with fragmented Al2O3 fibres as abrasives was observed. Wear resistance improvement of composite materials was obtained when with alumina Saffil fibres Carbon C fibres in the preforms were applied.

  4. THERMOMECHANICAL PROPERTIES OF JUTE/BAGASSE HYBRID FIBRE REINFORCED EPOXY THERMOSET COMPOSITES

    Directory of Open Access Journals (Sweden)

    Sudhir Kumar Saw

    2009-11-01

    Full Text Available Natural fibres are partly replacing currently used synthetic fibres as reinforcement for polymer composites. Jute fibre bundles were high-cellulose-content modified by alkali treatment, while the bagasse fibre bundles were modified by creating quinones in the lignin portions of fibre surfaces and reacting them with furfuryl alcohol (FA to increase their adhesiveness. The effects of different fibre bundle loading and modification of bagasse fibre surfaces in hybrid fibre reinforced epoxy composites have been studied. The role of fibre/matrix interactions in chemically modified hybrid composites were investigated using Differential Scanning Calorimeter, Differential Thermo Gravimetry, and a Universal Tensile Machine and compared with those of unmodified bagasse fibre bundles incorporated with modified jute fibre bundles reinforced hybrid composites. Fibre surface modification reduced the hydrophilicity of fibre bundles, and significantly increased mechanical properties of hybrid composites were observed in conjunction with SEM images. The SEM analysis of the fibre and the composite fractured surfaces have confirmed the FA grafting and shown a better compatibility at the interface between chemically modified fibre bundles and epoxy resin. This paper incorporates interesting results of thermomechanical properties and evaluation of fibre/matrix interactions.

  5. Study on Effect of Thickness and Fibre Orientation on a Tensile and Flexural Properties of a Hybrid Composite

    Directory of Open Access Journals (Sweden)

    Mr. Santhosh Kumar. M

    2014-08-01

    Full Text Available This project presents the study of tensile, flexural & moisture absorption properties of composites made from S-glass, Carbon and E-glass fibre. The specimens are prepared using hand lay-up techniques as per ASTM standard for different thickness 2mm and 3mm and fibre orientation of 30º, 45º and 60º, where an attempt is made to study the properties of composite materials by composing the different materials together to obtain the desired properties by increasing the thickness and fibre orientation. By the variation of thickness tensile strength of hybrid composite is observed for each thickness and is compared with the finite element analysis results. The test ready specimens were subjected to tensile and flexural loads on UTM. This research indicates that tensile strength is mainly dependent on the fiber orientation & thickness of laminated polymer composites. The moisture absorption increases with the fibre, filler content and duration of immersion in water.

  6. Effects of hybrid composition of LCP and glass fibres on abrasive wear of reinforced LLDPE

    Indian Academy of Sciences (India)

    S A R Hashmi; Ajay Naik; Navin Chand

    2006-02-01

    The hybrid of liquid crystalline polymer (LCP) fibres and glass fibres (GF) provide a combination of modulus and toughness to semi-crystalline linear-low-density-polyethylene (LLDPE). LCP and GF fibres reinforced composites were studied using two-body abrasion tester under different applied loads. Two sets of fibre reinforced LLDPE, 10 and 20 vol%, were investigated. The contents of LCP and glass fibres were varied as 25, 50, 75 and 100 vol% of overall volume of fibres in LLDPE. The effect of replacing glass fibre with LCP fibre on wear is reported. Wear loss increased with the applied loads and glass fibre contents in LLDPE. The replacements of glass fibres with LCP fibres improved abrasive wear resistance of composite. The composite containing 20 vol% of glass fibres in LLDPE showed the specific wear rate nearly double to that of LCP fibre reinforced LLDPE. Incorporation of LCP fibre improved wear resistance of glass fibre reinforced LLDPE. Worn surfaces were studied using SEM. Glass fibres were broken in small debris and removed easily whereas LCP fibres yielded to fibrillation during abrasive action. The overall wear rate was governed by the composition and test conditions.

  7. STRAIN HARDENING PROPERTIES OF STEEL FIBRE REINFORCED LATEX CONCRETE COMPOSITE

    Directory of Open Access Journals (Sweden)

    V.M. Sounthararajan

    2013-04-01

    Full Text Available Steel fibre addition in concrete possesses high merits in terms of achieving homogeneity and tensile strength properties. Polymeric addition in concrete has high advantages in terms of pore fillingeffect and subsequent increase in durability index. The combined addition of steel and polymeric latex additions in concrete leads to increased strength, durability, toughness, resistance to cracking and crack propagation. Studies were conducted in the present study to analyse the properties of concrete that can be further improved with the addition of polymer styrene butadiene rubber emulsion (SBR along with steel fibres. In this research analysis, styrene-butadiene rubber (SBR latex as a polymeric admixture was used in steel fibre reinforced concrete. The effect of curing conditions on the strength gain properties of composite steel fibre latex matrix on the compressive, flexural strength, and split tensile test of polymermodified steel fibre reinforced concrete (PSFC concrete was examined. Including SBR latex at a certain % of binder in the PSFC concrete improves the bonds within the cement matrix and steel fibres (SF. This is due to the SBR films formed in the matrix. By the comparison of properties of SFC and PSFC, it can be shown that a tremendous increase in compressive strength when 4% and 8% SBR is added along with 0.75% and 1.5% SF. The increase in flexural strength was noticed and post cracking ductility is imparted to concrete.

  8. Effect of alkali treated jute fibres on composite properties

    Indian Academy of Sciences (India)

    Dipa Ray; B K Sarkar; A K Rana; N R Bose

    2001-04-01

    Jute fibres were subjected to a 5% alkali (NaOH) solution treatment for 0, 2, 4, 6 and 8 h at 30°C. An improvement in the crystallinity in the jute fibres increased its modulus by 12%, 68% and 79% after 4, 6 and 8 h of treatment respectively. The tenacity of the fibres improved by 46% after 6 and 8 h treatment and the % breaking strain was reduced by 23% after 8 h treatment. For the 35% composites with 4 h treated fibres, the flexural strength improved from 199.1 MPa to 238.9 MPa by 20%, modulus improved from 11.89 GPa to 14.69 GPa by 23% and laminar shear strength increased from 0.238 MPa to 0.2834 MPa by 19%. On plotting the different values of slopes obtained from the rates of improvement of the flexural strength and modulus, against the NaOH treatment time, two different failure modes were apparent before and after 4 h of treatment. In the first region between 0 and 4 h, fibre pull out was predominant whereas in the second region between 6 and 8 h, transverse fracture occurred with a minimum fibre pull out. This observation was well supported by the SEM investigations of the fracture surfaces.

  9. ESTIMATING FIBRE DIRECTION DISTRIBUTIONS OF REINFORCED COMPOSITES FROM TOMOGRAPHIC IMAGES

    Directory of Open Access Journals (Sweden)

    Oliver Wirjadi

    2016-12-01

    Full Text Available Fibre reinforced composites constitute a relevant class of materials used chiefly in lightweight constructions for example in fuselages or car bodies. The spatial arrangement of the fibres and in particular their direction distribution have huge impact on macroscopic properties and, thus, its determination is an important topic of material characterisation. The fibre direction distribution is defined on the unit sphere, and it is therefore preferable to work with fully three-dimensional images of the microstructure as obtained, e.g., by computed micro-tomography. A number of recent image analysis algorithms exploit local grey value variations to estimate a preferred direction in each fibre point. Averaging these local results leads estimates of the volume-weighted fibre direction distribution. We show how the thus derived fibre direction distribution is related to quantities commonly used in engineering applications. Furthermore, we discuss four algorithms for local orientation analysis, namely those based on the response of anisotropic Gaussian filters, moments and axes of inertia derived from directed distance transforms, the structure tensor, or the Hessian matrix. Finally, the feasibility of these algorithms is demonstrated for application examples and some advantages and disadvantages of the underlying methods are pointed out.

  10. Fibre reinforced polymer nanocomposites

    NARCIS (Netherlands)

    Vlasveld, D.P.N.

    2005-01-01

    In this thesis the results are described of the research on a combination of two types of composites: thermoplastic nanocomposites and continuous fibre composites. In this three-phase composite the main reinforcing phase are continuous glass or carbon fibres, and the matrix consists of a polyamide 6

  11. CHLORINE DIOXIDE TREATMENT OF SISAL FIBRE: SURFACE LIGNIN AND ITS INFLUENCES ON FIBRE SURFACE CHARACTERISTICS AND INTERFACIAL BEHAVIOUR OF SISAL FIBRE/PHENOLIC RESIN COMPOSITES

    Directory of Open Access Journals (Sweden)

    Linxin Zhong

    2010-11-01

    Full Text Available This paper describes an investigation of the influences of chlorine dioxide treatment on fibre surface lignin. The fibre surface characteristics and the interfacial behaviour of the sisal fibre/phenolic resin composites were also studied by SEM, AFM, and XPS. The results show that the surface of the untreated fibre contains a large amount of lignin with granular structure and non-granular structure. The surface lignin concentration is up to 51% for the untreated fibre, and then it decreases to 24% and 20% for fibres treated with 1.5 % and 2.0% chlorine dioxide, respectively. The removal of lignin from the fibre surface can enhance the interfacial strength of the composites, giving rise to increases by 36% and 28% in tensile strength and internal bonding strength. These results indicate that the surface properties of single sisal fibres can be tailored to improve the fibre/resin interface. Chlorine dioxide treatment has potential for surface modification of sisal fibre in engineering the interfacial behaviour of composites.

  12. Thermal Conductivity of Structural Glass/Fibre Epoxy Composite as a Function of Fibre Orientation

    CERN Document Server

    Cugnet, D; Kuijper, A; Parma, Vittorio; Vandoni, Giovanna

    2002-01-01

    The LHC, the new superconducting particle accelerator presently under construction at CERN, makes use of some 1200 dipole magnets for orbit bending and 500 quadrupole magnets for focusing/defocusing of the circulating high-energy proton beams. Two or three column-type support posts sustain each cryomagnet. The choice of a convenient material for these supports is critical, because of the required high positioning accuracy of the magnets in their cryostats and stringent thermal budget requirements imposed by the LHC cryogenic system. A glass-fibre/epoxy resin composite has been chosen for its good combination of high stiffness and low thermal conductivity over the 2-293 K temperature range. Plies of long glass-fibres are stacked optimally yielding the best mechanical behaviour. However, heat leaks from the supports are influenced by the thermal characteristics of the composite, which in turn depend on the orientation of the fibres. To study the dependence of the thermal conductivity on fibre's orientation, we ...

  13. The electro-structural behaviour of yarn-like carbon nanotube fibres immersed in organic liquids

    Science.gov (United States)

    Terrones, Jeronimo; Windle, Alan H.; Elliott, James A.

    2014-10-01

    Yarn-like carbon nanotube (CNT) fibres are a hierarchically-structured material with a variety of promising applications such as high performance composites, sensors and actuators, smart textiles, and energy storage and transmission. However, in order to fully realize these possibilities, a more detailed understanding of their interactions with the environment is required. In this work, we describe a simplified representation of the hierarchical structure of the fibres from which several mathematical models are constructed to explain electro-structural interactions of fibres with organic liquids. A balance between the elastic and surface energies of the CNT bundle network in different media allows the determination of the maximum lengths that open junctions can sustain before collapsing to minimize the surface energy. This characteristic length correlates well with the increase of fibre resistance upon immersion in organic liquids. We also study the effect of charge accumulation in open interbundle junctions and derive expressions to describe experimental data on the non-ohmic electrical behaviour of fibres immersed in polar liquids. Our analyses suggest that the non-ohmic behaviour is caused by progressively shorter junctions collapsing as the voltage is increased. Since our models are not based on any property unique to carbon nanotubes, they should also be useful to describe other hierarchical structures.

  14. Further development of the tungsten-fibre reinforced tungsten composite

    Energy Technology Data Exchange (ETDEWEB)

    Gietl, Hanns; Hoeschen, Till; Riesch, Johann [Max-Planck-Institut fuer Plasmaphysik, 85748 Garching (Germany); Aumann, Martin; Coenen, Jan [Forschungszentrum Juelich, IEK4, 52425 Juelich (Germany); Huber, Philipp [Lehrstuhl fuer Textilmaschinenbau und Institut fuer Textiltechnik (ITA), 52062 Aachen (Germany); Neu, Rudolf [Max-Planck-Institut fuer Plasmaphysik, 85748 Garching (Germany); Technische Universitaet Muenchen, 85748 Garching (Germany)

    2016-07-01

    For the use in a fusion device tungsten has a unique property combination. The brittleness below the ductile-to-brittle transition temperature and the embrittlement during operation e.g. by overheating, neutron irradiation are the main drawbacks for the use of pure tungsten. Tungsten fibre-reinforced tungsten composites utilize extrinsic mechanisms to improve the toughness. After proofing that this idea works in principle the next step is the conceptual proof for the applicability in fusion reactors. This will be done by producing mock-ups and testing them in cyclic high heat load tests. For this step all constituents of the composite, which are fibre, matrix and interface, and all process steps need to be investigated. Tungsten fibres are investigated by means of tension tests to find the optimum diameter and pretreatment. New interface concepts are investigated to meet the requirements in a fusion reactor, e.g. high thermal conductivity, low activation. In addition weaving processes are evaluated for their use in the fibre preform production. This development is accompanied by an extensive investigation of the materials properties e.g. single fibre tension tests.

  15. Ductile Cement-Based Composites with Wood Fibres - material design and experimental approach

    NARCIS (Netherlands)

    Sierra-Beltran, M.G.

    2011-01-01

    In order to turn a brittle cement matrix into a ductile composite different types of man-made fibres such as steel, glass and polyvinyl alcohol are currently used as reinforcement, as well as some natural fibres. Compared to synthetic fibres, natural fibres are more easily available worldwide and th

  16. Optimum Design of Steered Fibre Composite Cylinders with Arbitrary Cross-sections

    NARCIS (Netherlands)

    Khani, A.

    2013-01-01

    Automated fibre placement (AFP) machines are able to place simultaneously several bundles of fibres, called tows, on a surface. Using AFP machines, it is also possible to manufacture composite laminates with fibres placed in curvilinear paths. The fibre orientations and stiffness properties of these

  17. COMMERCIAL VIABILITY ANALYSIS OF LIGNIN BASED CARBON FIBRE

    OpenAIRE

    2014-01-01

    Lignin is a rich renewable source of aromatic compounds. As a potentialpetroleum feedstock replacement, lignin can reduce environmental impacts such ascarbon emission. Due to its complex chemical structure, lignin is currently underutilized.Exploiting lignin as a precursor for carbon fibre adds high economic value to lignin andencourages further development in lignin extraction technology. This report includes apreliminary cost analysis and identifies the key aspects of lignin-based carbon fi...

  18. FibreChain: characterization and modeling of thermoplastic composites processing

    NARCIS (Netherlands)

    Rietman, A.D.; Niazi, M.S.; Akkerman, R.; Lomov, S.V.

    2013-01-01

    Thermoplastic composites feature the advantage of melting and shaping. The material properties during processing and the final product properties are to a large extent determined by the thermal history of the material. The approach in the FP7-project FibreChain for process chain modeling of thermopl

  19. Comparison of traditional field retting and Phlebia radiata Cel 26 retting of hemp fibres for fibre-reinforced composites.

    Science.gov (United States)

    Liu, Ming; Ale, Marcel T; Kołaczkowski, Bartłomiej; Fernando, Dinesh; Daniel, Geoffrey; Meyer, Anne S; Thygesen, Anders

    2017-12-01

    Classical field retting and controlled fungal retting of hemp using Phlebia radiata Cel 26 (a mutant with low cellulose degrading ability) were compared with pure pectinase treatment with regard to mechanical properties of the produced fibre/epoxy composites. For field retting a classification of the microbial evolution (by gene sequencing) and enzyme profiles were conducted. By phylogenetic frequency mapping, different types of fungi, many belonging to the Ascomycota phylum were found on the fibres during the first 2 weeks of field retting, and thereafter, different types of bacteria, notably Proteobacteria, also proliferated on the field retted fibres. Extracts from field retted fibres exhibited high glucanase activities, while extracts from P. radiata Cel 26 retted fibres showed high polygalacturonase and laccase activities. As a result, fungal retting gave a significantly higher glucan content in the fibres than field retting (77 vs. 67%) and caused a higher removal of pectin as indicated by lower galacturonan content of fibres (1.6%) after fibres were retted for 20 days with P. radiata Cel 26 compared to a galacturonan content of 3.6% for field retted fibres. Effective fibre stiffness increased slightly after retting with P. radiata Cel 26 from 65 to 67 GPa, while it decreased after field retting to 52 GPa. Effective fibre strength could not be determined similarly due to variations in fibre fracture strain and fibre-matrix adhesion. A maximum composite strength with 50 vol% fibres of 307 MPa was obtained using P. radiata Cel 26 compared to 248 MPa with field retting.

  20. The Compressive Strength of Carbon Fibre Reinforced Plastics.

    Science.gov (United States)

    1982-08-01

    and resin properties . Therefore, throughout this Report the term compressive failure will imply a microbuckling failure mode. A microbuckling failure...Compressive strength of fibre reinforced composite materials. ASTM STP 580, pp 364-377 (1975) 16 D.B.S. Berry Handbook of resin properties . Part A - cast

  1. Influence of fibre-surface treatment on structural, thermal and mechanical properties of jute fibre and its composite

    Indian Academy of Sciences (India)

    E Sinha; S K Rout

    2009-02-01

    Jute fibres (Corchorus olitorious), an environmentally and ecologically friendly product, were chemically modified and treated with 5% NaOH solution at room temperature for 2 h, 4 h and 8 h. The above samples were characterized and morphologically analysed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT–IR), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Instron 1185. Alkali treatment affects the supramolecular structure of the fibre as shown by XRD by improving the degree of crystallinity of the fibre. Surface chemistry of the fibre also altered as depicted by FT–IR studies. This chemical treatment was also found to alter the characteristic of the fibre surface topography as seen by the SEM. From the mechanical single fibre test it was found that the tenacity and modulus of the fibre improved after alkali treatment. This might be due to the improvement in the crystallinity. DSC data demonstrated that the thermal degradation temperature for the cellulose get lowered from 365.26°C to 360.62°C after alkali treatment led to the reduction in fibre thermal stability. Jute fibre reinforced composite were prepared with treated and untreated jute fibre (15 wt%) reinforced unsaturated polyester (UPE). Effectiveness of these composites was experimentally investigated through the study of the composites by DSC, Instron 1195 for mechanical property of composites, volume fraction of the porosity and hydrophobic finishing of the composite. From the DSC analysis it was found that thermal stability enhanced for treated fibre reinforced composite. This could be due to the resistance offered by the closely packed cellulose chain in combination with the resin. Flexural strength of the composite prepared with 2 h and 4 h alkali treated fibre were found to increase by 3.16% and 9.5%, respectively. Although 8 h treated fibre exhibited maximum strength properties, but the composite prepared with them showed lower strength

  2. Use of Macro Fibre Composite Transducers as Acoustic Emission Sensors

    Directory of Open Access Journals (Sweden)

    Mark Eaton

    2009-04-01

    Full Text Available The need for ever lighter and more efficient aerospace structures and components has led to continuous optimization pushing the limits of structural performance. In order to ensure continued safe operation during long term service it is desirable to develop a structural health monitoring (SHM system. Acoustic emission (AE offers great potential for real time global monitoring of aerospace structures, however currently available commercial sensors have limitations in size, weight and adaptability to complex structures. This work investigates the potential use of macro-fibre composite (MFC film transducers as AE sensors. Due to the inhomogeneous make-up of MFC transducers their directional dependency was examined and found to have limited effect on signal feature data. However, signal cross-correlations revealed a strong directional dependency. The sensitivity and signal attenuation with distance of MFC sensors were compared with those of commercially available sensors. Although noticeably less sensitive than the commercial sensors, the MFC sensors still had an acceptable operating range. Furthermore, a series of compressive carbon fiber coupon tests were monitored in parallel using both an MFC sensor and a commercially available sensor for comparison. The results showed good agreement of AE trends recorded by both sensors.

  3. Lamb wave detection in prepreg composite materials with fibre Bragg grating sensors

    OpenAIRE

    Miesen. N.; Mizutani, Y; Groves, R.M.; Sinke, J.; Benedictus, R.

    2011-01-01

    This paper demonstrates that existing Structural Health Monitoring (SHM) techniques have potential during the production phase in addition to their application for maintenance and for in-flight monitoring. Flaws occur during composite fabrication in industry, due to an imperfect process control and human errors. This decreases production efficiency and increases costs. In this paper, the monitoring of Lamb waves in unidirectional carbon fibre (UD-CFRP) prepreg material is demonstrated using b...

  4. Effect of fibre shape on transverse thermal conductivity of unidirectional composites

    Indian Academy of Sciences (India)

    B Raghava Rao; V Ramachandra Raju; K Mohana Rao

    2015-04-01

    The determination of thermal conductivities of a composite lamina is of paramount importance in the effective design and application of composite materials. The thermal conductivity of a lamina along the fibre direction can be easily estimated from the Rule of Mixtures but, the thermal conductivity in the transverse direction which depends on many factors need to be determined effectively. The transverse thermal conductivities of continuous fibre reinforced composite lamina are computed by numerical method using finite element analysis. Different fibre concentrations, fibre shapes and different fibre-matrix combinations are examined. A Regular array of square pattern of fibres is considered. The finite element model is validated with the available experimental results and theoretical models for a circular fibre and then extended to other shapes of fibres. Two-dimensional finite element model is adopted for the analysis, due to the restriction of heat flow only in transverse direction and the fibres are assumed to be continuous and perfectly bonded to the matrix. Analysis is carried out for a wide range of fibre-matrix combinations and up to the maximum fibre concentration in the composite. The analysis is extended for circular, square, elliptical and rhombus shaped fibres. From the results it is observed that there is a significant variation in the transverse thermal conductivity due to the shape of fibre, concentration ratios and fibre matrix combinations. This variation in thermal conductivity of a composite lamina results into a broader choice for the selection of composite materials in thermal applications.

  5. Evaluation of Defects in Multilayer Carbon Fibre Epoxy for Aeronautics Applications

    Directory of Open Access Journals (Sweden)

    M. Buonsanti

    2009-01-01

    Full Text Available Production of carbon fibre reinforced polymers is an elaborate process unfree from faults and problems. Problems during the manufacturing, such as plies' overlapping, can cause flaws in the resulting material, so compromising its integrity. Compared with metallic materials, carbon epoxy composites show a number of advantages. Within this framework, ultrasonic tests are effective to identify the presence of defects. In this paper a Finite Element Method approach is proposed for evaluating the most effective incidence angle of an ultrasonic probe with regard to defects' identification. According to our goal, the analysis has been carried out considering a single-line plane emitting source varying the probe angle of inclination. The proposed model looks promising to specially emphasize the presence of delaminations as well as massive breaking in a specimen of multilayer carbon fibre epoxy. Subsequently, simulation parameters and results have been exploited and compared, respectively, for a preliminary experimental in-lab campaign of measurements with encouraging results.

  6. Expansion of carbon fibres induced by lithium intercalation for structural electrode applications

    OpenAIRE

    Jacques, Eric; Kjell, Maria; Zenkert, Dan; Lindbergh, Göran; Behm, Mårten

    2013-01-01

    Carbon fibres (CFs) can work as lightweight structural electrodes in CF-reinforced composites able to store energy as lithium (Li)-ion batteries. The CF has high stiffness and strength-to-weight ratios and a carbonaceous microstructure which enables Li intercalation. An innovative in situ technique for studying the longitudinal expansion of the CF and the relationship with the amount of intercalated Li is described in the present paper. The polyacrylonitrile-based CFs, T800H and unsized IMS65...

  7. Properties of hemp fibre polymer composites - An optimisation of fibre properties using novel defibration methods and fibre characterisation

    DEFF Research Database (Denmark)

    Thygesen, Anders

    2006-01-01

    Characterization of hemp fibres was carried out with fibres obtained with low handling damage and defibration damage to get an indication of how strong cellulose based fibres that can be produced from hemp. Comparison was made with hemp yarn producedunder traditional conditions where damage...... obtained by steam explosion of hemp fibres prior defibrated with pectin degrading enzymes. The S2 layer in the fibre wall of the hemp fibres consisted of1-4 cellulose rich and lignin poor concentric layers constructed of ca. 100 nm thick lamellae. The microfibril angle showed values in the range 0......-10° for the main part of the S2-layer and 70-90° for the S1-layer. The microfibrils that are mainly parallelwith the fibre axis explain the high fibre stiffness, which in defibrated hemp fibres reached 94 GPa. The defibrated hemp fibres had higher fibre stiffness (88-94 GPa) than hemp yarn (60 GPa), which...

  8. Drilling analysis of coir–fibre-reinforced polyester composites

    Indian Academy of Sciences (India)

    S Jayabal; U Natarajan

    2011-12-01

    An investigation has been carried out to make use of coir, a natural fibre abundantly available in India. Coir–polyester composites were prepared and their mechanical and machinability characteristics were studied. The short coir–fibre-reinforced composites exhibited the tensile, flexural and impact strength of 16.1709 MPa, 29.2611 MPa and 46.1740 J/m, respectively. The regression equations were developed and optimized for studying drilling characteristics of coir–polyester composites using the Taguchi approach. A drill bit diameter of 6 mm, spindle speed of 600 rpm and feed rate of 0.3 mm/rev gave the minimum value of thrust force, torque and tool wear in drilling analysis.

  9. Composite Strain Hardening Properties of High Performance Hybrid Fibre Reinforced Concrete

    Directory of Open Access Journals (Sweden)

    Vikram Jothi Jayakumar

    2014-01-01

    Full Text Available Hybrid fibres addition in concrete proved to be a promising method to improve the composite mechanical properties of the cementitious system. Fibre combinations involving different fibre lengths and moduli were added in high strength slag based concrete to evaluate the strain hardening properties. Influence of hybrid fibres consisting of steel and polypropylene fibres added in slag based cementitious system (50% CRL was explored. Effects of hybrid fibre addition at optimum volume fraction of 2% of steel fibres and 0.5% of PP fibres (long and short steel fibre combinations were observed in improving the postcrack strength properties of concrete. Test results also indicated that the hybrid steel fibre additions in slag based concrete consisting of short steel and polypropylene (PP fibres exhibited a the highest compressive strength of 48.56 MPa. Comparative analysis on the performance of monofibre concrete consisting of steel and PP fibres had shown lower residual strength compared to hybrid fibre combinations. Hybrid fibres consisting of long steel-PP fibres potentially improved the absolute and residual toughness properties of concrete composite up to a maximum of 94.38% compared to monofibre concrete. In addition, the relative performance levels of different hybrid fibres in improving the matrix strain hardening, postcrack toughness, and residual strength capacity of slag based concretes were evaluated systematically.

  10. Monitoring Pre-Stressed Composites Using Optical Fibre Sensors

    Directory of Open Access Journals (Sweden)

    Sriram Krishnamurthy

    2016-05-01

    Full Text Available Residual stresses in fibre reinforced composites can give rise to a number of undesired effects such as loss of dimensional stability and premature fracture. Hence, there is significant merit in developing processing techniques to mitigate the development of residual stresses. However, tracking and quantifying the development of these fabrication-induced stresses in real-time using conventional non-destructive techniques is not straightforward. This article reports on the design and evaluation of a technique for manufacturing pre-stressed composite panels from unidirectional E-glass/epoxy prepregs. Here, the magnitude of the applied pre-stress was monitored using an integrated load-cell. The pre-stressing rig was based on a flat-bed design which enabled autoclave-based processing. A method was developed to end-tab the laminated prepregs prior to pre-stressing. The development of process-induced residual strain was monitored in-situ using embedded optical fibre sensors. Surface-mounted electrical resistance strain gauges were used to measure the strain when the composite was unloaded from the pre-stressing rig at room temperature. Four pre-stress levels were applied prior to processing the laminated preforms in an autoclave. The results showed that the application of a pre-stress of 108 MPa to a unidirectional [0]16 E-glass/913 epoxy preform, reduced the residual strain in the composite from −600 µε (conventional processing without pre-stress to approximately zero. A good correlation was observed between the data obtained from the surface-mounted electrical resistance strain gauge and the embedded optical fibre sensors. In addition to “neutralising” the residual stresses, superior axial orientation of the reinforcement can be obtained from pre-stressed composites. A subsequent publication will highlight the consequences of pres-stressing on fibre alignment, the tensile, flexural, compressive and fatigue performance of unidirectional E

  11. Properties of hemp fibre polymer composites - An optimisation of fibre properties using novel defibration methods and fibre characterisation

    OpenAIRE

    Thygesen, Anders

    2006-01-01

    Characterization of hemp fibres was carried out with fibres obtained with low handling damage and defibration damage to get an indication of how strong cellulose based fibres that can be produced from hemp. Comparison was made with hemp yarn producedunder traditional conditions where damage is unavoidable. The mild defibration was performed by degradation of the pectin and lignin rich middle lamellae around the fibres by cultivation of the mutated white rot fungus Phlebia radiata Cel 26. Fibr...

  12. Structure and properties of a pulp fibre-reinforced composite with regenerated cellulose matrix

    Science.gov (United States)

    Gindl, W.; Schöberl, T.; Keckes, J.

    2006-04-01

    Fully bio-based cellulose cellulose composites were produced by partly dissolving beech pulp fibres in lithium chloride/dimethylacetamide (LiCl/DMAc) and subsequent regeneration of matrix cellulose in the presence of undissolved fibres. Compared to cellulose epoxy composites produced from the same fibres, a two-fold increase in tensile strength and elastic modulus was observed for cellulose cellulose composites. From scanning electron microscopy and nanoindentation it is concluded that changes in the fibre cell wall during LiCl/DMAc treatment, improved matrix properties of regenerated cellulose compared to epoxy, and improved fibre matrix adhesion are responsible for the superior properties of cellulose cellulose composites.

  13. Modelling of polypropylene fibre-matrix composites using finite element analysis

    Directory of Open Access Journals (Sweden)

    2009-01-01

    Full Text Available Polypropylene (PP fibre-matrix composites previously prepared and studied experimentally were modelled using finite element analysis (FEA in this work. FEA confirmed that fibre content and composition controlled stress distribution in all-PP composites. The stress concentration at the fibre-matrix interface became greater with less fibre content. Variations in fibre composition were more significant in higher stress regions of the composites. When fibre modulus increased, the stress concentration at the fibres decreased and the shear stress at the fibre-matrix interface became more intense. The ratio between matrix modulus and fibre modulus was important, as was the interfacial stress in reducing premature interfacial failure and increasing mechanical properties. The model demonstrated that with low fibre concentration, there were insufficient fibres to distribute the applied stress. Under these conditions the matrix yielded when the applied stress reached the matrix yield stress, resulting in increased fibre axial stress. When the fibre content was high, there was matrix depletion and stress transfer was inefficient. The predictions of the FEA model were consistent with experimental and published data.

  14. Mechanical and electrical performance of Roystonea regia/glass fibre reinforced epoxy hybrid composites

    Indian Academy of Sciences (India)

    Govardhan Goud; R N Rao

    2012-08-01

    The present paper investigates mechanical and electrical properties of Roystonea regia/glass fibre reinforced epoxy hybrid composites. Five varieties of hybrid composites have been prepared by varying the glass fibre loading. Roystonea regia (royal palm), a natural fibre was collected from the foliage of locally available royal palm tree through the process of water retting and mechanical extraction. Roystonea regia, -glass short fibres were used together as reinforcement in epoxy matrix to form hybrid composites. It has been observed that tensile, flexural, impact and hardness properties of hybrid composites considerably increased with increase in glass fibre loading. But electrical conductivity and dielectric constant values decreased with increase in glass fibre content in the hybrid composites at all frequencies. Scanning electron microscopy of fractured hybrid composites has been carried out to study the fibre matrix adhesion.

  15. Preparation of silicon nitride/carbon fibre/epoxy resin composites%氮化硅/碳纤维/环氧树脂复合材料的制备研究

    Institute of Scientific and Technical Information of China (English)

    王明明; 张炜巍

    2013-01-01

    The silicon nitride (Si3N4) microparticles before and after modification were employed to prepare Si3N4/carbon fibre/epoxy resin (Si3N4/CF/EP) composite via high temperature molding press method.The effects of the mass fraction and surface modification of Si3N4 on the thermal conductivity,electrical properties and mechanical properties of the composite were investigated.The results showed that for the Si3N4/CF/EP composite its thermal conductivity increased with increasing the mass fraction of Si3N4,and the thermal conductivity was 1.02 W/mK when the mass fraction of Si3N4 was 40%.The electrical properties of the composite decrease linearly with increasing the mass fraction of Si3N4.The mechanical properties of the composite increased firstly and then decreased with adding of Si3N4.The thermal conductivity and mechanical properties of the composite were further improved after the modification of Si3N4.%采用高温模压成型法制备氮化硅/碳纤维/环氧树脂导热复合材料(Si3N4/CF/EP).研究了Si3N4用量和表面改性对Si3N4/CF/EP复合材料导热性能、导电性能和力学性能的影响.结果表明,复合材料的导热性能随Si3N4质量分数的增加而增大,当Si3N4质量分数为40%时,导热率为1.02 W/mK;而Si3N4/CF/EP复合材料的导电率随Si3N4质量分数的增加而呈线性降低;力学性能则随Si3N4质量分数的增加先增大后降低.表面改性有助于进一步提高Si3N4/CF/EP复合材料的导热性能和力学性能.

  16. Composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

    1997-05-06

    Carbon aerogels used as a binder for granulated materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy. 1 fig.

  17. Composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Steven T. (San Leandro, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    1997-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivty and power to system energy.

  18. Effect of inter-laminar fibre orientation on the tensile properties of sisal fibre reinforced polyester composites

    Science.gov (United States)

    Senthilkumar, K.; Siva, I.; Winowlin Jappes, J. T.; Amico, S. C.; Cardona, F.; Sultan, M. T. H.

    2016-10-01

    In this present work, effects of interlamina fibre orientation on the tensile properties of composites were studied and the results were discussed. The varying types of fibre oriented composites were prepared using the compression moulding technique at a pressure of 17 MPa. The different types of oriented composites investigated were 90°/0 ° /90 °, 0 ° /90 ° /0 °, 90 ° /0 ° /0 ° /90 °, 0 ° /45 ° /0 °, 0 ° /90 ° /45 ° /45 ° /90 ° /0 °, 0 ° /45 ° /90 ° /90 ° /45 ° /0 ° and these composites were subjected to tensile testing according to ASTM: D3039-08. The sisal fibres were arranged in various angles with the help of specially designed mould. It was found that the tensile strength of sisal fibre composites improved when 0 ° oriented fibres were positioned at the extreme layers of the composites compared to 90 ° oriented fibres. The highest tensile strength among the types of composites was observed for 0 ° /90 ° /0 °. The scanning electron microscopy (SEM) analysis was performed to understand the interphase adhesion mechanism.

  19. Solution electrospinning of particle-polymer composite fibres

    DEFF Research Database (Denmark)

    Christiansen, Lasse; Fojan, Peter

    2016-01-01

    Electrospinning is a fast, simple way to produce nano/microfibers, resulting in porous mats with a high surface to volume ratio. Another material with high surface to volume ratio is aerogel. A drawback of aerogels is its inherent mechanical weakness. To counteract this, aerogels can be embedded......-supporting abilities of these fibres are discussed. It is concluded that selfsupporting polymer/aerogel composites can be made by electrospinning....

  20. Natural composites: Strength, packing ability and moisture sorption of cellulose fibres, and the related performance of composites

    DEFF Research Database (Denmark)

    Lilholt, Hans; Madsen, Bo

    2012-01-01

    Biobased materials are becoming of increasing interest as potential structural materials for the future. A useful concept in this context is the fibre reinforcement of materials by stiff and strong fibres. The bio-resources can contribute with cellulose fibres and (bio) polymers from hemicellulos...... in stiffness, on the packing ability of cellulose fibres and the related maximum fibre volume fraction in composites, on the moisture sorption of cellulose fibres and the related mass increase and (large) hygral strains induced, and on the mechanical performance of composites....

  1. Modelling of volumetric composition and mechanical properties of unidirectional hemp/epoxy composites - Effect of enzymatic fibre treatment

    DEFF Research Database (Denmark)

    Liu, Ming; Thygesen, Anders; Meyer, Anne S.

    2016-01-01

    the changes in volumetric composition and mechanical properties of the composites when differently treated hemp fibres are used. The decrease in the fibre correlated porosity factor with the enzymatic fibre treatments shows that the removal of pectin by pectinolytic enzymes results in a better fibre......The objective of the present study is to assess the effect of enzymatic fibre treatments on the fibre performance in unidirectional hemp/epoxy composites by modelling the volumetric composition and mechanical properties of the composites. It is shown that the applied models can well predict...... efficiency exponent is set equal to 2. Altogether, it is demonstrated that the applied models provide a concept to be used for the evaluation of performance of treated fibres in composites....

  2. Modelling of volumetric composition and mechanical properties of unidirectional hemp/epoxy composites - Effect of enzymatic fibre treatment

    Science.gov (United States)

    Liu, M.; Thygesen, A.; Meyer, AS; Madsen, B.

    2016-07-01

    The objective of the present study is to assess the effect of enzymatic fibre treatments on the fibre performance in unidirectional hemp/epoxy composites by modelling the volumetric composition and mechanical properties of the composites. It is shown that the applied models can well predict the changes in volumetric composition and mechanical properties of the composites when differently treated hemp fibres are used. The decrease in the fibre correlated porosity factor with the enzymatic fibre treatments shows that the removal of pectin by pectinolytic enzymes results in a better fibre impregnation by the epoxy matrix, and the mechanical properties of the composites are thereby increased. The effective fibre stiffness and strength established from the modelling show that the enzymatic removal of pectin also leads to increased mechanical properties of the fibres. Among the investigated samples, the composites with hydrothermally pre-treated and enzymatically treated fibres have the lowest porosity factor of 0.08 and the highest mechanical properties. In these composites, the effective fibre stiffness and strength are determined to be 83 GPa and 667 MPa, respectively, when the porosity efficiency exponent is set equal to 2. Altogether, it is demonstrated that the applied models provide a concept to be used for the evaluation of performance of treated fibres in composites.

  3. Synthesis and Characterization of Short Saccaharum Cilliare Fibre Reinforced Polymer Composites

    Directory of Open Access Journals (Sweden)

    A. S. Singha

    2009-01-01

    Full Text Available This paper deals with the synthesis of short Saccaharum Cilliare fibre (SC reinforced Urea-Formaldehyde (UF matrix based polymer composites. Present work reveals that mechanical properties such as: tensile strength, compressive strength, flexural strength and wear resistance of the UF matrix increase up to 30% fibre loading(in terms of weight and then decreases for higher loading when fibers are incorporated into the matrix polymer. Morphological and Thermal studies of the matrix, fibre and short fibre reinforced (SF-Rnf green composites have also been carried out. The results obtained emphasize the applications of these fibres, as potential reinforcing materials in bio based composites.

  4. Study of 1-3 PZT fibre/epoxy composite force sensor

    Science.gov (United States)

    Choy, S. H.; Chan, H. L. W.; Ng, M. W.; Liu, P. C. K.

    2005-09-01

    Lead zirconate titanate (PZT) fibres were prepared by a powder-based extrusion method. Pre-sintered PZT powder mixed with poly(acrylic acid) was spun in a spinnerette to produce fibres. The fibre of ˜400 μm diameter was used to fabricate 1-3 PZT fibre/epoxy composite discs with different volume fractions (ϕ) of PZT. Since the ceramic fibres are rather brittle, their elastic properties cannot be measured directly. In order to determine the properties of the ceramic fibres, effective properties of the fibres/epoxy 1-3 composite were measured. By using a modified series and parallel model, the properties of 1-3 composites can be calculated. Then, the elastic coefficient s33,fibreE, relative permittivity ɛ33,fibreT and piezoelectric strain coefficient d33,fibre of the ceramic fibre could be found. Ring-shaped PZT fibre/epoxy materials composites with different ϕ were fabricated to be used as the sensing material in force sensor applications. The ring-shape composite with ϕ=0.5 was installed into a housing and the sensor was calibrated by different methods and its sensitivity was found to be 144 pC/N within the frequency range of 0.5 6.4 kHz which is much higher than that of a quartz force sensor with a similar structure.

  5. Thermal recycling and re-manufacturing of glass fibre thermosetting composites

    Science.gov (United States)

    Fraisse, A.; Beauson, J.; Brøndsted, P.; Madsen, B.

    2016-07-01

    The impact of using thermally recycled glass fibre in re-manufactured composites was investigated. A unidirectional glass fibre thermosetting composite laminate was manufactured. The matrix in one part of the laminate was burnt off to recover the glass fibres. These recycled glass fibres were used to manufacture a new composite laminate with the same fibre architecture as the pristine one. The fibres, the matrix and the composite laminates were thoroughly characterised and analysed. The results show that good materials quality was obtained for both laminates. A difference in fibre packing behaviour was observed in the composites with the pristine and the recycled fibres, which lead to a lower fibre volume fraction in the latter one. The Young's modulus of the composites was not changed by the recycling process, if the lower fibre volume fraction is taken into account. However, a marked drop in the maximum stress of the composites was reported, which was found to be related to the loss in maximum stress of the fibres.

  6. Ultrasound detection of damage in complex carbon fibre/metal structures

    Science.gov (United States)

    Thursby, G. J.; MacLean, A.; Hogg, H.; Culshaw, B.

    2006-03-01

    carbon fibre) or bolted together (carbon fibre to aluminium). In the case of the bonded structures we are looking at the effects of failure of the bond layer, whilst in the case of the bolted samples we are looking at loosening of the bolts. The debonding was simulated by joining together a flat plate of carbon fibre composite with an L-shaped carbon fibre piece using a couplant such as grease. Similar experiments were carried out using an aluminium anglebar bolted to the plate, with the bolts both tightened and loose. Signals of both the transmitted wave in the plate and the power coupled to the L piece were measured before and after debonding. This gives a more reliable measure of the change in power transfer between the two components as the joint/bond degrades. It was found that in order to get maximum coupling to the second component the frequency of the acoustic wave had to be altered. This is because in the bonding region the combined thickness of the components alters the modal propagation characteristics of the structure compared with those of the single component region.

  7. Mechanical properties of kenaf bast and core fibre reinforced unsaturated polyester composites

    Energy Technology Data Exchange (ETDEWEB)

    Ishak, M R; Leman, Z; Sapuan, S M [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia); Edeerozey, A M M; Othman, I S, E-mail: zleman@eng.upm.edu.my [Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, 76109 Durian Tunggal, Melaka (Malaysia)

    2010-05-15

    Kenaf fibre has high potential to be used for composite reinforcement in biocomposite material. It is made up of an inner woody core and an outer fibrous bark surrounding the core. The aim of this study was to compare the mechanical properties of short kenaf bast and core fibre reinforced unsaturated polyester composites with varying fibre weight fraction i.e. 0%, 5%, 10%, 20%, 30% and 40%. The compression moulding technique was used to prepare the composite specimens for tensile, flexural and impact tests in accordance to the ASTM D5083, ASTM D790 and ASTM D256 respectively. The overall results showed that the composites reinforced with kenaf bast fibre had higher mechanical properties than kenaf core fibre composites. The results also showed that the optimum fibre content for achieving highest tensile strength for both bast and core fibre composites was 20%wt. It was also observed that the elongation at break for both composites decreased as the fibre content increased. For the flexural strength, the optimum fibre content for both composites was 10%wt while for impact strength, it was at 10%wt and 5%wt for bast and core fibre composites respectively.

  8. Glass fibres reinforced polyester composites degradation monitoring by surface analysis

    Science.gov (United States)

    Croitoru, Catalin; Patachia, Silvia; Papancea, Adina; Baltes, Liana; Tierean, Mircea

    2015-12-01

    The paper presents a novel method for quantification of the modifications that occur on the surface of different types of gel-coated glass fibre-reinforced polyester composites under artificial UV-ageing at 254 nm. The method implies the adsorption of an ionic dye, namely methylene blue, on the UV-aged composite, and computing the CIELab colour space parameters from the photographic image of the coloured composite's surface. The method significantly enhances the colour differences between the irradiated composites and the reference, in contrast with the non-coloured ones. The colour modifications that occur represent a good indicative of the surface degradation, alteration of surface hydrophily and roughness of the composite and are in good correlation with the ATR-FTIR spectroscopy and optical microscopy results. The proposed method is easier, faster and cheaper than the traditional ones.

  9. Creep behavior of abaca fibre reinforced composite material

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, B.C.; Lieng, V.T. [Victoria Univ. of Technology, Victoria (Australia)

    1996-12-31

    This study investigates the creep behavior of abaca fibre reinforced composite lamina. The optimum proportions of constituents and loading conditions, temperature and stresses, are investigated in terms of creep properties. Lamina with abaca fibre volume fractions of 60, 70 and 80 percent, embedded in polyester resin were fabricated. Creep tests in tension at three temperature levels 20{degrees}C, 100{degrees}C and 120{degrees}C and three constant stress levels of 0. 1 MPa, 0. 13 Mpa and 0. 198 MPa using a Dynamic Mechanical Analyzer (DMA) were performed. The creep curves show standard regions of an ideal creep curve such as primary and secondary creep stage. The results also show that the minimum creep rate of abaca fibre reinforced composite increases with the increase of temperature and applied stress. Plotting the minimum creep rate against stress, depicts the variations of stress exponents which vary from 1.6194 at 20{degrees}C to 0.4576 at 120{degrees}C.

  10. Machining analysis of natural fibre reinforced composites using fuzzy logic

    Science.gov (United States)

    Balasubramanian, K.; Sultan, M. T. H.; Cardona, F.; Rajeswari, N.

    2016-10-01

    In this work, a new composite plate with natural jute fibre as the reinforcement fibres and isophthalic polyester as the resin was manufactured and subjected to a series of end milling operation by changing three input factors namely speed, feed rate and depth of cut. During each operation, the output responses namely thrust force and torque were measured. The responses were analyzed using Taguchi method to examine the relation between the input factors and output responses, and also to know the most influencing factors on the responses. The data was also analyzed using fuzzy rule model for prediction of responses for a range of input factors. The results showed that all three factors chosen have significant effect on the responses. The fuzzy model data in comparison with the experimental values shows only a marginal error and hence the prediction was highly satisfactory.

  11. A Micro Raman Investigation of Viscoelasticity in Short Fibre Reinforced Polymer Matrix Composites

    DEFF Research Database (Denmark)

    Schjødt-Thomsen, Jan

    The purpose of the present Ph.D. project is to investigate the load transfer mechanisms between the fibre and matrix and the stress/strain fields in and around single fibres in short fibre reinforced viscoelastic polymer matrix composites subjected to various loading histories. The materials...

  12. Single fibre and multifibre unit cell analysis of strength and cracking of unidirectional composites

    DEFF Research Database (Denmark)

    Wang, H.W.; Zhou, H.W.; Mishnaevsky, Leon;

    2009-01-01

    Numerical simulations of damage evolution in composites reinforced with single and multifibre are presented. Several types of unit cell models are considered: single fibre unit cell, multiple fibre unit cell with one and several damageable sections per fibres, unit cells with homogeneous and inho...

  13. Review of current strategies to induce self-healing behaviour in fibre reinforced polymer based composites

    NARCIS (Netherlands)

    Zwaag, van der S.; Grande, A.M.; Post, W.; Garcia, S.J.; Bor, T.C.

    2014-01-01

    This paper addresses the various strategies to induce self-healing behaviour in fibre reinforced polymer based composites. A distinction is made between the extrinsic and intrinsic healing strategies. These strategies can be applied at the level of the fibre, the fibre/matrix interface or at the lev

  14. Evaluation on mechanical properties of woven aloevera and sisal fibre hybrid reinforced epoxy composites

    Indian Academy of Sciences (India)

    A Shadrach Jeya Sekaran; K Palani Kumar; K Pitchandi

    2015-09-01

    Natural fibres as reinforcement in polymer composite for making low-cost materials are growing day by day. Researcher’s main attention is to apply appropriate technology to utilize these natural fibres as effectively and economically as possible to produce good quality fibre-reinforced polymer composites for various engineering applications. In this research, the experiments of tensile, flexural and impact tests were carried out for woven aloevera and sisal fibre hybrid-reinforced epoxy composites. The hand layup method of fabrication was employed in preparing the composites. The surface morphology of the composites was examined through scanning electron microscope. Due to the low-density and high-specific properties of sisal fibre composites, it offer cost savings when compared with synthetic fibres. Hence it has very good implications in the automotive and transportation industry.

  15. Carbon fibre-reinforced, alkali-activated slag mortars

    Directory of Open Access Journals (Sweden)

    Garcés, P.

    2007-12-01

    Full Text Available The paper describes the effect of carbon fibre on alkaliactivated slag mortar (AAS mechanical strength, volume stability and reinforcing steel corrosion, compared to its effect on the same properties in Portland cement (PC properties. Mechanical strength and volume stability tests were performed as set out in the respective Spanish UNE standards. The corrosion rate of steel embedded in the specimens studied was determined from polarization resistance analysis. One of the findings of the study performed was that carbon fibre failed to improve AAS or CP mortar strength. As far as volume stability is concerned, the inclusion of carbon fibres in AAS with a liquid/solid ratio of 0.5 reduced drying shrinkage by about 50%. The effect of carbon fibre on PC mortars differed from its effect on AAS mortars. Studies showed that in the presence of carbonation, steel corrosion reached higher levels in carbon-fibre reinforced AAS mortars; the inclusion of 1% carbon fibre improved corrosion resistance perceptibly in these same mortars, however, when exposed to chloride attack.Se ha estudiado el efecto de la incorporación de fibras de carbón en el comportamiento mecánico, estabilidad de volumen y nivel de corrosión de la armadura en morteros de escorias activadas alcalinamente (AAS. Se evalúa la influencia de las fibras de carbón en el comportamiento de morteros alcalinos en comparación con el efecto que producen en morteros de Portland (CP. Los ensayos mecánicos y de estabilidad de volumen se han realizado según lo establecido en la norma UNE que los regula. Se ha utilizado la técnica de la Resistencia a la Polarización para determinar la velocidad de corrosión del acero embebido en las muestras estudiadas. Como consecuencia del estudio realizado, se ha podido concluir que la adición de fibras de carbón a morteros de AAS y CP no mejora las características resistentes de los mismos. En relación con la estabilidad de volumen, la incorporación de

  16. Highly stretchable electric circuits from a composite material of silver nanoparticles and elastomeric fibres.

    Science.gov (United States)

    Park, Minwoo; Im, Jungkyun; Shin, Minkwan; Min, Yuho; Park, Jaeyoon; Cho, Heesook; Park, Soojin; Shim, Mun-Bo; Jeon, Sanghun; Chung, Dae-Young; Bae, Jihyun; Park, Jongjin; Jeong, Unyong; Kim, Kinam

    2012-12-01

    Conductive electrodes and electric circuits that can remain active and electrically stable under large mechanical deformations are highly desirable for applications such as flexible displays, field-effect transistors, energy-related devices, smart clothing and actuators. However, high conductivity and stretchability seem to be mutually exclusive parameters. The most promising solution to this problem has been to use one-dimensional nanostructures such as carbon nanotubes and metal nanowires coated on a stretchable fabric, metal stripes with a wavy geometry, composite elastomers embedding conductive fillers and interpenetrating networks of a liquid metal and rubber. At present, the conductivity values at large strains remain too low to satisfy requirements for practical applications. Moreover, the ability to make arbitrary patterns over large areas is also desirable. Here, we introduce a conductive composite mat of silver nanoparticles and rubber fibres that allows the formation of highly stretchable circuits through a fabrication process that is compatible with any substrate and scalable for large-area applications. A silver nanoparticle precursor is absorbed in electrospun poly (styrene-block-butadiene-block-styrene) (SBS) rubber fibres and then converted into silver nanoparticles directly in the fibre mat. Percolation of the silver nanoparticles inside the fibres leads to a high bulk conductivity, which is preserved at large deformations (σ ≈ 2,200 S cm(-1) at 100% strain for a 150-µm-thick mat). We design electric circuits directly on the electrospun fibre mat by nozzle printing, inkjet printing and spray printing of the precursor solution and fabricate a highly stretchable antenna, a strain sensor and a highly stretchable light-emitting diode as examples of applications.

  17. Highly stretchable electric circuits from a composite material of silver nanoparticles and elastomeric fibres

    Science.gov (United States)

    Park, Minwoo; Im, Jungkyun; Shin, Minkwan; Min, Yuho; Park, Jaeyoon; Cho, Heesook; Park, Soojin; Shim, Mun-Bo; Jeon, Sanghun; Chung, Dae-Young; Bae, Jihyun; Park, Jongjin; Jeong, Unyong; Kim, Kinam

    2012-12-01

    Conductive electrodes and electric circuits that can remain active and electrically stable under large mechanical deformations are highly desirable for applications such as flexible displays, field-effect transistors, energy-related devices, smart clothing and actuators. However, high conductivity and stretchability seem to be mutually exclusive parameters. The most promising solution to this problem has been to use one-dimensional nanostructures such as carbon nanotubes and metal nanowires coated on a stretchable fabric, metal stripes with a wavy geometry, composite elastomers embedding conductive fillers and interpenetrating networks of a liquid metal and rubber. At present, the conductivity values at large strains remain too low to satisfy requirements for practical applications. Moreover, the ability to make arbitrary patterns over large areas is also desirable. Here, we introduce a conductive composite mat of silver nanoparticles and rubber fibres that allows the formation of highly stretchable circuits through a fabrication process that is compatible with any substrate and scalable for large-area applications. A silver nanoparticle precursor is absorbed in electrospun poly (styrene-block-butadiene-block-styrene) (SBS) rubber fibres and then converted into silver nanoparticles directly in the fibre mat. Percolation of the silver nanoparticles inside the fibres leads to a high bulk conductivity, which is preserved at large deformations (σ ~ 2,200 S cm-1 at 100% strain for a 150-µm-thick mat). We design electric circuits directly on the electrospun fibre mat by nozzle printing, inkjet printing and spray printing of the precursor solution and fabricate a highly stretchable antenna, a strain sensor and a highly stretchable light-emitting diode as examples of applications.

  18. Carbonized asphaltene-based carbon-carbon fiber composites

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-12-27

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

  19. In situ observations of microscale damage evolution in unidirectional natural fibre composites

    DEFF Research Database (Denmark)

    Rask, Morten; Madsen, Bo; Sørensen, Bent F.;

    2012-01-01

    damage state at each stress level. The overall aim of the study is to gain a better understanding of the damage mechanisms in natural fibre composites. This is necessary if they are to be optimized to fulfil their promising potential. Three dominating damage mechanisms have been identified: (i) interface...... splitting cracks typically seen at the interfaces of bundles of unseparated fibres, (ii) matrix shear cracks, and (iii) fibre failures typically seen at fibre defects. Based on the findings in the present study, well separated fibres with a low number of defects are recommended for composite reinforcements....

  20. THE USE OF SISAL FIBRE AS REINFORCEMENT IN CEMENT BASED COMPOSITES

    Directory of Open Access Journals (Sweden)

    Romildo Dias Tolêdo Filho

    1999-08-01

    Full Text Available ABSTRACT The inclusion of fibre reinforcement in concrete, mortar and cement paste can enhance many of the engineering properties of the basic materials, such as fracture toughness, flexural strength and resistance to fatigue, impact, thermal shock and spalling. In recent years, a great deal of interest has been created worldwide on the potential applications of natural fibre reinforced, cement based composites. Investigations have been carried out in many countries on various mechanical properties, physical performance and durability of cement based matrices reinforced with naturally occurring fibres including sisal, coconut, jute, bamboo and wood fibres. These fibres have always been considered promising as reinforcement of cement based matrices because of their availability, low cost and low consumption of energy. In this review, the general properties of the composites are described in relation to fibre content, length, strength and stiffness. A chronological development of sisal fibre reinforced, cement based matrices is reported and experimental data are provided to illustrate the performance of sisal fibre reinforced cement composites. A brief description on the use of these composite materials as building products has been included. The influence of sisal fibres on the development of plastic shrinkage in the pre-hardened state, on tensile, compressive and bending strength in the hardened state of mortar mixes is discussed. Creep and drying shrinkage of the composites and the durability of natural fibres in cement based matrices are of particular interest and are also highlighted. The results show that the composites reinforced with sisal fibres are reliable materials to be used in practice for the production of structural elements to be used in rural and civil construction. This material could be a substitute asbestos-cement composite, which is a serious hazard to human and animal health and is prohibited in industrialized countries. The

  1. A Review of the Flammability Factors of Kenaf and Allied Fibre Reinforced Polymer Composites

    Directory of Open Access Journals (Sweden)

    C. H. Lee

    2014-01-01

    Full Text Available Natural fibre is a well-known reinforcement fibre in polymer-matrix Composites (PMC lately. Natural fibre has fast growing and abundance properties which make it available at very low cost. For kenaf fibre there is long lists of research projects which have been done regarding its behaviour, and properties and modification made to it. In this paper, fire flammability is the main concern for natural fibre reinforced polymer (NFRP composites especially kenaf fibre. To estimate its flammability, a wide range of factors can be considered such as fibre content, type of matrices, pH conditions, treatment, and fire retardant (FR filler’s type. The most important criteria are the ignition time, rate of propagation, and fire behavior. thermogravimetric analysis (TGA, different scanning calorimetric (DSC, and dynamic mechanical analysis (DMA are the three most famous methods used to investigate the fire behaviour of composites.

  2. Experimental study of bamboo using banana and linen fibre reinforced polymeric composites

    Directory of Open Access Journals (Sweden)

    Ramachandran M.

    2016-09-01

    Full Text Available The application of natural fibres such as bamboo, jute, banana, coir, linen and the like in Fibre Reinforced Polymeric (FRP composites have become so vital due to their high effective stiffness and strength, availability, low cost, specific strength, better dimensional stability and mechanical properties, eco-friendly and biodegradable as compared with synthetic fibres. The interest in natural fibre reinforced polymeric composites is rapidly springing up in terms of research and industrial applications. The increased applications of these natural fibres in such composites are a proof to this claim. The paper deals with the detailed study of bamboo fibre, banana fibre and linen fibre cut into 2−4 mm of length with epoxy resin having random orientations. Various tests like Impact test (IZOD and CHARPY test, Fourier Transform Infra-Red (FTIR test and Rockwell Hardness test were conducted on 10 specimens of bamboo epoxy resin composite, bamboo−banana epoxy resin composite and bamboo−linen epoxy resin composite. It is analysed and proved that bamboo−banana epoxy resin composite shows better results in Impact test with values of 4 Joules for Izod test and 5 Joules for Charpy test and in FTIR test, compatibility of fibres with polymers in bamboo−banana epoxy resin composite are the best while bamboo−linen epoxy resin composite shows better result in Rockwell hardness test with value of 40 RHN.

  3. Fabrication and tribological properties of Al reinforced with carbon fibres

    Energy Technology Data Exchange (ETDEWEB)

    Estrems Amestoy, M.; Faura Mateu, F. [Universidad Politecnica de Cartagena (Spain); Froyen, L. [Department of Metallurgy and Materials Engineering. Katholieke Universiteit Lewen. Heverlee. Belgium (Belgium)

    2000-07-01

    The present work studies the manufacturing process of Al reinforced with Carbon Fibres (CF) by Squeeze Casting, establishing the variables for obtaining and acceptable product with little Al{sub 4}C{sub 3} at the interface. Friction and wear tests are performed and the necessary conditions for the formation of a tribofilm are established. The tests how an increasing resistance to abrasion due to their own wear mechanism. Certain design criteria for those components subjected to friction are recommended in order to maximize the mechanical performance of the tribological system. (Author ) 16 refs.

  4. Hybrid Fibre Polylactide Acid Composite with Empty Fruit Bunch: Chopped Glass Strands

    Directory of Open Access Journals (Sweden)

    K. Y. Tshai

    2014-01-01

    Full Text Available Hybrid polylactide acid (PLA composites reinforced with palm empty fruit bunch (EFB and chopped strand E-glass (GLS fibres were investigated. The hybrid fibres PLA composite was prepared through solution casting followed by pelletisation and subsequent hot compression press into 1 mm thick specimen. Chloroform and dichloromethane were used as solvent and their effectiveness in dissolving PLA was reported. The overall fibre loading was kept constant at volume fraction, Vf, of 20% while the ratio of EFB to GLS fibre was varied between Vf of 0 : 20 to 20 : 0. The inclusion of GLS fibres improved the tensile and flexural performance of the hybrid composites, but increasing the glass fibre length from 3 to 6 mm has a negative effect on the mechanical properties of the hybrid composites. Moreover, the composites that were prepared using chloroform showed superior tensile and flexural properties compared to those prepared with dichloromethane.

  5. Influence of reprocessing on fibre length distribution, tensile strength and impact strength of injection moulded cellulose fibre-reinforced polylactide (PLA composites

    Directory of Open Access Journals (Sweden)

    N. Graupner

    2016-08-01

    Full Text Available The present study focuses on the reprocessing behaviour of recycled injection moulded polylactide (PLA composites. The composites are reinforced with regenerated cellulose fibres (lyocell of variable fineness and a fibre mass content of 30%. They were reprocessed up to three times. The influence of reprocessing on the fibre length distribution and the resulting composite mechanical properties (tensile and impact strength was analysed. While the first reprocessing cycle does not affect the mechanical characteristics of the neat PLA matrix, the strength of the composites decreases significantly due to a decreasing fibre aspect ratio. It was shown that fibres having a larger cross-sectional area display a lower aspect ratio than finer fibres, after reprocessing. This phenomenon leads to a larger decrease in tensile strength of composites reinforced with coarser fibres when compared to composites reinforced with finer fibres. A comparison of virgin composites and threefold reprocessed composites with a similar fibre length distribution resulted in a significantly higher tensile strength compared to the virgin sample. This result leads to the conclusion that not only the fibre length is drastically reduced by reprocessing but also that the fibres and the matrix were damaged.

  6. Lamb wave detection in prepreg composite materials with fibre Bragg grating sensors

    Science.gov (United States)

    Miesen, Nick; Mizutani, Yoshihiro; Groves, Roger M.; Sinke, Jos; Benedictus, Rinze

    2011-04-01

    This paper demonstrates that existing Structural Health Monitoring (SHM) techniques have potential during the production phase in addition to their application for maintenance and for in-flight monitoring. Flaws occur during composite fabrication in industry, due to an imperfect process control and human errors. This decreases production efficiency and increases costs. In this paper, the monitoring of Lamb waves in unidirectional carbon fibre (UD-CFRP) prepreg material is demonstrated using both Fibre Bragg Gratings (FBG)s and piezolectric acoustic sensors, and that these SHM sensors may be used for flaw detection and production monitoring. The detection of Lamb waves in a one ply thick sheet of prepreg UD-CFRP material is demonstrated for an FBG sensor aligned with the carbon fibre orientation and bonded to the surface of the prepreg, Furthermore, the velocity of Lamb waves in prepreg UD-CFRP in different orientations is investigated. Finally the successful detection of a material crack in a prepreg UD-CFRP sheet using the Lamb wave detection method is demonstrated.

  7. Molecular mechanistic origin of the toughness of natural adhesives, fibres and composites

    Science.gov (United States)

    Smith, Bettye L.; Schäffer, Tilman E.; Viani, Mario; Thompson, James B.; Frederick, Neil A.; Kindt, Johannes; Belcher, Angela; Stucky, Galen D.; Morse, Daniel E.; Hansma, Paul K.

    1999-06-01

    Natural materials are renowned for their strength and toughness,,,,. Spider dragline silk has a breakage energy per unit weight two orders of magnitude greater than high tensile steel,, and is representative of many other strong natural fibres,,. The abalone shell, a composite of calcium carbonate plates sandwiched between organic material, is 3,000 times more fracture resistant than a single crystal of the pure mineral,. The organic component, comprising just a few per cent of the composite by weight, is thought to hold the key to nacre's fracture toughness,. Ceramics laminated with organic material are more fracture resistant than non-laminated ceramics,, but synthetic materials made of interlocking ceramic tablets bound by a few weight per cent of ordinary adhesives do not have a toughness comparable to nacre. We believe that the key to nacre's fracture resistance resides in the polymer adhesive, and here we reveal the properties of this adhesive by using the atomic force microscope to stretch the organic molecules exposed on the surface of freshly cleaved nacre. The adhesive fibres elongate in a stepwise manner as folded domains or loops are pulled open. The elongation events occur for forces of a few hundred piconewtons, which are smaller than the forces of over a nanonewton required to break the polymer backbone in the threads. We suggest that this `modular' elongation mechanism might prove to be quite general for conveying toughness to natural fibres and adhesives, and we predict that it might be found also in dragline silk.

  8. TESTS ON STRUCTURALLY DEFICIENT RC SLABS STRENGTHENED WITH FIBRE REINFORCED POLYMER (FRP) COMPOSITES

    Institute of Scientific and Technical Information of China (English)

    S.T. Smith; S.J. Kim

    2004-01-01

    This paper reports the results of a series of tests on fibre reinforced polymer (FRP) strengthened reinforced concrete (RC) slabs, which were recently undertaken at the University of Technology,Sydney. The slabs were reinforced with high-strength low-ductile steel reinforcement and strengthened with either carbon FRP (CFRP) or glass FRP (GFRP) composites. The unstrengthened control slabs failed by fracture of the steel tension reinforcement while the FRP strengthened slabs failed by debonding of the FRP followed by rupture of the tension steel. The FRP-strengthened slabs were stronger than their unstrengthened counterparts and displayed considerable ductility.

  9. FLEXURAL PROPERTIES OF ALKALINE TREATED SUGAR PALM FIBRE REINFORCED EPOXY COMPOSITES

    Directory of Open Access Journals (Sweden)

    D. Bachtiar

    2010-06-01

    Full Text Available A study of the effect of alkaline treatment on the flexural properties of sugar palm fibre reinforced epoxy composites is presented in this paper. The composites were reinforced with 10% weight fraction of the fibres. The fibres were treated using sodium hydroxide (NaOH with 0.25 M and 0.5 M concentration solution for 1 hour, 4 hours and 8 hours soaking time. The purpose of treating fibres with alkali was to enhance the interfacial bonding between matrix and fibre surfaces. The maximum flexural strength occurred at 0.25 M NaOH solution with 1 hour of soaking time, i.e 96.71 MPa, improving by 24.41% from untreated fibre composite. But, the maximum flexural modulus took place at 0.5 M NaOH solution with 4 hours soaking time, i.e. 6948 MPa, improving by 148% from untreated composite.

  10. Fatigue Micromechanism Characterization in Carbon Fibre Reinforced Polymers Using Synchrotron Radiation Computed Tomography

    Science.gov (United States)

    2014-12-18

    AFRL-AFOSR-UK-TR-2015-0002 Fatigue micromechanism characterization in carbon fibre reinforced polymers using synchrotron radiation computed...SUBTITLE Fatigue micromechanism characterization in carbon fibre reinforced polymers using synchrotron radiation computed tomography 5a. CONTRACT...particularly within the aerospace sector due to their high specific stiffness and strength. CFRPs are widely identified as being very fatigue resistant, but

  11. Life Cycle Assessment of Biobased Fibre-Reinforced Polymer Composites (Levenscyclusanalyse van biogebaseerde, vezelversterkte polymeercomposieten)

    OpenAIRE

    Deng, Yelin

    2014-01-01

    Today, global environmental issues, such as global warming and fossil depletion, drive a paradigm shift in material applications from conventional fossil sources to renewable sources. Following this trend, the topic of this thesis is to analyse the use of biobased resources for fibre reinforced composite fabrication. Currently the most widely used fibre reinforced composites are composed of glass fibre reinforcements and polymeric matrices. In this thesis, the biobased alternative, i.e. flax ...

  12. Long Fibre Composite Modelling Using Cohesive User's Element

    Science.gov (United States)

    Kozák, Vladislav; Chlup, Zdeněk

    2010-09-01

    The development glass matrix composites reinforced by unidirectional long ceramic fibre has resulted in a family of very perspective structural materials. The only disadvantage of such materials is relatively high brittleness at room temperature. The main micromechanisms acting as toughening mechanism are the pull out, crack bridging, matrix cracking. There are other mechanisms as crack deflection etc. but the primer mechanism is mentioned pull out which is governed by interface between fibre and matrix. The contribution shows a way how to predict and/or optimise mechanical behaviour of composite by application of cohesive zone method and write user's cohesive element into the FEM numerical package Abaqus. The presented results from numerical calculations are compared with experimental data. Crack extension is simulated by means of element extinction algorithms. The principal effort is concentrated on the application of the cohesive zone model with the special traction separation (bridging) law and on the cohesive zone modelling. Determination of micro-mechanical parameters is based on the combination of static tests, microscopic observations and numerical calibration procedures.

  13. POLYMER COMPOSITES MODIFIED BY WASTE MATERIALS CONTAINING WOOD FIBRES

    Directory of Open Access Journals (Sweden)

    Bernardeta Dębska

    2016-11-01

    Full Text Available In recent years, the idea of sustainable development has become one of the most important require-ments of civilization. Development of sustainable construction involves the need for the introduction of innovative technologies and solutions that will combine beneficial economic effects with taking care of the health and comfort of users, reducing the negative impact of the materials on the environment. Composites obtained from the use of waste materials are part of these assumptions. These include modified epoxy mortar containing waste wood fibres, described in this article. The modification consists in the substitution of sand by crushed waste boards, previously used as underlays for panels, in quantities of 0%, 10%, 20%, 35% and 50% by weight, respectively. Composites containing up to 20% of the modifier which were characterized by low water absorption, and good mechanical properties, also retained them after the process of cyclic freezing and thawing.

  14. Cellulose kraft pulp reinforced polylactic acid (PLA composites: effect of fibre moisture content

    Directory of Open Access Journals (Sweden)

    Elias Retulainen

    2016-06-01

    Full Text Available PLA offers a competitive and CO2 neutral matrix to commonly used polyolefin polymer based composites. Moreover, the use of PLA reduces dependency on oil when producing composite materials. However, PLA has a tendency of hydrolytic degradation under melt processing conditions in the presence of moisture, which remains a challenge when processing PLA reinforced natural fibre composites. Natural fibres such as cellulose fibres are hygroscopic with 6–10 wt% moisture content at 50–70% relative humidity conditions. These fibres are sensitive to melt processing conditions and fibre breakage (cutting also occur during processing. The degradation of PLA, moisture absorption of natural fibres together with fibre cutting and uneven dispersion of fibres in polymer matrix, deteriorates the overall properties of the composite. In the given research paper, bleached softwood kraft pulp (BSKP reinforced PLA compounds were successfully melt processed using BSKP with relatively high moisture contents. The effect of moist BSKP on the molecular weight of PLA, fibre length and the mechanical properties of the composites were investigated. By using moist never-dried kraft pulp fibres for feeding, the fibre cutting was decreased during the melt compounding. Even though PLA degradation occurred during the melt processing, the final damage to the PLA was moderate and thus did not deteriorate the mechanical properties of the composites. However, comprehensive moisture removal is required during the compounding in order to achieve optimal overall performance of the PLA/BSKP composites. The economic benefit gained from using moist BSKP is that the expensive and time consuming drying process steps of the kraft pulp fibres prior to processing can be minimized.

  15. Mechanical property analysis of kenaf–glass fibre reinforced polymer composites using finite element analysis

    Indian Academy of Sciences (India)

    M Ramesh; S Nijanthan

    2016-02-01

    Nowadays, natural fibres are used as a reinforcing material in polymer composites, owing to severe environmental concerns. Among many different types of natural resources, kenaf plants have been extensively exploited over the past few years. In this experimental study, partially eco-friendly hybrid composites were fabricated by using kenaf and glass fibres with two different fibre orientations of 0° and 90°. The mechanical properties such as tensile, flexural and impact strengths of these composites have been evaluated. From the experiment, it was observed that the composites with the 0° fibre orientation can withstand the maximum tensile strength of 49.27 MPa, flexural strength of 164.35 MPa, and impact strength of 6 J. Whereas, the composites with the 90° fibre orientation hold the maximum tensile strength of 69.86 MPa, flexural strength of 162.566 MPa and impact strength of 6.66 J. The finite element analysis was carried out to analyse the elastic behaviour of the composites and to predict the mechanical properties by using NX Nastran 9.0 software. The experimental results were compared with the predicted values and a high correlation between the results was observed. The morphology of the fractured surfaces of the composites was analysed using a scanning electron microscopy analysis. The results indicated that the properties were in the increasing trend and comparable with pure synthetic fibre reinforced composites, which shows the potential for hybridization of kenaf fibre with glass fibre.

  16. A New Method for Descaling Wool Fibres by Nano Abrasive Calcium Carbonate Particles in Ultrasonic Bath

    Directory of Open Access Journals (Sweden)

    Ali rezaghasemi

    2016-08-01

    Full Text Available Up to now, the most conventional methods for descaling of wool fibre are based on chemical degradation and resin covering of scales or a combination of them. These methods are producing wastewater and can cover physical properties of the fibres beside scales orderly. In this study, a new and clean method is developed on the basis of abrasion effect of calcium carbonate Nano particles (CCNP in an ultrasonic bath. Woolen Samples (fibre and yarn were sonicated with different levels of CCNP. Tensile properties of the yarns, directional friction effect of the fibres and scanning electron microscope images of the fibres were studied. Test results showed that sonicated Nano treatment of woolyarn reduced its tenacity, extension and work of rupture and increased its coefficient of friction. Scanning electron microscope images of fibres and measurement of fibres directional displacement confirmed descaling of Nano abrasive treated wool samples in comparison to the raw wool.

  17. Toughening and healing of continuous fibre reinforced composites with bis-maleimide based pre-pregs

    Science.gov (United States)

    Kostopoulos, V.; Kotrotsos, A.; Tsantzalis, S.; Tsokanas, P.; Christopoulos, A. C.; Loutas, T.

    2016-08-01

    Unidirectional (UD) pre-pregs containing self-healing materials based on Diels-Alder reaction bis-maleimide (BMI) polymers were successfully incorporated on the mid-plane of UD carbon fibre reinforced polymers. The fracture toughness of these composites and the introduced healing capability were measured under mode I loading. The interlaminar fracture toughness was enhanced considerably, since the maximum load (P max) of the modified composite increased approximately 1.5 times and the mode I fracture energy (G IC) displayed a significant increase of almost 3.5 times when compared to the reference composites. Furthermore the modified composites displayed a healing efficiency (HE) value of about 30% for P max and 20% for G IC after the first healing, appearing to be an almost stable behaviour after the third healing cycle. The HE displayed a decrease of 20% and 15% for P max and G IC values, respectively, after the fifth healing cycle. During the tests, the monitored acoustic emission (AE) activity of the samples showed that there is no significant difference due to the presence of BMI polymer in terms of AE hits. Moreover, optical microscopy not only showed that the epoxy matrix at the interface is partly infiltrated by the BMI polymer, but it also revealed the presence of pulled out fibres at the fractured surface, indicating ductile behaviour.

  18. Multifunctional composites using reinforced laminae with carbon-nanotube forests

    Science.gov (United States)

    Veedu, Vinod P.; Cao, Anyuan; Li, Xuesong; Ma, Kougen; Soldano, Caterina; Kar, Swastik; Ajayan, Pulickel M.; Ghasemi-Nejhad, Mehrdad N.

    2006-06-01

    Traditional fibre-reinforced composite materials with excellent in-plane properties fare poorly when out-of-plane through-thickness properties are important. Composite architectures with fibres designed orthogonal to the two-dimensional (2D) layout in traditional composites could alleviate this weakness in the transverse direction, but all of the efforts so far have only produced limited success. Here, we unveil an approach to the 3D composite challenge, without altering the 2D stack design, on the basis of the concept of interlaminar carbon-nanotube forests that would provide enhanced multifunctional properties along the thickness direction. The carbon-nanotube forests allow the fastening of adjacent plies in the 3D composite. We grow multiwalled carbon nanotubes on the surface of micro-fibre fabric cloth layouts, normal to the fibre lengths, resulting in a 3D effect between plies under loading. These nanotube-coated fabric cloths serve as building blocks for the multilayered 3D composites, with the nanotube forests providing much-needed interlaminar strength and toughness under various loading conditions. For the fabricated 3D composites with nanotube forests, we demonstrate remarkable improvements in the interlaminar fracture toughness, hardness, delamination resistance, in-plane mechanical properties, damping, thermoelastic behaviour, and thermal and electrical conductivities making these structures truly multifunctional.

  19. Healable thermoset polymer composite embedded with stimuli-responsive fibres.

    Science.gov (United States)

    Li, Guoqiang; Meng, Harper; Hu, Jinlian

    2012-12-07

    Severe wounds in biological systems such as human skin cannot heal themselves, unless they are first stitched together. Healing of macroscopic damage in thermoset polymer composites faces a similar challenge. Stimuli-responsive shape-changing polymeric fibres with outstanding mechanical properties embedded in polymers may be able to close macro-cracks automatically upon stimulation such as heating. Here, a stimuli-responsive fibre (SRF) with outstanding mechanical properties and supercontraction capability was fabricated for the purpose of healing macroscopic damage. The SRFs and thermoplastic particles (TPs) were incorporated into regular thermosetting epoxy for repeatedly healing macroscopic damages. The system works by mimicking self-healing of biological systems such as human skin, close (stitch) then heal, i.e. close the macroscopic crack through the thermal-induced supercontraction of the SRFs, and bond the closed crack through melting and diffusing of TPs at the crack interface. The healing efficiency determined using tapered double-cantilever beam specimens was 94 per cent. The self-healing process was reasonably repeatable.

  20. Computational modelling of fibre-reinforced cementitious composites: An analysis of discrete and mesh-independent techniques

    NARCIS (Netherlands)

    Radtke, F.K.F.

    2012-01-01

    Failure patterns and mechanical behaviour of high performance fibre-reinforced cementitious composites depend to a large extent on the distribution of fibres within a specimen. A discrete treatment of fibres enables us to study the influence of various fibre distributions on the mechanical propertie

  1. Low temperature synthesis of fibres composed of carbon-nickel nanoparticles in super-critical carbon dioxide

    Science.gov (United States)

    Hasumura, Takashi; Fukuda, Takahiro; Whitby, Raymond L. D.; Aschenbrenner, Ortrud; Maekawa, Toru

    2010-06-01

    We show that fibres composed of carbon-nickel nanoparticles are self-assembled by mixing nickelocene and oxygen with super-critical carbon dioxide in a dc electric field. The fibres grow in the direction of the electric field and the growth rate increases with an increase in the strength of the electric field. We also irradiate the fibres with electron beams and find that crystallized nickel particles are captured by carbon particles. The present result suggests that a low temperature method of creating carbon-metal hybrid nanostructures may be developed by mixing metallocene and trigger molecules with super-critical fluids subjected to a dc electric field.

  2. Effects of moisture on the mechanical properties of glass fibre reinforced vinylester resin composites

    Indian Academy of Sciences (India)

    Rita Roy; B K Sarkar; N R Bose

    2001-02-01

    Glass fibre reinforced vinylester resin composites incorporating varying amounts of fibres (63.5, 55.75, 48.48, 38.63 and 27.48 wt%) were characterized for their mechanical properties both as prepared and after treatment with boiling water for 2, 4, 6, 8 and 24 h. Weights of the samples were found to increase to a saturation at about 8 h with boiling water treatment. In keeping with the composite principle, the mechanical properties improved with fibre loading. However, the properties were relatively inferior when treated with boiling water for longer hours attributing to ingress of moisture by capillary action through the interface between the fibre and the resin matrix. Considering the rates of moisture absorption and correlating with the mechanical properties, it was observed that the deteriorating effects were predominant up to 4 h treatment with boiling water. Estimation of defect concentrations for 63.5 wt% of nascent fibre reinforced composites as well as those composites treated with boiling water for 24 h were 56.93% and 64.16% respectively. Similarly, 27.48 wt% nascent fibre reinforced composites and those composites with boiling water treatment showed the estimation of defect concentrations of 39.94% and 50.55% respectively. SEM study of the fractured surfaces showed heavy fibre pull-out in the tensile zone whilst shear fracture of the fibre bundles was predominant at the compressive zone of the samples tested for flexural strength properties.

  3. Effect of Moisture Absorption Behavior on Mechanical Properties of Basalt Fibre Reinforced Polymer Matrix Composites

    Directory of Open Access Journals (Sweden)

    Amuthakkannan Pandian

    2014-01-01

    Full Text Available The study of mechanical properties of fibre reinforced polymeric materials under different environmental conditions is much important. This is because materials with superior ageing resistance can be satisfactorily durable. Moisture effects in fibre reinforced plastic composites have been widely studied. Basalt fibre reinforced unsaturated polyester resin composites were subjected to water immersion tests using both sea and normal water in order to study the effects of water absorption behavior on mechanical properties. Composites specimens containing woven basalt, short basalt, and alkaline and acid treated basalt fibres were prepared. Water absorption tests were conducted by immersing specimens in water at room temperature for different time periods till they reached their saturation state. The tensile, flexural, and impact properties of water immersed specimens were conducted and compared with dry specimens as per the ASTM standard. It is concluded that the water uptake of basalt fibre is considerable loss in the mechanical properties of the composites.

  4. Properties of drawn W wire used as high performance fibre in tungsten fibre-reinforced tungsten composite

    Science.gov (United States)

    Riesch, J.; Almanstötter, J.; Coenen, J. W.; Fuhr, M.; Gietl, H.; Han, Y.; Höschen, T.; Linsmeier, Ch; Travitzky, N.; Zhao, P.; Neu, R.

    2016-07-01

    High strength and creep resistance also at high temperature, combined with a high thermal conductivity and high melting point make tungsten (W) an ideal material for highly loaded areas in future fusion reactors. However, as a typical bcc metal tungsten features an intrinsic brittleness up to very high temperature and is prone to operational embrittlement. Tungsten fibre-reinforced tungsten composite (Wf/W) utilizes extrinsic toughening mechanisms similar to ceramic fibre-reinforced ceramics and therefore overcomes the brittleness problem. The properties of the composite are to a large extend determined by the properties of the drawn tungsten wire used as reinforcement fibres. W wire exhibits a superior strength and shows ductile behaviour with exceptional local plasticity. Beside the typical mechanisms observed for ceramic composites the ductile deformation of the fibres is therefore an additional very effective toughening mechanism. Tension tests were used to investigate this phenomenon in more detail. Results show that there is a region of enhanced localized plastic deformation. The specific energy consumption in this region was estimated and used to suggest optimisation options for Wf/W composites.

  5. Comparison of traditional field retting and Phlebia radiata Cel 26 retting of hemp fibres for fibre-reinforced composites

    DEFF Research Database (Denmark)

    Liu, Ming; Ale, Marcel Tutor; Kołaczkowski, Bartłomiej

    2017-01-01

    Classical field retting and controlled fungal retting of hemp using Phlebia radiata Cel 26 (a mutant with low cellulose degrading ability) were compared with pure pectinase treatment with regard to mechanical properties of the produced fibre/epoxy composites. For field retting a classification...... was obtained using P. radiata Cel 26 compared to 248 MPa with field retting....

  6. MECHANICAL BEHAVIOUR OF ABACA-GLASS-BANANA FIBRE REINFORCED HYBRID COMPOSITES

    Directory of Open Access Journals (Sweden)

    H. VENKATASUBRAMANIAN

    2015-08-01

    Full Text Available Hybrid composites comprising of natural and synthetic fibres with phenolic resin is one of the present composite manufacturing techniques for achieving enhanced mechanical properties. In this study Abaca-banana-glass composites has been fabricated and its mechanical properties were analysed. Tensile, flexural and impact strength were investigated in the process of mechanical characterisation. Matrix material used is a phenolic resin of Ortho-Phthalic acid. The manufacture of the composite is done by hand layup technique where the fibre content is varied through volume fraction of 0.4 to 0.5. Setup is arranged in such a way that glass fibre is arranged on the top and bottom layers of the laminate which adds up strength and produces a better surface finish, where in the natural fibre is sandwiched in intermediate layers within the glass fibre. Fibre orientation and the detailed internal structure of matrix were studied by using SEM photography. The results showed that Abaca-banana-glass hybrid composite has better tensile property, Banana-glass composite has the best flexural property and Abaca-glass composite has the best impact property. The results obtained show a substantial increase in mechanical properties and hence these hybrid composites can be used as an effective alternative for synthetic fibres and can be used as an alternate for different industrial application.

  7. The effects of acetylation on properties of flax fibre and its polypropylene composites

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available Flax fibre was modified with acetylation. The influence of the acetylation on the structure and properties of flax fibre were investigated as well as modified flax fibre reinforced polypropylene composites were also prepared. The catalyst was used to accelerate acetylation reaction rate. Flax fibre was characterised after modification. Surface morphology, moisture absorption property, components content, degree of polymerisation, crystallinity of cellulose and thermal stability of flax fibres were studied. Due to acetylation, the flax fibre surface morphology and moisture resistance properties improved remarkably. Flax fibre (modified and unmodified reinforced polypropylene composites were fabricated with 30 wt% fibre loading. The mechanical properties were investigated for those composites. Tensile and flexural strengths of composites were found to increase with increasing degree of acetylation up to 18% and then decreased. Charpy impact strengths of composites were found to decrease with increasing degree of acetylation. Owing to addition of coupling agent (maleated polypropylene -MAH, the tensile and flexural strength properties were found to increase in between 20 to 35% depending on degree of acetylation.

  8. Experimental and theoretical assessment of flexural properties of hybrid natural fibre composites

    DEFF Research Database (Denmark)

    Raghavalu Thirumalai, Durai Prabhakaran; Toftegaard, Helmuth Langmaack; Markussen, Christen Malte

    2014-01-01

    The concept of hybridization of natural fibre composites with synthetic fibres is attracting increasing scientific attention. The present study addresses the flexural properties of hybrid flax/glass/epoxy composites to demonstrate the potential benefits of hybridization. The study covers both...... experimental and theoretical assessments. Composite laminates with different hybrid fibre mixing ratios and different layer configurations were manufactured, and their volumetric composition and flexural properties were measured. The relationship between volume fractions in the composites is shown to be well...... predicted as a function of the hybrid fibre mixing ratio. The flexural modulus of the composites is theoretically assessed by using micromechanical models and laminate theory. The model predictions are compared with the experimentally determined flexural properties. Both approaches show that the flexural...

  9. Deformation mechanisms of carbon nanotube fibres under tensile loading by in situ Raman spectroscopy analysis.

    Science.gov (United States)

    Li, Qiu; Kang, Yi-Lan; Qiu, Wei; Li, Ya-Li; Huang, Gan-Yun; Guo, Jian-Gang; Deng, Wei-Lin; Zhong, Xiao-Hua

    2011-06-03

    Deformation mechanisms of carbon nanotube (CNT) fibres under tensile loading are studied by means of in situ Raman spectroscopy to detect the CNT deformation and stress distributions in the fibres. The G' band in the Raman spectrum responds distinctly to the tensile stress in Raman shift, width and intensity. The G' band changes with the tensile deformation of the fibre at different stages, namely elastic deformation, strengthening and damage-fracture. It is deduced that the individual CNTs only deform elastically without obvious damage or bond breaking. The yield and fracture of fibres can be due to the slippage among the CNTs.

  10. Excellent bonding behaviour of novel surface-tailored fibre composite rods with cementitious matrix

    Indian Academy of Sciences (India)

    Fernando Cunha; Sohel Rana; Raul Fangueiro; Graça Vasconcelos

    2014-08-01

    Novel composite rods were produced by a special braiding technique that involves braiding of polyester yarns around a core of resin-impregnated carbon fibres and subsequent curing. The surface roughness of these braided rods was tailored by replacing one or two simple yarns in the outer-braided layer with braided yarns (produced from 8 simple yarns) and adjusting the take-up velocity. Pull-out tests were carried out to characterize the bond behaviour of these composite rods with cementitious matrix. It was observed that the rod produced with two braided yarns in the outer cover and highest take-up speed was ruptured completely before pull-out, leading to full utilization of its tensile strength, and exhibited 134% higher pull-out force as compared to the rods produced using only simple braiding yarns.

  11. Recent Development of Flax Fibres and Their Reinforced Composites Based on Different Polymeric Matrices

    Directory of Open Access Journals (Sweden)

    Hrushikesh Abhyankar

    2013-11-01

    Full Text Available This work describes flax fibre reinforced polymeric composites with recent developments. The properties of flax fibres, as well as advanced fibre treatments such as mercerization, silane treatment, acylation, peroxide treatment and coatings for the enhancement of flax/matrix incompatibility are presented. The characteristic properties and characterizations of flax composites on various polymers including polypropylene (PP and polylactic acid, epoxy, bio-epoxy and bio-phenolic resin are discussed. A brief overview is also given on the recent nanotechnology applied in flax composites.

  12. Study on durability of natural fibre concrete composites using mechanical strength and microstructural properties

    Indian Academy of Sciences (India)

    M Sivaraja; Kandasamy; N Velmani; M Sudhakaran Pillai

    2010-12-01

    Investigations to overcome the brittle response and limiting post-yield energy absorption of concrete led to the development of fibre reinforced concrete using discrete fibres within the concrete mass. Out of the commonly used fibres, easily available low cost natural fibres are renewable source materials. Though these fibres are ecologically advantageous, they have some limitations such as lower durability and lesser strength. But recent research provides several treatment processes to enhance the durability of natural fibres. In this paper, the durability of natural fibres such as coconut coir and sugarcane bagasse has been reported by conducting an experimental investigation. This investigation includes two parts. The first part focuses on the determination of mechanical strength properties such as compressive, tensile, modulus of rupture and flexural properties of natural fibre reinforced concrete specimens once every 3 months for a period for 2 years under alternate wetting and drying conditions. Gain or loss in strength of composite concrete at 9 intervals were computed and are reported here. The second part covers the microstructural properties of fresh natural fibres in as received condition and natural fibres reacted with concrete under accelerated curing conditions for two years. SEM and EDAC test results are discussed.

  13. UV radiation effect towards mechanical properties of Natural Fibre Reinforced Composite material: A Review

    Science.gov (United States)

    Mahzan, Shahruddin; Fitri, Muhamad; Zaleha, M.

    2017-01-01

    The use of natural fibres as reinforcement material have become common in human applications. Many of them are used in composite materials especially in the polymer matrix composites. The use of natural fibres as reinforcement also provide alternative solution of usage instead of being a waste materials. In some applications, these natural reinforced polymer composites were used as the outer layer, making them exposed to ultra violet exposure, hence prone to UV radiation. This paper reviews the effect of UV radiation towards the mechanical properties of natural fibre reinforced polymer matrix composite material. The effect of chemical treatment towards the natural fibre is also investigated. One of the important features that was critically explored was the degradation of the composite materials. The influence of UV radiation on the degradation rate involve several parameters such as wavelength, intensity and exposure time. This review highlights the influence of these parameters in order to provide better solution for polymer matrix composite’s development.

  14. Microstructure and mechanical performance of modified mortar using hemp fibres and carbon nanotubes

    KAUST Repository

    Hamzaoui, Rabah

    2014-04-01

    Mechanical performance of modified mortar using hemp fibres is studied following various processing conditions. Hemp fibres combined with carbon nanotubes (CNT) are introduced in mortar and their effect is studied as function of curing time. The cement phase is replaced by different percentages of dry or wet hemp fibres ranging from 1.1. wt% up to 3.1. wt% whereas carbon nanotubes are dispersed in the aqueous solution. Our experimental results show that compressive and flexural strengths of wet fibres modified mortar are higher than those for dry hemp-mortar material. The achieved optimal percentage of wet hemp fibres is 2.1. wt% allowing a flexural strength higher than that of reference mortar. The addition of an optimal CNT concentration (0.01. wt%) combined with wet hemp has a reinforcing effect which turns to be related to an improvement of compressive and flexural strengths by 10% and 24%, respectively, in comparison with reference condition. © 2013 Elsevier Ltd.

  15. Durability and inflammogenic impact of carbon nanotubes compared with asbestos fibres

    Directory of Open Access Journals (Sweden)

    Clark Steve

    2011-05-01

    Full Text Available Abstract Background It has been suggested that carbon nanotubes might conform to the fibre pathogenicity paradigm that explains the toxicities of asbestos and other fibres on a continuum based on length, aspect ratio and biopersistence. Some types of carbon nanotubes satisfy the first two aspects of the fibre paradigm but only recently has their biopersistence begun to be investigated. Biopersistence is complex and requires in vivo testing and analysis. However durability, the chemical mimicking of the process of fibre dissolution using in vitro treatment, is closely related to biopersistence and more readily determined. Here, we describe an experimental process to determine the durability of four types of carbon nanotubes in simulated biological fluid (Gambles solution, and their subsequent pathogenicity in vivo using a mouse model sensitive to inflammogenic effects of fibres. The in vitro and in vivo results were compared with well-characterised glass wool and asbestos fibre controls. Results After incubation for up to 24 weeks in Gambles solution, our control fibres were recovered at percentages consistent with their known in vitro durabilities and/or in vivo persistence, and three out of the four types of carbon nanotubes tested (single-walled (CNTSW and multi-walled (CNTTANG2, CNTSPIN showed no, or minimal, loss of mass or change in fibre length or morphology when examined by electron microscopy. However, the fourth type [multi-walled (CNTLONG1] lost 30% of its original mass within the first three weeks of incubation, after which there was no further loss. Electron microscopy of CNTLONG1 samples incubated for 10 weeks confirmed that the proportion of long fibres had decreased compared to samples briefly exposed to the Gambles solution. This loss of mass and fibre shortening was accompanied by a loss of pathogenicity when injected into the peritoneal cavities of C57Bl/6 mice compared to fibres incubated briefly. CNTSW did not elicit an

  16. Effect of pectin and hemicellulose removal from hemp fibres on the mechanical properties of unidirectional hemp/epoxy composites

    DEFF Research Database (Denmark)

    Liu, Ming; Meyer, Anne S.; Fernando, Dinesh

    2016-01-01

    fibre separation. Hemicellulose removal by NaOH further improved fibre surface cleanliness. Removal of epidermal and parenchyma cells combined with improved fibre separation decreased composite porosity factor. As a result, pectin removal increased composite stiffness and ultimate tensile strength (UTS...

  17. From nanoparticles to fibres: effect of dispersion composition on fibre properties

    Energy Technology Data Exchange (ETDEWEB)

    Schirmer, Katharina S. U.; Esrafilzadeh, Dorna; Thompson, Brianna C.; Quigley, Anita F.; Kapsa, Robert M. I.; Wallace, Gordon G., E-mail: gwallace@uow.edu.au [University of Wollongong, ARC Centre for Electromaterials Science and Intelligent Polymer Research Institute (Australia)

    2015-06-15

    A polyvinyl alcohol (PVA)-stabilized polypyrrole nanodispersion has been optimised for conductivity and processability by decreasing the quantity of PVA before and after synthesis. A reduction of PVA before synthesis leads to the formation of particles with a slight increase in dry particle diameter (51 ± 6 to 63 ± 3 nm), and conversely a reduced hydrodynamic diameter. Conductivity of the dried nanoparticle films was not measureable after a reduction of PVA prior to synthesis. Using filtration of particles after synthesis, PVA content was sufficiently reduced to achieve dried thin film conductivity of 2 S cm{sup −1}, while the electroactivity of the dispersed particles remained unchanged. The as-synthesized and PVA-reduced polypyrrole particles were successfully spun into all-nanoparticle fibres using a wet-extrusion approach without the addition of any polymer or gel matrix. Using nanoparticles as a starting material is a novel approach, which allowed the production of macro-scale fibres that consisted entirely of polypyrrole nanoparticles. Fibres made from PVA-reduced polypyrrole showed higher electroactivity compared to fibres composed of the dispersion high in PVA. The mechanical properties of the fibres were also improved by reducing the amount of PVA present, resulting in a stronger, more ductile and less brittle fibre, which could find potential application in various fields.

  18. Effect of fibre arrangement on the multiaxial fatigue of fibrous composites: a micromechanical computational model

    Directory of Open Access Journals (Sweden)

    Roberto Brighenti

    2015-10-01

    Full Text Available Structural components made of fibre-reinforced materials are frequently used in engineering applications. Fibre-reinforced composites are multiphase materials, and complex mechanical phenomena take place at limit conditions but also during normal service situations, especially under fatigue loading, causing a progressive deterioration and damage. Under repeated loading, the degradation mainly occurs in the matrix material and at the fibre-matrix interface, and such a degradation has to be quantified for design structural assessment purposes. To this end, damage mechanics and fracture mechanics theories can be suitably applied to examine such a problem. Damage concepts can be applied to the matrix mechanical characteristics and, by adopting a 3-D mixed mode fracture description of the fibre-matrix detachment, fatigue fracture mechanics concepts can be used to determine the progressive fibre debonding responsible for the loss of load bearing capacity of the reinforcing phase. In the present paper, a micromechanical model is used to evaluate the unixial or multiaxial fatigue behaviour of structures with equi-oriented or randomly distributed fibres. The spatial fibre arrangement is taken into account through a statistical description of their orientation angles for which a Gaussian-like distribution is assumed, whereas the mechanical effect of the fibres on the composite is accounted for by a homogenization approach aimed at obtaining the macroscopic elastic constants of the material. The composite material behaves as an isotropic one for randomly distributed fibres, while it is transversally isotropic for unidirectional fibres. The fibre arrangement in the structural component influences the fatigue life with respect to the biaxiality ratio for multiaxial constant amplitude fatigue loading. One representative parametric example is discussed.

  19. Low-weight Impact Behaviour of Carbon Fibre Reinforced Methyl Methacrylate Nanocomposites

    Directory of Open Access Journals (Sweden)

    Virginija Jankauskaitė

    2015-06-01

    Full Text Available Inthis study, the carbon fibre reinforced methyl methacrylate (CF/MMA compositetoecap for safety shoes was manufactured to increase the energy absorptioncapacity during impact. Different types of nanofillers such as organic andinorganic nanotubes, unmodified and organically modified nanoclays were appliedto modify matrix impact properties. The drop-weight impact tests of thenanocomposite toecap were performed with respect to nanofiller nature andcarbon fibre stacking sequence. It was found that the most influence on thestiffness and impact damage of the carbon fibre methyl methacrylatenanocomposite toecaps besides stacking sequence show organic and inorganic nanotubesor unmodified nanoclay.DOI: http://dx.doi.org/10.5755/j01.ms.21.2.7075

  20. Treatments of non-wood plant fibres used as reinforcement in composite materials

    Directory of Open Access Journals (Sweden)

    Marie-Ange Arsène

    2013-01-01

    Full Text Available This paper presents a summary of the knowledge on fibres and pulps of non wood tropical plants used as reinforcement in cementitious composites accumulated during the recent years by Guadeloupean and Brazilian teams participating in collaborative work. Vegetable fibres represent a good alternative as non-conventional materials for the construction of ecological and sustainable buildings. The use of such renewable resources contributes to the development of sustainable technologies. The main objective of the paper is to emphasize the use of agricultural wastes in the production of cement based composites. The botanical, chemical, physical, morphological and mechanical properties of fibres from various plants are described. The effects of different treatments on physical, chemical and mechanical properties of fibres are presented. The most effective treatments in influencing the mechanical and physical properties are pyrolysis and alkaline ones, according to the type of plant. The final choice will have to consider fibre availability, and treatment costs.

  1. In vitro adsorption study of fluoxetine in activated carbons and activated carbon fibres

    Energy Technology Data Exchange (ETDEWEB)

    Nabais, J.M. Valente; Mouquinho, A.; Galacho, C.; Carrott, P.J.M.; Ribeiro Carrott, M.M.L. [Centro de Quimica de Evora e Departamento de Quimica da Universidade de Evora, Rua Romao Ramalho no. 59, 7000-671 Evora (Portugal)

    2008-05-15

    We study the in vitro adsorption of fluoxetine hydrochloride by different adsorbents in simulated gastric and intestinal fluid, pH 1.2 and 7.5, respectively. The tested materials were two commercial activated carbons, carbomix and maxsorb MSC30, one activated carbon fibre produced in our laboratory and also three MCM-41 samples, also produced by us. Selected samples were modified by liquid phase oxidation and thermal treatment in order to change the surface chemistry without significant modifications to the porous characteristics. The fluoxetine adsorption follows the Langmuir model. The calculated Q{sub 0} values range from 54 to 1112 mg/g. A different adsorption mechanism was found for the adsorption of fluoxetine in activated carbon fibres and activated carbons. In the first case the most relevant factors are the molecular sieving effect and the dispersive interactions whereas in the activated carbons the mechanism seams to be based on the electrostatic interactions between the fluoxetine molecules and the charged carbon surface. Despite the different behaviours most of the materials tested have potential for treating potential fluoxetine intoxications. (author)

  2. Mechanical properties and fabrication of small boat using woven glass/sugar palm fibres reinforced unsaturated polyester hybrid composite

    Science.gov (United States)

    Misri, S.; Leman, Z.; Sapuan, S. M.; Ishak, M. R.

    2010-05-01

    In recent years, sugar palm fibre has been found to have great potential to be used as fibre reinforcement in polymer matrix composites. This research investigates the mechanical properties of woven glass/sugar palm fibres reinforced unsaturated polyester hybrid composite. The composite specimens made of different layer of fibres such as strand mat, natural and hand woven of sugar palm fibres. The composites were fabricated using a compression moulding technique. The tensile and impact test was carried out in accordance to ASTM 5083 and ASTM D256 standard. The fibre glass boat is a familiar material used in boat industry. A lot of research on fabrication process such as lay-up, vacuum infusion mould and resin transfer mould has been conducted. Hybrid material of sugar palm fibre and fibre glass was used in fabricating the boat. This research investigates the method selection for fabrication of small boat application of natural fibre composites. The composite specimens made of different layer of fibres; woven glass fibre, strand mat, natural and hand woven of woven sugar palm fibres were prepared. The small boat were fabricated using a compression moulding and lay up technique. The results of the experiment showed that the tensile strength, tensile modulus, elongation at break value and impact strength were higher than the natural woven sugar palm fibre. The best method for fabricating the small boat was compression moulding technique. As a general conclusion, the usage of glass fibre had improved the tensile properties sugar palm fibre composites and compression moulding technique is suitable to be used in making a small boat application of natural fibre composites.

  3. Investigation on mechanical properties of woven alovera/sisal/kenaf fibres and their hybrid composites

    Indian Academy of Sciences (India)

    K PALANI KUMAR; A SHADRACH JEYA SEKARAN; K PITCHANDI

    2017-02-01

    The go-green concept results in multipoint focus towards materials made from nature; easily decomposable and recyclable polymeric materials and their composites along with natural fibres ignited the manufacturing sectors to go for higher altitudes in engineering industries. This is due to the health hazard and environmental problems faced in manufacturing and disposal of synthetic fibres. This study was undertaken to analyse the suitability of new natural fibre as an alternative reinforcement for composite materials. In this paper, tensile, flexural and impact test is made for the woven alovera and kenaf (AK), sisal and kenaf (SK), alovera, sisal and kenaf fibre hybrid epoxy composites (ASK). The composite laminates are made through a hand-layup process. The surface analysis is studied through scanning electron microscopy. From the investigation the SK hybrid composite shows good tensile property, AK hybrid composite shows better flexural property and the best impact strength is observed for ASK hybrid composite. The natural fibres slowly replace the synthetic fibres from its environmental impact, marching towards a revolution in engineering materials.

  4. Prediction of process induced shape distortions and residual stresses in large fibre reinforced composite laminates

    DEFF Research Database (Denmark)

    Nielsen, Michael Wenani

    The present thesis is devoted to numerical modelling of thermomechanical phenomena occurring during curing in the manufacture of large fibre reinforced polymer matrix composites with thick laminate sections using vacuum assisted resin transfer moulding (VARTM). The main application of interest...

  5. The effects of fibre architecture on fatigue life-time of composite materials

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Østergaard, Rasmus

    Wind turbine rotor blades are among the largest composite structures manufactured of fibre reinforced polymer. During the service life of a wind turbine rotor blade, it is subjected to cyclic loading that potentially can lead to material failure, also known as fatigue. With reference to glass fibre...... reinforced composites used for the main laminate of a wind turbine rotor blade, the problem addressed in the present work is the effect of the fibre and fabric architecture on the fatigue life-time under tension-tension loading. Fatigue of composite materials has been a central research topic for the last...... decades; however, a clear answer to what causes the material to degrade, has not been given yet. Even for the simplest kind of fibre reinforced composites, the axially loaded unidirectional material, the fatigue failure modes are complex, and require advanced experimental techniques and characterisation...

  6. Interface and internal compatibility in a copper fibre cement composite

    Directory of Open Access Journals (Sweden)

    Kittl, P.

    1993-09-01

    Full Text Available This paper presents the mechanical behaviour of a compacted composite formed by short ductile copper fibres randomly distributed in portland cement matrix. The samples, a half with fibres and the other without them, were subjected to compression fatigue. So, 1 hertz and the value of stress corresponding to the 1% of the probability of fracture by gradual load were used. Diagrams of cumulative probability of fracture against cycles are obtained for both types of samples. Scanning electron microscopy shows that the mechanisms of fracture are different in each case. Samples of compacted neat-cement paste finish their life with a catastrophic fracture whereas samples of composite behave like a pseudoductile material devoid of catastrophic failure. The results are discussed and compared with the ones obtained by thermal shock and by the interface brittleness theory, as well as with the statistical theory of time-dependent fracture for cementitious materials subjected to cyclic loading. So, in the thermal shock microcracks are generated in the interface matrix-fibre which simultaneously act as emmitings and sumps of cracks whereas this does not occur in mechanical fatigue.

    Este trabajo presenta el comportamiento mecánico de un compuesto fabricado por compactación y constituido por fibras de cobre distribuidas aleatoriamente en una matriz de cemento portland. Las muestras, la mitad con fibras y la otra sin ellas, se sometieron a fatiga por compresión. El ciclo de carga fue de 1 hertz y la carga aplicada aquella correspondiente a la tensión asociada a un 1% de probabilidad de fractura cuando la carga se aplica gradualmente. Para ambos tipos de muestras se graficaron los diagramas de probabilidad acumulativa de fractura en función del número de ciclos. Con microscopía electrónica de barrido se observó que el mecanismo de fractura es diferente para cada tipo de muestras. Aquellas de pasta pura de cemento compactada terminaron su ciclo de

  7. The Effects of Fibre Volume Fraction on a Glass-Epoxy Composite Material

    Directory of Open Access Journals (Sweden)

    Ciprian LARCO

    2015-09-01

    Full Text Available This paper focuses on the analysis of the longitudinal mechanical properties of Glass Fibre Reinforce Plastic (GFRP plates with different fibre volume fraction, Vf, by considering both analytical and experimental methods. The laminate is 0/90 E-glass/epoxy woven composite material made by hand lay-up technique. Fiber volume fraction, determined by ignition loss method, has a direct influence on the ultimate strength and modulus of elasticity of the composite plate. Tensile tests on specimens with different volume fractions allow the identification of the mathematical relationship between the fibre volume fraction and the longitudinal elastic modulus.

  8. Pulsed ytterbium-doped fibre laser with a combined modulator based on single-wall carbon nanotubes

    Science.gov (United States)

    Khudyakov, D. V.; Borodkin, A. A.; Lobach, A. S.; Vartapetov, S. K.

    2015-09-01

    This paper describes an all-normal-dispersion pulsed ytterbium-doped fibre ring laser mode-locked by a nonlinear combined modulator based on single-wall carbon nanotubes. We have demonstrated 1.7-ps pulse generation at 1.04 μm with a repetition rate of 35.6 MHz. At the laser output, the pulses were compressed to 180 fs. We have examined an intracavity nonlinear modulator which utilises nonlinear polarisation ellipse rotation in conjunction with a saturable absorber in the form of a polymer-matrix composite film containing single-wall carbon nanotubes.

  9. Pulsed ytterbium-doped fibre laser with a combined modulator based on single-wall carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Khudyakov, D V; Borodkin, A A; Vartapetov, S K [Physics Instrumentation Center, A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Troitsk, Moscow Region (Russian Federation); Lobach, A S [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2015-09-30

    This paper describes an all-normal-dispersion pulsed ytterbium-doped fibre ring laser mode-locked by a nonlinear combined modulator based on single-wall carbon nanotubes. We have demonstrated 1.7-ps pulse generation at 1.04 μm with a repetition rate of 35.6 MHz. At the laser output, the pulses were compressed to 180 fs. We have examined an intracavity nonlinear modulator which utilises nonlinear polarisation ellipse rotation in conjunction with a saturable absorber in the form of a polymer-matrix composite film containing single-wall carbon nanotubes. (lasers)

  10. Regenerated thermosetting styrene-co-acrylonitrile sandwich composite panels reinforced by jute fibre: structures and properties

    Indian Academy of Sciences (India)

    Jinglong Li; Qin Peng; Anrong Zeng; Junlin Li; Xiaole Wu; Xiaofei Liu

    2016-02-01

    Jute fibres-reinforced sandwich regenerated composite panels were fabricated using industrial waste thermosetting styrene-co-acrylonitrile (SAN) foam scraps via compression moulding for the purpose of recycling waste SAN foam and obtaining high physical performance. The jute fibres were, respectively, treated by heat, sodium hydroxide (NaOH) solution (5.0 wt%), and N,N-dimethylacetamide (DMAc) in order to improve the mechanical properties of the composites. The structures and mechanical properties of the composites were studied. The SAN matrix got compact and some crystalline region formed in SAN matrix via compression moulding. The composite reinforced by DMAc-treated jute fibres performed optimum mechanical properties among the regenerated panels whose impact strength, flexural strength, and compressive strength were 19.9 kJ m−2, 41.7 MPa, and 61.0 MPa, respectively. Good interfacial bonding between DMAc-treated fibres and SAN matrix was verified by peel test and exhibited in SEM photographs. Besides, the water absorption of DMAc-treated fibres composite was lower than other SAN/jute fibre-reinforced sandwich composite panels.

  11. The study of mechanical properties of pineapple leaf fibre reinforced tapioca based bioplastic resin composite

    Directory of Open Access Journals (Sweden)

    Mathivanan D.

    2016-01-01

    Full Text Available Natural fibre reinforced composite has brought the material engineering to a high new level of research. Natural fibres are compatible with matrices like polypropylene and can be used as reinforcement material to reduce the composition of plastic in a material. Natural fibres such as kenaf, pineapple leaf, and coir already found its importance in reducing the dependence of petroleum based products. However the biodegradability of the product at the end of the intended lifespan is still questionable. This has led many researches to look for a suitable replacement for synthetic fibres and achieve better adhesion between fibre and matrix. In this study, fiber and matrix which are hydrophilic in nature was used and the mixture was extruded and hot compressed to acquire better mechanical properties. The specimens were fabricated and tested according to ASTM D638. The 30% composition illustrates the best average modulus value among other composition and from this result it can be concluded that the increase of PALF fibre in TBR composite increases the modulus strength of the composite.

  12. Study of Mechanical Properties of Composite Materials Made from Palm Fruit Fibre and Sawdust

    Directory of Open Access Journals (Sweden)

    E.K. Sosu

    2011-12-01

    Full Text Available To study the possibility of using a composite material made from palm fruit fibre and sawdust as a building material, the modulus of elasticity, fracture load and the maximum deflection of mahogany sawdust and palm fruit fibre-kotolyn veneer composites have been determined using the static bending test. The sawdust particles were sieved into different particle sizes (d: coarse (1.1 mm≤d≤4.8 mm, medium (0.8 mm≤d≤1.1 mm and fine (d≤0.8 mm. Briquettes were made from the sawdust of approximately same particle sizes mixed with palm fibre in different weights proportions, using ‘wood’ glue as a binder. The briquettes were then sandwiched between two pieces of Kotolyn veneer to form the composites. They were then subjected to bending tests. The composite materials made from 100wt% of coarse size sawdust recorded the highest fracture load and modulus of elasticity of 48.00×102 N and 2.23× 106 Nm-2, respectively. Among the composites containing both fibre and sawdust, the 90% wt coarse size-10 wt% fibre recorded the highest fracture load and modulus of elasticity of 30.90×102 N and 1.07×106 Nm-2. Mechanical strength of the composite decreased with decreasing fibre content. The maximum deflection, however, increased with increasing fibre content. The incorporation of fibre into the sawdust briquettes introduces some degree of flexibility into the composite materials with a decrease in the strength and doesn’t make good building material but can be used for domestic finishing’s.

  13. Laser recrystallization and inscription of compositional microstructures in crystalline SiGe-core fibres

    Science.gov (United States)

    Coucheron, David A.; Fokine, Michael; Patil, Nilesh; Breiby, Dag Werner; Buset, Ole Tore; Healy, Noel; Peacock, Anna C.; Hawkins, Thomas; Jones, Max; Ballato, John; Gibson, Ursula J.

    2016-10-01

    Glass fibres with silicon cores have emerged as a versatile platform for all-optical processing, sensing and microscale optoelectronic devices. Using SiGe in the core extends the accessible wavelength range and potential optical functionality because the bandgap and optical properties can be tuned by changing the composition. However, silicon and germanium segregate unevenly during non-equilibrium solidification, presenting new fabrication challenges, and requiring detailed studies of the alloy crystallization dynamics in the fibre geometry. We report the fabrication of SiGe-core optical fibres, and the use of CO2 laser irradiation to heat the glass cladding and recrystallize the core, improving optical transmission. We observe the ramifications of the classic models of solidification at the microscale, and demonstrate suppression of constitutional undercooling at high solidification velocities. Tailoring the recrystallization conditions allows formation of long single crystals with uniform composition, as well as fabrication of compositional microstructures, such as gratings, within the fibre core.

  14. Compartemented fibres: The concept of multiple self-healing in advanced fibre composites

    NARCIS (Netherlands)

    Prajer, M.; Wu, X.; Garcia Espallargas, S.J.; Van der Zwaag, S.

    2013-01-01

    Polymers reinforced with high performance fibres are successfully replacing metal alloys in lightweight aircraft structures. A critical factor in structural design is the resistance of a structure to progressive damage which develops during its service time. The brittle nature of matrix cracking is

  15. Carbon nanofibre composites, preparation and use, EP application 04076211.4

    NARCIS (Netherlands)

    2005-01-01

    The invention is directed to a carbon nanofibre composite having a bulk density of at least 800kg/m3, obtainable by the process of growing carbon nanofibres on the surface of a supported carbon fibre producing metal catalyst, such as a catalyst based on nickel, cobalt, iron, ruthenium or combination

  16. Measurement of Surface Strains from a Composite Hydrofoil using Fibre Bragg Grating Sensing Arrays

    Science.gov (United States)

    2015-07-01

    UNCLASSIFIED UNCLASSIFIED Measurement of Surface Strains from a Composite Hydrofoil using Fibre Bragg Grating Sensing Arrays Claire...arrays to the surface of a composite hydrofoil and reports on an experiment to measure surface strains from the hydrofoil under static and fatigue...July 2015 APPROVED FOR PUBLIC RELEASE UNCLASSIFIED UNCLASSIFIED Measurement of Surface Strains from a Composite Hydrofoil using

  17. Utilisation of fibre reinforced polymer (FRP) composites in the confinement of concrete

    OpenAIRE

    Ciupala, Mihaela Anca; Pilakoutas, K.; Mortazavi, A.A.

    2007-01-01

    This paper presents an experimental investigation carried out on concrete cylinders\\ud confined with fibre reinforced polymers (FRP), subjected to monotonic and cyclic loading.\\ud Carbon fibres (CFRP) were used as confining material for the concrete specimens. The failure\\ud mode, reinforcement ratio based on jacket thickness and type of loading are examined. The study\\ud shows that external confinement of concrete can enhance its strength and ductility as well as result\\ud in large energy ab...

  18. Water Absorption Behaviour and Its Effect on the Mechanical Properties of Flax Fibre Reinforced Bioepoxy Composites

    Directory of Open Access Journals (Sweden)

    E. Muñoz

    2015-01-01

    Full Text Available In the context of sustainable development, considerable interest is being shown in the use of natural fibres like as reinforcement in polymer composites and in the development of resins from renewable resources. This paper focuses on eco-friendly and sustainable green composites manufacturing using resin transfer moulding (RTM process. Flax fibre reinforced bioepoxy composites at different weight fractions (40 and 55 wt% were prepared in order to study the effect of water absorption on their mechanical properties. Water absorption test was carried out by immersion specimens in water bath at room temperature for a time duration. The process of water absorption of these composites was found to approach Fickian diffusion behavior. Diffusion coefficients and maximum water uptake values were evaluated; the results showed that both increased with an increase in fibre content. Tensile and flexural properties of water immersed specimens were evaluated and compared to dry composite specimens. The results suggest that swelling of flax fibres due to water absorption can have positive effects on mechanical properties of the composite material. The results of this study showed that RTM process could be used to manufacture natural fibre reinforced composites with good mechanical properties even for potential applications in a humid environment.

  19. Effect of carbon nanofibre addition on the mechanical properties of different f carbon-epoxy composites

    Indian Academy of Sciences (India)

    I Srikanth; Suresh Kumar; Vajinder Singh; B Rangababu; Partha Ghosal; Ch Subrahmanyam

    2015-04-01

    Carbon-epoxy (C-epoxy) laminated composites having different fibre volume fractions (40, 50, 60 and 70) were fabricated with and without the addition of aminofunctionalized carbon nanofibres (A-CNF). Flexural strength, interlaminar shear strength (ILSS) and tensile strength of the composite laminates were determined. It was observed that, the ability of A-CNF to enhance the mechanical properties of C-epoxy diminished significantly as the fibre volume fraction (f) of the C-epoxy increased from 40 to 60. At 70f, the mechanical properties of the A-CNF reinforced C-epoxy were found to be lower compared to the C-epoxy composite made without the addition of A-CNF. In this paper suitable mechanisms for the observed trends are proposed on the basis of the fracture modes of the composite.

  20. Proposition of an Accelerated Ageing Method for Natural Fibre/Polylactic Acid Composite

    Science.gov (United States)

    Zandvliet, Clio; Bandyopadhyay, N. R.; Ray, Dipa

    2015-10-01

    Natural fibre composite based on polylactic acid (PLA) composite is of special interest because it is entirely from renewable resources and biodegradable. Some samples of jute/PLA composite and PLA alone made 6 years ago and kept in tropical climate on a shelf shows too fast ageing degradation. In this work, an accelerated ageing method for natural fibres/PLA composite is proposed and tested. Experiment was carried out with jute and flax fibre/PLA composite. The method was compared with the standard ISO 1037-06a. The residual flexural strength after ageing test was compared with the one of common wood-based panels and of real aged samples prepared 6 years ago.

  1. A high-porosity carbon molybdenum sulphide composite with enhanced electrochemical hydrogen evolution and stability

    DEFF Research Database (Denmark)

    Laursen, Anders B.; Vesborg, Peter C. K.; Chorkendorff, Ib

    2013-01-01

    This work describes a highly active and stable acid activated carbon fibre and amorphous MoSx composite hydrogen evolution catalyst. The increased electrochemical-surface area is demonstrated to cause increased catalyst electrodeposition and activity. These composite electrodes also show an impro......This work describes a highly active and stable acid activated carbon fibre and amorphous MoSx composite hydrogen evolution catalyst. The increased electrochemical-surface area is demonstrated to cause increased catalyst electrodeposition and activity. These composite electrodes also show...

  2. CARBON-FIBRE-REINFORCED POLYMER PARTS EFFECT ON SPACECRAFT OPTOELECTRONIC MODULE LENS SCATTERING

    Directory of Open Access Journals (Sweden)

    S. S. Kolasha

    2016-01-01

    Full Text Available Spacecraft optoelectronic modules traditionally have aluminum alloy or titanium alloy casing which substantial weight increases fuel consumption required to put them into orbit and, consequently, total cost of the project. Carbon fiber reinforced polymer based composite constructive materials is an efficient solution that allows reducing weight and dimensions of large optoelectronic modules 1,5–3 times and the coefficient of linear thermal expansion 15–20 times if compared with metals. Optical characteristic is a crucial feature of carbon-fibre-reinforced polymer that determines composite material interaction with electromagnetic emission within the optical range. This work was intended to develop a method to evaluate Carbon fiber reinforced polymer optoelectronic modules casing effect on lens scattering by computer simulation with Zemax application software package. Degrees of scattered, reflected and absorbed radiant flux effect on imaging quality are described here. The work included experimental study in order to determine bidirectional reflectance distribution function by goniometric method for LUP-0.1 carbon fabric check test pieces of EDT-69U epoxy binder with EPOFLEX-0.4 glue layer and 5056-3.5-23-A aluminium honeycomb filler. The scattered emission was registered within a hemisphere above the check test piece surface. Optical detection direction was determined with zenith (0º < θ < 90º and azimuth (0º < φ < 180º angles with 10° increment. The check test piece surface was proved to scatter emission within a narrow angle range (approximately 20° with clear directivity. Carbon fiber reinforced polymers was found to feature integrated reflectance coefficient 3 to 4 times greater than special coatings do. 

  3. Research of glass fibre used in the electromagnetic wave shielding and absorption composite material

    Science.gov (United States)

    Xu, M.; Jia, F.; Bao, H. Q.; Cui, K.; Zhang, F.

    2016-07-01

    Electromagnetic shielding and absorption composite material plays an important role in the defence and economic field. Comparing with other filler, Glass fibre and its processed product—metal-coated glass fibre can greatly reduce the material's weight and costs, while it still remains the high strength and the electromagnetic shielding effectiveness. In this paper, the electromagnetic absorption mechanism and the reflection mechanism have been investigated as a whole, and the shielding effectiveness of the double-layer glass fibre composite material is mainly focused. The relationship between the shielding effectiveness and the filled glass fibre as well as its metal-coated product's parameters has also been studied. From the subsequent coaxial flange and anechoic chamber analysis, it can be confirmed that the peak electromagnetic shielding effectiveness of this double-layer material can reach -78dB while the bandwidth is from 2GHz to 18GHz.

  4. Fatigue damage propagation in unidirectional glass fibre reinforced composites made of a non-crimp fabric

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Brøndsted, Povl; Gillespie Jr., John W.

    2014-01-01

    Damage progression in unidirectional glass fibre reinforced composites manufactured of a non-crimp fabric subjected to tension-tension fatigue is investigated, and a quantitative explanation is given for the experimentally observed stiffness degradation. The underlying damage-mechanisms are exami......Damage progression in unidirectional glass fibre reinforced composites manufactured of a non-crimp fabric subjected to tension-tension fatigue is investigated, and a quantitative explanation is given for the experimentally observed stiffness degradation. The underlying damage...... fatigue, gives rise to axial fibre fractures and a loss of stiffness, eventually leading to final failure. The uniqueness of the present work is identification of the mechanisms associated with tension fatigue failure of unidirectional non-crimp fabrics used for wind turbine blades. The observed damage...... mechanisms need further attention and understanding in order to improve the fatigue life-time of unidirectional glass fibre reinforced non-crimp fabrics....

  5. Fibre-matrix interfaces in titanium matrix composites made with sigma monofilament

    Energy Technology Data Exchange (ETDEWEB)

    Shatwell, R.A. [DERA, Farnborough (United Kingdom). Struct. Mater. Centre

    1999-01-31

    A review of the development of coatings for sigma monofilament is given. The coating must protect the underlying silicon carbide before, during and after consolidation. This requires the coating outer surface to be under negative or zero residual stress at room temperature. The coating should also be well bonded to the SiC. It is shown that stoichiometric TiB{sub 2} is under a tensile stress of around 3 GPa under these conditions and hence is unsuitable. The boron-rich outer surface of SM1240 is essentially unstressed and the carbon surface of SM1140+ is under {approx}300 MPa axial compressive stress. Failure of monofilament in the composite initiates at the W-SiC interface, rather than at the metal-fibre interface characteristic of SCS-6. In order to ensure this behaviour, the coating in the composite must be thick enough to ensure that the stress concentration field arising from irregularities at the TiC-C boundary do not initiate fracture of the SiC. This requires a minimum thickness of around 1 {mu}m of carbon. (orig.) 10 refs.

  6. Mechanical properties of sisal fibre reinforced urea-formaldehyde resin composites

    Directory of Open Access Journals (Sweden)

    2007-10-01

    Full Text Available Alkali-treated sisal fibres were used as novel reinforcement to obtain composites with self-synthesized ureaformaldehyde resin as matrix phase. The composites were prepared by means of compression molding, and then the effects of sisal loading on mechanical properties such as impact strength, flexural strength, and wear resistance were investigated. In addition, water uptake was studied and structural features were revealed by the scanning electron microscopy (SEM. The composite with 30 wt% sisal fibres gives excellent flexural strength, water absorption, and especially the wear resistance showing that it has the most superior bonding and adhesion of all the composites. In particular, the highest value 9.42 kJ/m2 of charpy impact strength is observed in the composite with 50 wt% sisal fibre. SEM micrographs of impact fractured and worn surfaces clearly demonstrate the interfacial adhesion between fibre and matrix. This work shows the potential of sisal fibre (SF to improve the composite wear resistance and to be used in fibreboard.

  7. The anatomy and fibre type composition of the human adductor pollicis in relation to its contractile properties.

    Science.gov (United States)

    Round, J M; Jones, D A; Chapman, S J; Edwards, R H; Ward, P S; Fodden, D L

    1984-01-01

    We have examined the anatomy and fibre type composition of the human adductor pollicis in muscles taken post mortem. Histochemical staining of muscle fibres showed that type I fibres predominated in all cases with a mean occurrence of 80%. This composition is similar to that of the soleus muscle and unlike that of the quadriceps which has approximately equal proportions of the two fibre types. Comparing the contractile characteristics, however, the adductor pollicis has similar properties to the quadriceps and both are quite distinct from those of the slowly contracting soleus muscle. The lack of correlation between fibre composition, as revealed by histochemical staining, and contractile properties in these muscles must mean that fibres of the same type from different muscles do not necessarily have the same contractile speed. The results also suggest that the type I fibres of the human adductor pollicis are faster than those of both the soleus and quadriceps muscles.

  8. The effects of fibre architecture on fatigue life-time of composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Zangenberg Hansen, J.

    2013-09-15

    Wind turbine rotor blades are among the largest composite structures manufactured of fibre reinforced polymer. During the service life of a wind turbine rotor blade, it is subjected to cyclic loading that potentially can lead to material failure, also known as fatigue. With reference to glass fibre reinforced composites used for the main laminate of a wind turbine rotor blade, the problem addressed in the present work is the effect of the fibre and fabric architecture on the fatigue life-time under tension-tension loading. Fatigue of composite materials has been a central research topic for the last decades; however, a clear answer to what causes the material to degrade, has not been given yet. Even for the simplest kind of fibre reinforced composites, the axially loaded unidirectional material, the fatigue failure modes are complex, and require advanced experimental techniques and characterisation methodologies in order to be assessed. Furthermore, numerical evaluation and predictions of the fatigue damage evolution are decisive in order to make future improvements. The present work is focused around two central themes: fibre architecture and fatigue failure. The fibre architecture is characterised using real material samples and numerical simulations. Experimental fatigue tests identify, quantify, and analyse the cause of failure. Different configurations of the fibre architecture are investigated in order to determine and understand the tension-tension fatigue failure mechanisms. A numerical study is used to examine the onset of fatigue failure. Topics treated include: experimental fatigue investigations, scanning electron microscopy, numerical simulations, advanced measurements techniques (micro computed tomography and thermovision), design of test specimens and preforms, and advanced materials characterisation. The results of the present work show that the fibre radii distribution has limited effect on the fibre architecture. This raises the question of which

  9. Hydrogen evolution reaction at Ru-modified nickel-coated carbon fibre in 0.1 M NaOH

    Directory of Open Access Journals (Sweden)

    Pierożyński Bogusław

    2015-03-01

    Full Text Available The electrochemical activity towards hydrogen evolution reaction (HER was studied on commercially available (Toho-Tenax and Ru-modified nickel-coated carbon fibre (NiCCF materials. Quality and extent of Ru electrodeposition on NiCCF tows were examined by means of scanning electron microscopy (SEM. Kinetics of the hydrogen evolution reaction were investigated at room temperature, as well as over the temperature range: 20-50°C in 0.1 M NaOH solution for the cathodic overpotential range: -100 to -300 mV vs. RHE. Corresponding values of charge-transfer resistance, exchange current-density for the HER and other electrochemical parameters for the examined fibre tow composites were recorded.

  10. Fatigue Damage Monitoring of a Composite Step Lap Joint Using Distributed Optical Fibre Sensors

    Directory of Open Access Journals (Sweden)

    Leslie Wong

    2016-05-01

    Full Text Available Over the past few decades, there has been a considerable interest in the use of distributed optical fibre sensors (DOFS for structural health monitoring of composite structures. In aerospace-related work, health monitoring of the adhesive joints of composites has become more significant, as they can suffer from cracking and delamination, which can have a significant impact on the integrity of the joint. In this paper, a swept-wavelength interferometry (SWI based DOFS technique is used to monitor the fatigue in a flush step lap joint composite structure. The presented results will show the potential application of distributed optical fibre sensor for damage detection, as well as monitoring the fatigue crack growth along the bondline of a step lap joint composite structure. The results confirmed that a distributed optical fibre sensor is able to enhance the detection of localised damage in a structure.

  11. Abrasive wear: The efects of fibres size on oil palm empty fruit bunch polyester composite

    Science.gov (United States)

    Kasolang, S.; Kalam, A.; Ahmad, M. A.; Rahman, N. A.; Suhadah, W. N.

    2012-06-01

    This paper presents an experimental investigation carried out to determine the effect of palm oil empty fruit bunch (OPEFB) fibre size in dry sliding testing of polyester composite. These composite samples were produced by mixing raw OPEFB fibre with resin. The samples were prepared at different sizes of fibre (100, 125, 180 and 250μm). Abrasion Resistance Tester (TR-600) was used to carried out abrasive wear tests in dry sliding conditions. These tests were performed at room temperature for two different loads (10 and 30N) and at a constant sliding velocity of 1.4m/s. The specific wear rates of OPEFB polyester composites were obtained. The morphology of composite surface before and after tests was also examined using 3D microscope imaging. Preliminary work on thermal distribution at the abrasive wheel point was also conducted for selected samples.

  12. Corn gluten meal as a biodegradable matrix material in wood fibre reinforced composites

    Energy Technology Data Exchange (ETDEWEB)

    Beg, M.D.H. [Department of Materials and Process Engineering, University of Waikato, Private Bag 3105, Hamilton (New Zealand); Pickering, K.L. [Department of Materials and Process Engineering, University of Waikato, Private Bag 3105, Hamilton (New Zealand)]. E-mail: klp@waikato.ac.nz; Weal, S.J. [Department of Materials and Process Engineering, University of Waikato, Private Bag 3105, Hamilton (New Zealand)

    2005-12-05

    This study was undertaken to investigate corn gluten meal (CGM) as a biodegradable matrix material for wood fibre reinforced composites. CGM was used alone, as well as hybridized with polypropylene, and reinforced with radiata pine (Pinus Radiata) fibre using a twin-screw extruder followed by injection moulding. Tensile testing, scanning electron microscopy and differential scanning calorimetry were carried out to assess the composites. For composites from CGM and wood fibres, extrusion was carried out with the aid of the following plasticizers: octanoic acid, glycerol, polyethylene glycol and water. Windows of processability for the different plasticizers were obtained for all plasticizers. These were found to lie between 20 and 50 wt.% of plasticizer with a maximum of approximately 20% wood fibre reinforcement. The best mechanical properties were obtained with a matrix containing 10 wt.% octanoic acid and 30 wt.% water, which gave a tensile strength and Young's modulus of 18.7 MPa and 4 GPa, respectively. Hybrid matrix composites were compounded with a maleated polypropylene coupling agent and benzoyl peroxide as a cross-linking agent. The highest tensile strength and Young's modulus obtained from hybrid matrix composites were 36.9 MPa and 5.8 GPa with 50 wt.% fibre.

  13. Carbon fibre tips for scanning probe microscopy based on quartz tuning fork force sensors

    Energy Technology Data Exchange (ETDEWEB)

    Castellanos-Gomez, A; Agrait, N; Rubio-Bollinger, G, E-mail: gabino.rubio@uam.es [Departamento de Fisica de la Materia Condensada (C-III), Universidad Autonoma de Madrid, Campus de Cantoblanco, 28049 Madrid (Spain)

    2010-04-09

    We report the fabrication and the characterization of carbon fibre tips for use in combined scanning tunnelling and force microscopy based on piezoelectric quartz tuning fork force sensors. We find that the use of carbon fibre tips results in a minimum impact on the dynamics of quartz tuning fork force sensors, yielding a high quality factor and, consequently, a high force gradient sensitivity. This high force sensitivity, in combination with high electrical conductivity and oxidation resistance of carbon fibre tips, make them very convenient for combined and simultaneous scanning tunnelling microscopy and atomic force microscopy measurements. Interestingly, these tips are quite robust against occasionally occurring tip crashes. An electrochemical fabrication procedure to etch the tips is presented that produces a sub-100-nm apex radius in a reproducible way which can yield high resolution images.

  14. Effect of degumming time on silkworm silk fibre for biodegradable polymer composites

    Science.gov (United States)

    Ho, Mei-po; Wang, Hao; Lau, Kin-tak

    2012-02-01

    Recently, many studies have been conducted on exploitation of natural materials for modern product development and bioengineering applications. Apart from plant-based materials (such as sisal, hemp, jute, bamboo and palm fibre), animal-based fibre is a kind of sustainable natural materials for making novel composites. Silkworm silk fibre extracted from cocoon has been well recognized as a promising material for bio-medical engineering applications because of its superior mechanical and bioresorbable properties. However, when producing silk fibre reinforced biodegradable/bioresorbable polymer composites, hydrophilic sericin has been found to cause poor interfacial bonding with most polymers and thus, it results in affecting the resultant properties of the composites. Besides, sericin layers on fibroin surface may also cause an adverse effect towards biocompatibility and hypersensitivity to silk for implant applications. Therefore, a proper pre-treatment should be done for sericin removal. Degumming is a surface modification process which allows a wide control of the silk fibre's properties, making the silk fibre possible to be used for the development and production of novel bio-composites with unique/specific mechanical and biodegradable properties. In this paper, a cleaner and environmentally friendly surface modification technique for tussah silk in polymer based composites is proposed. The effectiveness of different degumming parameters including degumming time and temperature on tussah silk is discussed through the analyses of their mechanical and morphological properties. Based on results obtained, it was found that the mechanical properties of tussah silk are affected by the degumming time due to the change of the fibre structure and fibroin alignment.

  15. Shear Strengthening of Corbels with Carbon Fibre Reinforced Polymers (CFRP

    Directory of Open Access Journals (Sweden)

    Nawaz, A.

    2010-09-01

    Full Text Available Corbels constitute what are known as “disturbed” regions in concrete structures, where typical shear failure may be anticipated on the grounds of small shear span-to-depth ratios. The concentration of stress induced by the weight of girders on the very small loadbearing areas in corbels often causes cracking in bridges and other structures. Little experimental research can be found in the literature on the shear strengthening of corbels. In the present study, nine such members were tested. Two had no carbon fibre reinforced polymers attached, while CFRP laminates were externally bonded to the other seven, in a number of different spatial arrangements. Ultimate shear strength was found and compared for all specimens. The results showed that CFRP configuration and geometry directly affected corbel shear strength, which was higher in all the CFRPstrengthened corbels than in the controls. The highest strength values were recorded for specimens whose shear-critical area was wrapped in CFRP.

    Las ménsulas constituyen lo que conocemos como regiones de “distorsión” en las estructuras de hormigón, zonas en que pueden preverse roturas por cortante debido a las bajas relaciones luz de cortante-canto presentes en ellas. La concentración de solicitaciones producida por el peso de las vigas sobre superficies de carga muy reducidas en las ménsulas a menudo provoca el agrietamiento de puentes y otras estructuras de obra civil. En la literatura especializada sobre el refuerzo a cortante de las ménsulas existen escasos ejemplos de estudios experimentales. Para la presente investigación se han realizado ensayos con nueve elementos de este tipo. Dos de ellos no incluían polímeros reforzados con fibra de carbono (CFRP, mientras que los siete restantes llevaban láminas externas de CFRP, dispuestas siguiendo distintas configuraciones espaciales. Los resultados indican que la configuración y la disposición geométrica de los CFRP repercuten

  16. Properties of compression moulded new fully biobased thermoset composites with aligned flax fibre textiles

    DEFF Research Database (Denmark)

    Pohl, Th.; Bierer, M.; Natter, E.

    2011-01-01

    The development of aligned natural fibre reinforced composites utilising biobased thermosets is an essential step towards the manufacture of ecofriendly composite systems. In many cases, the matrix system, which is usually oil based in nature, is disregarded. Therefore, a new fully biobased...

  17. Fatigue behaviour of uni-directional flax fibre/epoxy composites

    DEFF Research Database (Denmark)

    Ueki, Yosuke; Lilholt, Hans; Madsen, Bo

    2015-01-01

    A study related to the fatigue behaviour of natural fibre-reinforced composites was conducted to expand their range of product applications. A uni-directional flax-epoxy composite was fabricated and several conditions of tension-tension fatigue tests were performed. During fatigue testing...

  18. Atmospheric pressure plasma treatment of glass fibre composite for adhesion improvement

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Mortensen, H.; Stenum, Bjarne

    2007-01-01

    Glass-fibre-reinforced polyester composite plates were treated with an atmospheric pressure dielectric barrier discharge. Synthetic air was used as the treatment gas. The water contact angle dropped markedly from 84 to 22° after a 2-s treatment, and decreased to 0° when the composite plates were...

  19. A Spray Pyrolysis Method to Grow Carbon Nanotubes on Carbon Fibres, Steel and Ceramic Bricks.

    Science.gov (United States)

    Vilatela, Juan J; Rabanal, M E; Cervantes-Sodi, Felipe; García-Ruiz, Máximo; Jiménez-Rodríguez, José A; Reiband, Gerd; Terrones, Mauricio

    2015-04-01

    We demonstrate a spray pyrolysis method to grow carbon nanotubes (CNTs) with high degree of crystallinity, aspect ratio and degree of alignment on a variety of different substrates, such as conventional steel, carbon fibres (CF) and ceramics. The process consists in the chemical vapour deposition of both a thin SiO2 layer and CNTs that subsequently grow on this thin layer. After CNT growth, increases in specific surface by factors of 1000 and 30 for the steel and CF samples, respectively, are observed. CNTs growth on ceramic surfaces results in a surface resistance of 37.5 Ohm/sq. When using conventional steel as a rector tube, we observed CNTs growth rates of 0.6 g/min. Details of nanotube morphology and the growth mechanism are discussed. Since the method discussed here is highly versatile, it opens up a wide variety of applications in which specific substrates could be used in combination with CNTs.

  20. In-situ polymerisation of fully bioresorbable polycaprolactone/phosphate glass fibre composites: In vitro degradation and mechanical properties.

    Science.gov (United States)

    Chen, Menghao; Parsons, Andrew J; Felfel, Reda M; Rudd, Christopher D; Irvine, Derek J; Ahmed, Ifty

    2016-06-01

    Fully bioresorbable composites have been investigated in order to replace metal implant plates used for hard tissue repair. Retention of the composite mechanical properties within a physiological environment has been shown to be significantly affected due to loss of the integrity of the fibre/matrix interface. This study investigated phosphate based glass fibre (PGF) reinforced polycaprolactone (PCL) composites with 20%, 35% and 50% fibre volume fractions (Vf) manufactured via an in-situ polymerisation (ISP) process and a conventional laminate stacking (LS) followed by compression moulding. Reinforcing efficiency between the LS and ISP manufacturing process was compared, and the ISP composites revealed significant improvements in mechanical properties when compared to LS composites. The degradation profiles and mechanical properties were monitored in phosphate buffered saline (PBS) at 37°C for 28 days. ISP composites revealed significantly less media uptake and mass loss (pcomposites were substantially higher (pcomposites, which showed that the ISP manufacturing process provided a significantly enhanced reinforcement effect than the LS process. During the degradation study, statistically higher flexural property retention profiles were also seen for the ISP composites compared to LS composites. SEM micrographs of fracture surfaces for the LS composites revealed dry fibre bundles and poor fibre dispersion with polymer rich zones, which indicated poor interfacial bonding, distribution and adhesion. In contrast, evenly distributed fibres without dry fibre bundles or polymer rich zones, were clearly observed for the ISP composite samples, which showed that a superior fibre/matrix interface was achieved with highly improved adhesion.

  1. Fibrous Polymeric Composites Based on Alginate Fibres and Fibres Made of Poly-ε-caprolactone and Dibutyryl Chitin for Use in Regenerative Medicine

    Directory of Open Access Journals (Sweden)

    Elżbieta Menaszek

    2013-03-01

    Full Text Available This work concerns the production of fibrous composite materials based on biodegradable polymers such as alginate, dibutyryl chitin (DBC and poly-ε-caprolactone (PCL. For the production of fibres from these polymers, various spinning methods were used in order to obtain composite materials of different composition and structure. In the case of alginate fibres containing the nanoadditive tricalcium phosphate (TCP, the traditional method of forming fibres wet from solution was used. However in the case of the other two polymers the electrospinning method was used. Two model systems were tested for biocompatibility. The physicochemical and basic biological tests carried out show that the submicron fibres produced using PCL and DBC have good biocompatibility. The proposed hybrid systems composed of micrometric fibres (zinc and calcium alginates containing TCP and submicron fibres (DBC and PCL meet the requirements of regenerative medicine. The biomimetic fibre system, the presence of TCP nanoadditive, and the use of polymers with different resorption times provide a framework with specific properties on which bone cells are able to settle and proliferate.

  2. Effects of chemical-physical pre-treatment processes on hemp fibres for reinforcement of composites and textiles

    DEFF Research Database (Denmark)

    Thomsen, Anne Belinda; Thygesen, Anders; Bohn, Vibeke

    2006-01-01

    Retted hemp fibres were treated using chemical-physical pre-treatments and the material was characterised chemically in order to evaluate the effect of the pre-treatments, respectively, wet oxidation (WO), hydrothermal treatment (HT) and steam explosion (STEX). Process variables were addition...... of base and oxidant. These treatments were performed to make fibres that are useful as reinforcement in composite materials and for textiles. All pre-treatments tested increased the content of cellulose in the fibres by degrading and dissolving non-cell wall material (NCWM, e.g., pectin and waxes), lignin......, the pre-treatments gave fibre colours ranging from white to dark brown. Alkaline wet oxidation produced the brightest fibres with potential for use in textiles. Use of retted fibres in the pre-treatment resulted in fibres with high cellulose content (86-90%) of potential as reinforcement in composite...

  3. A composite fibre optic catheter for monitoring peristaltic transit of an intra-luminal bead.

    Science.gov (United States)

    Arkwright, John W; Underhill, Ian D; Dodds, Kelsi N; Brookes, Simon J H; Costa, Marcello; Spencer, Nick J; Dinning, Phil G

    2016-03-01

    A fibre optic motion sensor has been developed for monitoring the proximity and direction of motion of a ferrous bead travelling axial to the sensor. By integrating an array of these sensors into our previously developed fibre optic manometry catheters we demonstrate simultaneous detection of peristaltic muscular activity and the associated motion of ferrous beads through a colonic lumen. This allows the motion of solid content to be temporally and spatially related to pressure variations generated by peristaltic contractions without resorting to videoflouroscopy to track the motion of a radio opaque bolus. The composite catheter has been tested in an in-vitro animal preparation consisting of excised sections of rabbit colon. Cut-away image of the fibre optic motion sensor showing the location of the fibre Bragg gratings and the rare earth magnet.

  4. Carbon nanotube composite materials

    Energy Technology Data Exchange (ETDEWEB)

    O' Bryan, Gregory; Skinner, Jack L; Vance, Andrew; Yang, Elaine Lai; Zifer, Thomas

    2015-03-24

    A material consisting essentially of a vinyl thermoplastic polymer, un-functionalized carbon nanotubes and hydroxylated carbon nanotubes dissolved in a solvent. Un-functionalized carbon nanotube concentrations up to 30 wt % and hydroxylated carbon nanotube concentrations up to 40 wt % can be used with even small concentrations of each (less than 2 wt %) useful in producing enhanced conductivity properties of formed thin films.

  5. The application of the eshelby method of internal stress determination to short fibre metal matrix composites

    DEFF Research Database (Denmark)

    Withers, P.J.; Stobbs, W.M.; Pedersen, O.B.

    1989-01-01

    Eshelby's equivalent inclusion approach is used to provide a rigorous theoretical basis for the prediction of the mechanical properties of short fibre composites. The equivalent inclusion construction which is central to this method is described in detail. The elastic, thermoelastic and plastic...... behaviour of short fibre metal matrix composites is predicted, and, taking the Al/SiC system as an example, compared with experiment. Finally, it is shown that relaxation phenomena play an important role in the development of internal stresses, and that the energetics and the resultant stress redistribution...

  6. Coefficient of Friction Measurements for Thermoplastics and Fibre Composites Under Low Sliding Velocity and High Pressure

    DEFF Research Database (Denmark)

    Poulios, Konstantinos; Svendsen, Gustav Winther; Hiller, Jochen

    2013-01-01

    that friction materials which are untypical for brake applications, like thermoplastics and fibre composites, can offer superior performance in terms of braking torque, wear resistance and cost than typical brake linings. In this paper coefficient of friction measurements for various thermoplastic and fibre...... composite materials running against a steel surface are presented. All tests were carried out on a pinon-disc test-rig in reciprocating operation at a fixed sliding speed and various pressure levels for both dry and grease lubricated conditions. Moreover, a generic theoretical framework is introduced...

  7. Constructive applications of composite gypsum reinforced with Typha Latifolia fibres

    Directory of Open Access Journals (Sweden)

    Garcia Santos, A.

    2004-03-01

    Full Text Available The present research analyses the possibility to reinforce gypsum using enea fibres (Typha Latifolia creating a compound material in wich the fibres contribute to increase mechanical resistance, producing as well a reduction of the weight and a possible regulation of the set time.

    La investigación presente analiza la posibilidad de reforzar los morteros de escayola mediante la utilización dé fibras de Typha Latifolia, creando un material compuesto en el que las fibras contribuyen al aumento de resistencia mecánica, a la vez que se produce una reducción del peso y una regulación de los tiempos de fraguado. Las propiedades de estos materiales hacen que, en determinadas aplicaciones, su utilización resulte ventajosa con respecto a materiales tradicionales.

  8. Mechanical behaviour of degradable phosphate glass fibres and composites-a review.

    Science.gov (United States)

    Colquhoun, R; Tanner, K E

    2015-12-23

    Biodegradable materials are potentially an advantageous alternative to the traditional metallic fracture fixation devices used in the reconstruction of bone tissue defects. This is due to the occurrence of stress shielding in the surrounding bone tissue that arises from the absence of mechanical stimulus to the regenerating bone due to the mismatch between the elastic modulus of bone and the metal implant. However although degradable polymers may alleviate such issues, these inert materials possess insufficient mechanical properties to be considered as a suitable alternative to current metallic devices at sites of sufficient mechanical loading. Phosphate based glasses are an advantageous group of materials for tissue regenerative applications due to their ability to completely degrade in vivo at highly controllable rates based on the specific glass composition. Furthermore the release of the glass's constituent ions can evoke a therapeutic stimulus in vivo (i.e. osteoinduction) whilst also generating a bioactive response. The processing of these materials into fibres subsequently allows them to act as reinforcing agents in degradable polymers to simultaneously increase its mechanical properties and enhance its in vivo response. However despite the various review articles relating to the compositional influences of different phosphate glass systems, there has been limited work summarising the mechanical properties of different phosphate based glass fibres and their subsequent incorporation as a reinforcing agent in degradable composite materials. As a result, this review article examines the compositional influences behind the development of different phosphate based glass fibre compositions intended as composite reinforcing agents along with an analysis of different potential composite configurations. This includes variations in the fibre content, matrix material and fibre architecture as well as other novel composites designs.

  9. Behaviour of -glass fibre reinforced vinylester resin composites under impact fatigue

    Indian Academy of Sciences (India)

    Rita Roy; B K Sarkar; N R Bose

    2001-04-01

    An impact fatigue study has been made for the first time on 63.5% glass fibre reinforced vinylester resin notched composites. The study was conducted in a pendulum type repeated impact apparatus especially designed and fabricated for determining single and repeated impact strengths. A well-defined impact fatigue (S–N) behaviour, having a progressive endurance below the threshold single cycle impact fracture stress with decreasing applied stress has been demonstrated. Fractographic analysis revealed fracture by primary debonding having fibre breakage and pullout at the tensile zone, but a shear fracture of fibre bundles at the compressive zone of the specimen. The residual strength, modulus and toughness showed retention of the properties at high impact stress levels up to 1000 impacts followed by a sharp drop. Cumulative residual stresses with each number of impacts not withstanding the static fatigue failure at long endurances have been ascribed for the composite failures under the repeated impact stresses.

  10. Tensile properties of unidirectional glass/epoxy composites at different orientations of fibres

    Directory of Open Access Journals (Sweden)

    Alok Hegde

    2015-03-01

    Full Text Available In this work, Diglycidyl Ether of BisphenolA(DGEBA / TriEthylene Tetra Amine(TETA system is used as the epoxy matrix and unidirectional glass fabric is used to reinforce with the polymer matrix by hand layup and vacuum bagging process. The glass fibre reinforced composites are prepared with fibre orientations of 0°, 45° and 90°. The specimens, after preparation, are tested for various tensile properties at different angles of the laminate. The tensile properties studied in this case are Tensile Strength, Tensile Modulus, Specific Tensile Strength and Specific Tensile Modulus. The result shave then been tabulated and studied to understand variation in the properties with orientation of fibre in the composite. Experimental procedure is carried out as per ASTM D3039 standards.

  11. A Preliminary Study on Ultrasonic Cutting Process for Carbon Fibre Prepreg

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In ultrasonic cutting process, the cutting pressure is still essential for achieving good quality cut edge compared with traditional mechanical cutting process. With the increase of the cutting power, the cutting pressure demand decreases. The cutting velocity range is extended broadly. The experiment results show that ultrasonic cutting technique is an effective, clean and controllable method for machining of carbon fibre prepreg.

  12. Pulse-Width Increase of Reflex Triode Vircator Using the Carbon Fibre Cathode

    Institute of Scientific and Technical Information of China (English)

    LIU Lie; LI Li-Min; ZHANG Xiao-Ping; WEN Jian-Chun; WAN Hong

    2006-01-01

    @@ We present the investigation on the reflex triode virtual cathode oscillator in which performances of carbonfibre and stainless-steel cathodes are compared with each other. The experimental results and analyses show that surface tracking induces the electron emission of the carbon fibre cathode.

  13. Pressure impact of autoclave treatment on water sorption and pectin composition of flax cellulosic-fibres.

    Science.gov (United States)

    Alix, S; Colasse, L; Morvan, C; Lebrun, L; Marais, S

    2014-02-15

    The tensile properties of flax fibres might permit them to be used in composites as reinforcement in organic resin, as long as their mechanical properties are reproducible and their water sorption are reduced. In this study, to minimise the variability of mechanical properties, several samples of flax fibres were blended as a non-woven fabric. In order to reduce the water absorption of this non-woven technical fibres, an autoclave treatment was performed which was expected to remove the pectins and then to reduce the water sorption on their negative charges. The impact of autoclave pressure (0.5, 1 and 2 bars) on water sorption was investigated by using a gravimetric static equilibrium method. The Park model based on the three sorption modes: Langmuir, Henry's law and clustering, was successfully used to simulate the experimental sorption data. The lowest pressure treatments impacted only the Langmuir contribution while the 2 bar autoclave-treatment positively impacted the water resistance in the core of fibres by reducing Henry's absorption rate. This was shown to be related to the chemical modifications at the surface and in the core of fibres. A schematic model is presented relating the water sorption and the pectic composition of the fabric.

  14. Ballistic Applications of Glass and Kevlar Fibre Vinylester Composites

    Directory of Open Access Journals (Sweden)

    S. P. Panda

    1994-10-01

    Full Text Available Void-free E-glass and Kevlar-49 fibre reinforced vinylester laminates prepared under compression moulding were found to have Charpy impact strength of 576 KJlm2 and 304 KJlm2, respectively. Ballistic immunisation tests carried out on the glass reinforced vinylester laminates with thickness ranging from 12 mm to 54 mm against 7.62 mm rifle bullets produced an exponential relationship between the per cent attenuation in bullet velocity and the areal density of the laminates; whereas the relationship was linear for 9 mm carbine fire with laminate thicknessvarying from 5.5 mm to 12 mm .

  15. Metabolic response to dietary fibre composition in horses

    DEFF Research Database (Denmark)

    Brøkner, Christine; Austbø, D; Næsset, Jon Anders

    2016-01-01

    . The feed rations consisted of only timothy hay (H), hay plus molassed sugar beet pulp combined with either whole oats (OB) or barley (BB) and hay plus a loose chaff-based concentrate (M). Four horses were fitted with permanent caecal cannulas and liquid caecal content was withdrawn manually and blood...... was drawn from the jugular vein at 0, 3 and 9 h postprandial. The horses were exercised daily at medium level for about 1 h. Samples were analysed for short-chain fatty acids (SCFA) and metabolic traits. Caecal SCFA and propionic acid concentrations increased with increased dietary starch and soluble fibre...... energy for horses at medium work level....

  16. Effect of fibre content and alkali treatment on mechanical properties of Roystonea regia-reinforced epoxy partially biodegradable composites

    Indian Academy of Sciences (India)

    Govardhan Goud; R N Rao

    2011-12-01

    The present paper investigates the effect of fibre content and alkali treatment on tensile, flexural and impact properties of unidirectional Roystonea regia natural-fibre-reinforced epoxy composites which are partially biodegradable. The reinforcement Roystonea regia (royal palm) fibre was collected from the foliage of locally available royal palm tree through the process of water retting and mechanical extraction. The poor adhesion between fibre and matrix is commonly encountered problem in natural-fibre-reinforced composites. To overcome this problem, specific physical and chemical treatments were suggested for surface modification of fibres by investigators. Alkali treatment is one of the simple and effective surface modification techniques which is widely used in natural fibre composites. In the present study both untreated and alkali-treated fibres were used as reinforcement in Roystonea regia epoxy composites and the tensile, flexural and impact properties were determined at different fibre contents. The alkali treatment found to be effective in improving the tensile and flexural properties while the impact strength decreased.

  17. Myosin heavy chain composition of single fibres from m. biceps brachii of male body builders

    DEFF Research Database (Denmark)

    Klitgaard, H; Zhou, M.-Y.; Richter, Erik

    1990-01-01

    The myosin heavy chain (MHC) composition of single fibres from m. biceps brachii of young sedentary men (28 +/- 0.4 years, mean +/- SE, n = 4) and male body builders (25 +/- 2.0 years, n = 4) was analysed with a sensitive one-dimensional electrophoretic technique. Compared with sedentary men...

  18. Mercury Removal from Aqueous Solution and Flue Gas by Adsorption on Activated Carbon Fibres

    OpenAIRE

    2006-01-01

    The use of two activated carbon fibres, one laboratorial sample prepared from a commercial acrylic textile fibre and one commercial sample of Kynol1, as prepared/received and modified by reaction with powdered sulfur and H2S gas in order to increase the sulfur content were studied for the removal of mercury from aqueous solution and from flue gases from a fluidized bed combustor. The sulfur introduced ranged from 1 to 6 wt.% depending on the method used. The most important parameter ...

  19. Alginate fibres containing discrete liquid filled vacuoles for controlled delivery of healing agents in fibre reinforced composites

    NARCIS (Netherlands)

    Mookhoek, S.D.; Fischer, H.R.; Zwaag, S. van der

    2012-01-01

    The work addressed involves the preparation and application of a compartmented polymer fibre, containing multiple separated domains with liquid agent for controlled release. The created fibre is a design for improvement to the existing liquid encapsulated self-healing systems such as fibre reinforce

  20. Quantitative study on the statistical properties of fibre architecture of genuine and numerical composite microstructures

    DEFF Research Database (Denmark)

    Hansen, Jens Zangenberg; Brøndsted, Povl

    2013-01-01

    is compared to a numerical microstructure generator using Monte Carlo simulations. It is shown that the numerical microstructure generator produces fibre arrangements that are statistically similar to the observed, which indicates a reliable and consistent SRVE. The microstructural effects of a parametric......A quantitative study is carried out regarding the statistical properties of the fibre architecture found in composite laminates and that generated numerically using Statistical Representative Volume Elements (SRVE’s). The aim is to determine the reliability and consistency of SRVE...

  1. High performance carbon-carbon composites

    Indian Academy of Sciences (India)

    Lalit M Manocha

    2003-02-01

    Carbon-carbon composites rank first among ceramic composite materials with a spectrum of properties and applications in various sectors. These composites are made of fibres in various directions and carbonaceous polymers and hydrocarbons as matrix precursors. Their density and properties depend on the type and volume fraction of reinforcement, matrix precursor used and end heat treatment temperature. Composites made with thermosetting resins as matrix precursors possess low densities (1.55–1.75 g/cm3) and well-distributed microporosity whereas those made with pitch as the matrix precursor, after densification exhibit densities of 1.8–2.0 g/cm3 with some mesopores, and those made by the CVD technique with hydrocarbon gases, possess intermediate densities and matrices with close porosities. The former (resin-based) composites exhibit high flexural strength, low toughness and low thermal conductivity, whereas the latter (pitch- and CVD-based) can be made with very high thermal conductivity (400–700 W/MK) in the fibre direction. Carbon-carbon composites are used in a variety of sectors requiring high mechanical properties at elevated temperatures, good frictional properties for brake pads in high speed vehicles or high thermal conductivity for thermal management applications. However, for extended life applications, these composites need to be protected against oxidation either through matrix modification with Si, Zr, Hf etc. or by multilayer oxidation protection coatings consisting of SiC, silica, zircon etc.

  2. Caractérisation microstructurale et mécanique d’un composite cimentaire renforcé par des fibres de lin Characterizations mechanical and microstructural of flax fibre cement composite reinforced

    Directory of Open Access Journals (Sweden)

    Boutouil M.

    2012-09-01

    Full Text Available Dans la perspective de valorisation des fibres de lin dans les matériaux de construction, la présente étude s’intéresse à la caractérisation microstructurale et mécanique d’un composite cimentaire renforcé par des fibres de lin. Les analyses microstructurales au MEB ont été menées pour évaluer l’homogénéité de la distribution des fibres, la qualité de l’interaction fibre/matrice et l’influence de leur présence sur les défauts microstructuraux. Le comportement mécanique en flexion du mortier renforcé par les fibres de lin est étudié en fonction de la longueur et la teneur en fibres. Les résultats indiquent une bonne adhésion entre les fibres et la matrice à l’état frais. Mais les fibres étant hydrophiles, elles gonflent pendant la prise du ciment et le retrait lors du séchage engendre alors des déchaussements. Les résultats de caractérisation mécanique sont encourageants. Tout d’abord, la fissuration du mortier due au retrait au jeune âge est fortement réduite du fait de la présence des fibres. Ensuite, la rupture brutale de la matrice en monolithe laisse place à un comportement quasi-ductile quand la teneur ou la longueur de fibre augmente. Ce changement de comportement, analysé en termes d’indice de ténacité, illustre la capacité remarquable des fibres de lin à renforcer les matrices cimentaires du fait de leurs bonnes propriétés mécaniques. With the purpose of the flax fibre valuing in construction materials, this study focuses on the characterizations mechanical and microstructural of flax fibre cement composite reinforced. The mechanical strength was studied as the function of fibre volume ratio and length. Meanwhile, the microstructural analysis investigated the homogeneity of fibre scattering, the interaction fibre/cement matrix and the influence of flax fibres on the defects microstructures. The results show the interesting mechanical properties of flax fibre in comparison with

  3. Development of high temperature resistant ceramic matrix composites based on SiC- and novel SiBNC-fibres; Entwicklung hochtemperaturbestaendiger keramischer Faserverbundwerkstoffe auf der Basis von SiC- und neuartigen SiBNC-Fasern

    Energy Technology Data Exchange (ETDEWEB)

    Daenicke, Enrico

    2014-10-01

    Novel ceramic fibres in the quaternary system Si-B-C-N exhibit excellent high temperature stability and creep resistance. In th is work it was investigated, to what extent these outstanding properties of SiBNC-fibres can be transferred into ceramic matrix composites (CMC) in comparison to commercial silicon carbide (SiC) fibres. For the CMC development the liquid silicon infiltration (LSI) as well as the polymer infiltration and pyrolysis process (PIP) was applied. Extensive correlations between fibre properties, fibre coating (without, pyrolytic carbon, lanthanum phosphate), process parameters of the CMC manufacturing method and the mechanical and microstructural properties of the CMC before and after exposure to air could be established. Hence, the potential of novel CMCs can be assessed and application fields can be derived.

  4. Mullite-zirconium composites reinforced with ceramic fibres resistant to 1450 C; obtaining and properties

    Energy Technology Data Exchange (ETDEWEB)

    Cerchez, L.; Constantinescu, S. [PROCEMA S.A. Bucharest - Research, Design and Experimental Production, Bucharest (Romania). Inst. for Construction and Construction Materials; Muntean, M. [Universitatea Politehnica, Bucharest (Romania). Faculty of Industrial Chemistry

    2002-07-01

    The purpose of this paper was the obtaining of some mullite-zirconium matrix composites, reinforced with ceramic fibres resistant to 1450 C. In order to establish the compositions, the raw materials were ground, depending on their nature, in many ways, and there were established the characteristics of ground resulted powders. On the obtained materials it was followed the evolution of the ceramic, mechanical and structural characteristics, depending on the heat treatment temperature, for various reinforcing coefficients. (orig.)

  5. Experimental Investigation of Mechanical and Thermal properties of sisal fibre reinforced composite and effect of sic filler material

    Science.gov (United States)

    Surya Teja, Malla; Ramana, M. V.; Sriramulu, D.; Rao, C. J.

    2016-09-01

    With a view of exploring the potential use of natural recourses, we made an attempt to fabricate sisal fibre polymer composites by hand lay-up method. Natural fiber composites are renewable, cheap and biodegradable. Their easy availability, lower density, higher specific properties, lower cost, satisfactory mechanical and thermal properties, non-corrosive nature, makes them an attractive ecological alternative to glass, carbon or other man-made synthetic fibers. In this work, the effect of SiC on mechanical and thermal properties of natural sisal fiber composites are investigated. The composite has been made with and without SiC incorporating natural sisal fiber with polyester as bonding material. The experimental outcomes exhibited that the tensile strength of composite with 10%SiC 2.53 times greater than that of composite without SiC. The impact strength of composite with 10% SiC is 1.73 times greater than that of composite without SiC plain polyester. Thermal properties studied include thermal conductivity, specific heat capacity, thermal diffusivity, thermal degradation and stability. Three different samples with 0%, 5%, 10% SiC powder are considered. With the addition of SiC filler powder, thermal conductivity increases, specific heat capacity gradually increases then decreases, thermal diffusivity increases and thermal stability improves with Sic powder.

  6. Fluoro-edenite and carbon nanotubes: The health impact of ‘asbestos-like’ fibres

    Science.gov (United States)

    MIOZZI, EDOARDO; RAPISARDA, VENERANDO; MARCONI, ANDREA; COSTA, CHIARA; POLITO, IRENE; SPANDIDOS, DEMETRIOS A.; LIBRA, MASSIMO; FENGA, CONCETTINA

    2016-01-01

    Several decades have passed since Wagner et al demonstrated a causal link between asbestos fibre inhalation and the development of pleural mesothelioma in 1960. It was later suggested that pleural plaques are a benign consequence of exposure to these fibres. Most recently, a significant association between exposure to asbestos and cancer diagnosed at various sites, such as the peritoneum, stomach, pharynx, colon and ovaries has been demonstrated. The great concerns about public health that arose from the scientific evidence presented above have led to the banning of asbestos in several countries. Over the years, the suspicion that particles with a high aspect ratio may have asbestos-like pathogenicity has been supported by increasing evidence. Natural occurring minerals, as well as man-made fibres, have proven capable of inducing either chronic inflammation of serous membranes, or, in some cases, the development of peritoneal and pleural mesothelioma. The pathogenic role of both fluoro-edenite and carbon nanotubes, two ‘asbestos-like’ fibres is summarized and discussed in this review. The data presented herein support the notion that occupational exposure to these two types of fibre contributes to the development of different types of cancer. PMID:26889212

  7. Fluoro-edenite and carbon nanotubes: The health impact of 'asbestos-like' fibres.

    Science.gov (United States)

    Miozzi, Edoardo; Rapisarda, Venerando; Marconi, Andrea; Costa, Chiara; Polito, Irene; Spandidos, Demetrios A; Libra, Massimo; Fenga, Concettina

    2016-01-01

    Several decades have passed since Wagner et al demonstrated a causal link between asbestos fibre inhalation and the development of pleural mesothelioma in 1960. It was later suggested that pleural plaques are a benign consequence of exposure to these fibres. Most recently, a significant association between exposure to asbestos and cancer diagnosed at various sites, such as the peritoneum, stomach, pharynx, colon and ovaries has been demonstrated. The great concerns about public health that arose from the scientific evidence presented above have led to the banning of asbestos in several countries. Over the years, the suspicion that particles with a high aspect ratio may have asbestos-like pathogenicity has been supported by increasing evidence. Natural occurring minerals, as well as man-made fibres, have proven capable of inducing either chronic inflammation of serous membranes, or, in some cases, the development of peritoneal and pleural mesothelioma. The pathogenic role of both fluoro-edenite and carbon nanotubes, two 'asbestos-like' fibres is summarized and discussed in this review. The data presented herein support the notion that occupational exposure to these two types of fibre contributes to the development of different types of cancer.

  8. Injection moulding of long glass fibre reinforced poly(ethylene terephtalate: Influence of carbon black and nucleating agents on impact properties

    Directory of Open Access Journals (Sweden)

    E. Lafranche

    2012-09-01

    Full Text Available This paper aims at highlighting the influence of different additives (carbon black and nucleating agents on both the notched and unnotched Charpy impact properties of long glass fibre reinforced poly(ethylene terephtalate injection mouldings. The relationship with the polymer matrix and composite microstructure modifications (variations of crystalline morphology and local fibre content was investigated. Adding carbon black alone decreases the impact performances. This highly conductive additive actually increases the cooling rate, and therefore the fibre ‘frettage’ effect (higher internal stresses. It also acts as filler, which increases the material brittleness. The nucleating agents allow reducing the mould temperature, but their effect on the impact strength may be favourable or not depending on the processing temperatures. The addition of such additives induces perturbations of the polymer melt rheology in the mould cavity and of the cooling kinetics of the part, which both act on the fibre distribution during mould filling and on the degree of crystallinity of the composite parts.

  9. Modelling the influence of steel fibres on the electrical resistivity of cementitious composites

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe; Michel, Alexander; Stang, Henrik

    2009-01-01

    work concerns the electrical resistivity of cementitious composites and some of the parameters influencing it in order to get a more thorough understanding of the factors governing the overall resistivity. The basis of the present study is an experimental investigation of the electrical resistivity...... the overall resistivity of the material and thereby the corrosion rate of the embedded reinforcement. To the knowledge of the authors, only preliminary studies have been made on the influence of corrosion of the reinforcement bars from the addition of the electrical conductive steel fibres. Thus the present......One of the governing factors on the corrosion of embedded reinforcement is the electrical resistivity of the concrete. The combination of steel fibres and conventional reinforcement bars has been used in a number of structures. However, the addition of electrical con-ductive fibres might influence...

  10. Expression of interleukin-15 in human skeletal muscle effect of exercise and muscle fibre type composition

    DEFF Research Database (Denmark)

    Nielsen, Anders Rinnov; Mounier, Remi; Plomgaard, Peter

    2007-01-01

    of recovery without any changes in muscle IL-15 protein content or plasma IL-15 at any of the investigated time points. In conclusion, IL-15 mRNA level is enhanced in skeletal muscles dominated by type 2 fibres and resistance exercise induces increased muscular IL-15 mRNA levels. IL-15 mRNA levels in skeletal......The cytokine interleukin-15 (IL-15) has been demonstrated to have anabolic effects in cell culture systems. We tested the hypothesis that IL-15 is predominantly expressed by type 2 skeletal muscle fibres, and that resistance exercise regulates IL-15 expression in muscle. Triceps brachii, vastus...... lateralis quadriceps and soleus muscle biopsies were obtained from normally physically active, healthy, young male volunteers (n = 14), because these muscles are characterized by having different fibre-type compositions. In addition, healthy, normally physically active male subjects (n = 8) not involved...

  11. Finite element investigations on the microstructure of fibre-reinforced composites

    Directory of Open Access Journals (Sweden)

    2008-09-01

    Full Text Available The effect of residual stress due to the curing process on damage evolution in unidirectional (UD fibre-reinforced polymer-matrix composites under longitudinal and transverse loading has been investigated using a three-dimensional micromechanical representative volume element (RVE model with a hexagonal packing geometry and the finite element method. Residual stress has been determined by considering two contributions: volume shrinkage of matrix resin from the crosslink polymerization during isothermal curing and thermal contraction of both resin and fibre as a result of cooling from the curing temperature to room temperature. To examine the effect of residual stress on failure, a study based on different failure criteria and a stiffness degradation technique has been used for damage analysis of the RVE subjected to mechanical loading after curing for a range of fibre volume fractions. Predicted damage initiation and evolution are clearly influenced by the presence of residual stress.

  12. Improving Impact Strength Recovery of Fractured and Healed Rice Husks Fibre Reinforced Polypropylene Composites.

    Directory of Open Access Journals (Sweden)

    Odhong, O.V.E

    2016-10-01

    Full Text Available Rice husks fibre reinforced polypropylene composite (rhfrpc is a natural plant fibre reinforced polymer composite having advantages of high strength, light weight and affordability. They are commonly used for light load structural and non structural applications. They are mainly used as particle boards, for fencing post, roofing tiles, for interiors of car and aircrafts among other usages. This material once cracked by impact forces cannot be repaired using traditional repair methods for engineering materials such as metals or other composites that can be repaired by welding or by patch repair methods respectively, thus a method of repair of rice husks fibre reinforced polypropylene composites by refilling the damaged volume by injection of various healing agents has been investigated. The composite coupons were produced by injection moulding, cooled sufficiently and prepared for charpy impact tests. Test results for pristine coupons were a maximum of 48 J/mm2 . The destroyed coupons were then subjected to healing in a fabricated healing fixture. Healing agents such as epoxy resin, ethyl cyanoacrylate, and tannin gum have been investigated for their use as possible healing agents to fill the damaged volume and perform healing action at the fractured surfaces. The impact test results were recorded and compared with those of unhealed pristine coupons. The recovered strengths were a maximum of 60 J/mm2 translating into a 125% impact strength recovery, and this is good enough for the healed composites to be recommended for reuse in their second lives of their respective original functions.

  13. Micro-macro understanding of fatigue of fibre composites

    DEFF Research Database (Denmark)

    Sørensen, Bent F.

    2014-01-01

    Degradation of composite materials during cyclic loading is being better understood. Better understanding enables better material models and the development of more durable composite materials that have longer life for e.g. wind turbine rotor blades......Degradation of composite materials during cyclic loading is being better understood. Better understanding enables better material models and the development of more durable composite materials that have longer life for e.g. wind turbine rotor blades...

  14. Glass fibre polyester composite with in vivo vascular channel for use in self-healing

    Science.gov (United States)

    Fifo, Omosola; Ryan, Kevin; Basu, Biswajit

    2014-09-01

    The embedment of adhesive-filled hollow glass fibres (HGF) has been reported as a way of combating micro-crack development in fibre-reinforced polymer (FRP) structures. However, hollow fibres can critically undermine the effectiveness of self-healing systems and have been reported to be a potential impediment to the healing agent flow path. On the other hand, attempting to use non-hollow vascular systems in higher dimensions has largely been restricted to bulk polymers that lack reinforcing fibres. This paper investigates an alternative technique where a simple two-dimensional (2D) network of hollow channels is created within a glass-fibre-reinforced polyester-composite structure. The network is created using a fugitive preforming material at the ply level of interest, similar to a direct ink writing procedure. The temporary structure is extracted as a part of the curing and post-curing processes. The channels formed are used to deliver cyanoacrylate adhesive (CA) to areas that have been damaged under a flexural three-point bending test. Subsequent post-repair mechanical testing, under the same mode, evaluates the success of the repair process. The results show good recovery of the stiffness, a paramount mechanical property, and indicate how the grade of the repairing agent used influences the recovered loading strength of the FRP samples.

  15. Potential Coir Fibre Composite for Small Wind Turbine Blade Application

    Directory of Open Access Journals (Sweden)

    Bakri Bakri

    2017-03-01

    Full Text Available Natural fibers have been developed as reinforcement of composite to shift synthetic fibers. One of potential natural fibers developed is coir fiber. This paper aims to describe potential coir fiber as reinforcement of composite for small wind turbine blade application. The research shows that mechanical properties ( tensile, impact, shear, flexural and compression strengths of coir fiber composite have really similar to wood properties for small wind turbine blade material, but inferior to glass fiber composite properties. The effect of weathering was also evaluated to coir fiber composite in this paper.

  16. Stiffness Characteristics of Fibre-reinforced Composite Shaft Embedded with Shape Memory Alloy Wires

    Directory of Open Access Journals (Sweden)

    K. Gupta

    2003-04-01

    Full Text Available Frequent coast up/coast down operations of rotating shafts in the power and aerospace industry expose the flexible rotors to the risk of fatigue failures. Resonant vibrations during passage through critical speeds induce large stresses that may lead to failures. In this paper, the use of nitinol [shape memory alloy (SMA] wires in the fibre-reinforced composite shaft, for the purpose ofmodifying shaft stiffness properties to avoid such failures, is discussed. A setup has been developed to fabricate the composite shaft (made of fibre glass and epoxy resin embedded with pre-stressed SMA wires. Experiments have been carried out on the shaft to estimate the changes in the natural frequency of the composite shaft due to activation and deactivation ofSMA wires. The comparisonofthe experimental results with the established analytical results indicates feasibility ofvibration control using the special properties of SMA wires.

  17. Influence of fibre distribution and grain size on the mechanical behaviour of friction stir processed Mg–C composites

    Energy Technology Data Exchange (ETDEWEB)

    Mertens, A., E-mail: anne.mertens@ulg.ac.be [Université de Liège, Faculty of Applied Science, A& M Department, Metallic Materials Science Unit (Belgium); Simar, A. [Université catholique de Louvain, Institute of Mechanics, Materials and Civil Engineering (Belgium); Adrien, J.; Maire, E. [Institut National des Sciences Appliquées de Lyon (INSA Lyon), MATEIS Laboratory (France); Montrieux, H.-M. [Université de Liège, Faculty of Applied Science, A& M Department, Metallic Materials Science Unit (Belgium); Delannay, F. [Université catholique de Louvain, Institute of Mechanics, Materials and Civil Engineering (Belgium); Lecomte-Beckers, J. [Université de Liège, Faculty of Applied Science, A& M Department, Metallic Materials Science Unit (Belgium)

    2015-09-15

    Short C fibres–Mg matrix composites have been produced by friction stir processing sandwiches made of a layer of C fabric stacked between two sheets of Mg alloy AZ31B or AZ91D. This novel processing technique can allow the easy production of large-scale metal matrix composites. The paper investigates the microstructure of FSPed C fibre–Mg composites in relation with the fragmentation of the C fibres during FSP and their influence on the tensile properties. 3D X-ray tomography reveals that the fibres orient like onion rings and are more or less fragmented depending on the local shear stress during the process. The fibre volume fraction can be increased from 2.3% to 7.1% by reducing the nugget volume, i.e. by using a higher advancing speed in AZ31B alloy or a stronger matrix alloy, like AZ91D alloy. A higher fibre volume fraction leads to a smaller grain size which brings about an increase of the composite yield strength by 15 to 25%. However, a higher fibre volume fraction also leads to a lower fracture strain. Fracture surface observations reveal that damage occurs by fibre/matrix decohesion along fibres oriented perpendicularly to the loading direction. - Graphical abstract: Display Omitted - Highlights: • C–Mg MMCs were produced by FSP sandwiches made of a C fabric between Mg sheets. • Fibre fragmentation and erosion is larger when the temperature reached during FSP is lower. • A lower advancing speed brings a lower fibre volume fraction and a lower grain size. • X-ray tomography reveals that fibres orient along the FSP material flow. • The fibres and grain size reduction increase the yield strength by 15 to 25%.

  18. Weight loss, ion release and initial mechanical properties of a binary calcium phosphate glass fibre/PCL composite.

    Science.gov (United States)

    Ahmed, I; Parsons, A J; Palmer, G; Knowles, J C; Walker, G S; Rudd, C D

    2008-09-01

    Composites comprising a biodegradable polymeric matrix and a bioactive filler show considerable promise in the field of regenerative medicine, and could potentially serve as degradable bone fracture fixation devices, depending on the properties obtained. Therefore, glass fibres from a binary calcium phosphate (50P(2)O(5)+50CaO) glass were used to reinforce polycaprolactone, at two different volume fractions (V(f)). As-drawn, non-treated and heat-treated fibres were assessed. Weight loss, ion release and the initial mechanical properties of the fibres and composites produced have been investigated. Single fibre tensile testing revealed a fibre strength of 474MPa and a tensile modulus of 44GPa. Weibull analysis suggested a scale value of 524. The composites yielded flexural strength and modulus of up to 30MPa and 2.5GPa, respectively. These values are comparable with human trabecular bone. An 8% mass loss was seen for the lower V(f) composite, whereas for the two higher V(f) composites an approximate 20% mass loss was observed over the course of the 5week study. A plateau in the degradation profile at 350h indicated that fibre dissolution was complete at this interval. This assertion was further supported via ion release studies. The leaching of fibres from the composite created a porous structure, including continuous channels within the polymer matrix. This offers further scope for tailoring scaffold development, as cells from the surrounding tissue may be induced to migrate into the resulting porous matrix.

  19. Thermoplastic impact property improvement in hybrid natural fibre epoxy composite bumper beam

    Science.gov (United States)

    Davoodi, M. M.; Sapuan, S. M.; Ali, Aidy; Ahmad, D.; Khalina, A.

    2010-05-01

    Utilization of thermoset resin as a bumper beam composite matrix is currently more dominated in car manufacturer suppliers, because of availability, easy processing, low material cost and production equipment investment. Moreover, low viscosity, shrinkage and excellent flow facilitate better fibre impregnation and proper surface resin wetting. Three-dimensional cross linking curing increase impact, creep and environmental stress cracking resistance properties. Low impact properties of natural fibre epoxy composite, are main issues in its employment for automotive structural components. Impact properties in epoxy composite bumper beam could be increased by modifying the resin, reinforcement and manufacturing process as well as geometry parameters such as cross section, thickness, added ribs and fixing method optimizations could strengthen impact resistance. There are two main methods, flexibilisation and toughening, as modifying the resin in order to improve the impact properties of epoxy composite, which form single phase or two-phase morphology to make modifier as epoxy or from separate phase to keep the thermo-mechanical properties. Liquid rubber, thermoplastic, core shell particle and rigid particle are different methods of toughening improvements. In this research, thermoplastic toughening has used to improve impact properties in hybrid natural fibre epoxy composite for automotive bumper beam and has achieved reasonable impact improvements.

  20. Thermoplastic impact property improvement in hybrid natural fibre epoxy composite bumper beam

    Energy Technology Data Exchange (ETDEWEB)

    Davoodi, M M; Sapuan, S M; Ali, Aidy [Department of Mechanical and Manufacturing Engineering, Universiti Putra Malaysia 43400 UPM Serdang, Selangor (Malaysia); Ahmad, D; Khalina, A, E-mail: makinejadm2@asme.org [Department of Biological and Agricultural Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor (Malaysia)

    2010-05-15

    Utilization of thermoset resin as a bumper beam composite matrix is currently more dominated in car manufacturer suppliers, because of availability, easy processing, low material cost and production equipment investment. Moreover, low viscosity, shrinkage and excellent flow facilitate better fibre impregnation and proper surface resin wetting. Three-dimensional cross linking curing increase impact, creep and environmental stress cracking resistance properties. Low impact properties of natural fibre epoxy composite, are main issues in its employment for automotive structural components. Impact properties in epoxy composite bumper beam could be increased by modifying the resin, reinforcement and manufacturing process as well as geometry parameters such as cross section, thickness, added ribs and fixing method optimizations could strengthen impact resistance. There are two main methods, flexibilisation and toughening, as modifying the resin in order to improve the impact properties of epoxy composite, which form single phase or two-phase morphology to make modifier as epoxy or from separate phase to keep the thermo-mechanical properties. Liquid rubber, thermoplastic, core shell particle and rigid particle are different methods of toughening improvements. In this research, thermoplastic toughening has used to improve impact properties in hybrid natural fibre epoxy composite for automotive bumper beam and has achieved reasonable impact improvements.

  1. Tannin-based flax fibre reinforced composites for structural applications in vehicles

    Science.gov (United States)

    Zhu, J.; Abhyankar, H.; Nassiopoulos, E.; Njuguna, J.

    2012-09-01

    Innovation is often driven by changes in government policies regulating the industries, especially true in case of the automotive. Except weight savings, the strict EU regulation of 95% recyclable material-made vehicles drives the manufactures and scientists to seek new 'green materials' for structural applications. With handing at two major drawbacks (production cost and safety), ECHOSHELL is supported by EU to develop and optimise structural solutions for superlight electric vehicles by using bio-composites made of high-performance natural fibres and resins, providing enhanced strength and bio-degradability characteristics. Flax reinforced tannin-based composite is selected as one of the candidates and were firstly investigated with different fabric lay-up angles (non-woven flax mat, UD, [0, 90°]4 and [0, +45°, 90°, -45°]2) through authors' work. Some of the obtained results, such as tensile properties and SEM micrographs were shown in this conference paper. The UD flax reinforced composite exhibits the best tensile performance, with tensile strength and modulus of 150 MPa and 9.6 MPa, respectively. It was observed that during tension the oriented-fabric composites showed some delamination process, which are expected to be eliminated through surface treatment (alkali treatment etc.) and nanotechnology, such as the use of nano-fibrils. Failure mechanism of the tested samples were identified through SEM results, indicating that the combination of fibre pull-out, fibre breakage and brittle resins failure mainly contribute to the fracture failure of composites.

  2. The effect of ion implantation on the tribomechanical properties of carbon fibre reinforced polymers

    Energy Technology Data Exchange (ETDEWEB)

    Mistica, R.; Sood, D.K. [Royal Melbourne Inst. of Tech., VIC (Australia); Janardhana, M.N. [Deakin University, Geelong, VIC (Australia). School of Engineering and Technology

    1993-12-31

    Graphite fibre reinforced epoxy composite material (GFRP) is used extensively in the aerospace and other industries for structural application. The trend is to address the 20 to 30 year life endurance of this material in service. Mechanical joints in air crafts are exposed to dynamic loads during service and wear may be experienced by the composite material joint. Generally it has been shown that graphite fibre reinforced polymers have superior wear and friction properties as compared with the unfilled polymers. In the described experiment, ion implantation was used as a novel surface treatment. Wear and friction of a polymer composite material (GFRP) was studied and ion implantation was used in order to observe the effect on the tribomechanical properties of the material. It was found that ion implantation of C on GFRP sliding against Ti changes the tribological properties of the system, and in particular decreases the coefficient of friction and wear. 4 refs., 2 figs.

  3. Synthesis, characterization and antibacterial activity of biodegradable starch/PVA composite films reinforced with cellulosic fibre.

    Science.gov (United States)

    Priya, Bhanu; Gupta, Vinod Kumar; Pathania, Deepak; Singha, Amar Singh

    2014-08-30

    Cellulosic fibres reinforced composite blend films of starch/poly(vinyl alcohol) (PVA) were prepared by using citric acid as plasticizer and glutaraldehyde as the cross-linker. The mechanical properties of cellulosic fibres reinforced composite blend were compared with starch/PVA crossed linked blend films. The increase in the tensile strength, elongation percentage, degree of swelling and biodegradability of blend films was evaluated as compared to starch/PVA crosslinked blend films. The value of different evaluated parameters such as citric acid, glutaraldehyde and reinforced fibre to starch/PVA (5:5) was found to be 25 wt.%, 0.100 wt.% and 20 wt.%, respectively. The blend films were characterized using Fourier transform-infrared spectrophotometry (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA/DTA/DTG). Scanning electron microscopy illustrated a good adhesion between starch/PVA blend and fibres. The blend films were also explored for antimicrobial activities against pathogenic bacteria like Staphylococcus aureus and Escherichia coli. The results confirmed that the blended films may be used as exceptional material for food packaging.

  4. Fracture characteristics of carbon fibre, ceramic and non-palladium endodontic post systems at monotonously increasing loads.

    Science.gov (United States)

    Ottl, P; Hahn, L; Lauer, H Ch; Fay, M

    2002-02-01

    A carbon fibre post system, three non-palladium and one palladium metal post systems, two ceramic post systems, and a metal post system with a ceramic core were studied in vitro. The control group consisted of root-filled test teeth without posts. The test teeth were identical artificial roots of an upper central incisor made from a posterior composite whose module of elasticity was similar to that of natural dentine. All posts were cemented in the roots using Panavia 21 TC. Subsequently, standardized full crowns were cemented onto all roots. On a universal testing machine, the test teeth were loaded palatally at monotonously increasing loads until root fracture. The highest mean fracture loads were found for the carbon fibre post system (312.5 +/- 58.8 N). The fracture load of non-palladium metal posts (242.3-300.4 N) did not differ significantly from that of the Perma-dor post (265.9 N), which does contain palladium. Values of 300.3 +/- 89.3 N (aluminium oxide ceramics) and 193.5 +/-57.0 N (zirconia ceramics) were found for the ceramic posts. The control group exhibited a fracture load of 228.8 +/- 35.7 N. The mean distance between the vestibular end of the fracture gap and the point of force application was between 10.1 +/- 2.3 and 14.7 +/- 1.2 mm.

  5. Ultra-pure single wall carbon nanotube fibres continuously spun without promoter

    Science.gov (United States)

    Paukner, Catharina; Koziol, Krzysztof K. K.

    2014-02-01

    We report a new strategy towards the control of carbon nanotube (CNT) structure and continuous fibre formation using a floating catalyst direct spinning CVD process. In the procedures used to date, a sulphur promoter precursor is added to significantly enhance the rate of CNT formation in the floating catalyst synthesis. Within the reaction zone, the rapidly grown nanotubes self-assemble into bundles, followed by their continuous spinning into fibres, yarns, films or tapes. In this paper we demonstrate a catalyst control strategy in the floating catalyst system, where the CNT formation process is independent of the presence of a promoter but leads to successful spinning of the macroscopic carbon nanotube assemblies with specific morphology, high purity (Raman D/G 0.03) and very narrow diameter range (0.8-2.5 nm). This can be achieved by the control of catalyst precursor decomposition and subsequent formation of homogeneous nano-sized catalyst particles.

  6. Plant Fibre: Molecular Structure and Biomechanical Properties, of a Complex Living Material, Influencing Its Deconstruction towards a Biobased Composite

    Directory of Open Access Journals (Sweden)

    Mathias Sorieul

    2016-07-01

    Full Text Available Plant cell walls form an organic complex composite material that fulfils various functions. The hierarchical structure of this material is generated from the integration of its elementary components. This review provides an overview of wood as a composite material followed by its deconstruction into fibres that can then be incorporated into biobased composites. Firstly, the fibres are defined, and their various origins are discussed. Then, the organisation of cell walls and their components are described. The emphasis is on the molecular interactions of the cellulose microfibrils, lignin and hemicelluloses in planta. Hemicelluloses of diverse species and cell walls are described. Details of their organisation in the primary cell wall are provided, as understanding of the role of hemicellulose has recently evolved and is likely to affect our perception and future study of their secondary cell wall homologs. The importance of the presence of water on wood mechanical properties is also discussed. These sections provide the basis for understanding the molecular arrangements and interactions of the components and how they influence changes in fibre properties once isolated. A range of pulping processes can be used to individualise wood fibres, but these can cause damage to the fibres. Therefore, issues relating to fibre production are discussed along with the dispersion of wood fibres during extrusion. The final section explores various ways to improve fibres obtained from wood.

  7. Myosin heavy chain isoform composition and stretch activation kinetics in single fibres of Xenopus laevis iliofibularis muscle.

    Science.gov (United States)

    Andruchova, Olena; Stephenson, Gabriela M M; Andruchov, Oleg; Stephenson, D George; Galler, Stefan

    2006-07-01

    Skeletal muscle is composed of specialized fibre types that enable it to fulfil complex and variable functional needs. Muscle fibres of Xenopus laevis, a frog formerly classified as a toad, were the first to be typed based on a combination of physiological, morphological, histochemical and biochemical characteristics. Currently the most widely accepted criterion for muscle fibre typing is the myosin heavy chain (MHC) isoform composition because it is assumed that variations of this protein are the most important contributors to functional diversity. Yet this criterion has not been used for classification of Xenopus fibres due to the lack of an effective protocol for MHC isoform analysis. In the present study we aimed to resolve and visualize electrophoretically the MHC isoforms expressed in the iliofibularis muscle of Xenopus laevis, to define their functional identity and to classify the fibres based on their MHC isoform composition. Using a SDS-PAGE protocol that proved successful with mammalian muscle MHC isoforms, we were able to detect five MHC isoforms in Xenopus iliofibularis muscle. The kinetics of stretch-induced force transients (stretch activation) produced by a fibre was strongly correlated with its MHC isoform content indicating that the five MHC isoforms confer different kinetics characteristics. Hybrid fibre types containing two MHC isoforms exhibited stretch activation kinetics parameters that were intermediate between those of the corresponding pure fibre types. These results clearly show that the MHC isoforms expressed in Xenopus muscle are functionally different thereby validating the idea that MHC isoform composition is the most reliable criterion for vertebrate skeletal muscle fibre type classification. Thus, our results lay the foundation for the unequivocal classification of the muscle fibres in the Xenopus iliofibularis muscle and for gaining further insights into skeletal muscle fibre diversity.

  8. Influence of bulk fibre properties of PAN-based carbon felts on their performance in vanadium redox flow batteries

    Science.gov (United States)

    Schweiss, Rüdiger

    2015-03-01

    Polyacrylonitrile (PAN)-based carbon felts with different fibre properties were studied in terms of their suitability as porous flow-through electrode materials in all vanadium redox flow batteries. The crystallinity and their bulk hetero element content (in particular nitrogen) of the carbon fibres was shown to produce a significant effect on the electrocatalytical properties of the electrodes towards vanadium species. Similar effects were seen on the capacity losses associated with concomitant hydrogen evolution. Adjustments of fibre properties offer the potential of manufacturing improved electrode materials, potentially without additional steps such as surface activation or decoration with catalytically active species.

  9. Natural fibre high-density polyethylene and lead oxide composites for radiation shielding

    Energy Technology Data Exchange (ETDEWEB)

    El-Sayed Abdo, A. E-mail: attiaabdoll@hotmail.com; Ali, M.A.M.; Ismail, M.R

    2003-03-01

    Study has been made of the radiation shielding provided by recycled agricultural fibre and industrial plastic wastes produced as composite materials. Fast neutron and gamma-ray spectra behind composites of fibre-plastic ({rho} = 1.373 g cm{sup -3}) and fibre-plastic-lead ({rho} = 2.756 g cm{sup -3}) have been measured using a collimated reactor beam and neutron-gamma spectrometer with a stilbene scintillator. The pulse shape discriminating technique based on the zero-cross-over method was used to discriminate between neutron and gamma-ray pulses. Slow neutron fluxes have been measured using a collimated reactor beam and BF{sub 3} counter, leading to determination of the macroscopic cross-section ({sigma}). The removal cross-sections ({sigma}{sub R}) of fast neutrons have been determined from measured results and elemental composition of the composites. For gamma-rays, total linear attenuation coefficients ({mu}) and total mass attenuation coefficients ({mu}/{rho}) have been determined from use of the XCOM code and measured results. Reasonable agreement was found between measured and calculated results.

  10. Natural fibre high-density polyethylene and lead oxide composites for radiation shielding

    CERN Document Server

    El-Sayed, A; Ismail, M R

    2003-01-01

    Study has been made of the radiation shielding provided by recycled agricultural fibre and industrial plastic wastes produced as composite materials. Fast neutron and gamma-ray spectra behind composites of fibre-plastic (rho = 1.373 g cm sup - sup 3) and fibre-plastic-lead (rho = 2.756 g cm sup - sup 3) have been measured using a collimated reactor beam and neutron-gamma spectrometer with a stilbene scintillator. The pulse shape discriminating technique based on the zero-cross-over method was used to discriminate between neutron and gamma-ray pulses. Slow neutron fluxes have been measured using a collimated reactor beam and BF sub 3 counter, leading to determination of the macroscopic cross-section (SIGMA). The removal cross-sections (SIGMA sub R) of fast neutrons have been determined from measured results and elemental composition of the composites. For gamma-rays, total linear attenuation coefficients (mu) and total mass attenuation coefficients (mu/rho) have been determined from use of the XCOM code and me...

  11. Natural fibre high-density polyethylene and lead oxide composites for radiation shielding

    Science.gov (United States)

    El-Sayed Abdo, A.; Ali, M. A. M.; Ismail, M. R.

    2003-03-01

    Study has been made of the radiation shielding provided by recycled agricultural fibre and industrial plastic wastes produced as composite materials. Fast neutron and gamma-ray spectra behind composites of fibre-plastic ( ρ = 1.373 g cm -3) and fibre-plastic-lead ( ρ = 2.756 g cm -3) have been measured using a collimated reactor beam and neutron-gamma spectrometer with a stilbene scintillator. The pulse shape discriminating technique based on the zero-cross-over method was used to discriminate between neutron and gamma-ray pulses. Slow neutron fluxes have been measured using a collimated reactor beam and BF 3 counter, leading to determination of the macroscopic cross-section ( Σ). The removal cross-sections ( ΣR) of fast neutrons have been determined from measured results and elemental composition of the composites. For gamma-rays, total linear attenuation coefficients ( μ) and total mass attenuation coefficients ( μ/ ρ) have been determined from use of the XCOM code and measured results. Reasonable agreement was found between measured and calculated results.

  12. An engineering analysis of penetration of metal ball into fibre-reinforced composite targets

    Institute of Scientific and Technical Information of China (English)

    Yong-chi LI; Zhi-hai WANG; Xiao-jun WANG; Xiu-zhang HU

    2009-01-01

    An engineering analysis of computing the penetration problem of a steel ball penetrating into fibre-reinforced composite targets is presented. Assume the metal ball is a rigid body, and the composite target is a transversely isotropic elasto-plastic material. In the analysis, a spherical cavity dilatation model is incorporated in the cylindrical cavity penetration method. Simulation results based on the modified model are in good agreement with the results for 3-D Kevlar woven (3DKW) composite anti-penetration experiments. Effects of the target material parameters and impact parameters on the penetration problem are also studied.

  13. Damage tolerance of continuous fibre composites: material and environmental effects

    Energy Technology Data Exchange (ETDEWEB)

    Bibo, G.A.; Hogg, P.J. [Queen Mary and Westfield Coll., London (United Kingdom). Dept. of Materials

    1998-05-01

    Aerospace design philosophies are used to discuss critically, the suitability of composite materials to primary structural applications. The principal issues limiting the use of composites, compression after impact performance and high cost, are examined in terms of material/manufacturing form and environmental conditioning. The material types investigated consist of thermoset and thermoplastic matrix reinforced unidirectional prepreg tape and textile manufactured architectures. (orig.) 141 refs.

  14. Metallic-fibre-reinforced ceramic-matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, F.; Schnedecker, G.; Boncoeur, M.

    1994-12-31

    A refractory metal wire cloth is embedded in an oxide ceramic matrix, using a plasma spraying technology, in order to elaborate composite plates. When mechanically tested, the composite fails with a pseudo-ductile fracture mode whereas the ceramic alone is originally brittle. It exhibits a higher fracture strength, and remains in the form of a single piece even when straining is important. No further heat treatment is needed after the original processing to reach these characteristics. (authors). 2 figs., 2 refs.

  15. Vacuum performance of a carbon fibre cryosorber for the LHC LSS beam screen

    CERN Document Server

    Anashin, V V; Dostovalov, R V; Korotaeva, Z A; Krasnov, A A; Malyshev, O B; Poluboyarov, V A

    2004-01-01

    A new carbon fibre material was developed at the Institute of Solid State Chemistry and Mechanochemistry at the Siberian Branch of the Russian Academy of Science (SB RAS) to meet the large hadron collider (LHC) vacuum chamber. The material must have a large sorbing capacity, a certain pumping speed, a working temperature range between 5 and 20K, a low activation temperature (below room temperature), a certain size in order to fit into the limited space available and it should be easy to mount. The vacuum parameters of the LHC vacuum chamber prototype with a carbon fibre cryosorber mounted onto the beam screen were studied in the beam screen temperature range from 14 to 25K at the Budker Institute of Nuclear Physics SB RAS. This carbon fibre material has shown sufficient sorption capacity for hydrogen at operational temperatures of the beam screen in the LHC long straight sections. It is also very important that this material does not crumble and makes a convenient fixation onto the beam screen in comparison t...

  16. Thermal shock resistance of ceramic fibre composites characterized by non-destructive methods

    Directory of Open Access Journals (Sweden)

    M. Dimitrijević

    2008-12-01

    Full Text Available Alumina based ceramic fibres and alumina based ceramic were used to produce composite material. Behaviour of composite ceramics after thermal shock treatments was investigated. Thermal shock of the samples was evaluated using water quench test. Surface deterioration level of samples was monitored by image analysis before and after a number of quenching cycles. Ultrasonic measurements were done on samples after quench tests. Dynamic Young modulus of elasticity and strength degradation were calculated using measured values of ultrasonic velocities. Strengths deterioration was calculated using the non-destructive measurements and correlated to degradation of surface area and number of quenches. The addition of small amount of ceramic fibres improves the strengths and diminishes the loss of mechanical properties of samples during thermal shock experiments.

  17. Measurement of composite shrinkage using a fibre optic Bragg grating sensor.

    Science.gov (United States)

    Milczewski, M S; Silva, J C C; Paterno, A S; Kuller, F; Kalinowski, H J

    2007-01-01

    Fibre Bragg grating is used to determine resin-based composite shrinkage. Two composite resins (Freedom from SDI and Z100 from 3M) were tested to determine the polymerization contraction behaviour. Each sample of resin was prepared with an embedded fibre Bragg grating. A LED activation unit with wavelength from 430 nm to 470 nm (Dabi Atlante) was used for resin polymerization. The wavelength position of the peak in the optical reflection spectra of the sensor was measured. The wavelength shift was related to the shrinkage deformation of the samples. Temperature and strain evolution during the curing phase of the material was monitored. The shrinkage in the longitudinal direction was 0.15 +/- 0.02% for resin Z100 (3M) and 0.06+/-0.01% for Freedom (SDI); two-thirds of shrinkage occurred after the first 50 s of illumination.

  18. Fibre-reinforced composite (FRC) bridge--a minimally destructive approach.

    Science.gov (United States)

    Van Rensburg, J J Jansen

    2015-05-01

    Replacing missing teeth is an integral part of the clinical services of the dental practitioner. The fibre-reinforced composite (FRC) bridge is a relatively new method for replacing missing teeth. This article will explain and discuss this alternative treatment option. Practical instructions on how to construct a FRC bridge will be given, by means of a clinical case. Different technique options will be illustrated to provide the reader with a good understanding of the most practical way to use the FRC strips. The fibre-reinforced composite provides a non-destructive, aesthetically pleasing and cost-effective way to restore missing teeth. Clinical Relevance: Minimally invasive options should always be considered and destruction of healthy enamel and dentine during the preparation phase of a replacement treatment should be avoided as much as possible.

  19. Gbit/s Data Transmission on Carbon Fibres

    CERN Document Server

    Flick, Tobias; Kappen, Götz C; Mättig, Peter; Möller, Judith; Sanny, Bernd

    2015-01-01

    Data transmission at the upgraded Large Hadron Collider experiments, foreseen for mid 2020s will be in the multi Gbit/s range per connection for the innermost detector layers. This paper reports on first tests on the possible use of carbon cables for electrical data transmission close to the interaction point. Carbon cables have the potential advantage of being light, having a low activation and easy integration into the detector components close to the interaction point. In these tests commercially available carbon cables were used, in which the filaments had a very thin nickel coating. For these cables data rates beyond 1 Gbit/s over more than 1m with an error rate of less than 10^{-12} could be transmitted. The characteristics of the cables have been measured in terms of S-parameters and could be reproduced with a Spice model. Some outlook on potential further improvements is presented.

  20. Tensile & impact behaviour of natural fibre-reinforced composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Tobias, B.C. [Victoria Univ. of Technology, Footscray (Australia). Dept. of Mechanical Engineering

    1993-12-31

    Short abaca fiber reinforced composite materials are fabricated and investigated for short term performance. Abaca plants which grow in abundance in Asia contain fibers that are inexpensive but underutilized. This study attempts to utilize the abaca fibers for composite material structure as a possible alternative to timber products in building applications. The composite material is fabricated using the hand lay-up method under varying fiber length and fiber volume fraction. The fibers are impregnated with a mixture of resins which cures at room temperature. A fabricating facility is designed to accommodate fabrication of lamina. Tensile and impact properties are determined in relation to the length and volume fraction of the fiber. For a given fiber length, the tensile and impact strength increase as the volume fraction increases up to a limiting value. And for a given fiber volume fraction, the tensile strength increases but the impact strength decreases as the fiber length increases. This behavior of abaca fiber-reinforced composite lamina will help in optimizing the design parameter in random composite panels.

  1. Coupling of plasticity and damage in glass fibre reinforced polymer composites

    Directory of Open Access Journals (Sweden)

    Osnes H.

    2012-08-01

    Full Text Available This study addresses the nonlinear stress-strain response in glass fibre reinforced polymer composite laminates. Loading and unloading of these laminates indicate that the nonlinear response is caused by both damage and plasticity. A user defined material model is implemented in the finite element code LS-DYNA. The damage evolution is based on the Puck failure criterion [1], and the plastic behaviour is based on the quadratic Hill yield criterion for anisotropic materials [2].

  2. Temperature Distribution in Fibre-glass Composite Impregnated with Epoxy-Cyanate ester Blend

    OpenAIRE

    Priyanka Brahmbhatt; Moni Banaudha; Subrata Pradhan

    2014-01-01

    Cyanate ester and epoxy blends have been identified as an attractive insulating material for fusion grade magnet winding packs. An insulation system comprising of fibre glass composites and cyanate ester and blend has been analyzed during its vacuum pressure impregnation and curing. The transient one dimensional distribution of temperature and extent of cure has been evaluated both analytically and experimentally in this paper. The one dimensional transient (1-D) heat transfer cha...

  3. Photoluminescence of Electrospun Poly-Methyl-Methacrylate:Alq3 Composite Fibres

    Institute of Scientific and Technical Information of China (English)

    TONG Ke-Qin; XU Chun-Xian; WANG Qiong; GU Bao-Xiang; ZHENG Ke; YE Li-Hua; LI Xin-Song

    2008-01-01

    @@ Tris(8-hydroxyquinoline) aluminium doped poly-methyl-methactylate (PMMA:AIq3) composite nanofibres are fabricated by electrospinning.The morphology of fibres is characterized by scanning electron microscopy.The photoluminescenee of a series of the nanofibres with various contents of Alq3 to PMMA is investigated.UV-visible absorption and the PL spectra analysis are employed to analyse the interaction between the polymer and the luminescent molecule.

  4. Electrospun PVDF graphene oxide composite fibre mats with tunable physical properties.

    OpenAIRE

    Issa, A. A. [احمد عبد السلام عيسى; Al-Maadeed, M.A.A.S.; Mrlik, M.; Luyt,A.S.

    2016-01-01

    This article is aimed at a basic physical characterization of electrospun PVDF/graphene oxide (GO) composite non-woven fibre mats. The morphological characterization of the prepared fabrics was performed via SEM investigations. Introduction of the GO during the electrospinning process caused significant changes in the crystalline structure of PVDF, and a transformation from α- to β-crystalline phases was achieved. Addition of the GO particles into PVDF did not only improve the thermal stabili...

  5. EFFECTS OF GEOMETRIC RATIOS AND FIBRE ORIENTATION ON THE NATURAL FREQUENCIES OF LAMINATED COMPOSITE PLATES

    Directory of Open Access Journals (Sweden)

    B. Attaf

    2015-08-01

    Full Text Available The present investigation aims to examine the influence of geometric ratios and fibre orientation on the natural frequencies of fibre-reinforced laminated composite plates using finite element method based on Yang’s theory and his collaborators. The transverse shear and rotatory inertia effects were taken into consideration in the developed Fortran computer program. It has been shown that the use of first-order displacement field provides the same accuracy as higher-order displacement field when the number of elements representing the plate structure is increased (refined mesh. However, poor precision may appear for plates with high thickness-to-side ratio h/a (thickness/side length. This discrepancy limits the application of the developed theory to thick plates (h/a<0.5. The various curves show the evolution of the dimensionless frequency (w* versus fibre orientation angle (q and illustrate the apparition of a “triple-point” phenomenon engendered by the increase of the plate aspect ratio a/b (length/width for a specific value of h/a. This point defines the maximum natural frequency and the associated fibre orientation. Also, results show that for high and/or low aspect ratios, the triple-point phenomenon does not occur. This latter is rapidly reached for thick plates than thin plates when the plate aspect ratio a/b is progressively increased.

  6. Development of epoxidized soybean oil and soy fibre composites with Polyhedral Oligomeric Silsesquioxane (POSS) nano reinforcement

    Science.gov (United States)

    de Boer, Ryan Sietze

    Soy fibre and soybean oil were utilized to produce a bio-composite targeted as a substitute for conventional petroleum-based materials. The study was divided into two parts; the first was the development of a bio-epoxy that consisted of conventional epoxy, epoxidized soybean oil, and two types of functionalized POSS. The second part of the study involved blending of the bio-epoxy with titanate treated soy fibre. Combined incorporation of epoxide and amine functionalized POSS in the bio-epoxy matrix resulted in a 29% impact strength improvement compared to the petroleum-based epoxy. Incorporation of the epoxide functionalized POSS resulted in improvements in tensile strength by 8%, tensile modulus by 2%, and an increase in the glass transition temperature by 4% compared to the petroleum-based epoxy and epoxidized soybean oil hybrid. The coupling of titanate to soy fibre in comparison to the soy fibre without titanate treatment resulted in an impact strength improvement of 37%. Furthermore, the coupling of titanate increased the tensile strength and tensile modulus by 24% and 22% respectively, and reduced the water absorption by 70%.

  7. Effect of curing temperature on flexural properties of silica-based geopolymer-carbon reinforced composite

    OpenAIRE

    2009-01-01

    Purpose: The aim of this paper is to find out the curing temperature at which we can achieve the best mechanical properties and adhesion between silica-based geopolymer matrix (Q1) and carbon HTS 5631 1600tex 24K fibre.Design/methodology/approach: The carbon fibre was impregnated with silica-based geopolymer by means of home-made “impregnation machine”. This equipment was designed based on simulating the real pultrusion or filament winding technique. Composite samples were made manually in si...

  8. Characterizing delamination of fibre composites by mixed mode cohesive laws

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Jacobsen, Torben K.

    2009-01-01

    A novel method is used for the determination of mixed mode cohesive laws and bridging laws for the characterisation of crack bridging in composites. The approach is based on an application of the J integral. The obtained cohesive laws were found to possess high peak stress values. Mixed mode...

  9. Nanographene reinforced carbon/carbon composites

    Science.gov (United States)

    Bansal, Dhruv

    Carbon/Carbon Composites (CCC) are made of carbon reinforcement in carbon matrix and have high thermal stability and fatigue resistance. CCC are used in nose cones, heat shields and disc brakes of aircrafts due to their exceptional mechanical properties at high temperature. The manufacturing process of CCC involves a carbonization stage in which unwanted elements, except carbon, are eliminated from the polymer precursor. Carbonization results in the formation of voids and cracks due to the thermal mismatch between the reinforcement and the matrix and expulsion of volatiles from the polymer matrix. Thermal cracks and voids decrease the density and mechanical properties of the manufactured CCC. In this work, Nanographene Platelets (NGP) were explored as nanofillers to fill the voids/cracks and reduce thermal shrinkage in CCC. They were first compared with Vapor Grown Carbon Nanofibers (VGCNF) by dispersion of different concentrations (0.5wt%, 1.5wt%, 3wt%) in resole-type phenolic resin and were characterized to explore their effect on rheology, heat of reaction and wetting behavior. The dispersions were then cured to form nanocomposites and were characterized for morphology, flexure and thermal properties. Finally, NGP were introduced into the carbon/carboncomposites in two stages, first by spraying in different concentrations (0.5wt%, 1.5wt%, 3wt%, 5wt %) during the prepreg formation and later during densification by directly mixing in the corresponding densification mix. The manufactured NGP reinforced CCC were characterized for microstructure, porosity, bulk density and mechanical properties (Flexure and ILSS) which were further cross-checked by non-destructive techniques (vibration and ultrasonic). In this study, it was further found that at low concentration (≤ 1.5 wt%) NGP were more effective in increasing the heat of reaction and in decreasing the viscosity of the phenolic resin. The decrease in viscosity led to better wetting properties of NGP / phenolic

  10. New Plaster Composite with Mineral Wool Fibres from CDW Recycling

    Directory of Open Access Journals (Sweden)

    Sonia Romaniega Piñeiro

    2015-01-01

    Full Text Available Over the last decade the intense activity of the building sector has generated large quantities of construction and demolition waste (CDW. In particular, in Europe around 890 million tons of CDW is generated every year; however, only 50% of them are recycled. In Spain, over the last years 40 millions of tons of construction and demolition waste have been generated. On the other hand, since the implementation of the Technical Building Code regulation the use of mineral wools as building insulation materials has become a widespread solution in both rehabilitation and new construction works, and because of that, this kind of insulation waste is increasing. This research analyzes the potential of a new composite (gypsum and fiber waste including several mineral wools waste into a plaster matrix. For this purpose, an experimental plan, characterizing the physical and mechanical behaviour as well as the Shore C hardness of the new composite, was elaborated fulfilling UNE Standards.

  11. Magnetic properties and microwave absorption properties of short carbon fibres coated by Ni–Fe alloy coatings

    Indian Academy of Sciences (India)

    Ying Liu; Chengwen Qiang

    2015-12-01

    Ni–Fe alloy coatings were successfully prepared on carbon fibre (CF) surfaces bymeans of electroplating at 25°C for 560 s. The structures and morphologies of the composite were characterized using X-ray diffraction and scanning electron microscopy. The coercivity () and saturation magnetization () of the Fe0.45Ni0.55/CF composites were 45.19 Oe and 1513.59 emu g−1, respectively. The reflectivity of Fe0.45Ni0.55/CF composites was less than −5 dB over the range of 1.1–5.4 GHz. The reflectivity of Fe0.45Ni0.55/CF composites was less than −10 dB over the range of 1.6–2.1 GHz. The lowest reflectivity of the Fe0.45Ni0.55/CF composites was −14.7 dB at 2.0 GHz and the corresponding thickness was 3.3 mm.

  12. Mercury removal from aqueous solution and flue gas by adsorption on activated carbon fibres

    Science.gov (United States)

    Nabais, João Valente; Carrott, P. J. M.; Carrott, M. M. L. Ribeiro; Belchior, Marisa; Boavida, Dulce; Diall, Tatiana; Gulyurtlu, Ibrahim

    2006-06-01

    The use of two activated carbon fibres, one laboratorial sample prepared from a commercial acrylic textile fibre and one commercial sample of Kynol ®, as prepared/received and modified by reaction with powdered sulfur and H 2S gas in order to increase the sulfur content were studied for the removal of mercury from aqueous solution and from flue gases from a fluidized bed combustor. The sulfur introduced ranged from 1 to 6 wt.% depending on the method used. The most important parameter for the mercury uptake is the type of sulfur introduced rather than the total amount and it was found that the H 2S treatment of ACF leads to samples with the highest mercury uptake, despite the lower sulfur amount introduced. The modified samples by both methods can remove HgCl 2 from aqueous solutions at pH 6 within the range 290-710 mg/g (ACF) which can be favourably compared with other studies already published. The use of a filter made with an activated carbon fibre modified by powdered sulfur totally removed the mercury species present in the flue gases produced by combustion of fossil fuel.

  13. Effect of fibre-reinforced composite on the fracture resistance of endodontically treated teeth.

    Science.gov (United States)

    Ozsevik, Abdul Semih; Yildirim, Cihan; Aydin, Ugur; Culha, Emre; Surmelioglu, Derya

    2016-08-01

    The aim of this study is to evaluate the fracture resistance of root-filled teeth restored with fibre-reinforced composite (everX posterior). Fifty mandibular molars were divided into five groups (n = 10). Group 1: no treatment was applied (intact teeth). Group 2-5: canals were prepared and root filled. Group 2: no coronal restoration was placed. Group 3: teeth were coronally restored with composite. Group 4: composite restorations were performed following polyethylene fibre insertion at the cavity base. Group 5: composite resin placed over everX posterior. After thermocycling (5-55°C, 5000×), fracture resistance was measured. Mean force load for each sample was recorded in Newtons (N). Results were statistically analysed with one-way analysis of variance and post hoc Tukey's tests. The mean force required to fracture samples and standard deviations are as follows: group 1: 2859.5 ± 551.27 N, group 2: 318.97 ± 108.67 N, group 3: 1489.5 ± 505.04 N, group 4: 1958.3 ± 362.94 N, group 5: 2550.7 ± 586.1 N. everX posterior (group 5) was higher than groups 2, 3 and 4 (P  0.05). Placing fibre-reinforced composite under composite increased the fracture strength of root-filled teeth to the level of intact teeth.

  14. Cytocompatibility and Mechanical Properties of Short Phosphate Glass Fibre Reinforced Polylactic Acid (PLA Composites: Effect of Coupling Agent Mediated Interface

    Directory of Open Access Journals (Sweden)

    Gavin Walker

    2012-10-01

    Full Text Available In this study three chemical agents Amino-propyl-triethoxy-silane (APS, sorbitol ended PLA oligomer (SPLA and Hexamethylene diisocyanate (HDI were identified to be used as coupling agents to react with the phosphate glass fibre (PGF reinforcement and the polylactic acid (PLA polymer matrix of the composite. Composites were prepared with short chopped strand fibres (l = 20 mm, ϕ = 20 µm in a random arrangement within PLA matrix. Improved, initial composite flexural strength (~20 MPa was observed for APS treated fibres, which was suggested to be due to enhanced bonding between the fibres and polymer matrix. Both APS and HDI treated fibres were suggested to be covalently linked with the PLA matrix. The hydrophobicity induced by these coupling agents (HDI, APS helped to resist hydrolysis of the interface and thus retained their mechanical properties for an extended period of time as compared to non-treated control. Approximately 70% of initial strength and 65% of initial modulus was retained by HDI treated fibre composites in contrast to the control, where only ~50% of strength and modulus was retained after 28 days of immersion in PBS at 37 °C. All coupling agent treated and control composites demonstrated good cytocompatibility which was comparable to the tissue culture polystyrene (TCP control, supporting the use of these materials as coupling agent’s within medical implant devices.

  15. Application of bridging-law concepts to short-fibre composites

    DEFF Research Database (Denmark)

    Lindhagen, J.E.; Gamstedt, Kristofer; Berglund, L.A.

    2000-01-01

    This is the third paper in a series of four where notch sensitivity, fracture energy and bridging laws are studied in short-fibre polymer composites. Here, bridging laws are derived from experimental crack-opening profiles in centre-hole notched tensile specimens. The materials studied are three...... types of commercial glass-mat composites with different reinforcement structures and matrices. The materials have softening bridging laws and the calculated fracture energies from bridging laws are in good agreement with values determined directly by experiment. The calculated maximum local bridging...

  16. Q-switched thulium-doped fibre laser operating at 1900 nm using multi-walled carbon nanotubes saturable absorber

    Directory of Open Access Journals (Sweden)

    Norazlina Saidin

    2014-06-01

    Full Text Available Simple, low-cost and stable passive Q-switched thulium-doped fibre lasers (TDFLs operating at 1892.4 and 1910.8 nm are demonstrated using 802 and 1552 nm pumping schemes, respectively, in conjunction with a multi-walled carbon nanotubes (MWCNTs saturable absorber (SA. The MWCNTs composite is prepared by mixing the MWCNTs homogeneous solution into a dilute polyvinyl alcohol (PVA polymer solution before it is left to dry at room temperature to produce thin film. Then the film is sandwiched between two FC/PC fibre connectors and integrated into the laser cavity for Q-switching pulse generation. The pulse repetition rate of the TDFL configured with 802 nm pump can be tuned from 3.8 to 4.6 kHz, whereas the corresponding pulse width reduces from 22.1 to 18.3 μs as the pump power is increased from 187.3 to 194.2 mW. On the other hand, with 1552 nm pumping, the TDFL generates optical pulse train with a repetition rate ranging from 13.1 to 21.7 kHz with a pulse width of 11.5–7.9 μs when the pump power is tuned from 302.2 to 382.1 mW. A higher performance Q-switched TDFL is expected to be achieved with the optimisation of the MWCNT-SA saturable absorber and laser cavity.

  17. Mechanical testing and modelling of carbon-carbon composites for aircraft disc brakes

    Science.gov (United States)

    Bradley, Luke R.

    The objective of this study is to improve the understanding of the stress distributions and failure mechanisms experienced by carbon-carbon composite aircraft brake discs using finite element (FE) analyses. The project has been carried out in association with Dunlop Aerospace as an EPSRC CASE studentship. It therefore focuses on the carbon-carbon composite brake disc material produced by Dunlop Aerospace, although it is envisaged that the approach will have broader applications for modelling and mechanical testing of carbon-carbon composites in general. The disc brake material is a laminated carbon-carbon composite comprised of poly(acrylonitrile) (PAN) derived carbon fibres in a chemical vapour infiltration (CVI) deposited matrix, in which the reinforcement is present in both continuous fibre and chopped fibre forms. To pave the way for the finite element analysis, a comprehensive study of the mechanical properties of the carbon-carbon composite material was carried out. This focused largely, but not entirely, on model composite materials formulated using structural elements of the disc brake material. The strengths and moduli of these materials were measured in tension, compression and shear in several orientations. It was found that the stress-strain behaviour of the materials were linear in directions where there was some continuous fibre reinforcement, but non-linear when this was not the case. In all orientations, some degree of non-linearity was observed in the shear stress-strain response of the materials. However, this non-linearity was generally not large enough to pose a problem for the estimation of elastic moduli. Evidence was found for negative Poisson's ratio behaviour in some orientations of the material in tension. Additionally, the through-thickness properties of the composite, including interlaminar shear strength, were shown to be positively related to bulk density. The in-plane properties were mostly unrelated to bulk density over the range of

  18. Potential Use of Plant Fibres and their Composites for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Farideh Namvar

    2014-05-01

    Full Text Available Plant-based fibers such as flax, jute, sisal, hemp, and kenaf have been frequently used in the manufacturing of biocomposites. Natural fibres possess a high strength to weight ratio, non-corrosive nature, high fracture toughness, renewability, and sustainability, which give them unique advantages over other materials. The development of biocomposites by reinforcing natural fibres has attracted attention of scientists and researchers due to environmental benefits and improved mechanical performance. Manufacturing of biocomposites from renewable sources is a challenging task, involving metals, polymers, and ceramics. Biocomposites are already utilized in biomedical applications such as drug/gene delivery, tissue engineering, orthopedics, and cosmetic orthodontics. The first essential requirement of materials to be used as biomaterial is its acceptability by the human body. A biomaterial should obtain some important common properties in order to be applied in the human body either for use alone or in combination. Biocomposites have potential to replace or serve as a framework allowing the regeneration of traumatized or degenerated tissues or organs, thus improving the patients’ quality of life. This review paper addresses the utilization of plant fibres and its composites in biomedical applications and considers potential future research directed at environment-friendly biodegradable composites for biomedical applications.

  19. CLASSIFICATION DE LA TENUE AU CHOC DES RESINES ORGANIQUES LORS D'ESSAIS EN COMPRESSION DYNAMIQUE ET D'IMPACT SUR PANNEAUX DES COMPOSITES A FIBRES DE VERRE

    OpenAIRE

    Dannawi, M.; Tournier, P.

    1988-01-01

    Cette recherche a permis de classer les résines organiques (époxyde, vinylester, polyester) utilisées dans la fabrication des composites à fibres de verre par rapport à deux types de sollicitations : monoaxiale (compression statique et dynamique dans le sens parallèle aux fibres et perpendiculaire aux fibres) et triaxiale (impact sur panneaux).

  20. Impact of chemical treatments on the mechanical and water absorption properties of coconut fibre (Cocos nucifera reinforced polypropylene composites

    Directory of Open Access Journals (Sweden)

    Isiaka O. OLADELE

    2016-07-01

    Full Text Available In this work, chemically treated coconut fibres were used to reinforce Homopolymer Polypropylene in order to ascertain the effect of the treatments on the mechanical and water absorption properties of the composites produced. Coconut fibre was first extracted from its husk by soaking it in water and was dried before it was cut into 10 mm lengths. It was then chemically treated in alkali solution of sodium hydroxide (NaOH and potassium hydroxide (KOH in a shaker water bath. The treated coconut fibres were used as reinforcements in polypropylene matrix to produce composites of varied fibre weight contents; 2, 4, 6, 8 and 10 wt.%. Tensile and flexural properties were investigated using universal testing machine while water absorption test was carried out on the samples for 7 days. It was observed from the results that, NaOH treated samples gave the best tensile properties while KOH treated samples gave the best flexural and water repellent properties.

  1. Active IR-thermography as a method of fiber content evaluation in carbon/epoxy composites

    OpenAIRE

    G. Wróbel; G. Muzia; S. Pawlak

    2008-01-01

    Purpose: The primary purpose of the present work was to find relationships between achieved results of thethermal non-destructive testing and the local fibre content in a carbon/epoxy composite materials. The paper alsodescribes the methodology, a prototype testing station and results achieved during investigations.Design/methodology/approach: The experiments have been performed using a prototype testing stationdesigned and built specially for the purpose of the investigation. Each carbon fib...

  2. EVITA Project: Comparison Between Traditional Non-Destructive Techniques and Phase Contrast X-Ray Imaging Applied to Aerospace Carbon Fibre Reinforced Polymer

    Science.gov (United States)

    Gresil, Matthieu; Revol, Vincent; Kitsianos, Konstantinos; Kanderakis, Georges; Koulalis, Ilias; Sauer, Marc-Olivier; Trétout, Hervé; Madrigal, Ana-Maria

    2016-10-01

    The EU-project EVITA (Non-Destructive EValuation, Inspection and Testing of Primary Aeronautical Composite Structures Using Phase Contrast X-Ray Imaging) aims at bringing Grating-based Phase Contrast X-ray imaging technology to Non-Destructive Evaluation and Inspection of advanced primary and/or complex aerospace composite structures. Grating-based Phase Contrast X-Ray Imaging is based on the so-called Talbot-Lau interferometer, which is made of the combination of a standard X-ray apparatus with three transmission gratings as documented in the literature. This paper presents a comparison of two traditional non-destructive techniques (NDT): ultrasonic through transmission (immersed and water jet) and ultrasonic phased-array pulse echo, with the developed phase contrast X-Ray Imaging applied to advanced aerospace carbon fibre reinforced polymer. Typical defects produced during manufacture is examined as part of the testing and validation procedure. The following defects have been identified as being those most likely to be detected more effectively by the Grating-based Phase Contrast X-Ray Imaging process than other state of the art industrial NDT techniques: porosity, foreign objects, cracks, resin rich, cut fibres, and wavy fibres. The introduction of this innovative methodology is expected to provide the aeronautical industry with a reliable and detailed insight of the integrity of thin and thick composite structures as well as of complex geometry ones, such as integrated closed boxes and sandwiches.

  3. EVITA Project: Comparison Between Traditional Non-Destructive Techniques and Phase Contrast X-Ray Imaging Applied to Aerospace Carbon Fibre Reinforced Polymer

    Science.gov (United States)

    Gresil, Matthieu; Revol, Vincent; Kitsianos, Konstantinos; Kanderakis, Georges; Koulalis, Ilias; Sauer, Marc-Olivier; Trétout, Hervé; Madrigal, Ana-Maria

    2017-04-01

    The EU-project EVITA (Non-Destructive EValuation, Inspection and Testing of Primary Aeronautical Composite Structures Using Phase Contrast X-Ray Imaging) aims at bringing Grating-based Phase Contrast X-ray imaging technology to Non-Destructive Evaluation and Inspection of advanced primary and/or complex aerospace composite structures. Grating-based Phase Contrast X-Ray Imaging is based on the so-called Talbot-Lau interferometer, which is made of the combination of a standard X-ray apparatus with three transmission gratings as documented in the literature. This paper presents a comparison of two traditional non-destructive techniques (NDT): ultrasonic through transmission (immersed and water jet) and ultrasonic phased-array pulse echo, with the developed phase contrast X-Ray Imaging applied to advanced aerospace carbon fibre reinforced polymer. Typical defects produced during manufacture is examined as part of the testing and validation procedure. The following defects have been identified as being those most likely to be detected more effectively by the Grating-based Phase Contrast X-Ray Imaging process than other state of the art industrial NDT techniques: porosity, foreign objects, cracks, resin rich, cut fibres, and wavy fibres. The introduction of this innovative methodology is expected to provide the aeronautical industry with a reliable and detailed insight of the integrity of thin and thick composite structures as well as of complex geometry ones, such as integrated closed boxes and sandwiches.

  4. On the elastic properties of carbon nanotube-based composites: modelling and characterization

    CERN Document Server

    Thostenson, E T

    2003-01-01

    The exceptional mechanical and physical properties observed for carbon nanotubes has stimulated the development of nanotube-based composite materials, but critical challenges exist before we can exploit these extraordinary nanoscale properties in a macroscopic composite. At the nanoscale, the structure of the carbon nanotube strongly influences the overall properties of the composite. The focus of this research is to develop a fundamental understanding of the structure/size influence of carbon nanotubes on the elastic properties of nanotube-based composites. Towards this end, the nanoscale structure and elastic properties of a model composite system of aligned multi-walled carbon nanotubes embedded in a polystyrene matrix were characterized, and a micromechanical approach for modelling of short fibre composites was modified to account for the structure of the nanotube reinforcement to predict the elastic modulus of the nanocomposite as a function of the constituent properties, reinforcement geometry and nanot...

  5. Kinetic Adsorption of Cd onto Nanometer Al2O3/Carbon Fibre

    Institute of Scientific and Technical Information of China (English)

    LI Yu; WANG Yue; HAN Wei; LI Su-wen; ZHAO Hui; ZHU Chang-yun; WANG Heng

    2005-01-01

    A new nanometer material, nano-Al2O3 with carbon fibre as the carrier, was employed for the removal of Cd with low concentrations from polluted water. The characterization of the material was carried out by means of SEM and TEM. Batch adsorption and elution experiments were carried out to determine the adsorption properties of Cd on the new adsorbent. The classical Thomas model was applied to estimating the equilibrium coefficients of Cd adsorption and the saturated adsorption ability. The results show that the Thomas model is fit for describing the kinetic adsorption process, and the maximum adsorption capacity of the nanometer Al2O3/carbon is 69.29 mg/g. The resulting information also indicates that the desorption of Cd eluted with de-ionized water at a rate of 9.8 mL/min can be neglected. With the advantage of a high adsorption capacity for removing low concentration Cd, the Al2O3/carbon fibre possesses the potentiality to be an effective adsorbent for the removal of Cd from polluted water.

  6. Surface modification of quartz fibres for dental composites through a sol-gel process.

    Science.gov (United States)

    Wang, Yazi; Wang, Renlin; Habib, Eric; Wang, Ruili; Zhang, Qinghong; Sun, Bin; Zhu, Meifang

    2017-05-01

    In this study, quartz fibres (QFs) surface modification using a sol-gel method was proposed and dental posts reinforced with modified QFs were produced. A silica sol (SS) was prepared using tetraethoxysilane (TEOS) and 3-methacryloxypropyltrimethoxysilane (γ-MPS) as precursors. The amount of γ-MPS in the sol-gel system was varied from 0 to 24wt.% with a constant molar ratio of TEOS, ethanol, deionized water, and HCl. Thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), and contact angle (CA) measurements were used to characterize the modified QFs, which confirmed that SS had successfully coated the surface of QFs. SEM images showed good interfacial bonding between the modified QFs and the resin matrix. The results of three-point bending tests of the fibre reinforced composite (FRC) posts showed that the QFs modified by SS with 12wt.% γ-MPS presented the best mechanical properties, demonstrating improvements of 108.3% and 89.6% for the flexural strength and flexural modulus, respectively, compared with untreated QFs. Furthermore, the sorption and solubility of the prepared dental posts were also studied by immersing the posts in artificial saliva (AS) for 4weeks, and yielded favourable results. This sol-gel surface modification method promises to resolve interfacial bonding issues of fibres with the resin matrix, and produce FRC posts with excellent properties.

  7. The reinforcement effect of polyethylene fibre and composite impregnated glass fibre on fracture resistance of endodontically treated teeth: An in vitro study

    Directory of Open Access Journals (Sweden)

    Archana Luthria

    2012-01-01

    Full Text Available Aim: The aim of this study was to evaluate the fracture resistance of endodontically treated maxillary premolars with wide mesio-occluso-distal (MOD cavities restored with either composite resin, or composite resin reinforced with different types of fibres. Materials and Methods: Fifty human maxillary premolars were selected. Five intact teeth served as positive controls. Endodontic therapy was carried out in the remaining forty-five teeth. Standardized MOD cavities were prepared in all the teeth. The teeth were restored with a nanocomposite using an incremental technique. These forty five teeth were randomly divided into three experimental groups (Group A, B and C (n = 15. The teeth in Group A did not undergo any further procedures. The teeth in Group B and C were reinforced with composite impregnated glass fibre and polyethylene fibre, respectively. Fracture resistance was measured in Newtons (N. Results: The positive controls showed the highest mean fracture resistance (811.90 N, followed by Group B (600.49N, Group A (516.96N and Group C (514.64N, respectively. One Way analysis of variance (ANOVA test revealed a statistically significant difference between all the groups (P = 0.001. Post-hoc Tukey test revealed a moderately significant difference (P = 0.034 between Control and Group B, and a strongly significant difference between Control and Group A (P = 0.002, and Control and Group C (P = 0.001. Conclusions: Endodontic therapy and MOD cavity preparation significantly reduced the fracture resistance of endodontically treated maxillary premolars (P = 0.001. No statistically significant difference was found between the experimental groups (Group A, B and C (P > 0.1. However, the fracture resistance of the composite impregnated glass fibre reinforced group was much higher than the others.

  8. The role of the epoxy resin: Curing agent ratio in composite interfacial strength by single fibre microbond test

    DEFF Research Database (Denmark)

    Minty, Ross; Thomason, James L.; Petersen, Helga Nørgaard

    2015-01-01

    This paper focuses on an investigation into the role of the epoxy resin: curing agent ratio in composite interfacial shear strength of glass fibre composites. The procedure involved changing the percentage of curing agent (Triethylenetetramine [TETA]) used in the mixture with several different...... percentages used, ranging from 4% up to 30%, including the stoichiometric ratio. It was found by using the microbond test, that there may exist a relationship between the epoxy resin to curing agent ratio and the level of adhesion between the reinforcing fibre and the polymer matrix of the composite....

  9. Fabrication, property characterization and toushening mechanism of HA-ZrO2(CaO)/316L fibre composite biomaterials

    Institute of Scientific and Technical Information of China (English)

    ZOU JianPeng; HE ZeQiang; ZHOU ZhongCheng; HUANG BaiYun; CHEN QiYuan; RUAN JianMing

    2008-01-01

    HA-ZrO2(CaO)/316L fibre composites were successfully fabricated with vacuum sintering method and their properties and toughening mechanism were studied.The results showed that HA-ZrO2(CaO)/316L fibre biocomposite having 20 vol% fibres had optimal comprehensive properties with bending strength,Young's modulus,fracture toughness and relative density equal to 140.1 MPa,117.8 GPa,5.81 MPa.m1/2and 87.1%,respectively.The research also addressed that different volume ratios of the composites led to different metallographic microstructures,and that metallographic morphologies change regularly with volume ratios of the composites.316L fibres were distributed randomly and evenly in the composites and the integration circumstance of the two phases was very well since there were no obvious flaws or pores in the composites.Two toughening mechanisms in-cluding ZrO2 phase transformation toughening mechanism and fibre pulling-out toughening mechanism existed in the compsites with the latter being the main toughening mechanism.

  10. Combining electrospinning and sputtering to improve rechargeable lithium battery cathodes: coating carbon fibre felt with nickel sulfide

    Science.gov (United States)

    Lee, Dong Kyu; Ryu, Ho Suk; Ahn, Chi Won; Jeon, Hwan-Jin

    2016-11-01

    Various nickel sulfide nanostructures have been developed for the fabrication of high surface area electrodes for rechargeable lithium batteries. In this study, we fabricated a nickel sulfide covered carbon fibre felt with high uniformity, high density, and large area for cathode materials for use in rechargeable lithium batteries, by using a combined electrospinning and sputtering deposition technique. In particular, the nickel sulfide/carbon fibre felt is a multi-functional material that can act as a conducting electrode itself without the use of binders and conductive materials owing to the high conductivity of the interlinked carbon fibre structures. A Li/nickel sulfide cell with current density of 100 mA g-1 exhibits good cycle performance and high first discharge capacity (970.46 mAh g-1) and good coulombic efficiency of 99% at 20 cycles. This electrode has good structural and electrochemical properties and has a potential to be commercialized when the properties are matured.

  11. Real-time monitoring system of composite aircraft wings utilizing Fibre Bragg Grating sensor

    Science.gov (United States)

    Vorathin, E.; Hafizi, Z. M.; Che Ghani, S. A.; Lim, K. S.

    2016-10-01

    Embedment of Fibre Bragg Grating (FBG) sensor in composite aircraft wings leads to the advancement of structural condition monitoring. The monitored aircraft wings have the capability to give real-time response under critical loading circumstances. The main objective of this paper is to develop a real-time FBG monitoring system for composite aircraft wings to view real-time changes when the structure undergoes some static loadings and dynamic impact. The implementation of matched edge filter FBG interrogation system to convert wavelength variations to strain readings shows that the structure is able to response instantly in real-time when undergoing few loadings and dynamic impact. This smart monitoring system is capable of updating the changes instantly in real-time and shows the weight induced on the composite aircraft wings instantly without any error. It also has a good agreement with acoustic emission (AE) sensor in the dynamic test.

  12. Assessing the Environmental Impact of Flax Fibre Reinforced Polymer Composite from a Consequential Life Cycle Assessment Perspective

    Directory of Open Access Journals (Sweden)

    Yelin Deng

    2015-08-01

    Full Text Available The study implements the consequential life cycle assessment (CLCA to provide a market based perspective on how overall environmental impact will change when shifting glass fibres to flax fibres as reinforcements in composite fabrication. With certain assumptions, the marginal flax fibre supply is identified to be a combination of Chinese flax fibre (70% and French flax fibre (30%. Due to inferior cultivars and coal-fired electricity in Chinese flax cultivation, the CLCA study reveals that flax mat-PP has 0.8–2 times higher environmental impact values than the glass mat-PP in most environmental impact categories over the production and end-of-life (EoL phases. For purpose of providing potential trajectories of marginal flax fibre supply, additional scenarios: the “all French fibre”, and “all Chinese fibre” are evaluated formulating the lower and upper boundaries in terms of environmental impact change, respectively. A “the attributional fibre supply mix” scenario is supplied as well. All of these scenarios are useful for policy analysis.

  13. Recycling and Fibre Reinforcement of Thermoplastic Wastes to Produce Composites for Construction Works

    Directory of Open Access Journals (Sweden)

    P.M. Wambua

    2012-04-01

    Full Text Available Thermoplastics are among polymers that biodegrades very slowly over a very long period and can be regarded as nonbiodegradable despite their rapid accumulation in the environment. The use of plant natural fibres as reinforcement for thermoplastics to produce composites is an important area for research. In this study, composites of high density polyethylene wastes reinforced with wood flour, rice husks and bagasse fibers were prepared. The fibers were heated to reduce their moisture content and improve their compatibilities with heated high density polyethylene wastes so as to increase adhesion at the interface. Binders were used to improve interfacial strength of the composite. Composites were prepared by extrusion. From preliminary laboratory test results based on Fratios using ANOVA, optimal coupon was found to be wood flour mixed with high density polyethylene and polyurethane resin (X 17 heated to 210ºC and extruded at 140ºC. The final test results for mechanical properties for optimal wood flour, rice husks and bagasse composites respectively were: Tensile strength; 83.87, 74, and 62.73 MPa. Flexural strength; 26.73, 39and 15.22 MPa. Compressive; 225, 190.5 and 140 MPa and Impact; 78, 81 and 66 J/mm2. The use of binders significantly improved impact strengths and widely expanded the usage of such product to include light load structural applications thus offering alternative source of construction materials to supplement timber and hence save forests. The technology can create employment to thermoplastic waste collectors, fibre collectors and composite producers.

  14. Carbon fibre and nitinol needles for MRI-guided interventions: First in vitro and in vivo application

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Christoph, E-mail: Christoph.thomas@med.uni-tuebingen.de [Department of Diagnostic and Interventional Radiology, University of Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Wojtczyk, Hanne [Section of Experimental Radiology, University of Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Rempp, Hansjoerg; Clasen, Stephan; Horger, Marius [Department of Diagnostic and Interventional Radiology, University of Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Lassberg, Christoph von [Department of Sports Medicine, University of Tuebingen, Silcherstrasse 5, 72076 Tuebingen (Germany); Fritz, Jan [Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287 (United States); Claussen, Claus D. [Department of Diagnostic and Interventional Radiology, University of Tuebingen, Hoppe-Seyler-Strasse 3, 72076 Tuebingen (Germany); Pereira, Philippe L. [Department of Radiology, Minimally Invasive Therapies and Nuclearmedicine, SLK-Kliniken Heilbronn GmbH, Am Gesundbrunnen 20-26, 74078 Heilbronn (Germany)

    2011-09-15

    Objective: To assess the artefact properties of a MR-compatible carbon fibre needle with a nitinol mandrin in vitro and to report first clinical experiences. Materials and methods: In vitro, the carbon fibre/nitinol needle was imaged at different angles against the main magnetic field (1.5 T open bore magnet). A gradient echo MR fluoroscopy sequence (GRE: TR 9.3 ms, TE 3.12 ms, bandwidth 200 Hz/pixel, flip-angle 12{sup o}) and a fast turbo spin echo sequence (FSE: TR 412 ms, TE 9.7 ms, bandwidth 200 Hz/pixel, flip-angle 150{sup o}) were used. Artefact width, needle intensity contrast and needle tip location errors were assessed. In vivo, lumbar periradicular corticosteroid injections and one sclerotherapy were performed with carbon fibre needles (10 procedures) and with titanium alloy needles (2 procedures). The artefact sizes and contrasts were measured. Results: In vitro, artefact diameters of the carbon fibre needle ranged from 3.3 to 4.6 mm, contrasts from 0.11 to 0.52, with larger artefact contrasts and widths with the GRE sequence. Needle tip location errors of -2.1 to -2.8 mm were observed. Decreasing angles to the main field lead to smaller artefacts. In vivo, the carbon fibre/nitinol needle produced smaller artefacts (mean width FSE/GRE: 2.8 mm/4.6 mm) with lower contrast (0.30-0.42) than the titanium alloy needle (mean width FSE/GRE: 4.1 mm/7.5 mm, contrast 0.60-0.73). Conclusions: The carbon fibre/nitinol needle is useful for performing MR-guided interventions at 1.5 T, producing more subtle artefacts than a titanium alloy needle, but with an incomplete depiction and thus inaccurate localization of the needle tip.

  15. Scalable synthesis of hierarchically structured carbon nanotube-graphene fibres for capacitive energy storage

    Science.gov (United States)

    Yu, Dingshan; Goh, Kunli; Wang, Hong; Wei, Li; Jiang, Wenchao; Zhang, Qiang; Dai, Liming; Chen, Yuan

    2014-07-01

    Micro-supercapacitors are promising energy storage devices that can complement or even replace batteries in miniaturized portable electronics and microelectromechanical systems. Their main limitation, however, is the low volumetric energy density when compared with batteries. Here, we describe a hierarchically structured carbon microfibre made of an interconnected network of aligned single-walled carbon nanotubes with interposed nitrogen-doped reduced graphene oxide sheets. The nanomaterials form mesoporous structures of large specific surface area (396 m2 g-1) and high electrical conductivity (102 S cm-1). We develop a scalable method to continuously produce the fibres using a silica capillary column functioning as a hydrothermal microreactor. The resultant fibres show a specific volumetric capacity as high as 305 F cm-3 in sulphuric acid (measured at 73.5 mA cm-3 in a three-electrode cell) or 300 F cm-3 in polyvinyl alcohol (PVA)/H3PO4 electrolyte (measured at 26.7 mA cm-3 in a two-electrode cell). A full micro-supercapacitor with PVA/H3PO4 gel electrolyte, free from binder, current collector and separator, has a volumetric energy density of ~6.3 mWh cm-3 (a value comparable to that of 4 V-500 µAh thin-film lithium batteries) while maintaining a power density more than two orders of magnitude higher than that of batteries, as well as a long cycle life. To demonstrate that our fibre-based, all-solid-state micro-supercapacitors can be easily integrated into miniaturized flexible devices, we use them to power an ultraviolet photodetector and a light-emitting diode.

  16. Scalable synthesis of hierarchically structured carbon nanotube-graphene fibres for capacitive energy storage.

    Science.gov (United States)

    Yu, Dingshan; Goh, Kunli; Wang, Hong; Wei, Li; Jiang, Wenchao; Zhang, Qiang; Dai, Liming; Chen, Yuan

    2014-07-01

    Micro-supercapacitors are promising energy storage devices that can complement or even replace batteries in miniaturized portable electronics and microelectromechanical systems. Their main limitation, however, is the low volumetric energy density when compared with batteries. Here, we describe a hierarchically structured carbon microfibre made of an interconnected network of aligned single-walled carbon nanotubes with interposed nitrogen-doped reduced graphene oxide sheets. The nanomaterials form mesoporous structures of large specific surface area (396 m(2) g(-1)) and high electrical conductivity (102 S cm(-1)). We develop a scalable method to continuously produce the fibres using a silica capillary column functioning as a hydrothermal microreactor. The resultant fibres show a specific volumetric capacity as high as 305 F cm(-3) in sulphuric acid (measured at 73.5 mA cm(-3) in a three-electrode cell) or 300 F cm(-3) in polyvinyl alcohol (PVA)/H(3)PO(4) electrolyte (measured at 26.7 mA cm(-3) in a two-electrode cell). A full micro-supercapacitor with PVA/H(3)PO(4) gel electrolyte, free from binder, current collector and separator, has a volumetric energy density of ∼6.3 mWh cm(-3) (a value comparable to that of 4 V-500 µAh thin-film lithium batteries) while maintaining a power density more than two orders of magnitude higher than that of batteries, as well as a long cycle life. To demonstrate that our fibre-based, all-solid-state micro-supercapacitors can be easily integrated into miniaturized flexible devices, we use them to power an ultraviolet photodetector and a light-emitting diode.

  17. Chopped basalt fibres: A new perspective in reinforcing poly(lactic acid to produce injection moulded engineering composites from renewable and natural resources

    Directory of Open Access Journals (Sweden)

    P. Tamas

    2013-02-01

    Full Text Available This paper focuses on the reinforcing of Poly(lactic acid with chopped basalt fibres by using silane treated and untreated basalt fibres. Composite materials with 5–10–15–20–30–40 wt% basalt fibre contents were prepared from silane sized basalt fibres using extrusion, and injection moulding, while composites with 5–10–15 wt% basalt fibre contents were also prepared by using untreated basalt fibres as control. The properties of the injection moulded composites were extensively examined by using quasi-static (tensile, three-point bending and dynamic mechanical tests (notched and unnotched Charpy impact tests, dynamic mechanical analysis (DMA, differential scanning calorimetry (DSC, heat deflection temperature (HDT analysis, dimensional stability test, as well as melt flow index (MFI analysis and scanning electron microscopic (SEM observations. It was found that silane treated chopped basalt fibres are much more effective in reinforcing Poly(lactic acid than natural fibres; although basalt fibres are not biodegradable but they are still considered as natural (can be found in nature in the form of volcanic rocks and biologically inert. It is demonstrated in this paper that by using basalt fibre reinforcement, a renewable and natural resource based composite can be produced by injection moulding with excellent mechanical properties suitable even for engineering applications. Finally it was shown that by using adequate drying of the materials, composites with higher mechanical properties can be achieved compared to literature data.

  18. ZnO thin films on single carbon fibres fabricated by Pulsed Laser Deposition (PLD)

    Science.gov (United States)

    Krämer, André; Engel, Sebastian; Sangiorgi, Nicola; Sanson, Alessandra; Bartolomé, Jose F.; Gräf, Stephan; Müller, Frank A.

    2017-03-01

    Single carbon fibres were 360° coated with zinc oxide (ZnO) thin films by pulsed laser deposition using a Q-switched CO2 laser with a pulse duration τ ≈ 300 ns, a wavelength λ = 10.59 μm, a repetition frequency frep = 800 Hz and a peak power Ppeak = 15 kW in combination with a 3-step-deposition technique. In a first set of experiments, the deposition process was optimised by investigating the crystallinity of ZnO films on silicon and polished stainless steel substrates. Here, the influence of the substrate temperature and of the oxygen partial pressure of the background gas were characterised by scanning electron microscopy and X-ray diffraction analyses. ZnO coated carbon fibres and conductive glass sheets were used to prepare photo anodes for dye-sensitised solar cells in order to investigate their suitability for energy conversion devices. To obtain a deeper insight of the electronic behaviour at the interface between ZnO and substrate I-V measurements were performed.

  19. Development of Activated Carbon from Cotton Fibre Waste as Potential Mercury Adsorbent: Kinetic and Equilibrium Studies

    Directory of Open Access Journals (Sweden)

    Jatindra N. Bhakta

    2014-01-01

    Full Text Available The study attempted to develop the activated carbon of cotton fibre (ACCF from cotton waste as a high Hg2+ adsorbent media and characterize physicochemical properties using scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS and Hg2+ adsorption kinetic by batch adsorption study with the function of contact time, solution pH, dosages of ACCF, and Hg concentration. The SEM-EDS study revealed that ACCF is composed of carbon (95.1% and phosphorus pentoxide (4.9%. Obtained results of adsorption kinetics showed that 15 min of contact time is required to achieve the equilibrium state and wide range of pH (4.08–7 is favourable for maximum Hg adsorption. The Hg2+ adsorption capacity showed a decreasing trend with increasing dose of ACCF, whereas a reverse response of adsorption capacity was pronounced with increasing Hg concentration. The data was well described by Freundlich isotherm model and determined the high Hg2+ adsorption capacity of ACCF (169.2 mg/g. To our knowledge, the application of ACCF in removing Hg2+ is the first study. High Hg2+ adsorption capacity, economic feasibility, availability of cotton fibre waste, and simple preparation method concluded that it could be used as a novel low-cost and environmentally sound adsorbent media for removing high rate of Hg2+ from aqueous phase.

  20. Controlled retting of hemp fibres: Effect of hydrothermal pre-treatmen tand enzymatic retting on the mechanical properties of unidirectiona lhemp/epoxy composites

    DEFF Research Database (Denmark)

    Liu, Ming; Silva, Diogo Alexandre Santos; Fernando, Dinesh

    2016-01-01

    The objective of this work was to investigate the use of hydrothermal pre-treatment and enzymatic retting to remove non-cellulosic compounds and thus improve the mechanical properties of hemp fibre/epoxy composites. Hydrothermal pre-treatment at 100 kPa and 121 °C combined with enzymatic retting...... produced fibres with the highest ultimate tensile strength (UTS) of 780 MPa. Compared to untreated fibres, this combined treatment exhibited a positive effect on the mechanical properties of hemp fibre/epoxy composites, resulting in high quality composites with low porosity factor (αpf) of 0.08.Traditional...

  1. Mechanical and thermal characterisation of poly (l-lactide) composites reinforced with hemp fibres

    Science.gov (United States)

    Shakoor, A.; Muhammad, R.; Thomas, N. L.; Silberschmidt, V. V.

    2013-07-01

    Polylactic acid (PLA) is the most promising in the bio-derived polymer's family. But its use can be constrained by its poor mechanical properties, poor thermal stability and processing difficulties. The objective of this research is to investigate and improve mechanical and dynamic thermal properties of PLA by developing PLA composites reinforced with natural fibres (hemp). Composites were prepared by melt blending of PLA with hemp fibres. Their properties were investigated using mechanical and dynamic thermal analysis. The elastic modulus increased significantly - from 4.1 ± 0.74 to 9.32 ± 0.86 (GPA) - when the weight fraction of hemp increased from 0 to 30(wt %). The storage modulus obtained by dynamic mechanical analysis increased from 2.20 to 4.58 (GPA) for the same change in the volume fraction of hemp. FE simulation of tensile testing and DMA were carried out to investigate the effect of strain rate and temperature on the observed properties respectively. The model was developed in the commercially available code MSC Marc mentate. The model validated all experimental results.

  2. Recycling solid residues recovered from glass fibre-reinforced composites – A review applied to wind turbine blade materials

    DEFF Research Database (Denmark)

    Beauson, Justine; Lilholt, Hans; Brøndsted, Povl

    2014-01-01

    to face large amount of future wind turbine (WT) blades coming to EoL. Among the EoL solutions available for WT blades, i.e. reuse, remanufacturing, recycling, incineration or disposal, this literature review focuses on recycling and particularly the recycling of shredded composite (SC) materials...... and recovered glass fibre (GF) into new polymer composite. WT blades are mainly made of glass fibre reinforced polymer (GFRP) using thermosetting resins. Shredding this material and recovering GF are possible recycling solutions for WT blade. Based on a detailed literature review, the formulations of new...

  3. Enhanced toughness and stable crack propagation in a novel tungsten fibre-reinforced tungsten composite produced by chemical vapour infiltration

    Science.gov (United States)

    Riesch, J.; Höschen, T.; Linsmeier, Ch; Wurster, S.; You, J.-H.

    2014-04-01

    Tungsten is a promising candidate for the plasma-facing components of a future fusion reactor, but its use is strongly restricted by its inherent brittleness. An innovative concept to overcome this problem is tungsten fibre-reinforced tungsten composite. In this paper we present the first mechanical test of such a composite material using a sample containing multiple fibres. The in situ fracture experiment was performed in a scanning electron microscope for close observation of the propagating crack. Stable crack propagation accompanied with rising load bearing capacity is observed. The fracture toughness is estimated using the test results and the surface observation.

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

    Directory of Open Access Journals (Sweden)

    Kamal Sharma

    2014-01-01

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

  5. A novel biaxial specimen for inducing residual stresses in thermoset polymers and fibre composite material

    DEFF Research Database (Denmark)

    Jakobsen, Johnny; Andreasen, Jens Henrik; Jensen, Martin

    2015-01-01

    A new type of specimen configuration with the purpose of introducing a well-defined biaxial residual (axisymmetric) stress field in a neat thermoset or a fibre composite material is presented. The ability to experimentally validate residual stress predictions is an increasing need for design...... engineers when they challenge the material limits in present and future thermoset and composite component. In addition to the new specimen configuration, this paper presents an analytical solution for the residual stress state in the specimen. The analytical solution assumes linear elastic and isotropic...... material behaviour. Experimental strain release measurements and the analytical solution determine the residual stress state present in the material. A demonstration on neat epoxy is conducted and residual stress predictions of high accuracy and repeatability have been achieved. The precise determination...

  6. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications.

    Science.gov (United States)

    Di Sante, Raffaella

    2015-07-30

    In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS) have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques.

  7. GRC: Composite material from an inorganic matrix reinforced with AR glass fibres

    Directory of Open Access Journals (Sweden)

    Comino Almenara, P. I.

    1996-06-01

    Full Text Available This article describes the historical background of Cem-FIL. Alkali Resistant Glass Fibre, as well as the composite characteristics of the element they generate: GRC. The most important advantages and properties of this type of Composite Material are also detailed.

    En este artículo se detallan cuáles son las bases históricas de las Fibras de Vidrio Álcali-Resistentes Cem-FIL así como las características del elemento compuesto que ellas generan: GRC. En este documento también se pueden encontrar indicaciones sobre las principales ventajas y propiedades de este tipo de Material Compuesto.

  8. Fibre Optic Sensors for Structural Health Monitoring of Aircraft Composite Structures: Recent Advances and Applications

    Directory of Open Access Journals (Sweden)

    Raffaella Di Sante

    2015-07-01

    Full Text Available In-service structural health monitoring of composite aircraft structures plays a key role in the assessment of their performance and integrity. In recent years, Fibre Optic Sensors (FOS have proved to be a potentially excellent technique for real-time in-situ monitoring of these structures due to their numerous advantages, such as immunity to electromagnetic interference, small size, light weight, durability, and high bandwidth, which allows a great number of sensors to operate in the same system, and the possibility to be integrated within the material. However, more effort is still needed to bring the technology to a fully mature readiness level. In this paper, recent research and applications in structural health monitoring of composite aircraft structures using FOS have been critically reviewed, considering both the multi-point and distributed sensing techniques.

  9. Capacitor with a composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, S.T.; Pekala, R.W.; Kaschmitter, J.L.

    1999-04-27

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy. 1 fig.

  10. Capacitor with a composite carbon foam electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Steven T. (San Leandro, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    1999-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid partides being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

  11. Method for fabricating composite carbon foam

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Steven T. (San Leandro, CA); Pekala, Richard W. (Pleasant Hill, CA); Kaschmitter, James L. (Pleasanton, CA)

    2001-01-01

    Carbon aerogels used as a binder for granularized materials, including other forms of carbon and metal additives, are cast onto carbon or metal fiber substrates to form composite carbon thin film sheets. The thin film sheets are utilized in electrochemical energy storage applications, such as electrochemical double layer capacitors (aerocapacitors), lithium based battery insertion electrodes, fuel cell electrodes, and electrocapacitive deionization electrodes. The composite carbon foam may be formed by prior known processes, but with the solid particles being added during the liquid phase of the process, i.e. prior to gelation. The other forms of carbon may include carbon microspheres, carbon powder, carbon aerogel powder or particles, graphite carbons. Metal and/or carbon fibers may be added for increased conductivity. The choice of materials and fibers will depend on the electrolyte used and the relative trade off of system resistivity and power to system energy.

  12. Impact of the carbonisation temperature on the activation of carbon fibres and their application for hydrogen storage

    Energy Technology Data Exchange (ETDEWEB)

    Kunowsky, M. [Departamento de Quimica Inorganica, Universidad de Alicante, Apartado de Correos 99, E-03080 Alicante (Spain); CNRS LIMHPUPR1311, Universite Paris 13, 99 Av. J.B. Clement, 93430 Villetaneuse (France); Weinberger, B.; Lamari Darkrim, F. [CNRS LIMHPUPR1311, Universite Paris 13, 99 Av. J.B. Clement, 93430 Villetaneuse (France); Suarez-Garcia, F.; Cazorla-Amoros, D.; Linares-Solano, A. [Departamento de Quimica Inorganica, Universidad de Alicante, Apartado de Correos 99, E-03080 Alicante (Spain)

    2008-06-15

    Porous materials are gaining interest due to their potential for storing hydrogen via physisorption. In the present work, two carbon fibres, carbonised at 973 and 1273 K, have been chemically activated with KOH and NaOH, in order to obtain materials with optimised characteristics for hydrogen storage application. Highly microporous activated carbon fibres were obtained from both precursors, especially from the fibre carbonised at the lower carbonisation temperature, remarking its importance on its subsequent activation process. As activation agent, KOH is more effective for developing the narrow microporosity, and higher yields are obtained. H{sub 2} adsorption isotherms were measured at 298 K for pressures up to 20 MPa, and at 77 K up to 4 MPa. The maximum excess adsorption of hydrogen reached 1 wt% at 298 K and 3.8 wt% at 77 K. The total volumetric storage capacity is of 17 g/l at 298 K, and 32 g/l at 77 K. (author)

  13. Multi scale analysis by acoustic emission of damage mechanisms in natural fibre woven fabrics/epoxy composites.

    Directory of Open Access Journals (Sweden)

    Touchard F.

    2010-06-01

    Full Text Available This paper proposes to develop an experimental program to characterize the type and the development of damage in composite with complex microstructure. A multi-scale analysis by acoustic emission has been developed and applied to hemp fibre woven fabrics/epoxy composite. The experimental program consists of tensile tests performed on single yarn, neat epoxy resin and composite materials to identify their AE amplitude signatures. A statistical analysis of AE amplitude signals has been realised and correlated with microscopic observations. Results have enabled to identify three types of damage in composites and their associated AE amplitudes: matrix cracking, interfacial debonding and reinforcement damage and fracture. Tracking of these damage mechanisms in hemp/epoxy composites has been performed to show the process of damage development in natural fibre reinforced composites.

  14. Multi scale analysis by acoustic emission of damage mechanisms in natural fibre woven fabrics/epoxy composites.

    Science.gov (United States)

    Bonnafous, C.; Touchard, F.; Chocinski-Arnault, L.

    2010-06-01

    This paper proposes to develop an experimental program to characterize the type and the development of damage in composite with complex microstructure. A multi-scale analysis by acoustic emission has been developed and applied to hemp fibre woven fabrics/epoxy composite. The experimental program consists of tensile tests performed on single yarn, neat epoxy resin and composite materials to identify their AE amplitude signatures. A statistical analysis of AE amplitude signals has been realised and correlated with microscopic observations. Results have enabled to identify three types of damage in composites and their associated AE amplitudes: matrix cracking, interfacial debonding and reinforcement damage and fracture. Tracking of these damage mechanisms in hemp/epoxy composites has been performed to show the process of damage development in natural fibre reinforced composites.

  15. Carbon nanostructure composite for electromagnetic interference shielding

    Indian Academy of Sciences (India)

    Anupama Joshi; Suwarna Datar

    2015-06-01

    This communication reviews current developments in carbon nanostructure-based composite materials for electromagnetic interference (EMI) shielding. With more and more electronic gadgets being used at different frequencies, there is a need for shielding them from one another to avoid interference. Conventionally, metal-based shielding materials have been used. But due to the requirement of light weight, corrosion resistive materials, lot of work is being done on composite materials. In this research the forerunner is the nanocarbon-based composite material whose different forms add different characteristics to the composite. The article focusses on composites based on graphene, graphene oxide, carbon nanotubes, and several other novel forms of carbon.

  16. Catalytic graphitization of carbon/carbon composites by lanthanum oxide

    Institute of Scientific and Technical Information of China (English)

    ZHANG Can; LU Guimin; SUN Ze; YU Jianguo

    2012-01-01

    Graphitized carbon/carbon composites were prepared by the process of catalytic graphitization with the rare-earth catalyst,lanthanum oxide (La2O3),in order to increase the degree of graphitization and reduce the electrical resistivity.The modified coal tar pitch and coal-based needle coke were used as carbon source,and a small amount of La2O3 was added to catalyze the graphitization of the disordered carbon materials.The effects of La2O3 catalyst on the graphitization degree and microstructure oftbe carbon/carbon composites were investigated by X-ray diffraction,scanning electron microscopy,and Raman spectroscopy.The results showed that La2O3 promoted the formation of more perfect and larger crystallites,and improved the electrical/mechanical properties of carbon/carbon composites.Carbon/carbon composites with a lower electrical resistivity (7.0 μΩ·m) could be prepared when adding 5 wt.% La2O3 powder with heating treatment at 2800 ℃.The catalytic effect of La2O3 for the graphitization of carbon/carbon composites was analyzed.

  17. Three-dimensional porous hollow fibre copper electrodes for efficient and high-rate electrochemical carbon dioxide reduction

    NARCIS (Netherlands)

    Kas, Recep; Hummadi, Khalid Khazzal; Kortlever, Ruud; Wit, de Patrick; Milbrat, Alexander; Luiten-Olieman, Mieke W.J.; Benes, Nieck E.; Koper, Marc T.M.; Mul, Guido

    2016-01-01

    Aqueous-phase electrochemical reduction of carbon dioxide requires an active, earth-abundant electrocatalyst, as well as highly efficient mass transport. Here we report the design of a porous hollow fibre copper electrode with a compact three-dimensional geometry, which provides a large area, three-

  18. Carbon Nanomaterials as Reinforcements for Composites

    Science.gov (United States)

    Zhu, Shen; Su, Ching-Hua; Lehoczky, S. L.; Curreri, Peter A. (Technical Monitor)

    2002-01-01

    Carbon nanomaterials including fellerenes, nanotubes (CNT) and nanofibers have been proposed for many applications. One of applications is to use the carbon nanomaterials as reinforcements for composites, especially for polymer matrices. Carbon nanotubes is a good reinforcement for lightweight composite applications due to its low mass density and high Young's modulus. Two obscures need to overcome for carbon nanotubes as reinforcements in composites, which are large quantity production and functioning the nanotubes. This presentation will discuss the carbon nanotube growth by chemical vapor deposition. In order to reduce the cost of producing carbon nanotubes as well as preventing the sliding problems, carbon nanotubes were also synthesized on carbon fibers. The synthesis process and characterization results of nanotubes and nanotubes/fibers will be discussed in the presentation.

  19. Machinability Study of Hybrid Nanoclay-Glass Fibre Reinforced Polyester Composites

    Directory of Open Access Journals (Sweden)

    P. Prabhu

    2013-01-01

    Full Text Available Glass fibre reinforced polyester composites (GRP and hybrid nanoclay and glass fibre reinforced polyester nanocomposites (CGRP are fabricated by vacuum assisted resin infusion technique. The optimum mechanical properties are obtained for CGRP with 3 wt.% nanoclay. Three types of drills (carbide twist drill D 5407060, HSS twist drill BS-328, and HSS end mill (4 flutes “N”-type end mill RH-helical flute of 6 mm diameters are used to drill holes on GRP and CGRP. Three different speeds (600, 852, and 1260 rpm and two different feeds (0.045, 0.1 mm/rev are selected as process parameters. The effect of process parameter on thrust force and delamination during drilling CGRP is analyzed for optimizing the machining parameters. The delamination factor is low for the optimum process parameter (feed = 0.1 mm/rev and speed 852 rpm. Microstructural analysis confirms that at higher feeds, delamination is low for CGRP drilled with carbide tools. In order to analyze the effect of nanoclay in CGRP on tool wear, 200 holes were drilled on CGRP samples with 3 wt.% nanoclay, and the tool wear is analyzed under optimized parametric condition. Tool wear is high in HSS twist drill compared with carbide drill. The presence of nanoclay also accelerates the tool wear.

  20. Assessment of microcapsule—catalyst particles healing system in high performance fibre reinforced polymer composite

    Science.gov (United States)

    Bolimowski, P. A.; Wass, D. F.; Bond, I. P.

    2016-08-01

    Autonomous self-healing in carbon fibre reinforced polymer (CFRP) is demonstrated using epoxy resin filled microcapsules and a solid-state catalyst. Microcapsules filled with oligomeric epoxy resin (20-450 μm) and particles of Sc(OTf)3 are embedded in an interleave region of a unidirectional CFRP laminate and tested under mode I loading. Double cantilever beam (DCB) test specimens containing variable concentrations of microcapsules and catalyst were prepared, tested and compared to those healed by manual injection with corresponding healing resin formulation. The healing efficiency was evaluated by comparing the maximum peak load recorded on load-displacement curves for pristine and healed specimens. A 44% maximum recovery was observed for specimens containing 10 wt% of solid phase catalyst and 11 wt% of epoxy microcapsules. However, a significant (80%) decrease in initial strain energy release rate (G IC) was observed for specimens with the embedded healing chemistries.

  1. Debonding of short fibres among particulates in a metal matrix composite

    DEFF Research Database (Denmark)

    Tvergaard, Viggo

    2003-01-01

    A numerical analysis is carried out for the development of damage by fibre-matrix debonding in aluminium reinforced by aligned, short SiC fibres. A unit cell-model that has earlier been applied to study materials with arrays of transversely staggered fibres is here extended to contain a number...

  2. Flexural testing on carbon fibre laminates taking into account their different behaviour under tension and compression

    Science.gov (United States)

    Serna Moreno, M. C.; Romero Gutierrez, A.; Martínez Vicente, J. L.

    2016-07-01

    An analytical model has been derived for describing the results of three-point-bending tests in materials with different behaviour under tension and compression. The shift of the neutral plane and the damage initiation mode and its location have been defined. The validity of the equations has been reviewed by testing carbon fibre-reinforced polymers (CFRP), typically employed in different weight-critical applications. Both unidirectional and cross-ply laminates have been studied. The initial failure mode produced depends directly on the beam span- thickness relation. Therefore, specimens with different thicknesses have been analysed for examining the damage initiation due to either the bending moment or the out-of-plane shear load. The experimental description of the damage initiation and evolution has been shown by means of optical microscopy. The good agreement between the analytical estimations and the experimental results shows the validity of the analytical model exposed.

  3. Effect of High Velocity Ballistic Impact on Pretensioned Carbon Fibre Reinforced Plastic (CFRP) Plates

    Science.gov (United States)

    Azhar KAMARUDIN, Kamarul; HAMID, Iskandar ABDUL

    2017-01-01

    This work describes an experimental investigation of the pretensioned thin plates made of Carbon Fibre Reinforced Plastic (CFRP) struck by hemispherical and blunt projectiles at various impact velocities. The experiments were done using a gas gun with combination of pretension equipment positioned at the end of gun barrel near the nozzle. Measurements of the initial and residual velocities were taken, and the ballistic limit velocity were calculated for each procedures. The pretension target results in reduction of ballistic limit compared to non-pretension target for both flat and hemispherical projectiles. Target impacted by hemispherical projectile experience split at earlier impact velocity compared to target by flat projectile. C-Scan images analysis technique was used to show target impact damaged by hemispherical and flat projectiles. The damage area was shown biggest at ballistic limit velocity and target splitting occurred most for pretention plate.

  4. Rigidity and retention of carbon fibre versus stainless steel root canal posts.

    Science.gov (United States)

    Purton, D G; Love, R M

    1996-07-01

    Two of the main requirements of a root canal post are that it is rigid so as to resist flexing under functional load, and that it is well retained in the root. This study compared these properties in two different 1-mm diameter root canal posts--smooth carbon fibre posts (Endopost) and serrated stainless steel posts (Parapost). Ten posts of each type were tested for rigidity in a three-point bend test. Ten posts of each type were cemented with resin cement into the roots of endodontically treated, extracted teeth. The tensile force required to remove the posts was recorded. The Paraposts proved to be significantly more rigid under load (P canals.

  5. Mechanical and thermal properties of polylactic acid composites reinforced with cellulose nanoparticles extracted from kenaf fibre

    Science.gov (United States)

    Ketabchi, Mohammad Reza; Khalid, Mohammad; Thevy Ratnam, Chantara; Walvekar, Rashmi

    2016-12-01

    Different approaches have been attempted to use biomass as filler for production of biodegradable polymer composites. In this study, cellulose nanoparticles (CNP) extracted from kenaf fibres were used to produce polylactic acid (PLA) based biodegradable nanocomposites. CNP concentration was varied from 1-5 wt. % and blended with PLA using Brabender twin-screw compounder. Effects of CNP loading on the mechanical, thermal and dynamic properties of PLA were investigated. Studies on the morphological properties and influence of CNP loading on the properties of CNP/PLA nanocomposite were also conducted. The results show an adequate compatibility between CNP and PLA matrix. Moreover, addition of 3 wt. % of CNP improved the PLA tensile strength by 25%.

  6. Study on Sound Absorption Properties of Coconut Coir Fibre Reinforced Composite with Added Recycled Rubber

    Directory of Open Access Journals (Sweden)

    S. Mahzan

    2010-06-01

    Full Text Available Sound pollutions have become worsen and creating concerns for many peoples. Conventionally, expensive sound absorption materials are employed to control noise disturbances. However, recent developments on natural fibres have created interest for researchers especially for acoustics application purposes. This paper investigates the viability of coconut coir added with recycled rubber to be implemented as sound absorption panel. The composite is constructed at prescribed percentages of fillers and polyurethane as resin. The two-microphone method was applied to obtain the acoustic properties of the samples. The samples were also tested for physical properties such as density and porosity, as well as the microstructures. The results demonstrate good acoustics performances and highlight the potential of the coconut coir reinforced with recycled rubber as the sound absorption panel.

  7. Carbon Nanotube Enhanced Aerospace Composite Materials A New Generation of Multifunctional Hybrid Structural Composites

    CERN Document Server

    Kostopoulos, V

    2013-01-01

    The well documented increase in the use of high performance composites as structural materials in aerospace components is continuously raising the demands in terms of dynamic performance, structural integrity, reliable life monitoring systems and adaptive actuating abilities. Current technologies address the above issues separately; material property tailoring and custom design practices aim to the enhancement of dynamic and damage tolerance characteristics, whereas life monitoring and actuation is performed with embedded sensors that may be detrimental to the structural integrity of the component. This publication explores the unique properties of carbon nanotubes (CNT) as an additive in the matrix of Fibre Reinforced Plastics (FRP), for producing structural composites with improved mechanical performance as well as sensing/actuating capabilities. The successful combination of the CNT properties and existing sensing actuating technologies leads to the realization of a multifunctional FRP structure. The curre...

  8. Preparation and properties of unidirectional boron nitride fibre reinforced boron nitride matrix composites via precursor infiltration and pyrolysis route

    Energy Technology Data Exchange (ETDEWEB)

    Li Duan, E-mail: whataboutduan@gmail.com [State Key Laboratory of Advanced Ceramic Fibres and Composites, College of Aerospace and Materials Engineering, National University of Defense Technology, Changsha 410073 (China); Zhang Changrui; Li Bin; Cao Feng; Wang Siqing; Li Junsheng [State Key Laboratory of Advanced Ceramic Fibres and Composites, College of Aerospace and Materials Engineering, National University of Defense Technology, Changsha 410073 (China)

    2011-10-25

    Highlights: {yields} BN fibres degrade little when exposed at elevated temperatures. {yields} Precursor infiltration and pyrolysis route is useful to prepare BNf/BN composites. {yields} Few reports have related to the preparation and properties of BNf/BN composites. {yields} BNf/BN composites have desirable high-temperature mechanical properties. {yields} BNf/BN composites have excellent dielectric properties at 2-18 GHz. - Abstract: The unidirectional boron nitride fibre reinforced boron nitride matrix (BN{sub f}/BN) composites were prepared via the precursor infiltration and pyrolysis (PIP) route, and the structure, composition, mechanical and dielectric properties were studied. The composites have a high content and fine crystallinity of BN. The density is 1.60 g cm{sup -3} with a low open porosity of 4.66%. The composites display good mechanical properties with the average flexural strength, elastic modulus and fracture toughness being 53.8 MPa, 20.8 GPa and 6.88 MPa m{sup 1/2}, respectively. Lots of long fibres pull-out from the fracture surface, suggesting a good fibre/matrix interface. As temperature increases, both of the flexural strength and elastic modulus exhibit a decreasing trend, with the lowest values being 36.2 MPa and 8.6 GPa at 1000 deg. C, respectively. The desirable residual ratios of the flexural strength and elastic modulus at 1000 deg. C are 67.3% and 41.3%, respectively. The composites have excellent dielectric properties, with the average dielectric constant and loss tangent being 3.07 and 0.0044 at 2-18 GHz, respectively.

  9. Lithographically defined microporous carbon-composite structures

    Energy Technology Data Exchange (ETDEWEB)

    Burckel, David Bruce; Washburn, Cody M.; Lambert, Timothy N.; Finnegan, Patrick Sean; Wheeler, David R.

    2016-12-06

    A microporous carbon scaffold is produced by lithographically patterning a carbon-containing photoresist, followed by pyrolysis of the developed resist structure. Prior to exposure, the photoresist is loaded with a nanoparticulate material. After pyrolysis, the nanonparticulate material is dispersed in, and intimately mixed with, the carbonaceous material of the scaffold, thereby yielding a carbon composite structure.

  10. Carbon Nanotubes Reinforced Composites for Biomedical Applications

    OpenAIRE

    Wei Wang; Yuhe Zhu; Susan Liao; Jiajia Li

    2014-01-01

    This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matr...

  11. Progress in reinforcing fibers of carbon and aramid

    Energy Technology Data Exchange (ETDEWEB)

    Blumberg, H.

    1989-01-01

    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.).

  12. An estimation of fatigue life for a carbon fibre/poly ether ether ketone hip joint prosthesis.

    Science.gov (United States)

    Akay, M; Aslan, N

    1995-01-01

    A fracture mechanics approach was applied to estimate the life of a prosthesis injection moulded from short carbon fibre reinforced poly ether ether ketone. Flexural modulus and strength, fracture toughness, fatigue endurance limit, fatigue crack growth rate and threshold stress intensity factor were determined. The dimensions of the test pieces were selected to yield fibre orientation and fibre length distributions similar to those obtained in the prosthesis. Stress levels generated in the prosthesis under different activities were estimated by conducting three-dimensional finite element analysis. It was shown by a fracture mechanics approach that a fatigue failure due to the propagation of an embedded elliptical slit, under these stresses, would be unlikely for a crack length smaller than 1.85 mm. However, the cement would fail under the same conditions, irrespective of the type of the prosthesis employed.

  13. EXPERIMENT OF THE PERFORMANCE OF HOME-MADE ACTIVATED CARBON FIBRE CARTRIDGE%国产活性炭纤维滤芯性能测试

    Institute of Scientific and Technical Information of China (English)

    万春新; 陈建国; 黄金钟; 胡望钧

    2001-01-01

    本文通过对国产活性炭纤维滤芯与国外进口活性炭纤维滤芯进行的各项性能对比测试结果的分析,指出国产活性炭纤维滤芯可替代国外进口同类产品。%The performance of home-made and import activated carbon fibre cartridge is studied here. By comparing the performances of these two kinds, we found that home-made activated carbon fibre cartridge can be substituted for import activated carbon fibre cartridge of the same kind.

  14. Effect of pMDI isocyanate additive on mechanical and thermal properties of Kenaf fibre reinforced thermoplastic polyurethane composites

    Indian Academy of Sciences (India)

    Y A El-Shekeil; S M Sapuan; K Abdan; E S Zainudin; O M Al-Shuja’a

    2012-12-01

    The effect of polymeric methylene diphenyl diisocyanate (pMDI) on mechanical and thermal properties of Kenaf fibre (KF) reinforced thermoplastic polyurethane (TPU) composites was studied. Various percentages viz. 2%, 4% and 6%, were studied. The composites were characterized by using tensile testing, thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and fourier transform infrared spectroscopy (FTIR). It was noticed that the addition of pMDI 2%, 4%and 6% did not induce a better tensile nor thermal properties.

  15. Self-healing of damage in fibre-reinforced polymer-matrix composites.

    Science.gov (United States)

    Hayes, S A; Zhang, W; Branthwaite, M; Jones, F R

    2007-04-22

    Self-healing resin systems have been discussed for over a decade and four different technologies had been proposed. However, little work on their application as composite matrices has been published although this was one of the stated aims of the earliest work in the field. This paper reports on the optimization of a solid-state self-healing resin system and its subsequent use as a matrix for high volume fraction glass fibre-reinforced composites. The resin system was optimized using Charpy impact testing and repeated healing, while the efficiency of healing in composites was determined by analysing the growth of delaminations following repeated impacts with or without a healing cycle. To act as a reference, a non-healing resin system was subjected to the same treatments and the results are compared with the healable system. The optimized resin system displays a healing efficiency of 65% after the first healing cycle, dropping to 35 and 30% after the second and third healing cycles, respectively. Correction for any healability due to further curing showed that approximately 50% healing efficiency could be achieved with the bisphenol A-based epoxy resin containing 7.5% of polybisphenol-A-co-epichlorohydrin. The composite, on the other hand, displays a healing efficiency of approximately 30%. It is therefore clear that the solid-state self-healing system is capable of healing transverse cracks and delaminations in a composite, but that more work is needed to optimize matrix healing within a composite and to develop a methodology for assessing recovery in performance.

  16. The effect of serrations on carbon fibre posts-retention within the root canal, core retention, and post rigidity.

    Science.gov (United States)

    Love, R M; Purton, D G

    1996-01-01

    The retention in root canals of serrated carbon fibre Composiposts and stainless steel Paraposts was tested under tensile load. Twenty unrestored human roots were endodontically prepared and root filled. Two groups of 10 roots received 1.4-mm Composiposts or 1.25-mm Paraposts luted with a resin cement. The specimens were then embedded in acrylic resin and mounted in an Instron machine. The tensile force (kg) required to dislodge the posts was recorded and analysed with Student's test. The results revealed that there was no significant difference in the retention of either post (P > .05). The rigidty of 10 1.4-mm serrated Composiposts was tested in a three-point bend test in an Instron machine, and the retention of composite cores to 10 of these posts under tensile force was also tested. The results from these tests were compared to previous data from the authors' laboratory and revealed that the serrations significantly reduced the rigidity of the post (P < .001) and increased the retention of a core material (P < .001).

  17. Carbon nanotube-polymer composite actuators

    Science.gov (United States)

    Gennett, Thomas; Raffaelle, Ryne P.; Landi, Brian J.; Heben, Michael J.

    2008-04-22

    The present invention discloses a carbon nanotube (SWNT)-polymer composite actuator and method to make such actuator. A series of uniform composites was prepared by dispersing purified single wall nanotubes with varying weight percents into a polymer matrix, followed by solution casting. The resulting nanotube-polymer composite was then successfully used to form a nanotube polymer actuator.

  18. A composite-appropriate integration method of thick functional components in fibre-reinforced plastics

    Science.gov (United States)

    Filippatos, A.; Höhne, R.; Kliem, M.; Gude, M.

    2016-03-01

    The use of integrated structural health monitoring systems for critical composite parts, such as wind turbine blades, fuselage and wing parts, is an promising approach to guarantee a safe and efficient operational lifetime of such components. Therefore, the integration of thick functional components like sensors, actuators and electronic components is often necessary. An optimal integration of such components should be ensured without material imperfections in the composite structure, i.e. voids and resin rich areas, and failure of the functional components. In this paper, first investigations were undertaken for a basic understanding of the mechanical performance of a fibre reinforced plastic component with integrated functional elements. The influence of different materials and treatment methods for the encapsulation of electronic components was experimentally investigated under static and dynamic loading tests. By means of a parametric finite element model, the effects of an encapsulation and various parameters such as the shape and orientation of the electronic components were examined. Several encapsulation variants were investigated in order to minimise the chance of failure initiations. Based both on experimental and numerical results, a preferred composite integration concept was selected for an electronic board and some first recommendations for an optimal integration were derived.

  19. An Experimental and Numerical Study of Low Velocity Impact of Unsaturated Polyester/Glass Fibre Composite

    Directory of Open Access Journals (Sweden)

    Sanita ZIKE

    2011-11-01

    Full Text Available In this paper validation of experimental and numerical results of low-velocity impact tests of unsaturated polyester/glass fibre composite laminate has been carried out. Impact response of composite laminates was experimentally studied with drop-tower Instron 9250HV determining impact force, energy absorption and deflection. In addition, quasi-static testing equipment Zwick Z100 has been used to determine material mechanical properties to ensure good input data for numerical predictions. Numerical model has been created with the finite element commercial code ANSYS/LS-DYNA to simulate impact response of composite laminate. Also non-destructive ultrasonic B- and C- scan imagining with USPC 3010 system has been used to identify the deformation regions in the specimens and compare to simulation results. During the impact test all samples were perforated, showing brittle response followed by matrix cracking and delamination. Overall good agreement between experimental and simulation results was achieved, comparing impact characterizing parameters as load, energy and deflection. Discrepancy has been observed between ultrasonic scanning and simulation code ANSYS/LS-DYNA results of rupture and delamination. Simulation shows less uniform and larger deformation than it was experimentally observed.http://dx.doi.org/10.5755/j01.ms.17.4.773

  20. Carbon nanotubes reinforced composites for biomedical applications.

    Science.gov (United States)

    Wang, Wei; Zhu, Yuhe; Liao, Susan; Li, Jiajia

    2014-01-01

    This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matrix composites, and CNTs reinforced ceramic matrix composites), their mechanical properties, cell experiments in vitro, and biocompatibility tests in vivo.

  1. Carbon Nanotubes Reinforced Composites for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-01-01

    Full Text Available This review paper reported carbon nanotubes reinforced composites for biomedical applications. Several studies have found enhancement in the mechanical properties of CNTs-based reinforced composites by the addition of CNTs. CNTs reinforced composites have been intensively investigated for many aspects of life, especially being made for biomedical applications. The review introduced fabrication of CNTs reinforced composites (CNTs reinforced metal matrix composites, CNTs reinforced polymer matrix composites, and CNTs reinforced ceramic matrix composites, their mechanical properties, cell experiments in vitro, and biocompatibility tests in vivo.

  2. Carbon fiber composite molecular sieves

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-06-01

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

  3. Radio frequency shielding behaviour of silane treated Fe2O3/E-glass fibre reinforced epoxy hybrid composite

    Science.gov (United States)

    Arun prakash, V. R.; Rajadurai, A.

    2016-10-01

    In this work, radio frequency shielding behaviour of polymer (epoxy) matrixes composed of E-glass fibres and Fe2O3 fillers have been studied. The principal aim of this project is to prepare suitable shielding material for RFID application. When RFID unit is pasted on a metal plate without shielding material, the sensing distance is reduced, resulting in a less than useful RFID system. To improve RF shielding of epoxy, fibres and fillers were utilized. Magnetic behaviour of epoxy polymer composites was measured by hysteresis graphs (B-H) followed by radio frequency identifier setup. Fe2O3 particles of sizes 800, 200 and 100 nm and E-glass fibre woven mat of 600 g/m2 were used to make composites. Particle sizes of 800 nm and 200 nm were prepared by high-energy ball milling, whereas particles of 100 nm were prepared by sol-gel method. To enhance better dispersion of particles within the epoxy matrix, a surface modification process was carried out on fillers by an amino functional coupling agent called 3-Aminopropyltrimethoxysilane (APTMS). Crystalline and functional groups of siliconized Fe2O3 particles were characterized by XRD and FTIR spectroscopy analysis. Variable quantity of E-glass fibre (25, 35, and 45 vol%) was laid down along with 0.5 and 1.0 vol% of 800, 200, and 100 nm size Fe2O3 particles into the matrix, to fabricate the hybrid composites. Scanning electron microscopy and transmission electron microscopy images reveal the shape and size of Fe2O3 particles for different milling times and particle dispersion in the epoxy matrix. The maximum improved sensing distance of 45.2, 39.4 and 43.5 % was observed for low-, high-, and ultra-high radio frequency identifier setup along with shielding composite consist of epoxy, 1 vol% 200 nm Fe2O3 particles and 45 vol% of E-glass fibre.

  4. Assessment of thermal shock induced damage in silicon carbide fibre reinforced glass matrix composites

    Directory of Open Access Journals (Sweden)

    Boccaccini, A. R.

    1998-09-01

    Full Text Available The development of microstructural damage in silicon carbide fibre (Nicalon™ reinforced glass matrix composite samples subjected to thermal shock was investigated by using a nondestructive forced resonance technique and fibre push out indentation tests. Thermal shock testing involved quenching samples in a water bath maintained at room temperature from a high temperature (650ºC. Changes in the Young's modulus and internal friction of the samples with increasing number of shocks were measured accurately by the forced resonance technique. Fibre push-out tests showed no significant changes in the properties of the fibre-matrix interface, indicating that damage in the composite was concentrated mainly in the development of matrix microcracking. It was also shown that the internal friction is a very sensitive parameter by which to detect the onset and development of such microcracking. A simple semi-empirical model is proposed to correlate the internal friction level with the microcracking density in the glass matrix. Finally, the relevance of detecting nondestructively the existence of microcracks in the glass matrix, before any significant interfacial degradation occurs, is emphasized, in conextion with the possibility of inducing a crack healing process by a thermal treatment (annealing, taking advantage of the viscous flow properties of the glass.

    El desarrollo de daño microestructural en materiales compuestos de matriz de vidrio reforzados con fibras de carburo de silicio (Nicalon™ sometidos a choque térmico fue investigado mediante la técnica no-destructiva de resonancia forzada y por mediciones de indentación "push-out" de fibras. Los ensayos de choque térmico involucraron el enfriamiento brusco en un baño de agua a temperatura ambiente de las piezas previamente calentadas a una temperatura elevada (650ºC. La técnica de resonancia forzada permitió medir cambios en el módulo de Young de elasticidad y en la fricci

  5. Satiety effects of a whole-grain fibre composite ingredient: reduced food intake and appetite ratings.

    Science.gov (United States)

    Harrold, Joanne; Breslin, Leanne; Walsh, Jennifer; Halford, Jason; Pelkman, Christine

    2014-10-01

    The current study assesses the impact on appetite and food intake of a novel co-processed ingredient containing a viscous fibre and whole-grain high-amylose corn flour, a source of type 1 and type 2 resistant starch (HAM-RS). Ninety adults completed a crossover, placebo-controlled study comparing two doses of the ingredient (20 and 30 g) to a maltodextrin control in a fruit-based smoothie served with breakfast. Ad libitum food intake was measured over the day and visual analogue scales were used to assess subjective appetite sensations. Subjects consumed 7% less energy intake at dinner following the 30 g dose (p = 0.02) compared to control. In addition, a trend for lower lunch intake (5% less weight of food) was observed for the 20 g dose (p = 0.10). Reductions were also observed for the two meals combined, with 3% lower energy intake for the 20 g dose (p = 0.04) and 5% less weight of food consumed for the 30 g dose (p = 0.04). Lower ratings of hunger were reported at 3 h after breakfast for both doses and also at 2 and 3 h after lunch for the 30 g dose. With ratings combined to compute an overall appetite score, a trend for lower appetite scores at 3 h after breakfast was found for both doses. Consistent with this, significant reductions in AUC hunger and prospective consumption were identified in the 30 g condition. A similar pattern of results was observed for fullness and desire to eat. The results of this study show that a new composite satiety ingredient comprised of a viscous fibre and whole-grain corn flour can affect acute satiety responses in men and women.

  6. Monitoring chemical degradation of thermally cycled glass-fibre composites using hyperspectral imaging

    Science.gov (United States)

    Papadakis, V. M.; Müller, B.; Hagenbeek, M.; Sinke, J.; Groves, R. M.

    2016-04-01

    Nowadays, the application of glass-fibre composites in light-weight structures is growing. Although mechanical characterizations of those structures are commonly performed in testing, chemical changes of materials under stresses have not yet been well documented. In the present work coupon tests and Hyperspectral Imaging (HSI) have been used to categorise possible chemical changes of glass-fibre reinforced polymers (GFRP) which are currently used in the aircraft industry. HSI is a hybrid technique that combines spectroscopy with imaging. It is able to detect chemical degradation of surfaces and has already been successfully applied in a wide range of fields including astronomy, remote sensing, cultural heritage and medical sciences. GFRP specimens were exposed to two different thermal loading conditions. One thermal loading condition was a continuous thermal exposure at 120°C for 24h, 48 h and 96h, i.e. ageing at a constant temperature. The other thermal loading condition was thermal cycling with three different numbers of cycles (4000, 8000, 12000) and two temperature ranges (0°C to 120°C and -25°C to 95°C). The effects of both conditions were measured using both HSI and interlaminar shear (ILSS) tests. No significant changes of the physical properties of the thermally cycled GFRP specimens were detected using interlaminar shear strength tests and optical microscopy. However, when using HIS, differences of the surface conditions were detected. The results showed that the different thermal loading conditions could be successfully clustered in different colours, using the HSI linear unmixing technique. Each different thermal loading condition showed a different chemical degradation level on its surface which was indicated using different colours.

  7. Glass Fibre-Reinforced Composite Post and Core Used in Decayed Primary Anterior Teeth: A Case Report

    Directory of Open Access Journals (Sweden)

    Leena Verma

    2011-01-01

    Full Text Available Aesthetic requirement of severely mutilated primary anterior teeth in the case of early childhood caries has been a challenge to pediatric dentist. Among restorative treatment options, prefabricated crown and biological and resin composite restoration either by means of direct or indirect technique are mentioned in the literature. This paper presents the clinical sequence of rehabilitation of maxillary anterior primary teeth. Endodontic treatment was followed by the placement of a glass fibre-reinforced composite resin post. The crown reconstruction was done with composite restoration. Resin glass fibre post has best properties in elasticity, translucency, adaptability, tenaciousness, and resistance to traction and to impact. Along with ease of application, fiber can be used as an alternative to traditionally used materials in the management of early childhood caries.

  8. Thermal, mechanical, and physical properties of seaweed/sugar palm fibre reinforced thermoplastic sugar palm Starch/Agar hybrid composites.

    Science.gov (United States)

    Jumaidin, Ridhwan; Sapuan, Salit M; Jawaid, Mohammad; Ishak, Mohamad R; Sahari, Japar

    2017-04-01

    The aim of this research is to investigate the effect of sugar palm fibre (SPF) on the mechanical, thermal and physical properties of seaweed/thermoplastic sugar palm starch agar (TPSA) composites. Hybridized seaweed/SPF filler at weight ratio of 25:75, 50:50 and 75:25 were prepared using TPSA as a matrix. Mechanical, thermal and physical properties of hybrid composites were carried out. Obtained results indicated that hybrid composites display improved tensile and flexural properties accompanied with lower impact resistance. The highest tensile (17.74MPa) and flexural strength (31.24MPa) was obtained from hybrid composite with 50:50 ratio of seaweed/SPF. Good fibre-matrix bonding was evident in the scanning electron microscopy (SEM) micrograph of the hybrid composites' tensile fracture. Fourier transform infrared spectroscopy (FT-IR) analysis showed increase in intermolecular hydrogen bonding following the addition of SPF. Thermal stability of hybrid composites was enhanced, indicated by a higher onset degradation temperature (259°C) for 25:75 seaweed/SPF composites than the individual seaweed composites (253°C). Water absorption, thickness swelling, water solubility, and soil burial tests showed higher water and biodegradation resistance of the hybrid composites. Overall, the hybridization of SPF with seaweed/TPSA composites enhances the properties of the biocomposites for short-life application; that is, disposable tray, plate, etc.

  9. Hybrid S2/Carbon Epoxy Composite Armours Under Blast Loads

    Science.gov (United States)

    Dolce, F.; Meo, Michele; Wright, A.; French, M.; Bernabei, M.

    2012-06-01

    Civil and military structures, such as helicopters, aircrafts, naval ships, tanks or buildings are susceptible to blast loads as terroristic attacks increases, therefore there is the need to design blast resistant structures. During an explosion the peak pressure produced by shock wave is much greater than the static collapse pressure. Metallic structures usually undergo large plastic deformations absorbing blast energy before reaching equilibrium. Due to their high specific properties, fibre-reinforced polymers are being considered for energy absorption applications in blast resistant armours. A deep insight into the relationship between explosion loads, composite architecture and deformation/fracture behaviour will offer the possibility to design structures with significantly enhanced energy absorption and blast resistance performance. This study presents the results of a numerical investigation aimed at understanding the performance of a hybrid composite (glass/carbon fibre) plate subjected to blast loads using commercial LS-DYNA software. In particular, the paper deals with numerical 3D simulations of damages caused by air blast waves generated by C4 charges on two fully clamped rectangular plates made of steel and hybrid (S2/Carbon) composite, respectively. A Multi Materials Arbitrary Lagrangian Eulerian (MMALE) formulation was used to simulate the shock phenomenon. For the steel plates, the Johnson-Cook material model was employed. For the composite plates both in-plane and out-of-plane failure criteria were employed. In particular, a contact tiebreak formulation with a mixed mode failure criteria was employed to simulate delamination failure. As for the steel plates the results showed that excellent correlation with the experimental data for the two blast load conditions in terms of dynamic and residual deflection for two different C4 charges. For the composite plates the numerical results showed that, as expected, a wider delamination damage was observed

  10. Cytocompatibility, mechanical and dissolution properties of high strength boron and iron oxide phosphate glass fibre reinforced bioresorbable composites.

    Science.gov (United States)

    Sharmin, Nusrat; Hasan, Muhammad S; Parsons, Andrew J; Rudd, Chris D; Ahmed, Ifty

    2016-06-01

    In this study, Polylactic acid (PLA)/phosphate glass fibres (PGF) composites were prepared by compression moulding. Fibres produced from phosphate based glasses P2O5-CaO-MgO-Na2O (P45B0), P2O5-CaO-MgO-Na2O-B2O3 (P45B5), P2O5-CaO-MgO-Na2O-Fe2O3 (P45Fe3) and P2O5-CaO-MgO-Na2O-B2O3-Fe2O3 (P45B5Fe3) were used to reinforce the bioresorbable polymer PLA. Fibre mechanical properties and degradation rate were investigated, along with the mechanical properties, degradation and cytocompatibility of the composites. Retention of the mechanical properties of the composites was evaluated during degradation in PBS at 37°C for four weeks. The fibre volume fraction in the composite varied from 19 to 23%. The flexural strength values (ranging from 131 to 184MPa) and modulus values (ranging from 9.95 to 12.29GPa) obtained for the composites matched those of cortical bone. The highest flexural strength (184MPa) and modulus (12.29GPa) were observed for the P45B5Fe3 composite. After 28 days of immersion in PBS at 37°C, ~35% of the strength profile was maintained for P45B0 and P45B5 composites, while for P45Fe3 and P45B5Fe3 composites ~40% of the initial strength was maintained. However, the overall wet mass change of P45Fe3 and P45B5Fe3 remained significantly lower than that of the P45B0 and P45B5 composites. The pH profile also revealed that the P45B0 and P45B5 composites degraded quicker, correlating well with the degradation profile. From SEM analysis, it could be seen that after 28 days of degradation, the fibres in the fractured surface of P45B5Fe3 composites remain fairly intact as compared to the other formulations. The in vitro cell culture studies using MG63 cell lines revealed both P45Fe3 and P45B5Fe3 composites maintained and showed higher cell viability as compared to the P45B0 and P45B5 composites. This was attributed to the slower degradation rate of the fibres in P45Fe3 and P45B5Fe3 composites as compared with the fibres in P45B0 and P45B5 composites.

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

    Directory of Open Access Journals (Sweden)

    Mehran Tehrani

    2014-05-01

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

  12. Carbon nanotube suspensions, dispersions, & composites

    Science.gov (United States)

    Simmons, Trevor John

    Carbon Nanotubes (CNTs) are amazing structures that hold the potential to revolutionize many areas of scientific research. CNTs can be behave both as semiconductors and metals, can be grown in highly ordered arrays and patterns or in random orientation, and can be comprised of one graphene cylinder (single wall nanotube, SWNT) or several concentric graphene cylinders (multi-wall nanotube, MWNT). Although these structures are usually only a few nanometers wide, they can be grown up to centimeter lengths, and in massive quantities. CNTs can be produced in a variety of processes ranging from repeated combustion of organic material such as dried grass, arc-discharge with graphite electrodes, laser ablation of a graphitic target, to sophisticated chemical vapor deposition (CVD) techniques. CNTs are stronger than steel but lighter than aluminum, and can be more conductive than copper or semiconducting like silicon. This variety of properties has been matched by the wide variety of applications that have been developed for CNTs. Many of these applications have been limited by the inability of researchers to tame these structures, and incorporating CNTs into existing technologies can be exceedingly difficult and prohibitively expensive. It is therefore the aim of the current study to develop strategies for the solution processing and deposition of CNTs and CNT-composites, which will enable the use of CNTs in existing and emerging technologies. CNTs are not easily suspended in polar solvents and are extremely hydrophobic materials, which has limited much of the solution processing to organic solvents, which also cannot afford high quality dispersions of CNTs. The current study has developed a variety of aqueous CNT solutions that employ surfactants, water-soluble polymers, or both to create suspensions of CNTs. These CNT 'ink' solutions were deposited with a variety of techniques that have afforded many interesting structures, both randomly oriented as well as highly

  13. A combined corrosion protection system for reinforced concrete structures using a carbon fibre mesh

    Energy Technology Data Exchange (ETDEWEB)

    Bruns, M.; Raupach, M. [Institut fuer Bauforschung der RWTH Aachen, IBAC, Institute of Building Materials Research of the Technical University of Aachen, Schinkelstrasse 3 Aachen (Germany)

    2004-07-01

    Cathodic Protection (CP) has become a world-wide used method to protect reinforced concrete structures against reinforcement corrosion. Another method to stop or reduce reinforcement corrosion, at least in case of lower chloride contents is the reduction of the water content of the concrete by applying sealing coatings on the concrete surface. At the Institute of Building Materials Research of Aachen University (IBAC) actually a surface protection system is investigated based on the combination of both methods mentioned above. The idea is to protect the reinforcement within the first years after system installation by cathodic protection until the water content of the concrete has decreased to a level due to the surface coating where the corrosion rate of the reinforcement is uncritical and does not lead to any damage. The system investigated, consists of a carbon fibre net embedded in a special mortar layer as impressed current anode for cathodic protection, covered by a 'dense' cement based polymer modified surface coating. In order to investigate the system, it has been installed on a test area on the weathered upper deck of a parking garage in Aachen, Germany. To investigate the effectiveness regarding the reduction of the water content of the concrete the test area was equipped with so called Multiring-Electrodes (MRE) for depth depended measurement of the concrete resistivity. Reference electrodes for potential and depolarization measurements as well a device for automatic measurement of the protection current were installed to investigate the effectiveness of the impressed current cathodic protection. Additionally 3 re bars were embedded into the concrete of the test area using mortar containing 1, 2 or 3 M.-% chloride by weight of cement respectively, to investigate the influence of the chloride content. First results of the MRE-measurements showing already within the first months after system installation a distinct drying of the concrete cover

  14. Effect of monomer composition of polymer matrix on flexural properties of glass fibre-reinforced orthodontic archwire.

    Science.gov (United States)

    Ohtonen, J; Vallittu, P K; Lassila, L V J

    2013-02-01

    To compare force levels obtained from glass fibre-reinforced composite (FRC) archwires. Specifically, FRC wires were compared with polymer matrices having different dimethacrylate monomer compositions. FRC material (E-glass provided by Stick Tech Ltd, Turku, Finland) with continuous unidirectional glass fibres and four different types of dimethacrylate monomer compositions for the resin matrix were tested. Cross-sectionally round FRC archwires fitting into the 0.3 mm slot of a bracket were divided into 16 groups with six specimens in each group. Glass fibres were impregnated by the manufacturer, and they were initially light-cured by hand light-curing unit or additionally post-cured in light-curing oven. The FRC archwire specimens were tested at 37°C according to a three-point bending test in dry and wet conditions using a span length of 10 mm and a crosshead speed of 1.0 mm/minute. The wires were loaded until final failure. The data were statistically analysed using analysis of variance (ANOVA). The dry FRC archwire specimens revealed higher load values than water stored ones, regardless of the polymer matrix. A majority of the FRC archwires showed higher load values after being post-cured. ANOVA revealed that the polymer matrix, curing method, and water storage had a significant effect (P composition, curing method, and water storage affected the flexural properties and thus, force level and working range which could be obtained from the FRC archwire.

  15. Optical Fibre Embedded in a Composite Laminated with Applications to Sensing

    Science.gov (United States)

    2000-09-29

    The possibility of using fibre optic instrumented plates in rehabilitation of civil structures was demonstrated, since strain measurements and...125-157, 1993. [4] W. W. Morey, G. Meltz, and W. H. Glenn, " Fibre optic bragg grating sensors", in Fiber Optic and Laser Sensors VII, in Proc. SPIE 1169, Boston, USA, pp. 98-107, 1989.

  16. Influence of Fibre Architecture on Impact Damage Tolerance in 3D Woven Composites

    Science.gov (United States)

    Potluri, P.; Hogg, P.; Arshad, M.; Jetavat, D.; Jamshidi, P.

    2012-10-01

    3D woven composites, due to the presence of through-thickness fibre-bridging, have the potential to improve damage tolerance and at the same time to reduce the manufacturing costs. However, ability to withstand damage depends on weave topology as well as geometry of individual tows. There is an extensive literature on damage tolerance of 2D prepreg laminates but limited work is reported on the damage tolerance of 3D weaves. In view of the recent interest in 3D woven composites from aerospace as well as non-aerospace sectors, this paper aims to provide an understanding of the impact damage resistance as well as damage tolerance of 3D woven composites. Four different 3D woven architectures, orthogonal, angle interlocked, layer-to-layer and modified layer-to-layer structures, have been produced under identical weaving conditions. Two additional structures, Unidirectional (UD) cross-ply and 2D plain weave, have been developed for comparison with 3D weaves. All the four 3D woven laminates have similar order of magnitude of damage area and damage width, but significantly lower than UD and 2D woven laminates. Damage Resistance, calculated as impact energy per unit damage area, has been shown to be significantly higher for 3D woven laminates. Rate of change of CAI strength with impact energy appears to be similar for all four 3D woven laminates as well as UD laminate; 2D woven laminate has higher rate of degradation with respect to impact energy. Undamaged compression strength has been shown to be a function of average tow waviness angle. Additionally, 3D weaves exhibit a critical damage size; below this size there is no appreciable reduction in compression strength. 3D woven laminates have also exhibited a degree of plasticity during compression whereas UD laminates fail instantly. The experimental work reported in this paper forms a foundation for systematic development of computational models for 3D woven architectures for damage tolerance.

  17. SEM/XPS analysis of fractured adhesively bonded graphite fibre surface resin-rich/graphite fibre composites

    Science.gov (United States)

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

    1988-01-01

    Samples of graphite fiber-reinforced polyimide were fabricated allowing the resin to accumulate at the composite surface. These surface resin-rich composites were then bonded together and tested for lap shear strength both before and after thermal aging. Lap shear strength did not appear to show a significant improvement over that previously recorded for resin-poor samples and was shown to decrease with increasing aging time and temperature.

  18. Carbon fiber content measurement in composite

    Science.gov (United States)

    Wang, Qiushi

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

  19. Average Frequency – RA Value for Reinforced Concrete Beam Strengthened with Carbon Fibre Sheet

    Directory of Open Access Journals (Sweden)

    Mohamad M. Z.

    2016-01-01

    Full Text Available Acoustic Emission (AE is one of the tools that can be used to detect the crack and to classify the type of the crack of reinforced concrete (RC structure. Dislocation or movement of the material inside the RC may release the transient elastic wave. In this situation, AE plays important role whereby it can be used to capture the transient elastic wave and convert it into AE parameters such as amplitude, count, rise time and duration. Certain parameter can be used directly to evaluate the crack behavior. But in certain cases, the AE parameter needs to add and calculate by using related formula in order to observe the behavior of the crack. Using analysis of average frequency and RA value, the crack can be classified into tensile or shear cracks. In this study, seven phases of increasing static load were used to observe the crack behavior. The beams were tested in two conditions. For the first condition, the beams were tested in original stated without strengthened with carbon fibre sheet (CFS at the bottom of the beam or called as tension part of the beam. For the second condition, the beams were strengthened with CFS at the tension part of the beam. It was found that, beam wrapped with CFS enhanced the strength of the beams in term of maximum ultimate load. Based on the relationship between average frequency (AF and RA value, the cracks of the beams can be classified.

  20. Mechanical properties and fire retardancy of bidirectional reinforced composite based on biodegradable starch resin and basalt fibres

    Directory of Open Access Journals (Sweden)

    2008-11-01

    Full Text Available Environmental problems caused by extensive use of polymeric materials arise mainly due to lack of landfill space and depletion of finite natural resources of fossil raw materials, such as petroleum or natural gas. The substitution of synthetic petroleum-based resins with natural biodegradable resins appears to be one appropriate measure to remedy the above-mentioned situation. This study presents the development of a composite that uses environmentally degradable starch-based resin as matrix and basalt fibre plain fabric as reinforcement. Prepreg sheets were manufactured by means of a modified doctor blade system and a hot power press. The sheets were used to manufacture bidirectional-reinforced specimens with fibre volume contents ranging from 33 to 61%. Specimens were tested for tensile and flexural strength, and exhibited values of up to 373 and 122 MPa, respectively. Through application of silane coupling agents to the reinforcement fibres, the flexural composite properties were subsequently improved by as much as 38%. Finally, in order to enhance the fire retardancy and hence the applicability of the composite, fire retardants were applied to the resin, and their effectiveness was tested by means of flame rating (according to UL 94 and thermogravimetric analysis (TGA, respectively.

  1. Temperature Distribution in Fibre-glass Composite Impregnated with Epoxy-Cyanate ester Blend

    Directory of Open Access Journals (Sweden)

    Priyanka Brahmbhatt

    2014-01-01

    Full Text Available Cyanate ester and epoxy blends have been identified as an attractive insulating material for fusion grade magnet winding packs. An insulation system comprising of fibre glass composites and cyanate ester and blend has been analyzed during its vacuum pressure impregnation and curing. The transient one dimensional distribution of temperature and extent of cure has been evaluated both analytically and experimentally in this paper. The one dimensional transient (1-D heat transfer characteristics evaluation has been carried out on 60:40 (epoxy : cyanate which has been optimally prescribed blend for fusion grade winding process. The analytical formulation solves the heat transfer differential equations incorporating internal heat generation resulting from the exothermic chemical reaction in both chemical and diffusional kinetic regimes. In support to the analytical formulation, carefully designed experiments have been carried out on such samples. On comparing the results obtained from analytical formulism and those measured during experiments have been found to be matching well. These results have the potential to design the vacuum pressure impregnation of large size fusion relevant winding packs.

  2. High-Strength Composite Fibers from Cellulose-Lignin Blends Regenerated from Ionic Liquid Solution.

    Science.gov (United States)

    Ma, Yibo; Asaadi, Shirin; Johansson, Leena-Sisko; Ahvenainen, Patrik; Reza, Mehedi; Alekhina, Marina; Rautkari, Lauri; Michud, Anne; Hauru, Lauri; Hummel, Michael; Sixta, Herbert

    2015-12-01

    Composite fibres that contain cellulose and lignin were produced from ionic liquid solutions by dry-jet wet spinning. Eucalyptus dissolving pulp and organosolv/kraft lignin blends in different ratios were dissolved in the ionic liquid 1,5-diazabicyclo[4.3.0]non-5-enium acetate to prepare a spinning dope from which composite fibres were spun successfully. The composite fibres had a high strength with slightly decreasing values for fibres with an increasing share of lignin, which is because of the reduction in crystallinity. The total orientation of composite fibres and SEM images show morphological changes caused by the presence of lignin. The hydrophobic contribution of lignin reduced the vapour adsorption in the fibre. Thermogravimetric analysis curves of the composite fibres reveal the positive effect of the lignin on the carbonisation yield. Finally, the composite fibre was found to be a potential raw material for textile manufacturing and as a precursor for carbon fibre production.

  3. The use of an interphase to improve the transverse properties of unidirectional glass fibre reinforced polymer composites

    Science.gov (United States)

    Ellis, Keith

    The aim of the project was to improve the transverse mechanical properties of unidirectional glass fibre reinforced plastics (G.R.P.)* In addition it was intended that the longitudinal mechanical properties should not be Significantly a result of the transverse improvement The scientific and commercial literature were consulted to determine the most feasible means of improving the transverse properties. Four possible methods were identified, the most promising of which was interfacial modification. Interfacial modification involves the introduction of a third material ("the interphase" ) at the interface between the fibre and the matrix. For this project the interphase material was selected to be compliant or rubbery in nature. The Kies model for predicting the magnification of strain in the resin between fibres was extended to include an interphase. The model was developed for two modes of applied stress. The first was pure tension acting transverse to the fibre axis. The second was shear in the plane transverse to the fibre axis. A novel apparatus was constructed to manufacture composites with a compliant interphase. The apparatus combined a self-regulating coating technique with filament winding to give a continuous production facility. A range of mechanical tests were performed on composites both with and without an interphase. Presence of an interphase improved the following properties: transverse flexural strength, interlaminar and intralaminar shear strength , and transverse fiexural fracture energy. No improvement was noted for pure transverse tension. These results indicated that the interphase acted beneficially only when the composite was stressed in a predominantly shear mode. Conclusions from mechanical test results were supported by S.E.M. fractography. Considerable deformation of the interphase was found in composite tested in shear. This deformation was absent in composite tested in tension. It was postulated that these differences between behaviour

  4. Carbon Fiber Composite Monoliths as Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-01-01

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

  5. Carbon Fiber Composite Monoliths for Catalyst Supports

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-01-01

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

  6. Micromechanical model of cross-over fibre bridging - Prediction of mixed mode bridging laws

    DEFF Research Database (Denmark)

    Sørensen, Bent F.; Gamstedt, E.K.; Østergaard, Rasmus Christian;

    2008-01-01

    on the observed bridging mechanism, a micromechanical model is developed for the prediction of macroscopic mixed mode bridging laws (stress-opening laws). The model predicts a high normal stress for very small openings, decreasing rapidly with increasing normal and tangential crack opening displacements......The fracture resistance of fibre composites can be greatly enhanced by crack bridging. In situ observations of mixed mode crack growth in a unidirectional carbon-fibre/epoxy composite reveal crack bridging by single fibres and by beam-like ligaments consisting of several fibres. Based...

  7. Multifunctional Hybrid Carbon Nanotube/Carbon Fiber Polymer Composites

    Science.gov (United States)

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

    2016-01-01

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

  8. Homogeneous Carbon Nanotube/Carbon Composites Prepared by Catalyzed Carbonization Approach at Low Temperature

    Directory of Open Access Journals (Sweden)

    Hongjiang Li

    2011-01-01

    Full Text Available We synthesize carbon nanotube (CNT/carbon composite using catalyzed carbonization of CNT/Epoxy Resin composite at a fairly low temperature of about 400∘C. The microstructure of the composite is characterized by scanning electron microscope (SEM, transmission electron microscope (TEM, and X-ray diffraction (XRD. The results indicate that CNTs and pyrolytic carbon blend well with each other. Pyrolytic carbon mainly stays in an amorphous state, with some of it forming crystalline structures. The catalyst has the effect of eliminating the interstices in the composites. Remarkable increases in thermal and electrical conductivity are also reported.

  9. Production and characterization of polypropylene composites filled with glass fibre recycled from pyrolysed waste printed circuit boards.

    Science.gov (United States)

    Li, Shenyong; Sun, Shuiyu; Liang, Haifeng; Zhong, Sheng; Yang, Fan

    2014-01-01

    Waste printed circuit boards (WPCBs) are composed of nearly 70% non-metals, which are generally recycled as low-value filling materials or even directly dumped in landfills. In this study, polypropylene (PP) composites reinforced by recycled pure glass fibres (RGF) from pyrolysed WPCBs were successfully produced. The manufacturing process, mechanical properties and thermal behaviour of the composites were investigated. The results showed that the appropriate addition of RGF in the composites can significantly improve the mechanical properties and thermal behaviour. When the added content of RGF was 30%, the maximum increment of tensile strength, impact strength, flexural strength and flexural modulus of the glass fibre (GF)/PP composites are 25.93%, 41.38%, 31.16% and 68.42%, respectively, and the vicat softening temperature could rise by 4.6°C. Furthermore, leaching of the GF/PP composites was also investigated. The GF/PP composites exhibited high performance and non-toxicity, offering a promising method to recycle RGF from pyrolysed WPCBs with high-value applications.

  10. Epoxy based photoresist/carbon nanoparticle composites

    DEFF Research Database (Denmark)

    Lillemose, Michael; Gammelgaard, Lauge; Richter, Jacob;

    2008-01-01

    We have fabricated composites of SU-8 polymer and three different types of carbon nanoparticles (NPs) using ultrasonic mixing. Structures of composite thin films have been patterned on a characterization chip with standard UV photolithography. Using a four-point bending probe, a well defined stress...... is applied to the composite thin film and we have demonstrated that the composites are piezoresistive. Stable gauge factors of 5-9 have been measured, but we have also observed piezoresistive responses with gauge factors as high as 50. As SU-8 is much softer than silicon and the gauge factor of the composite...... material is relatively high, carbon nanoparticle doped SU-8 is a valid candidate for the piezoresistive readout in polymer based cantilever sensors, with potentially higher sensitivity than silicon based cantilevers....

  11. Structure, composition and mechanical properties of the silk fibres of the egg case of the Joro spider, Nephila clavata (Araneae, Nephilidae)

    Indian Academy of Sciences (India)

    Ping Jiang; Cong Guo; Taiyong Lv; Yonghong Xiao; Xinjun Liao; Bing Zhou

    2011-12-01

    The silk egg case and orb web of spiders are elaborate structures that are assembled from a number of components. We analysed the structure, the amino acid and fibre compositions, and the tensile properties of the silk fibres of the egg case of Nephila clavata. SEM shows that the outer and inner covers of the egg case consist of thick, medium and thin silk fibres. The silk fibres of the outer cover of the egg case are probably produced by the major and minor ampullate glands. The silk fibres of the inner cover of the egg case from cylindrical glands appears to be distinct from the silk fibres of the major ampullate glands based on their micro-morphology, mole percent amino acid composition and types, and tensile behaviour and properties. Collectively, our investigations show that N. clavata uses silk fibres from relatively few glands in varying combinations to achieve different physical and chemical properties (e.g., color, diameter, morphology and amino acid composition) and functional and mechanical properties in the different layers of the egg case.

  12. Structure, composition and mechanical properties of the silk fibres of the egg case of the Joro spider, Nephila clavata (Araneae, Nephilidae).

    Science.gov (United States)

    Jiang, Ping; Guo, Cong; Lv, Taiyong; Xiao, Yonghong; Liao, Xinjun; Zhou, Bing

    2011-12-01

    The silk egg case and orb web of spiders are elaborate structures that are assembled from a number of components. We analysed the structure, the amino acid and fibre compositions, and the tensile properties of the silk fibres of the egg case of Nephila clavata. SEM shows that the outer and inner covers of the egg case consist of thick, medium and thin silk fibres. The silk fibres of the outer cover of the egg case are probably produced by the major and minor ampullate glands. The silk fibres of the inner cover of the egg case from cylindrical glands appears to be distinct from the silk fibres of the major ampullate glands based on their micro-morphology, mole percent amino acid composition and types, and tensile behaviour and properties. Collectively, our investigations show that N. clavata uses silk fibres from relatively few glands in varying combinations to achieve different physical and chemical properties (e.g., color, diameter, morphology and amino acid composition) and functional and mechanical properties in the different layers of the egg case.

  13. Fracture Resistance of Hybrid Glass Matrix Composite and Its Degradation Due to Thermal Ageing and Thermal Shock

    Science.gov (United States)

    Dlouhý, Ivo; Chlup, Zdenêk; Atiq, Shabbar; Boccaccini, Aldo R.

    In brittle matrix composites reinforced by continuous ceramic fibres, the favourable fracture behaviour is provided by the presence of weak fibre/matrix interfaces, which lead to the fibre pullout effect [1]. The thermal stability and high temperature mechanical properties of silicate matrix composites reinforced by carbon and SiC based fibres in oxidising environments have been investigated quite extensively in the past by conducting thermal aging and thermal cycling experiments over a wide range of temperatures [2-5]. A common result of investigations conducted at temperatures in the range 500-700°C is that there is a decrease of tensile and flexural strength of the composites. It has been shown that this is the consequence of oxidation of the fibres, in case of carbon fibre reinforced composites, or of degradation of the fibre/matrix interphase, which is in fact a carbon-rich nanometric interfacial layer, in SiC fibre reinforced composites [2-5].

  14. Control over the resonance wavelength of fibre Bragg gratings using resistive coatings based on single-wall carbon nanotubes

    Science.gov (United States)

    Gladush, Yu. G.; Medvedkov, O. I.; Vasil'ev, S. A.; Kopylova, D. S.; Yakovlev, V. Ya.; Nasibulin, A. G.

    2016-10-01

    We demonstrate that a thin resistive coating based on single-wall carbon nanotubes applied to the lateral surface of an optical fibre allows it to be uniformly heated up to a temperature of ∼ 400 \\circ{\\text{C}} without damage to the coating. Using a fibre Bragg grating (FBG) as an example, we assess the efficiency of resonance wavelength thermal tuning and examine frequency characteristics that can be achieved using such coating. In particular, we show that the resonance wavelength of the FBG can be tuned over 3.2 {\\text{nm}} with an efficiency of 8.7 {\\text{nm}} {\\text{W}}-1 and time constant of ∼ 0.4 {\\text{s}}.

  15. 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)

    R. YAHAYA; S.M. SAPUAN; M. JAWAID; Z. LEMAN; E.S. ZAINUDIN

    2016-01-01

    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.

  16. Composition of microfouling on aluminium and fibre glass panels exposed in Agatti waters (Lakshadweep Island)

    Digital Repository Service at National Institute of Oceanography (India)

    Raveendran, T.V.; Sankaran, P.D.; Wagh, A.B.

    Rate of microfouling build-up was high during the initial periods of exposure of test surfaces but decreased with the increasing duration. Fibre glass surfaces showed higher deposition than those of aluminium. Carbohydrates and lipids were the major...

  17. Incidence of pleural mesothelioma in a community exposed to fibres with fluoro-edenitic composition in Biancavilla (Sicily, Italy

    Directory of Open Access Journals (Sweden)

    Caterina Bruno

    2014-06-01

    Full Text Available INTRODUCTION. Amphibolic fibres with fluoro-edenitic composition characterize Biancavilla soil, including the major quarry from which building materials have been extensively extracted. These fibres induce mesothelioma in experimental animals and their in vitro biological action is similar to that of crocidolite. MATERIALS AND METHODS. Malignant mesothelioma case series and incidence were examined to evaluate the disease burden on Biancavilla inhabitants. RESULTS. The incidence of pleural mesothelioma in Biancavilla is steadily higher than in the Sicilian Region, risk estimates are more elevated in women than in men, the most affected age class is constituted by subjects aged less than 50. DISCUSSION AND CONCLUSIONS. Environmental exposure to fibres with fluoro-edenitic composition appears to be causally related to the elevated mesothelioma occurrence in Biancavilla. In this frame, environmental clean-up is the main goal to be pursued in public health terms. A contribution of scientific research to public health decision making with respect to priority setting for environmental clean-up can derive from some further selected epidemiological investigations.

  18. The production of silicon carbon nitride ceramic fibres from poly-silazane polymers. Herstellung von Siliciumcarbonitrid-Keramikfasern aus Polysilazan-Polymeren

    Energy Technology Data Exchange (ETDEWEB)

    Holzinger, R.

    1994-07-14

    The investigations carried out in this work can be divided into two main points. One, the process technique branch, goes along the polymer precursor route. This includes the melt spinning of the poly-silazane polymers, the stabilisation of the green fibres and finally pyrolysis to silicon-carbon nitride ceramic fibres. Starting from the polymers, all the reactions and structural changes during the individual steps are examined. These experiments represent the second main part of the work. The optimisation criterion is always the tensile strength of the resulting ceramic fibres. (orig.)

  19. 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)

    1989-07-01

    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.).

  20. LDRD final report on carbon nanotube composites

    Energy Technology Data Exchange (ETDEWEB)

    Cahill, P.A.; Rand, P.B.

    1997-04-01

    Carbon nanotubes and their composites were examined using computational and experimental techniques in order to modify the mechanical and electrical properties of resins. Single walled nanotubes were the focus of the first year effort; however, sufficient quantities of high purity single walled nanotubes could not be obtained for mechanical property investigations. The unusually high electrical conductivity of composites loaded with <1% of multiwalled nanotubes is useful, and is the focus of continuing, externally funded, research.

  1. 硅蒸镀法制备硬质碳毡表面SiC涂层组成及微观结构分析%Analysis on microstructure and composition of SiC coated rigid carbon fibre felt prepared by silicon evaporation

    Institute of Scientific and Technical Information of China (English)

    王兵; 施伟; 谭毅; 尤启凡; 李佳艳

    2014-01-01

    SiC coated rigid carbon fibre felt was produced via the direct reaction between silicon vapor and carbon stemming from graphite coating carbon fiber and substrates by silicon evaporation.Successful silicon carbide layer calls for a graphite coating given on the substrate surface by means of a slurry coating technology.The mi-crostructural characterisation including phase structure and components,surface and profile micrograph,micro-hardness of SiC coating were studied by XRD,SEM,EDS and microhardness tester.The influence of evapora-tion time and surface roughness of graphite coating on coating and forming course of SiC coating was investiga-ted.The main results show that onlyβ-SiC exists on coating surface evaporated after three hours and with the increase of evaporation time,density and continuity of coating increase and cracks and holes decrease.The grain size of silicon carbide becomes smaller with low surface roughness of graphite coating as reaction matrix.The microhardness of SiC coating evaporated on high surface roughness of graphite coating was larger.%采用浆料法在硬质碳纤维毡表面制备石墨涂层,利用硅蒸镀使硅蒸汽在石墨涂层、碳纤维、基体碳表面反应生成SiC涂层。利用XRD、SEM及显微硬度计等研究了蒸镀时间对涂层微观结构、晶粒尺寸及显微硬度的影响,并分析了涂层形成过程。研究结果表明,蒸镀时间增加,表面涂层的微裂纹及孔洞减少,逐渐形成连续、致密的SiC涂层;蒸镀时间为3 h,涂层表面仅存在β-SiC;表面粗糙度低的石墨涂层作为硅蒸镀反应基体,生成的SiC晶粒较小;而表面粗糙度高的石墨涂层作为反应基体,表面涂层的显微硬度较大。

  2. Fracture of Carbon Nanotube - Amorphous Carbon Composites: Molecular Modeling

    Science.gov (United States)

    Jensen, Benjamin D.; Wise, Kristopher E.; Odegard, Gregory M.

    2015-01-01

    Carbon nanotubes (CNTs) are promising candidates for use as reinforcements in next generation structural composite materials because of their extremely high specific stiffness and strength. They cannot, however, be viewed as simple replacements for carbon fibers because there are key differences between these materials in areas such as handling, processing, and matrix design. It is impossible to know for certain that CNT composites will represent a significant advance over carbon fiber composites before these various factors have been optimized, which is an extremely costly and time intensive process. This work attempts to place an upper bound on CNT composite mechanical properties by performing molecular dynamics simulations on idealized model systems with a reactive forcefield that permits modeling of both elastic deformations and fracture. Amorphous carbon (AC) was chosen for the matrix material in this work because of its structural simplicity and physical compatibility with the CNT fillers. It is also much stiffer and stronger than typical engineering polymer matrices. Three different arrangements of CNTs in the simulation cell have been investigated: a single-wall nanotube (SWNT) array, a multi-wall nanotube (MWNT) array, and a SWNT bundle system. The SWNT and MWNT array systems are clearly idealizations, but the SWNT bundle system is a step closer to real systems in which individual tubes aggregate into large assemblies. The effect of chemical crosslinking on composite properties is modeled by adding bonds between the CNTs and AC. The balance between weakening the CNTs and improving fiber-matrix load transfer is explored by systematically varying the extent of crosslinking. It is, of course, impossible to capture the full range of deformation and fracture processes that occur in real materials with even the largest atomistic molecular dynamics simulations. With this limitation in mind, the simulation results reported here provide a plausible upper limit on

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

    Science.gov (United States)

    Caliman, R.

    2016-06-01

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

  4. Functionally Graded Nanophase Beryllium/Carbon Composites

    Science.gov (United States)

    Choi, Michael K.

    2003-01-01

    Beryllium, beryllium alloys, beryllium carbide, and carbon are the ingredients of a class of nanophase Be/Be2C/C composite materials that can be formulated and functionally graded to suit a variety of applications. In a typical case, such a composite consists of a first layer of either pure beryllium or a beryllium alloy, a second layer of B2C, and a third layer of nanophase sintered carbon derived from fullerenes and nanotubes. The three layers are interconnected through interpenetrating spongelike structures. These Be/Be2C/C composite materials are similar to Co/WC/diamond functionally graded composite materials, except that (1) W and Co are replaced by Be and alloys thereof and (2) diamond is replaced by sintered carbon derived from fullerenes and nanotubes. (Optionally, one could form a Be/Be2C/diamond composite.) Because Be is lighter than W and Co, the present Be/Be2C/C composites weigh less than do the corresponding Co/WC/diamond composites. The nanophase carbon is almost as hard as diamond. WC/Co is the toughest material. It is widely used for drilling, digging, and machining. However, the fact that W is a heavy element (that is, has high atomic mass and mass density) makes W unattractive for applications in which weight is a severe disadvantage. Be is the lightest tough element, but its toughness is less than that of WC/Co alloy. Be strengthened by nanophase carbon is much tougher than pure or alloy Be. The nanophase carbon has an unsurpassed strength-to-weight ratio. The Be/Be2C/C composite materials are especially attractive for terrestrial and aerospace applications in which there are requirements for light weight along with the high strength and toughness of the denser Co/WC/diamond materials. These materials could be incorporated into diverse components, including cutting tools, bearings, rocket nozzles, and shields. Moreover, because Be and C are effective as neutron moderators, Be/Be2C/C composites could be attractive for some nuclear applications.

  5. Fabrication of metallic reinforcement fibres for metal matrix composites by in-rotating-liquid spinning. Herstellung metallischer Verstaerkungsfasern fuer Metallmatrixverbundwerkstoffe durch Schmelzspinnen in eine rotierende Fluessigkeit

    Energy Technology Data Exchange (ETDEWEB)

    Heyder, B.; Frommeyer, G. (Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany). Abt. Werkstofftechnik)

    1992-02-01

    The application of reinforced metal matrix composites reinforced by continuous fibres are in particular limited by the lack of inexpensive and high-strength reinforcement fibres. Starting-points for a solution offer new methods of rapid solidification technology such as the in-rotating-liquid spinning that is suitable for a broad acceptance by industry. Fundamental investigations of the influence factors and the process parameters showed the aptitude of this method. (orig.).

  6. Three-dimensional porous hollow fibre copper electrodes for efficient and high-rate electrochemical carbon dioxide reduction

    Science.gov (United States)

    Kas, Recep; Hummadi, Khalid Khazzal; Kortlever, Ruud; de Wit, Patrick; Milbrat, Alexander; Luiten-Olieman, Mieke W. J.; Benes, Nieck E.; Koper, Marc T. M.; Mul, Guido

    2016-02-01

    Aqueous-phase electrochemical reduction of carbon dioxide requires an active, earth-abundant electrocatalyst, as well as highly efficient mass transport. Here we report the design of a porous hollow fibre copper electrode with a compact three-dimensional geometry, which provides a large area, three-phase boundary for gas-liquid reactions. The performance of the copper electrode is significantly enhanced; at overpotentials between 200 and 400 mV, faradaic efficiencies for carbon dioxide reduction up to 85% are obtained. Moreover, the carbon monoxide formation rate is at least one order of magnitude larger when compared with state-of-the-art nanocrystalline copper electrodes. Copper hollow fibre electrodes can be prepared via a facile method that is compatible with existing large-scale production processes. The results of this study may inspire the development of new types of microtubular electrodes for electrochemical processes in which at least one gas-phase reactant is involved, such as in fuel cell technology.

  7. Three-dimensional porous hollow fibre copper electrodes for efficient and high-rate electrochemical carbon dioxide reduction.

    Science.gov (United States)

    Kas, Recep; Hummadi, Khalid Khazzal; Kortlever, Ruud; de Wit, Patrick; Milbrat, Alexander; Luiten-Olieman, Mieke W J; Benes, Nieck E; Koper, Marc T M; Mul, Guido

    2016-01-01

    Aqueous-phase electrochemical reduction of carbon dioxide requires an active, earth-abundant electrocatalyst, as well as highly efficient mass transport. Here we report the design of a porous hollow fibre copper electrode with a compact three-dimensional geometry, which provides a large area, three-phase boundary for gas-liquid reactions. The performance of the copper electrode is significantly enhanced; at overpotentials between 200 and 400 mV, faradaic efficiencies for carbon dioxide reduction up to 85% are obtained. Moreover, the carbon monoxide formation rate is at least one order of magnitude larger when compared with state-of-the-art nanocrystalline copper electrodes. Copper hollow fibre electrodes can be prepared via a facile method that is compatible with existing large-scale production processes. The results of this study may inspire the development of new types of microtubular electrodes for electrochemical processes in which at least one gas-phase reactant is involved, such as in fuel cell technology.

  8. Mathematical models of carbon-carbon composite deformation

    Science.gov (United States)

    Golovin, N. N.; Kuvyrkin, G. N.

    2016-09-01

    Mathematical models of carbon-carbon composites (CCC) intended for describing the processes of deformation of structures produced by using CCC under high-temperature loading are considered. A phenomenological theory of CCC inelastic deformation is proposed, where such materials are considered as homogeneous ones with effective characteristics and where their high anisotropy of mechanical characteristics and different ways of resistance to extension and compression are taken into account. Micromechanical models are proposed for spatially reinforced CCC, where the difference between mechanical characteristics of components and the reinforcement scheme are taken into account. Themodel parameters are determined from the results of experiments of composite macrospecimens in the directions typical of the material. A version of endochronictype theory with several internal times "launched" for each composite component and related to some damage accumulation mechanisms is proposed for describing the inelastic deformation. Some practical examples are considered.

  9. The effect of a fibre supplement compared to a healthy diet on body composition, lipids, glucose, insulin and other metabolic syndrome risk factors in overweight and obese individuals.

    Science.gov (United States)

    Pal, Sebely; Khossousi, Alireza; Binns, Colin; Dhaliwal, Satvinder; Ellis, Vanessa

    2011-01-01

    Optimum levels and types of dietary fibre that provide the greatest beneficial effects on metabolic syndrome risk factors in overweight and obese individuals have yet to be determined in clinical trials. The present parallel design study compared the effects of fibre intake from a healthy diet v. a fibre supplement (psyllium) or a healthy diet plus fibre supplement on fasting lipids, glucose, insulin and body composition. Overweight/obese adults were randomised to either control (with placebo), fibre supplement (FIB), healthy eating plus placebo (HLT) or healthy eating plus fibre supplement (HLT-FIB). There was a significant increase in fibre intake in HLT-FIB, HLT and FIB groups up to 59, 31 and 55 g, respectively, at 12 weeks when compared to control (20 g). Weight, BMI and % total body fat were significantly reduced in FIB and HLT-FIB groups, with weight and BMI significantly reduced in the HLT group compared with control at 12 weeks. HLT-FIB and HLT groups had significant reductions in TAG and insulin compared with control at 6 and 12 weeks, and in insulin compared with the FIB group at 12 weeks. The HLT-FIB, HLT and FIB groups all had significant reductions in total cholesterol and LDL-cholesterol compared with control after 6 and 12 weeks. The present study demonstrated that simply adding psyllium fibre supplementation to a normal diet was sufficient to obtain beneficial effects in risk factors. However, a high-fibre diet consisting of a psyllium supplement plus fibre from a healthy diet provided the greatest improvements in metabolic syndrome risk factors.

  10. Synthesis of Carbon Nanotube (CNT Composite Membranes

    Directory of Open Access Journals (Sweden)

    Dusan Losic

    2010-12-01

    Full Text Available Carbon nanotubes are attractive approach for designing of new membranes for advanced molecular separation because of their unique transport properties and ability to mimic biological protein channels. In this work the synthetic approach for fabrication of carbon nanotubes (CNTs composite membranes is presented. The method is based on growth of multi walled carbon nanotubes (MWCNT using chemical vapour deposition (CVD on the template of nanoporous alumina (PA membranes. The influence of experimental conditions including carbon precursor, temperature, deposition time, and PA template on CNT growth process and quality of fabricated membranes was investigated. The synthesis of CNT/PA composites with controllable nanotube dimensions such as diameters (30–150 nm, and thickness (5–100 µm, was demonstrated. The chemical composition and morphological characteristics of fabricated CNT/PA composite membranes were investigated by various characterisation techniques including scanning electron microscopy (SEM, energy-dispersive x-ray spectroscopy (EDXS, high resolution transmission electron microscopy (HRTEM and x-ray diffraction (XRD. Transport properties of prepared membranes were explored by diffusion of dye (Rose Bengal used as model of hydrophilic transport molecule.

  11. CARBON FIBER COMPOSITES IN HIGH VOLUME

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-01

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

  12. Preparation of composite electroheat carbon film

    Institute of Scientific and Technical Information of China (English)

    XIA Jin-tong; TU Chuan-jun; LI Yan; HU Li-min; DENG Jiu-hua

    2005-01-01

    A kind of conductive and heating unit, which can reach a high surface electroheat temperature at a low voltage, was developed in view of the traditional electroheat coating which has a low surface electroheat temperature and an insufficient heat resistance of its binder. The coating molded electroheat carbon film(CMECF) was prepared by carbonizing the coating which was prepared by adding modified resin into flake graphite and carbon fiber, coating molded onto the surface of the heat resisting matrix after dried, while the hot pressing molded electroheat thick carbon film(HPMETCF) was prepared by carbonizing the bodies whose powders were hot pressing molded directly.The surface and inner microstructure of the carbon film was characterized and analyzed by SEM and DSC/TG, while electroheat property was tested by voltage-current volume resistivity tester and electrical parameter tester. The results show that, close-packed carbon network configuration is formed within the composite electroheat carbon film film after anti-oxidizable treatment reaches a higher surface electroheat temperature than that of the existing electroheat coatings at a low voltage, and has excellent electroheat property, high thermal efficiency as well as stable physicochemical property. It is found that, at room temperature(19± 2 ℃) and 22 V for 5 min, the surface electroheat temperature of the self-produced CMECF (mfiller/mresin = 1. 8/1) reaches 112 ℃ while HPMETCF (mfiller/mresin = 3. 6/1) reaches 265 ℃.

  13. Fabrication,property characterization and toughening mechanism of HA-ZrO2(CaO)/316L fibre composite biomaterials

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    HA-ZrO2(CaO)/316L fibre composites were successfully fabricated with vacuum sintering method and their properties and toughening mechanism were studied. The results showed that HA-ZrO2(CaO)/316L fibre biocomposite having 20 vol% fibres had optimal comprehensive properties with bending strength, Young’s modulus, fracture toughness and relative density equal to 140.1 MPa, 117.8 GPa, 5.81 MPa·m1/2 and 87.1%, respectively. The research also addressed that different volume ratios of the composites led to different metallographic microstructures, and that metallographic morphologies change regularly with volume ratios of the composites. 316L fibres were distributed randomly and evenly in the composites and the integration circumstance of the two phases was very well since there were no obvious flaws or pores in the composites. Two toughening mechanisms including ZrO2 phase transformation toughening mechanism and fibre pulling-out toughening mechanism existed in the compsites with the latter being the main toughening mechanism.

  14. Effect of Grinding Process Parameters on Surface Area Roughness of Glass fibre Reinforced Composite Laminate under Dry and Coolant Environment

    Directory of Open Access Journals (Sweden)

    P. Chockalingam

    2016-04-01

    Full Text Available This paper presents a comparative study on dry and wet grinding of chopped strand mat glass fibre reinforced polymer laminates using an alumina wheel. Investigations were performed to study the impact of the grinding parameters, namely feed, speed, and depth of cut on grinding force ratio and surface area roughness. Effective grinding parameters were sought in this study to maximize grinding force ratio and minimize surface area roughness. Test results show that coolant helped to decrease surface area roughness, but inevitably reduced the grinding force ratio in some cases. These findings lead to economic machining solution for optimum grinding conditions in grinding composite laminates.

  15. Thermal diffusivity mapping of 4D carbon-carbon composites

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H.; Dinwiddie, R.B.

    1997-03-01

    High resolution, 2-D thermal diffusivity maps of carbon-carbon composites were obtained by a state-of-the-art infrared thermal imaging system. Unlike the traditional single-point IR detector used for thermal diffusivity measurements, the IR camera is capable of capturing images in its 256 x 256 pixel Focal Plane Array detector in a snap-shot mode. The camera takes up to 200 images at a rate of 120 frames/second. The temperature resolution of the Ir camera is 0.015 C and the spatial resolution is 20 {micro}m. Thermal diffusivity was calculated for each pixel. Four-direction carbon-carbon composites were used for the thermal diffusivity mapping study. The fiber bundles along the heat flow direction were found to have 25% higher diffusivity values than the surrounding matrix. The diffusivity map also showed detailed local variations in diffusivity which were impossible to measure using a single-point detector. Accurate diffusivity maps are very important to the design of composite materials.

  16. Development of tungsten fibre-reinforced tungsten composites towards their use in DEMO—potassium doped tungsten wire

    Science.gov (United States)

    Riesch, J.; Han, Y.; Almanstötter, J.; Coenen, J. W.; Höschen, T.; Jasper, B.; Zhao, P.; Linsmeier, Ch; Neu, R.

    2016-02-01

    For the next step fusion reactor the use of tungsten is inevitable to suppress erosion and allow operation at elevated temperature and high heat loads. Tungsten fibre-reinforced composites overcome the intrinsic brittleness of tungsten and its susceptibility to operation embrittlement and thus allow its use as a structural as well as an armour material. That this concept works in principle has been shown in recent years. In this contribution we present a development approach towards its use in a future fusion reactor. A multilayer approach is needed addressing all composite constituents and manufacturing steps. A huge potential lies in the optimization of the tungsten wire used as fibre. We discuss this aspect and present studies on potassium doped tungsten wire in detail. This wire, utilized in the illumination industry, could be a replacement for the so far used pure tungsten wire due to its superior high temperature properties. In tensile tests the wire showed high strength and ductility up to an annealing temperature of 2200 K. The results show that the use of doped tungsten wire could increase the allowed fabrication temperature and the overall working temperature of the composite itself.

  17. Effects of wheat starch on erosive wear of E-glass fibre reinforced epoxy resin composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, V.K. [Department of Mechanical Engineering, Institute of Technology, Banaras Hindu University, Varanasi 221005 (India)]. E-mail: vk_sa@yahoo.co.in

    2006-11-05

    Erosive wear tests were carried out to study the effects of particle, impingement angle and particle velocity on the solid particle erosion behaviour of E-glass fibre reinforced epoxy resin (GFRP) composites. The erosive wear of wheat flour powder filled composites is evaluated at different impingement angles from 30 deg. to 90 deg. and at three different velocities of 24, 35 and 52 m s{sup -1}. The erodent used is silica sand with the size range 150-250 {mu}m of irregular shapes. The result shows erosive wear rates of GFRP composite with 2 g wheat flour, as filler is the lowest. This restricts fiber-matrix debonding. Pure glass epoxy without any filler shows the highest erosion rate due to weak bonding strength. The morphologies of eroded surface were examined by the scanning electron microscope.

  18. Use of micro-tomography for validation of method to identify interfacial shear strength from tensile tests of short regenerated cellulose fibre composites

    DEFF Research Database (Denmark)

    Hajlane, A.; Miettinen, A.; Madsen, Bo;

    2016-01-01

    The interfacial shear strength of short regenerated cellulose fibre/polylactide composites was characterized by means of an industry-friendly adhesion test method. The interfacial shear strength was back-calculated from the experimental tensile stress-strain curves of composites by using a micro...

  19. The influence of framework design on the load-bearing capacity of laboratory-made inlay-retained fibre-reinforced composite fixed dental prostheses

    NARCIS (Netherlands)

    F. Keulemans; L.V.J. Lassilla; S. Garoushi; P.K. Vallittu; C.J. Kleverlaan; A.J. Feilzer

    2009-01-01

    Delamination of the veneering composite is frequently encountered with fibre-reinforced composite (FRC) fixed dental prosthesis (FDPs). The aim of this study is to evaluate the influence of framework design on the load-bearing capacity of laboratory-made three-unit inlay-retained FRC-FDPs. Inlay-ret

  20. Gliding arc discharge — Application for adhesion improvement of fibre reinforced polyester composites

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Teodoru, Steluta; Leipold, Frank;

    2008-01-01

    production, and surface treatment. However, the application for adhesion improvement of structural materials has been rarely reported. In the present work, glass fibre reinforced polyester plates were treated using atmospheric pressure gliding arcs with high speed air flow for adhesion improvement...

  1. Deposition of amorphous carbon-silver composites

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Zarco, O. [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, Ciudad Universitaria. 04510, Mexico D. F. Mexico (Mexico); Rodil, S.E., E-mail: ser42@iim.unam.m [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior s/n, Ciudad Universitaria. 04510, Mexico D. F. Mexico (Mexico); Camacho-Lopez, M.A. [Facultad de Quimica, Universidad Autonoma del Estado de Mexico, Tollocan s/n, esq. Paseo Colon, Toluca, Estado de Mexico, 50110 (Mexico)

    2009-12-31

    Composites of amorphous carbon films and silver were deposited by co-sputtering, where the target (10 cm diameter) was of pure graphite with small inclusion of pure silver (less than 1 cm{sup 2}). The films were deposited under different powers, from 40 to 250 W, and different target-substrate distances. The substrate was earthed and rotated in order to obtain a uniform distribution of the silver content. The addition of the Ag piece into the target increased the deposition rate of the carbon films, which could be related to the higher sputter yield of the silver, but there seems to be also a contribution from a larger emission of secondary electrons from the Ag that enhances the plasma and therefore the sputtering process becomes more efficient. Scanning electron micrographs acquired using backscattered electrons showed that the silver was segregated from the carbon matrix, forming nanoparticles or larger clusters as the power was increased. The X-ray diffraction pattern showed that the silver was crystalline and the carbon matrix remained amorphous, although for certain conditions a peak attributed to fullerene-like structures was obtained. Finally, we used Raman spectroscopy to understand the bonding characteristics of the carbon-silver composites, finding that there are variations in the D/G ratio, which can be correlated to the observed structure and X-ray diffraction results.

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

    Science.gov (United States)

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

    2014-01-01

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

  3. RADIATION EFFECTS ON EPOXY CARBON FIBER COMPOSITE

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, E

    2008-05-30

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

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

    Science.gov (United States)

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

    1999-05-01

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

  5. Processing and Characterization of Carbon Nanotube Composites

    Science.gov (United States)

    Can, Roberto J.; Grimsley, Brian W.; Czabaj, Michael W.; Siochi, Emilie J.; Hull, Brandon

    2014-01-01

    Recent advances in the synthesis of large-scale quantities of carbon nanotubes (CNT) have provided the opportunity to study the mechanical properties of polymer matrix composites using these novel materials as reinforcement. Nanocomp Technologies, Inc. currently supplies large sheets with dimensions up to 122 cm x 244 cm containing both single-wall and few-wall CNTs. The tubes are approximately 1 mm in length with diameters ranging from 8 to 12 nm. In the present study being conducted at NASA Langley Research Center (LaRC), single and multiple layers of CNT sheets were infused or coated with various polymer solutions that included commercial toughened-epoxies and bismaleimides, as well as a LaRC developed polyimide. The resulting CNT composites were tested in tension using a modified version of ASTM D882-12 to determine their strength and modulus values. The effects of solvent treatment and mechanical elongation/alignment of the CNT sheets on the tensile performance of the composite were determined. Thin composites (around 50 wt% CNT) fabricated from acetone condensed and elongated CNT sheets with either a BMI or polyimide resin solution exhibited specific tensile moduli approaching that of toughened epoxy/ IM7 carbon fiber unidirectional composites.

  6. CARBON-CONTAINING COMPOSITES BASED ON METALS

    Directory of Open Access Journals (Sweden)

    VAGANOV V. E.

    2015-10-01

    Full Text Available Problem statement Among the developed technologies metal-composites production,a special place takes powder metallurgy, having fundamental differences from conventionally used foundry technologies. The main advantages of this technology are: the possibility of sensitive control, the structure and phase composition of the starting components, and ultimately the possibility of obtaining of bulk material in nanostructured state with a minimum of processing steps. The potential reinforcers metals include micro and nano-sized oxides, carbides, nitrides, whiskers. The special position is occupied with carbon nanostructures (CNS: С60 fullerenes, single-layer and multi-layer nanotubes, onions (spherical "bulbs", nano-diamonds and graphite,their properties are being intensively studied in recent years. These objects have a high thermal and electrical conductivity values, superelasticity, and have a strength approximate to the theoretical value, which can provide an obtaining composite nanomaterial with a unique set of physical and mechanical properties. In creation of a metal matrix composite nanomaterials (CM, reinforced by various CNS, a special attention should be given to mechanical activation processes (MA already at the stage of preparation of the starting components affecting the structure, phase composition and properties of aluminum-matrix composites. Purpose. To investigate the influence of mechanical activation on the structure and phase composition of aluminum-matrix composites. Conclusion. The results of the study of the structure and phase composition of the initial and mechanically activated powders and bulk-modified metal-composites are shown, depending on the type and concentration of modifying varieties CNS, regimes of MA and parameters of compaction. The study is conducted of tribological properties of Al-CNS OF nanostructured materials.

  7. The effect of graphitization on the mechanical properties of twodimensional carbon-carbon composites

    Energy Technology Data Exchange (ETDEWEB)

    Sedghi, A. [Iran Univ. of Sci. and Technol., Teheran (Iran, Islamic Republic of). Dept. of Mater. Eng.; Golestani Fard, F. [Iran Univ. of Sci. and Technol., Teheran (Iran, Islamic Republic of). Dept. of Mater. Eng.

    1997-05-01

    In this article the effect of graphitization in twodimensional c-c composite bodies prepared by impregnation of novalak resin is reported. Mechanical properties were determined by bending tests and microstructural features were studied by SEM and XRD. It was found that primary graphitization at 2300 C followed by graphitization at 2500 C improves the mechanical strength remarkably. Repeated graphitization and long - term treatment at 2500 C, however, found to have an adverse effect. Microstructural observations revealed that the level of strength is mainly controlled by a sheath developed around the fibre during graphitization. Applying an improper thermal regime affects the matrix - fibre adherence and may cause the destruction of the fibres. This enhances the crack propagation and causes early failure of composite body under loading. (orig.)

  8. The study about the use of the natural fibres in composite materials

    Science.gov (United States)

    Hristian, L.; Ostafe, M. M.; Manea, L. R.; Leon, A. L.

    2016-08-01

    The current technological development, the crises of raw materials and energy, the increased aggression towards the environment have led to the development of the new materials and unconventional technologies. The composite materials have both many important advantages compared to the traditional materials and provide many functional advantages: low weight, mechanical resistance, low maintenance costs. The main advantage of the composites lies in their ability to combine the physical properties of components to achieve new structural functionalities, so the modulation of the properties and finally, to obtain a wide variety of materials which may be used in all areas of activities. Some biodegradable fibers, flax, hemp, may provide the specific mechanical properties compared to those of the glass fiber, due to their high strength and low density of their volume. To make the right choice, even if the natural fibers have very low power consumption compared with the synthetic fibers, such as glass or carbon, it should be considered a careful assessment of the environmental impact. The present study shows that the validity of the replacement of the synthetic fibers with natural fibers, depends on the reinforcement type and the complexity of the problems due to the processing of natural fibers.

  9. Tribological studies of composite material based on CuZn38Al2Mn1Fe brass strengthened with δ-alumina fibres

    Directory of Open Access Journals (Sweden)

    J. W. Kaczmar

    2010-10-01

    Full Text Available The results of tribological studies (friction coefficient, wear resistance of the frictional couple of composite material based on CuZn38Al2Mn1Fe brass strengthened with δ-alumina fibres (Saffil and cast iron are shown in this paper. The wear investigations were conducted applying the tribological pin-on-disc tester and the friction forces between composite materials containing 10 and 20 vol. % of δ-alumina fibres (Saffil and cast iron were registered. Wear was determined on the base of the specimen mass loss after 1, 3,5 and 8.5 km of friction distance.

  10. Structural changes during pitch-based carbon granular composites carbonisation

    Energy Technology Data Exchange (ETDEWEB)

    Mendez, A.; Santamaria, R.; Granda, M.; Menendez, R. [CSIC, Oviedo (Spain)

    2008-02-15

    This article deals with the study of carbon composites behavior during their carbonization. Composites were prepared using four granular carbons (graphite, anthracite, green petroleum coke, and foundry coke) and four pitches (a commercial impregnating coal-tar pitch, an air-blown and two thermally treated pitches). The evolution of the optical microstructure, porosity, volume, and weight of carbon composites was monitored at different intermediate carbonization temperatures (350, 500, 700, and finally 1000{sup o}C). The porosity of composites increases with carbonization due to volume changes and weight loss of pitches. Weight loss of carbon composites during their carbonization mainly depends on the pitch characteristics and it was slightly influenced by the presence of granular carbon. On the other hand, carbon composites with the commercial coal-tar pitch and foundry coke, anthracite, or graphite deform in the initial stages of carbonization (<350{sup o}C) probably due to the lower porosity of the green pellets and the high amount of low-molecular weight compounds of the pitch. Carbon composites with green petroleum coke underwent important dimensional changes during their carbonization, expanding initially and then shrinking at temperatures above 700{sup o}C. The type of granular carbon strongly influenced the microstructure of the final carbon composite, as a result of its effect on the development of mesophase. Graphite, anthracite and foundry coke delays mesophase development, whereas green petroleum coke accelerates mesophase formation.

  11. Time-resolved X-ray microtomographic measurement of water transport in wood-fibre reinforced composite material

    Science.gov (United States)

    Miettinen, Arttu; Harjupatana, Tero; Kataja, Markku; Fortino, Stefania; Immonen, Kirsi

    2016-07-01

    Natural fibre composites are prone to absorb moisture from the environment which may lead to dimensional changes, mold growth, degradation of mechanical properties or other adverse effects. In this work we develop a method for direct non-intrusive measurement of local moisture content inside a material sample. The method is based on X-ray microtomography, digital image correlation and image analysis. As a first application of the method we study axial transport of water in a cylindrical polylactic acid/birch pulp composite material sample with one end exposed to water. Based on the results, the method seems to give plausible estimates of water content profiles inside the cylindrical sample. The results may be used, e.g., in developing and validating models of moisture transport in biocomposites.

  12. Thermal Conductivity of Carbon Nanotube Composite Films

    Science.gov (United States)

    Ngo, Quoc; Cruden, Brett A.; Cassell, Alan M.; Walker, Megan D.; Koehne, Jessica E.; Meyyappan, M.; Li, Jun; Yang, Cary Y.

    2004-01-01

    State-of-the-art ICs for microprocessors routinely dissipate power densities on the order of 50 W/sq cm. This large power is due to the localized heating of ICs operating at high frequencies, and must be managed for future high-frequency microelectronic applications. Our approach involves finding new and efficient thermally conductive materials. Exploiting carbon nanotube (CNT) films and composites for their superior axial thermal conductance properties has the potential for such an application requiring efficient heat transfer. In this work, we present thermal contact resistance measurement results for CNT and CNT-Cu composite films. It is shown that Cu-filled CNT arrays enhance thermal conductance when compared to as-grown CNT arrays. Furthermore, the CNT-Cu composite material provides a mechanically robust alternative to current IC packaging technology.

  13. Effect of Fibre Supplementation on Body Weight and Composition, Frequency of Eating and Dietary Choice in Overweight Individuals

    Science.gov (United States)

    Solah, Vicky A.; Kerr, Deborah A.; Hunt, Wendy J.; Johnson, Stuart K.; Boushey, Carol J.; Delp, Edward J.; Meng, Xingqiong; Gahler, Roland J.; James, Anthony P.; Mukhtar, Aqif S.; Fenton, Haelee K.; Wood, Simon

    2017-01-01

    Fibre supplementation can potentially reduce energy intake and contribute to weight loss. The mechanism may be reduced frequency of eating, resulting in reduced food consumption. The objective of this research was to determine the effectiveness of fibre supplementation with PolyGlycopleX® (PGX®), on body weight and composition, frequency of eating and dietary intake in 118 overweight adults. In a three-arm, parallel, blind, randomised controlled trial participants were randomised to one of three groups; 4.5 g PGX as softgels (PGXS), 5 g PGX granules (PGXG) or 5 g rice flour (RF) control. Prior to supplementation and at 12 weeks, participants captured before and after images of all food and beverages consumed within 4 days using a mobile food record app (mFR). The mFR images were analysed for food group serving sizes and number of eating occasions. In the PGXG group, intention-to-treat analysis showed there was a significant reduction in waist circumference (2.5 cm; p = 0.003). Subgroup analysis showed that PGXG supplementation at the recommended dose resulted in a reduction in body weight (−1.4 ± 0.10 kg, p < 0.01), body mass index (BMI) reduction (−0.5 ± 0.10, p < 0.01), reduced number of eating occasions (−1.4 ± 1.2, p < 0.01) and a reduced intake of grain food (−1.52 ± 1.84 serves, p = 0.019). PGXG at the recommended dose resulted in a reduction in weight and BMI which was significantly greater than that for RF (p = 0.001). These results demonstrate the potential benefits of PGX fibre in controlling frequency of eating and in weight loss. PMID:28212353

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-06-25

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

  15. Obtention and dynamical mechanical behavior of polymer matrix carbon fire reinforced composites; Obtencao e comportamento mecanodinamico de compositos com matriz polimerica reforcada com fibras de carbono

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva, Nelson Marques

    2001-07-01

    Polymer matrix composites reinforced with carbon fibres have been extensively used in the nuclear, aeronautics, automotive and leisure industry. This is due to their superior performance when compared to conventional materials in terms of specific strength and specific modulus (3 to 4 times higher than that of mild steels). However, these materials are anisotropic, requiring characterisation for each process and particular application. In the present work, the evaluation of epoxy resin reinforced with unidirectional and continuous carbon fibres was carried out. The composites materials were obtained by filament winding, with three different cure cycles, with two types of carbon fibres (6000 and 12000 filaments per strand) and with fibres volumetric fraction around 60 %. The evaluation of the composites was undertaken using following techniques: scanning electron microscopy (SEM); dynamic mechanical analysis (DMA); thermogravimetric analysis (TGA), and differential scanning calorimeter (DSC). These techniques allowed the evaluation and comparison of storage modulus, internal energy dissipation, glass transition region and glass transition temperature - Tg, cure cycling. Besides, void volumetric fraction was measured. The results indicate that the DMA is a good alternative technique to DSC and TGA. It provides an indication of the quality of the produced composite, both thermal and mechanical. The technique can assist the quality control of composite components by measuring mechanical and thermal properties - modulus and Tg. The DMA technique was sensitive to cure cycling evaluation. Regarding the obtained composites, the results showed the need for the development of specific cure cycle for each application, establishing a compromise between properties such as storage modulus and internal energy dissipation, and involved costs. The results demonstrated differences between the storage modulus and internal energy dissipation for the two types of used fibres. (author)

  16. Effect of UV and electrochemical surface treatments on the adsorption and reaction of linear alcohols on non-porous carbon fibre

    Science.gov (United States)

    Osbeck, S.; Ward, S.; Idriss, H.

    2013-04-01

    The adsorption properties of untreated, electrochemically treated and ultra-violet/ozone treated polyacrylonitrile based carbon fibres were investigated using temperature programmed desorption (TPD) on a series of linear alcohols as probes in order to understand its surface properties. Surface uptake was found to be sensitive to both the surface treatment and the nature of the adsorbates. Surface coverage increased with increasing alcohol chain due to the increase in their polarizability. It also increased with the level of surface oxygen of the fibres most likely because it facilitates the Osbnd H bond dissociation of the alcohol functional group. In addition, the desorption temperature (during TPD) tracked the surface oxygen levels (as determined from XPS O1s signal) suggesting increasing in the adsorption energy. The reactions of C1-C4 linear alcohols were also investigated on the surface of the fibre carbon. The main reaction was dehydrogenation to the corresponding aldehydes; the dehydration reaction to olefins was not observed. The dehydrogenation reaction was sensitive to the length of the alky chain. It was highest for methanol (to formaldehyde) and decreased with increasing the carbon number. Overall TPD of linear alcohols was shown to be a promising method for quantifying the level and strength of bonding occurring on carbon fibre surfaces.

  17. Development of Hybrid Braided Composite Rods for Reinforcement and Health Monitoring of Structures

    OpenAIRE

    Sohel Rana; Emilija Zdraveva; Cristiana Pereira; Raul Fangueiro; A. Gomes Correia

    2014-01-01

    In the present study, core-reinforced braided composite rods (BCRs) were developed and characterized for strain sensing capability. A mixture of carbon and glass fibre was used in the core, which was surrounded by a braided cover of polyester fibres. Three compositions of core with different carbon fibre/glass fibre weight ratios (23/77, 47/53, and 100/0) were studied to find out the optimum composition for both strain sensitivity and mechanical performance. The influence of carbon f...

  18. Effect of length post and remaining root tissue on fracture resistance of fibre posts relined with resin composite.

    Science.gov (United States)

    Farina, A P; Weber, A L; Severo, B de P; Souza, M A; Cecchin, D

    2015-03-01

    To investigate the influence of post length and amount of remaining root tissue on the fracture resistance of roots restored with fibre posts relined with resin composite. Ninety upper canine teeth were divided into nine groups (n = 10). The post spaces were prepared resulting in different lengths, as follows: group 2/3, preparations with lengths of 10 mm; group 1/2, preparations with lengths of 7·5 mm; and group 1/3, preparations with lengths of 5 mm. Each group was divided into 3 subgroups according to amount of remaining root tooth tissue (2, 1 mm or 0·5 mm of thick root). Fibre posts relined with resin composite were cemented, and all teeth were restored with metal crowns. The samples were submitted to the fracture resistance test in a universal testing machine, at an angle of 135° and speed of 0·5 mm min(-1) . Failure modes were observed and the data of fracture resistance were submitted to the anova and Tukey's (α = 0·05). No statistically significant difference in fracture resistance was found among different post lengths (P > 0·05). Remaining dentin thickness of 2 and 1 mm did not differ statistically in fracture resistance (P > 0·05), which was higher than of 0·5 mm dentin thickness (P resin composite did not influence fracture resistance, but thickness was an important factor for the restoration of endodontically treated teeth.

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

    Science.gov (United States)

    Caliman, R.

    2015-11-01

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

  20. Fermentation based carbon nanotube multifunctional bionic composites

    Science.gov (United States)

    Valentini, Luca; Bon, Silvia Bittolo; Signetti, Stefano; Tripathi, Manoj; Iacob, Erica; Pugno, Nicola M.

    2016-06-01

    The exploitation of the processes used by microorganisms to digest nutrients for their growth can be a viable method for the formation of a wide range of so called biogenic materials that have unique properties that are not produced by abiotic processes. Here we produced living hybrid materials by giving to unicellular organisms the nutrient to grow. Based on bread fermentation, a bionic composite made of carbon nanotubes (CNTs) and a single-cell fungi, the Saccharomyces cerevisiae yeast extract, was prepared by fermentation of such microorganisms at room temperature. Scanning electron microscopy analysis suggests that the CNTs were internalized by the cell after fermentation bridging the cells. Tensile tests on dried composite films have been rationalized in terms of a CNT cell bridging mechanism where the strongly enhanced strength of the composite is governed by the adhesion energy between the bridging carbon nanotubes and the matrix. The addition of CNTs also significantly improved the electrical conductivity along with a higher photoconductive activity. The proposed process could lead to the development of more complex and interactive structures programmed to self-assemble into specific patterns, such as those on strain or light sensors that could sense damage or convert light stimulus in an electrical signal.