Littérature scientifique sur le sujet « Fibre reinforcements »
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Articles de revues sur le sujet "Fibre reinforcements"
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Ghazzawi, Yousof M., Andres F. Osorio et Michael T. Heitzmann. « Fire performance of continuous glass fibre reinforced polycarbonate composites : The effect of fibre architecture on the fire properties of polycarbonate composites ». Journal of Composite Materials 53, no 12 (23 octobre 2018) : 1705–15. http://dx.doi.org/10.1177/0021998318808052.
Texte intégralRésumé :
The fire performance of polycarbonate resin and the role of glass fibre reinforcement in altering the fire performance was investigated. Three different fibre weaves with comparable surface density, plain, twill, and unidirectional glass fabrics, were used as reinforcements. E-glass fabrics were solution-impregnated with polycarbonate/dichloromethyl, laid up, and compression-moulded to consolidate the glass fibre reinforced polycarbonate composite. Cone calorimetry tests with an incident radiant flux of 35 kW/m2 were used to investigate the fire properties of polycarbonate resin and its composites. Results showed that glass fibre reinforcement improves polycarbonate performance by delaying its ignition, decreasing its heat release rate, and lowering the mass loss rate. The three fibre weave types exhibited similar time to ignition. However, unidirectional fibre had a 35% lower peak heat release rate followed when compared to plain and twill weave fibres.
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Cullen, Richard K., Mary Margaret Singh et John Summerscales. « Characterisation of Natural Fibre Reinforcements and Composites ». Journal of Composites 2013 (18 décembre 2013) : 1–4. http://dx.doi.org/10.1155/2013/416501.
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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.
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Santhanam, V., et M. Chandrasekaran. « Effect of Surface Treatment on the Mechanical Properties of Banana-Glass Fibre Hybrid Composites ». Applied Mechanics and Materials 591 (juillet 2014) : 7–10. http://dx.doi.org/10.4028/www.scientific.net/amm.591.7.
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Natural fibre reinforced composites have attracted the attention of research community mainly because they are turning out to be an alternative to synthetic fibre. Various natural fibres such as jute, sisal, palm, coir and banana are used as reinforcements. In this paper, banana fibres and glass fibres have been used as reinforcement. Hybrid epoxy polymer composite was fabricated using chopped banana/glass fibre and the effect of alkali treatment was also studied. It is found that the alkali treatment improved the mechanical properties of the composite.
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Pantaloni, Delphin, Alain Bourmaud, Christophe Baley, Mike J. Clifford, Michael H. Ramage et Darshil U. Shah. « A Review of Permeability and Flow Simulation for Liquid Composite Moulding of Plant Fibre Composites ». Materials 13, no 21 (28 octobre 2020) : 4811. http://dx.doi.org/10.3390/ma13214811.
Texte intégralRésumé :
Liquid composite moulding (LCM) of plant fibre composites has gained much attention for the development of structural biobased composites. To produce quality composites, better understanding of the resin impregnation process and flow behaviour in plant fibre reinforcements is vital. By reviewing the literature, we aim to identify key plant fibre reinforcement-specific factors that influence, if not govern, the mould filling stage during LCM of plant fibre composites. In particular, the differences in structure (physical and biochemical) for plant and synthetic fibres, their semi-products (i.e., yarns and rovings), and their mats and textiles are shown to have a perceptible effect on their compaction, in-plane permeability, and processing via LCM. In addition to examining the effects of dual-scale flow, resin absorption, (subsequent) fibre swelling, capillarity, and time-dependent saturated and unsaturated permeability that are specific to plant fibre reinforcements, we also review the various models utilised to predict and simulate resin impregnation during LCM of plant fibre composites.
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Kandemir, Ali, Thomas R. Pozegic, Ian Hamerton, Stephen J. Eichhorn et Marco L. Longana. « Characterisation of Natural Fibres for Sustainable Discontinuous Fibre Composite Materials ». Materials 13, no 9 (4 mai 2020) : 2129. http://dx.doi.org/10.3390/ma13092129.
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Growing environmental concerns and stringent waste-flow regulations make the development of sustainable composites a current industrial necessity. Natural fibre reinforcements are derived from renewable resources and are both cheap and biodegradable. When they are produced using eco-friendly, low hazard processes, then they can be considered as a sustainable source of fibrous reinforcement. Furthermore, their specific mechanical properties are comparable to commonly used, non-environmentally friendly glass-fibres. In this study, four types of abundant natural fibres (jute, kenaf, curaua, and flax) are investigated as naturally-derived constituents for high performance composites. Physical, thermal, and mechanical properties of the natural fibres are examined to evaluate their suitability as discontinuous reinforcements whilst also generating a database for material selection. Single fibre tensile and microbond tests were performed to obtain stiffness, strength, elongation, and interfacial shear strength of the fibres with an epoxy resin. Moreover, the critical fibre lengths of the natural fibres, which are important for defining the mechanical performances of discontinuous and short fibre composites, were calculated for the purpose of possible processing of highly aligned discontinuous fibres. This study is informative regarding the selection of the type and length of natural fibres for the subsequent production of discontinuous fibre composites.
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Bernava, Aina, Maris Manins et Guntis Strazds. « Study of Mechanical Properties of Natural and Hybrid Yarns Reinforcements ». Advanced Materials Research 1117 (juillet 2015) : 231–34. http://dx.doi.org/10.4028/www.scientific.net/amr.1117.231.
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The present work was focused on development and studies of mechanical properties that natural fibres have in the woven reinforcements made from hemp and flax as well as hybrid yarns of hemp and glass fibres. Natural fibres such as hemp and flax are biodegradable, have low weight and show good flexibility. Glass fibre is widely used in the industry when low cost and good performance is required. The hemp yarns (100 Tex and 1186 Tex), the flax yarns (678 Tex) and the hybrid yarn of hemp and glass fibres (1644 Tex) were used to develop woven reinforcement structures. Average surface density for reinforcements of hemp yarns is 83- 529 g/m2 and for reinforcements of hybrid yarns 738- 741 g/m2.
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Wiemer, Niels, Alexander Wetzel, Maximilian Schleiting, Philipp Krooß, Malte Vollmer, Thomas Niendorf, Stefan Böhm et Bernhard Middendorf. « Effect of Fibre Material and Fibre Roughness on the Pullout Behaviour of Metallic Micro Fibres Embedded in UHPC ». Materials 13, no 14 (14 juillet 2020) : 3128. http://dx.doi.org/10.3390/ma13143128.
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The use of micro fibres in Ultra-High-Performance Concrete (UHPC) as reinforcement increases tensile strength and especially improves the post-cracking behaviour. Without using fibres, the dense structure of the concrete matrix results in a brittle failure upon loading. To counteract this behaviour by fibre reinforcement, an optimal bond between fibre and cementitious matrix is essential. For the composite properties not only the initial surfaces of the materials are important, but also the bonding characteristics at the interfacial transition zone (ITZ), which changes upon the joining of both materials. These changes are mainly induced by the bond of cementitious phases on the fibre. In the present work, three fibre types were used: steel fibres with brass coating, stainless-steel fibres as well as nickel-titanium shape memory alloys (SMA). SMA fibres have the ability of “remembering” an imprinted shape (referred to as shape memory effect), triggered by thermal activation or stress, principally providing for superior performance of the fibre-reinforced UHPC. However, previous studies have shown that NiTi-fibres have a much lower bond strength to the concrete matrix than steel fibres, eventually leading to a deterioration of the mechanical properties of the composite. Accordingly, the bond between both materials has to be improved. A possible strategy is to roughen the fibre surfaces to varying degrees by laser treatment. As a result, it can be shown that laser treated fibres are characterised by improved bonding behaviour. In order to determine the bond strength of straight, smooth fibres of different metal alloy compositions, the present study characterized multiple fibres in series with a Compact-Tension-Shear (CTS) device. For critical evaluation, results obtained by these tests are compared with the results of conventional testing procedures, i.e., bending tests employing concrete prisms with fibre reinforcements. The bond behaviour is compared with the results of the flexural strength of prisms (4 × 4 × 16 cm3) with fibre reinforcements.
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Černý, Miroslav, et Jaroslav Pokluda. « First Principles Study of Ideal Composites Reinforced by Coherent Nano-Fibres ». Key Engineering Materials 465 (janvier 2011) : 73–76. http://dx.doi.org/10.4028/www.scientific.net/kem.465.73.
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Ab initio calculations of elastic moduli and theoretical tensile strength of composite lamina having continuous nano-fibre reinforcements are performed using pseudopotential approach within density functional theory. Results for molybdenum or tungsten nano-fibres in vanadium or niobium matrices, presented as case studies, reveal that the theoretical strength approaches the value corresponding to the strength of the reinforcement already at about 60-80% atomic concentration of reinforcing fibres in the composite.
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Sridhar, M. K. « Fibre Reinforcements for Composites . » Defence Science Journal 43, no 4 (1 janvier 1993) : 365–68. http://dx.doi.org/10.14429/dsj.43.4290.
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El-Hage, Yue, Simon Hind et François Robitaille. « Thermal conductivity of textile reinforcements for composites ». Journal of Textiles and Fibrous Materials 1 (1 janvier 2018) : 251522111775115. http://dx.doi.org/10.1177/2515221117751154.
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Thermal conductivity data for dry carbon fibre fabrics are required for modelling heat transfer during composites manufacturing processes; however, very few published data are available. This article reports in-plane and through-thickness thermal conductivities measured as a function of fibre volume fraction ( Vf) for non-crimp and twill carbon reinforcement fabrics, three-dimensional weaves and reinforcement stacks assembled with one-sided carbon stitch. Composites made from these reinforcements and glass fibre fabrics are also measured. Clear trends are observed and the effects of Vf, de-bulking and vacuum are quantified along with orthotropy ratios. Limited differences between the conductivity of dry glass and carbon fibre fabrics in the through-thickness direction are reported. An unexpected trend in the relationship between that quantity and Vf is explained summarily through simple simulations.
Thèses sur le sujet "Fibre reinforcements"
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Wretfors, Christer. « Hemp fibre and reinforcements of wheat gluten plastics / ». Alnarp : Dept. of Agriculture - Farming Systems, Technology and Product Quality, Swedish University of Agricultural Sciences, 2008. http://epsilon.slu.se/11236319.pdf.
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Badripour, Yousef. « Characterization of Fibre Reinforcements for Non-structural Composite Parts ». Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/38430.
Texte intégralRésumé :
Fibre reinforced composite materials have attracted attention from industry and academia due to their high specific stiffness and strength. Commonly used manufacturing processes include the Liquid Composite Moulding (LCM) group of processes, where a liquid polymer resin impregnates a dry preform that is prepared in advance. The consistency of the resin infusion process and properties of the final composite are highly dependent on preform quality and reproducibility. Preform quality, in turn, depends on a process called draping. This work aims at understanding and developing quantitative knowledge of key elements of reinforcement behaviour during preforming.
Testing characterization methods for dry fabrics are introduced and discussed. Moreover, the thesis probes relations between fabric properties such as their architecture and fibre type, and elements of their draping and preforming behaviour such as bending stiffness and in-plane shear properties of the dry fabrics.
Most materials used in this work were selected by the industrial partner, Hutchinson Aerospace and Industry, based in Montreal. Some experiments were conducted using Hutchinson’s characterization devices, which are introduced in the relevant chapters.
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Somashekar, Arcot Arumugam. « Compression deformation of glass fibre reinforcements in composites manufacturing processes ». Thesis, University of Auckland, 2009. http://hdl.handle.net/2292/5579.
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Whole document restricted until 06/2011, see Access Instructions file below for details of how to access the print copy.Glass fibre reinforced polymer (GFRP) composites find application in diverse industries such as aerospace, marine, automotive, infrastructure and sport. GFRP composite products can be manufactured by a variety of methods, including the commonly employed Liquid Composite Moulding (LCM) group of techniques. Whatever the method, compression of the fibrous reinforcement is usually necessary in its natural dry state, and depending upon the technique, also after injection of a polymeric resin into a mould containing the reinforcement. A good understanding of the compression deformation behaviour of the reinforcement aids development of better models to describe and predict the manufacturing process, evaluate stresses acting on the mould, mould clamping and tooling forces required, and improvement of finished product quality. LCM models commonly assume non-linear elastic deformation of the fibre reinforcement network, while some also take into account viscoelastic behaviour. Earlier investigations demonstrated reinforcement stress relaxation under constant compressive strain. Reinforcements under loading (compaction) and unloading (release) follow different paths for the two phases. These phenomena indicate viscoelastic behaviour. Cyclic loading and unloading of reinforcements show a progressive shift of the fibre volume fraction - compression stress curve, signifying non-recoverable strain. This research further investigated these complex compression deformation phenomena which are not normally considered for modelling simulations. A series of experiments were conducted on glass fibre reinforcements of different architecture to determine and quantify in order of importance, different components of compression deformation. Permanent deformation was found to occur in all cases, and is comparable in magnitude to the elastic deformation of the reinforcement. Permanent deformation of the reinforcement considerably increased after just a few cycles of repeated compression and release. Time-dependent recovery of deformation on release of the compaction strain was found to largely depend on the number of layers of material in Continuous Filament Random Mat and Plain Weave Fabric reinforcements, it being of significant magnitude only with Plain Weave Fabric. A five component Maxwell-based model was developed to help explain and predict stress relaxation in the reinforcements under constant compressive strain. II III X-ray micro-computed tomography (micro-CT) scanning and imaging technology was utilised to investigate fibre reinforcement deformation in manufactured composite laminates. It was hypothesised that permanent deformation in Biaxial Stitched Fabric and Plain Weave Fabric reinforcements occurs by means of changes to fibre bundle cross-sections, while time-dependent recovery of deformation on release of the compaction strain is related to the undulations of fibre bundles in the direction of loading, and also to the tow crimp in the case of Plain Weave Fabric reinforcements. Analysis of the micro-CT images proved correct the hypothesis in the case of Continuous Filament Random Mat, while there was support for Plain Weave Fabric. It was also proposed that permanent deformation in Continuous Filament Random Mat reinforcements is via filament bending and displacement, while time-dependent recovery of deformation is based on filament – filament interactions. In this case CT scanning images provide some support towards understanding filament spread but more information is needed to conclusively prove the hypothesis.
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Ajayi, Olufemi. « The effect of fibre reinforcements on the mechanical behaviour of railway ballast ». Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/372762/.
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Ballast is a primary component of the railway track and it has several functions including the ability to resist vertical, lateral and longitudinal forces applied to the sleepers from the train wheels. In response to the stresses induced during a train passage, ballast typically experiences plastic settlement which can reach unacceptable magnitudes. Thus, ballast is the focus of the majority of maintenance and renewal activities. In response to the growing need for resilient track materials (including ballast) to cope with increasing train speed, load and frequency, means of optimizing its performance and minimizing maintenance requirements are required. Ballast improvement techniques, such as the use of geogrids, have attracted a great deal of attention in terms of research, but huge potential for reducing costs through ballast improvement still exist. It has been shown from previous research that the use of randomly oriented fibres in sands can significantly improve their strength. This technique might be used to improve ballast strength and reduce track geometry deterioration. In addition, fibre reinforcements in ballast can potentially provide a new method of reinforcing ballast whilst maintaining the capability of withstanding typical tamping operations which are incompatible with geogrids. However, there is a lack of rigorous scientific understanding of the effects of fibre reinforcements on relatively large aggregates such as railway ballast. This research examines the effect of random fibre inclusions on the packing structure of granular materials (coarse sand and scaled ballast) and describes the physical implications associated with the observed changes. The mechanical properties of fibre reinforced granular materials across different particle sizes and a hypothesis of fibre/particle reinforcement suitable for relatively large particles are presented. An image-based deformation measurement technique has also been used to investigate the effects of fibre reinforcements on the local deformation of triaxial specimens to corroborate the observed mechanical behaviour of the reinforced specimens. Finally, the mechanical behaviour of a fibre reinforced ballast layer below a cyclically loaded railway sleeper was investigated using a full scale laboratory tests.
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D'Agostino, Marco Valerio. « Generalized continua and applications to finite deformations of quasi-inextensible fiber reinforcements ». Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0061/document.
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La microstructure des matériaux constitue un outil essentiel pour optimiser les propriétés mécaniques des structures et ainsi améliorer leurs performances. Les modèles de Cauchy ne sont pas toujours adaptés à la description de la réponse dynamique de certains matériaux microstructurés montrant des comportements mécaniques exotiques. Les théories de milieux continus généralisés peuvent être de bonnes candidates pour modéliser ces matériaux d’une façon plus précise et plus réaliste, aussi bien en statique qu’en dynamique, puisqu’elles peuvent décrire, même d’une façon simplifiée, la manifestation macroscopique de la présence d’une microstructure. Ce manuscrit est organisé comme suit : - Dans le chapitre 1 nous introduisons les aspects généraux de la mécanique des renforts fibreux.- Dans le chapitre 2 nous rappelons certains concepts fondamentaux concernant la mécanique des milieux continus classiques. De plus, nous introduisons les théories de deuxième gradient à l’aide du Principe des Travaux Virtuels.- Dans le chapitre 3 nous nous proposons de présenter une première modélisation des renforts fibreux de composites en mettant en place des modèles numériques discrets. Cette modélisation discrète permet de rendre compte de certains effets de la microstructure des renforts fibreux sur leur comportement macroscopique global. En particulier, il sera montré que la flexion locale des mèches à l’échelle mesoscopique a un effet non-négligeable sur le comportement macroscopique global de ces matériaux. Dans un deuxième moment nous introduisons une modélisation continue de deuxième gradient pour la description des mêmes matériaux et nous montrons que les termes d’ordre supérieur permettent une description satisfaisante des effets de flexion locale sur-cités.- Dans le chapitre 4 on particularise le cadre général de la mécanique des milieux continus introduit dans le chapitre 2 au cas particulier des milieux continus 2D. On mettra un accent fort sur l’interprétation géométrique des mesures de déformation de deuxième gradient qui seront directement reliées aux courbures dans le plan de certaines lignes matérielles. Ces lignes matérielles seront ensuite interprétées dans les chapitres suivantes comme décrivant les mèches des renforts fibreux de composites qu’on se propose d’étudier.- Dans le chapitre 5 nous introduisons une hypothèse cinématique forte sur les déformations admissibles, en supposant que les mèches du renfort considéré sont inextensibles. Cette hypothèse nous permettra de construire un modèle simplifié de premier gradient pour le comportement des renforts de composites 2D qui est encore représentatif de leur comportement mécanique. Une méthode numérique permettant de montrer certaines solutions concernant le cas du bias extension test est codée en Mathematica et les résultats obtenus sont discutésDered materials in the simplest and more effective way. However, there are some cases in which the considered materials are heterogeneous even at relatively large scales and, as a consequence, the effect of microstructure on the overall mechanical behavior of the medium cannot be neglected. In such situations, Cauchy continuum theory may not be useful to fully describe the mechanical behavior of considered materials. It is in fact well known that such continuum theory is not able to catch significant phenomena related to concentrations of stress and strain and to specific deformation patterns in which high gradients of deformation occur and which are, in turn, connected to particular phenomena which take place at lower scales. Generalized continuum theories may be good candidates to model such micro-structured materials in a more appropriate way since they are able to account for the description of the macroscopic manifestation of the presence of microstructure in a rather simplified way. The present manuscript is organized as follows: In ch.1 a general description of fibrous composite reinforcements is given. In ch.2 some fundamental issues concerning classical continuum mechanical models are recalled. In ch.3 we start analyzing some discrete and continuum models for the description of the mechanical behavior of 2D woven composites. At this stage of the manuscript, we want to show how some discrete numerical simulations allowed us to unveil some very special deformation modes related to the effect of the local bending of fibers on the overall macroscopic deformation of fibrous composite reinforcements. Such discrete simulations showed rather clearly that microscopic bending of the fibers cannot be neglected when considering the deformation of fibrous composite reinforcements. For this reason, we subsequently introduced a continuum model which is able to account for such microstructure-related effects by means of second gradient terms appearing in the strain energy density. In ch.4 we reduce the general continuum mechanical framework introduced in ch.2 to the particular case of 2D continua. In ch.5 we introduce a strong kinematical hypothesis on the admissible deformations, assuming that the yarns composing the woven reinforcements are inextensible
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Rajpurohit, Ashok. « Development of advanced carbon/glass fibre based hybrid composites ». Thesis, Université Paris sciences et lettres, 2020. http://www.theses.fr/2020UPSLM020.
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Les composites hybrides offrent un moyen efficace d'améliorer les propriétés mécaniques des matériaux composites. Cette thèse vise à comprendre le comportement mécanique et l'effet synergique offerts par de tels composites hybrides sous plusieurs conditions de chargement. L'accent est mis, non seulement sur la caractérisation mécanique, mais également sur le développement et l'optimisation de nouvelles générations de renforts hybrides, permettant ainsi une hybridation aussi bien au niveau des nappes, qu’au niveau des mèches et des fibres. Dans ce travail, les fibres de carbone et de verre sont choisies comme les deux types de renforts pour les composites hybrides. Les propriétés de ces fibres unitaires sont d'abord caractérisées pour étudier l'impact des procédés textiles. De nouveaux renforts unidirectionnels ont été fabriqués après avoir optimisé les procédés, tels que la technologie UD cousu et l'étalement des fibres. Les composites ont été fabriqués via RTM basse pression en utilisant une résine époxy. Les caractéristiques en raideur et en résistance des composites de référence, des hybrides inter-plis, intra-plis et fibre à fibre ont ensuite été caractérisées dans des conditions de charge quasi-statique en traction, compression et flexion. L'effet d’hybridation (synergique) a été évalué pour ces composites en comparant les propriétés du composite hybride avec un composite de référence en carbone. Afin de comprendre le comportement à rupture de ces composites dans différentes conditions de charge, une étude de fractographie a été réalisée. Les hybrides inter-plis font apparaître une légère augmentation de la déformation à rupture en traction mais présentent une synergie négative pour toutes les autres conditions. Les hybrides intra-plis montrent eux, un effet synergique pour les résistances à la traction et à la compression, sans réduire leur déformation à rupture. Un composite hybride fibre à fibre réalisé par étalement montre une performance mécanique supérieure par rapport à d'autres hybrides. Les résultats présentés révèlent les avantages potentiels de l'hybridation à différents niveaux et dispersions. Les résultats ouvrent une voie pour les futurs travaux sur les composites hybrides et leurs procédésHybrid composites offer an effective way of enhancing mechanical properties of composite materials. This thesis aims to understand the mechanical behaviour and synergistic effect offered by such hybrid composites in several loading conditions. The focus not only lies on mechanical characterisation but also on development and optimization of new generation of hybrid reinforcements thus allowing hybridization both at ply levels and at tow and fibre levels. In this work, carbon and glass fibres are chosen as the two types of reinforcements for hybrid composites. Single fibre properties of these fibres were first characterised to study the effect of textile processes. Novel unidirectional reinforcements have been fabricated after optimising the processes such as unidirectional stitching and spreading technology. Composites were manufactured via low pressure RTM process using an epoxy resin. Stiffness and failure characteristics of reference, interply, intraply and intermingled hybrid composites were then characterised in quasi-static tensile, compression and flexural loading conditions. The hybrid (synergistic) effect were evaluated for these composites by comparing the hybrid composite properties with a carbon reference composite. To understand the failure behaviour under different loading conditions, a fractography study was conducted. Interply hybrids slightly increase the failure strain in tension but demonstrate negative synergy in all other properties. On the other hand, intraply hybrids show a synergistic effect in both tensile and compressive strengths, while not reducing the failure strain. A spread tape intermingled hybrid composite demonstrates a superior mechanical performance when compared to other hybrids. The presented results reveal the potential benefits of hybridisation at different levels and dispersions. The results provide a driving force for future work on hybrid composites and their processing
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Bassoumi, Amal. « Analyse et modélisation du choix des renforts pour optimiser la mise en forme de matériaux composites à base de fibres végétales ». Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2053.
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Cette thèse s’inscrit à mi-chemin entre l’étude de la déformabilité des structures tissées et la valorisation de la fibre de lin pour des applications dans le renforcement des matériaux composites. Le premier objectif de l’étude est de caractériser expérimentalement le comportement en flexion des mèches de différentes structures constituées de fibres de lin ainsi que des tissus de différentes armures. Les travaux ont abordé aussi des paramètres tels que l’humidité relative et la composition (des mèches comélées ou en lin pure). Le deuxième objectif des travaux est d’étudier le comportement en flexion des tissus en fonction du comportement en flexion des mèches. Cette partie a commencé par la modélisation géométrique des renforts tissés dans le but de suivre l’évolution de la section du tissu qui varie dans la direction de la flexion. La modélisation mésoscopique a permis de calculer analytiquement les propriétés géométriques du tissu en particulier son moment quadratique. Les résultats obtenus ont été utilisés dans la simulation de la flexion du tissu. L’étude a permis de voir jusqu’à quel point le comportement de la mèche et le moment quadratique du tissu pilotent le comportement en flexion du tissu. D’après ces travaux, le comportement en flexion du tissu semble être approché de façon satisfaisante sur toute la gamme de longueurs envisagées à partir de ces deux grandeurs sauf pour les forts taux d’humidité où d’autres phénomènes doivent être considérés. L’étude a souligné que la différence entre deux renforts testés expérimentalement peut être anticipée numériquement. Ainsi, le concepteur de tissus sera capable d’anticiper la rigidité expérimentale du tissu pour faire des tissages adaptés à la mise en forme du renfort. Une étude paramétrique de la flexion a été également réalisée dans le but de déduire les paramètres les plus influents sur lesquels il peut jouerThis thesis is halfway between the study of the deformability of woven structures and the use of flax fibre as reinforcement of composite materials. The first aim of the study is the experimental characterization of the bending behaviour of tows with different structures made of flax fibres and fabrics with different weaves. Parameters such as relative humidity and the composition (100% flax and commingled tows) were also considered. The second aim of the study is to link the bending behaviour of the fabric to the bending behaviour of its constituent tows. This part starts with the geometric modelling of woven fabrics in order to follow the variation of its section in the bending direction. Mesoscopic modelling allows the analytical calculation of the geometric properties of the fabric in particular its moment of inertia. The results obtained were used in the simulation of the fabrics bending to see how far the behaviour depends on the tows bending behaviour and the moment of inertia. The bending behaviour of the fabric seems to be approached satisfactorily from these two factors. This is verified within the range of lengths considered except for high humidity (in this case, other phenomena must be considered). The study pointed out that the difference between two reinforcements tested experimentally can be predicted numerically. Thus, the fabrics designer will be able to anticipate the experimental bending stiffness of the fabric in order to adapt the weaving to the shape forming. A parametric study of the bending was also achieved in order to deduce the most influential parameters of the fabric for an appropriate weaving
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Huang, Jin. « Simulation du drapage des renforts de composites multicouches liés par piquage ». Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI098.
Texte intégralRésumé :
De nos jours, les matériaux composites permettent de diminuer la masse des pièces et sont largement utilisés dans le domaine de l'aérospatial, de l'aéronautique et de l'automobile. De plus, les composites multicouches à renfort textiles permettent de la conception des structures épaisses telles que les aubes de la soufflante des réacteurs d'avion. Cependant, de nombreux défauts peuvent apparaître pendant le processus de mise en forme des renforts multicouches, comme des plissements. Des recherches sur la formation de plis, ainsi que sur la technique de piquage pour améliorer la propriété mécanique des renforts multicouches dans l'épaisseur sont présentées dans ce travail. La première partie de ce présent rapport consiste à étudier la formation de plis des renforts multicouches soumis à la flexion hors plan. Dans un premier temps, l'influence des différentes orientations des couches sur la formation de plis est explorée. La relation entre le chargement appliqué sur le tissu et la création de plissements est ainsi montrée. Le second chapitre consiste à comparer l'influence de deux types de tissage pour ce qui concerne la drapabilité du composite. La troisième partie propose deux modèles numériques adaptés pour simuler le drapage des renforts composites liés par piquage. Ces approches impliquent l'utilisation d'un élément fini de coque de type stress resultant pour représenter chaque couche de renfort et des éléments de barre pour représenter le fil de piquage. Ces modèles nécessitent un algorithme de contact propre pour gérer l'interaction entre le renfort et le fil de piquage. Enfin, la dernière partie consiste à valider les modèles par une comparaison entre les simulations et les essais expérimentauxNowadays, composite materials make it possible to reduce the mass of parts and are widely used in the aerospace, aeronautics and automotive industries. In addition, the multilayered reinforcement of composites allows the design of thick structures such as the fan blades of aircraft engines. However, many defects can occur during the forming process of multilayered reinforcements, such as the wrinkling problem. Research on the formation of wrinkles, as well as on the tufting technology to improve the mechanical property of multilayered reinforcements in the direction of thickness are presented in this work. The first part of this report is a study of the formation of the wrinkles of multilayered reinforcements subjected to out-of-plane bending. Firstly, the influence of the different orientations of the layers on the formation of wrinkles is explored. The relationship between the load applied to the fabric and the creation of wrinkles is thus shown. The second chapter compares two types of weaving pattern on the drapability of the composite. The third part consists of developing two numerical models adapted to simulate the forming of tuft-bonded composite reinforcements. These approaches involve the use of a stress resultant shell element to represent each layer of reinforcement and bar elements to represent the tufting yarn. These models require a specific contact algorithm to manage the interaction between the reinforcement and the tufting yarn. Finally, the last part consists of validating the models by comparing simulations and experiments
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Yang, Haomiao. « Study of a unidirectional flax reinforcement for biobased composite ». Thesis, Normandie, 2017. http://www.theses.fr/2017NORMC226/document.
Texte intégralRésumé :
Dans cette thèse, un composite unidirectionnel à renfort lin (composite UD biosourcé) a été développé et élaboré par la technique de presse à chaud. Le comportement en traction des composites à renfort végétal montre en général deux domaines, mais un troisième domaine est identifié dans ce travail. Un modèle phénoménologique développé précédemment pour décrire le comportement en traction d'un composite à renfort en fils torsadés a été testé avec le composite UD biosourcé. Nous montrons que l'ajout d'un phénomène de consolidation au modèle précédent est nécessaire pour simuler correctement le troisième domaine. Un second modèle mécanique a été par ailleurs développé pour identifier expérimentalement les propriétés mécaniques effectives du renfort en lin lorsqu'il est piégé dans la matrice. La distribution statistique de l'orientation locale du renfort a été mesurée pour pouvoir prendre en compte l'orientation des fibres. Pour cela, la technique du tenseur de structure a été appliquée sur des images optiques du pli de lin. Par ailleurs, ce modèle permet d'étudier l'influence des porosités sur les propriétés mécaniques. Les deux modèles permettent d'effectuer des prévisions efficaces du comportement mécanique du composite de fibre de lin unidirectionnel. En complément des modèles de mécanique, le comportement en sorption du composite de lin UD a également été analysé. Le modèle de Langmuir et le modèle de Fick ont été appliqués sur nos composites UD. Les résultats montrent que la configuration unidirectionnelle du renfort de lin favorise la sorption d'eau des composites associés.Résumé en anglaisIn this Ph.D work, unidirectional flax fiber composite (UD biobased composite) has been designed and manufactured based on the hot platen press process. Plant fiber composites usually exhibit two regions under tensile load, but three regions have been identified in this work. A phenomenological model, previously developed to describe the tensile mechanical behavior of twisted plant yarn composites, has been tested with the UD biobased composite. We show that the addition of a strengthening phenomenon to the previous model is necessary to simulate correctly the third region. A second mechanical model has also been developed for experimental identification of the effective mechanical properties of flax reinforcement when embeded in matrix. A statistical distribution of local orientation of UD reinforcement was obtained allowing taking the fiber orientation into account. To that end, structure tensor method was applied to optical images of flax ply. Furthermore, this model allows the effect of porosity on mechanical properties to be studied. Both models provide effective forecast of the mechanical behavior of unidirectional flax fiber composite. Besides the mechanic models, sorption behavior of UD flax composite also has been analyzed. Langmuir's model and Fick's model were applied on our UD composite. The results show that the unidirectional configuration of the flax reinforcement promotes the water sorption from the associated composites
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Goh, Kheng Lim. « Fibre reinforcement in fibre composite materials : effect of fibre shape ». Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395069.
Texte intégralRésumé :
The aim of this project was to investigate the effects of fibre shape on its ability to reinforce a fibre composite material. Analytical and finite element (FE) models of an axisymmetric fibre composite material were developed and used to achieve this aim. Fibres of cylindrical shape, ellipsoidal shape, with paraboloidal ends and with conical ends were considered: fibre geometry was further characterised by an axial ratio, q. The scope of this study covered elastic and plastic load transfer processes. The former corresponds to the initial loading stage whereby an applied tensile stress acting on a fibre composite causes stress in an elastic matrix to be transferred to an elastic fibre which is embedded in and adheres to the matrix. The latter corresponds to the next stage when, on progressive increase of the applied stress, the matrix yields and turns plastic and failure of adhesion at the fibre-matrix interface occurs. Two approaches were used to develop analytical models. In the first approach, equations were derived for calculating stress and displacement distributions in a general axisymmetric body. This approach was based on a stress function method for structural analysis of a statically indeterminate problem. The equations derived were implemented to model a fibre composite undergoing elastic load transfer by prescribing appropriate boundary conditions. However, the approach led to no useful solutions. In the second approach, first-order ordinary differential equations for solving axial, σz, and surface radial, σr, stresses in a fibre were formulated by considering forces at equilibrium in a stress element in a fibre subjected to a fibre-matrix interfacial stress. Equations for calculating these stresses to study plastic load transfer were derived from the differential equations by prescribing appropriate boundary conditions, σz was assumed to be constant in the radical direction of the fibre. For a cylindrical fibre, σz increases linearly, from zero at the ends, to a maximum value at the centre. At the other extreme, σz in a conical fibre was shown to be constant. The intermediate cases of a paraboloidal and an ellipsoidal fibre showed distribution of σz lying between these two extremes. The effectiveness of a fibre shape for reinforcement was defined for the plastic study. It was found that the conical fibre possessed the highest value; the cylindrical fibre gave the lowest value. From this study, it was concluded that: (1) an important property of all the tapers considered is to make the distribution of σz in a fibre more uniform; (2) fibres with conical ends are more effective for reinforcing fibre composite materials than cylindrical fibres.
Livres sur le sujet "Fibre reinforcements"
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R, Bunsell A., dir. Fibre reinforcements for composite materials. Amsterdam : Elsevier, 1988.
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Concretes with dispersed reinforcement. Rotterdam : A.A. Balkema, 1995.
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Frederick, Young John, et Construction Engineering Research Laboratory, dir. Synthetic fiber reinforcement for concrete. Champaign, Ill : US Army Corps of Engineers, Construction Engineering Research Laboratory, 1992.
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H, Rizkalla S., Nanni Antonio et American Concrete Institute, dir. Field applications of FRP reinforcement : Case studies. Farmington Hills, Mich : American Concrete Institute, 2003.
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Ballast, David Kent. Glass fiber reinforcement in building materials. Monticello, Ill., USA : Vance Bibliographies, 1988.
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Plastic matrix composites with continuous fiber reinforcement. [Washington, D.C.?] : U.S. Dept. of Defense, 1991.
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Pal, Pranab Kumar. Investigation of jute fibre as a reinforcement for plastics. Uxbridge : Brunel University, 1989.
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W, Jong B., dir. Fiber reinforcement of sulfur concrete to enhance flexural properties. Avondale, Md : U.S. Dept. of the Interior, Bureau of Mines, 1985.
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K, Dutta Piyush, et Construction Engineering Research Laboratories (U.S.), dir. Composite grids for reinforcement of concrete structures. [Champaign, IL] : US Army Corps of Engineers, Construction Engineering Research Laboratories, 1998.
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Antonio, Nanni, dir. Fiber-reinforced-plastic (FRP) reinforcement for concrete structures : Properties and applications. Amsterdam : Elsevier, 1993.
Trouver le texte intégralChapitres de livres sur le sujet "Fibre reinforcements"
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Starr, Trevor F. « Reinforcements for Thermosets ». Dans Glass-Fibre Databook, 67–148. Dordrecht : Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1492-9_5.
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Starr, Trevor F. « Reinforcements for Thermoplastics ». Dans Glass-Fibre Databook, 149–62. Dordrecht : Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1492-9_6.
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Starr, Trevor F. « Reinforcements for Cement & ; Gypsum ». Dans Glass-Fibre Databook, 163–65. Dordrecht : Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-1492-9_7.
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Umer, R., S. Bickerton et Alan Fernyhough. « Modelling Liquid Composite Moulding Processes Employing Wood Fibre Mat Reinforcements ». Dans Advances in Composite Materials and Structures, 113–16. Stafa : Trans Tech Publications Ltd., 2007. http://dx.doi.org/10.4028/0-87849-427-8.113.
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Feng, Chunxiang, et Zengyong Chu. « Fiber Reinforcement ». Dans Composite Materials Engineering, Volume 1, 63–150. Singapore : Springer Singapore, 2017. http://dx.doi.org/10.1007/978-981-10-5696-3_2.
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Gooch, Jan W. « Ceramic Fiber Reinforcements ». Dans Encyclopedic Dictionary of Polymers, 131. New York, NY : Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_2161.
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Gooch, Jan W. « Glass-Fiber Reinforcement ». Dans Encyclopedic Dictionary of Polymers, 341. New York, NY : Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-6247-8_5509.
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Fitzer, E., et Lalit M. Manocha. « Carbon Fiber Architecture ». Dans Carbon Reinforcements and Carbon/Carbon Composites, 82–96. Berlin, Heidelberg : Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-642-58745-0_3.
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El Messiry, Magdi. « Natural Fiber Reinforcement Design ». Dans Natural Fiber Textile Composite Engineering, 79–123. Toronto : Apple Academic Press, 2017. : Apple Academic Press, 2017. http://dx.doi.org/10.1201/9781315207513-3.
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Elseify, Lobna A., Mohamad Midani, Ayman El-Badawy et Mohammad Jawaid. « Natural Fiber Reinforcement Preparation ». Dans Manufacturing Automotive Components from Sustainable Natural Fiber Composites, 11–22. Cham : Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-83025-0_2.
Texte intégralActes de conférences sur le sujet "Fibre reinforcements"
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Ciambella, Jacopo, et David C. Stanier. « Orientation Effects in Short Fibre-Reinforced Elastomers ». Dans ASME 2014 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/imece2014-40430.
Texte intégralRésumé :
The large strain behaviour of a short fibre-reinforced composite is studied through numerical simulations. The reinforcing fibres yield the macroscopic response transversely isotropic which is indeed the case of many reinforcements currently used in composites: short carbon fibres, cellulose whiskers, carbon nanotubes. As a result of the analysis, it is shown that the reorientation of the fibres that takes place at large strain has a significant effect on the overall material response by changing the axis of isotropy. This behaviour can be adequately described by using a transversely isotropic model whose strain energy function depends on three invariants: two isotropic and one representing the stretch along the direction of the fibres. To assess its capabilities, the model is compared to the results of experiments carried out by the authors on nickel-coated chopped carbon fibres in a vulcanised natural rubber matrix for which the fibre orientation is achieved by controlling an external magnetic field prior to curing. Possible applications include micro-sized propulsion devices and actuators.
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Miura, Masaya, Horibe Yasumasa, Ishii Michiharu, Kanji Takaoka, Shintaro Kitakata et Atsushi Mikuni. « Development of Lightweight Thin-Walled Aluminum Bumper Reinforcement Adhered with Unidirectional CFRP Sheet ». Dans FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-mml-016.
Texte intégralRésumé :
"Since bumper reinforcements are positioned at front/rear ends of vehicles, weight reduction of the bumper reinforcements improves vehicle dynamic performance by reducing a yaw moment of inertia. CFRP (Carbon Fibre Reinforced Plastic) composites are attractive lightweight materials due to their excellent specific strength and rigidity. However, because of their relatively high cost, applications of CFRP materials to vehicle structural parts are limited. In this study, we developed a lightweight structural part which consists of a thin-walled Aluminum bumper reinforcement with a unidirectional CFRP sheet, in order not to increase part cost by reducing amount of Aluminum and by using only a little amount of CFRP. Compared to Aluminum, unidirectional CFRP sheets have even higher tensile strength and modulus. When vehicles crush, bumper reinforcements may be subjected to bending force. If a unidirectional CFRP sheet adhered on a tensile side of an Aluminum bumper reinforcement, not only Aluminum thickness on the tensile side but also thickness on the compression side can be reduced due to movement of a bending neutral axis. Bending strength of the developed parts can’t be predicted by a full plastic moment which could be used to predict metal parts’ bending strength because CFRP don’t deform plastically. In this study, based on Bernoulli-Euler theory, the bending neutral axis was decided considering elastic/plastic areas of the Aluminum bumper reinforcement, and bending strength of the part was predicted. To valid the calculation method, three-point bending tests on the parts were carried out. Experimental data of bending strength were in the range of predicted bounds. In addition, after the peak load, the load decreased gradually, like conventional all metal bumper reinforcements, without delamination of the unidirectional CFRP sheet. In order to launch the developed part, robustness of part’s performance was also evaluated. Finally, the part was adapted to a rear bumper reinforcement of LEXUS RC-F. The part weight is 11 % lighter compared to a conventional all Aluminum bumper reinforcement."
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Alemán, D. N. Castellanos, M. McCourt, M. P. Kearns, P. J. Martin et J. Butterfield. « The development of thermoplastic fibre based reinforcements for the rotational moulding process ». Dans PROCEEDINGS OF THE 21ST INTERNATIONAL ESAFORM CONFERENCE ON MATERIAL FORMING : ESAFORM 2018. Author(s), 2018. http://dx.doi.org/10.1063/1.5034970.
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Wielage, B., K. Fleisher et G. Zimmerman. « Investigations on Thermal Sprayed Carbon-Short-Fiber-Reinforced Aluminum Composites ». Dans ITSC 1996, sous la direction de C. C. Berndt. ASM International, 1996. http://dx.doi.org/10.31399/asm.cp.itsc1996p0349.
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Abstract Composite coatings are increasingly applied for the protection against wear in mechanical constructions. Especially, in the case of abrasion these coatings offer the possibility to protect the base material. The matrix is ductile and the reinforcements cause the higher strength and hardness. A research project presented in this paper dealt with the manufacture of carbon-short-fibre-reinforced aluminum composite coatings by vacuum plasma spraying. The basis of the processing is the agglomeration of aluminum powder and carbon fibres. During the spraying process the aluminum melts, covers the fibres, and so, contributes to the creation of the composite coating and/or the composites. The processing times are so short that the damaging formation of carbides can be suppressed mostly. For the creation of free standing bodies it is necessary to find a qualified core material which allows the removing of the sprayed composites. The investigations on the composites are focused on the metallographical judgement regarding the fibre and void content, the fibre distribution, the characterization of the interface as well as the determination of mechanical properties and the wear resistance.
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Salekrostam, Rasool, et Francois Robitaille. « Effect Of The Interlacing Pattern On The Compaction Behaviour Of 3D Carbon Fibre Textile Reinforcements ». Dans Canadian Society for Mechanical Engineering (CSME) International Congress 2018. York University Libraries, 2018. http://dx.doi.org/10.25071/10315/35421.
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Harhash, M. « Warm forming of thermoplastic fibre metal laminates ». Dans Sheet Metal 2023. Materials Research Forum LLC, 2023. http://dx.doi.org/10.21741/9781644902417-54.
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Abstract. In this paper, the forming behaviour of sheet-like metal/polymer/metal (MPM) and thermoplastic fibre metal laminates (TFMLs) is introduced. TFMLs are based on thin metallic cover sheets and fibre-reinforced thermoplastic matrix (here polyamide 6). With this material combination, the specific mechanical, structural, thermal and acoustic properties can be improved and designed compared to the monomaterials and laminates without fibre reinforcements. However, the restricted formability of TFMLs at room temperature is a strong limitation. Therefore, the approach of this study is concerned with the fundamental description of the influence of warm forming on the degree of the forming improvement of pre-bonded TFMLs sheets experimentally via the investigation of the deep drawability and determining the forming limit curves compared to the formability of steel and MPM sheets. Two elevated test temperatures (200 and 235 °C) besides the room temperature are considered. The results of this approach revealed that warm forming could lead to over 300 % improvement of the forming limit curve (FLC) level of TFML; however, an ignorable difference between 200 and 235 °C is found. For steel and MPM sheets, increasing the temperature showed a slight improvement. Regarding deep drawing, similar results like for FLC were found, where the drawing depth of TFML could be increased from approx. 15 mm up to at least 40 mm before cracking. However, other failure types arose like wrinkling and core squeezing-out. Therefore, a one-step deep drawing approach for TFMLs is foreseen, where the adhesion and forming processes take place simultaneously.
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Potluri, P., V. S. Thammandra et R. B. Ramgulam. « Modelling Tow Compression in Textile Preforms During Composites Processing ». Dans ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61470.
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Fiber assemblies, in the form of woven, braided, nonwoven or knitted structures, are used as reinforcements in composites. These textile structures are subjected to in-plane membrane stresses such as tensile and shear, and out-of-plane stresses such as bending and transverse compression. Amongst various modes of deformation, transverse compaction behaviour is the least understood mode; however this mode is very important for composites processing using vacuum forming, resin transfer moulding, thermoforming and hot compaction methods. The present paper reports a computational approach to predicting the load-deformation behaviour of textile structures under compressive loading. During the compression of a random fiber assembly, fibers are subjected to kinematic displacements, bending and finally transverse compression of individual fibres. In the case of interlaced architectures, such as woven and braided structures, it is convenient to deal with deformations at meso-scale involving yarns or tows, and deal with inter-fiber friction and fibre compression at yarn/tow level. It can be seen from the load deformation graphs that the initial part is dominated by bending energy and the final part by compression energy. A combined yarn bending and compression model was in good agreement with the experimental curve during the entire load-deformation cycle. On the other hand, an elastica-based bending model predicts well during the initial part while tow compression model predicts well during the final part. Inter-fiber friction was initially ignored — this is being introduced in the refined model for both the dry and wet states.
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Wang, Y., S. M. Grove et M. Moatamedi. « Modelling Tow Impregnation of Woven Fabric Reinforcements and Its Application in Liquid Composite Moulding Process Modelling ». Dans ASME 2008 Pressure Vessels and Piping Conference. ASMEDC, 2008. http://dx.doi.org/10.1115/pvp2008-61832.
Texte intégralRésumé :
This paper proposes a detail physical model for the micro-scale flow in plain woven reinforcements. The modelling results are formulated into a mathematical algorithm which is then directly incorporated into a continuum dual-scale model as a ‘sink’ term. When used to model liquid composite moulding (LCM) processes, this incorporated dual-scale model demonstrates the fact that the impregnation of fibre tows lags behind the resin front in macro pore spaces. The modelling results are in agreement with the experimental observations. It has been shown that the unsaturated region at the flow front could increase or have a fixed length under different circumstances. These differences are explained due to the variation in tow impregnation speed (or the time required for the tow to become fully impregnated) which is related to the weave infrastructure and the nesting and packing of plies. The modelling results have also demonstrated the drooping of the inlet pressure when the flow processes are carried out under constant injection rates.
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Wagner, David, Daniel Mainz, Thomas Gerhards et Xiaoming Chen. « Carbon Fiber Composite Chassis Components, Opportunities and Challenges ». Dans FISITA World Congress 2021. FISITA, 2021. http://dx.doi.org/10.46720/f2020-mml-059.
Texte intégralRésumé :
Using lightweight components to reduce vehicle mass is one of the tactics available to vehicle manufacturers to reduce CO2 emissions. Carbon fibre reinforced polymer composite with its high strength to density ratio is one of the potential materials to reduce component mass. The lessons learned from three research and development projects on automotive chassis structural components designed, manufactured and tested using carbon fibre composites provides insights into the opportunities for mass reduction and the cost, manufacturing and analysis challenges that combine to limit the applicability of carbon fibre composites in high volume automotive use. Projects investigated three structural cassis components, the Focus rear suspension tie blade knuckle, the F-150 front suspension lower control arm, and the Fusion (Mondeo) front subframe. All the projects developed, analysed, manufactured and tested carbon fibre composite replacement components that fit the package and met equivalent performance requirements to the production parts. Then the designs and manufacturing plans informed the cost estimates for these components at high automotive volumes. The tie blade knuckle chose thermoplastic resin while the front lower control arm and subframe investigated thermoset resin carbon fibre composites. Carbon fibre reinforced polymer composites offer the opportunity of approximately a 30% mass reduction compared to a steel component. This mass savings is less than anticipated. Due to the high constituent material costs of both the carbon fibre and the high performance resin, the complex manufacturing processes, and the final assembly processes the resultant "weight buy" exceeds an additional $35 USD of variable cost per kilogram of mass saved compared to the production steel component. All three of the components investigated require multi material solutions that include both random chopped and oriented continuous carbon fibre composites plus steel reinforcements at high point load areas such as the bolted connections. Also, the predictive CAE tools are not yet fully mature for carbon fibre composites leading to lower confidence initial designs.
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Renner, Axel, Wolf-Joachim Fischer et Uwe Marschner. « A New Imaging Approach to In Situ and Ex-Situ Inspections of Fibre Reinforced Composites by Magnetic Induction Tomography (MIT) ». Dans ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/smasis2012-8231.
Texte intégralRésumé :
Fiber reinforced composites (FRP) for industrial applications face constantly increasing demands regarding efficiency, reliability and economy. Furthermore, it was shown that FRP’s with tailored reinforcements are superior to metallic or monolithic materials. However, a trustworthy description of load-specific failure behaviour and damage evolution of composite structures can hardly be given, because these processes are very complex and are still not entirely understood. Amongst other things, several research groups have shown that material damages like fiber fracture, delamination, matrix cracking or flaws can be discovered by analyzing the electrical properties of conducting composites, e.g. carbon fiber reinforced plastics (CFRP). Furthermore, it was shown that this method could be used for structural health monitoring or non-destructive testing (NDT) [8–12].Within this work, Magnetic Induction Tomography (MIT), which is a new imaging approach, is introduced into the topic of NDT of CFRP’s. This non-contacting imaging method gains the inner spatial distribution of conductivity of a specimen and depicts material inhomogeneity, like damages, in 2D or 3D images. Numerical and experimental investigations are presented and give a first impression of the performance of this technique. It is demonstrated that MIT is a promising approach for NDT and could be used for fabrication quality control of conductive FRP’s and could potentially be used as a health monitoring system using an integrated setup.
Rapports d'organisations sur le sujet "Fibre reinforcements"
1
Vande Kieft, L. J., et W. W. Hillstrom. Fiber Reinforcement of Gun Propellant. Fort Belvoir, VA : Defense Technical Information Center, février 1985. http://dx.doi.org/10.21236/ada152296.
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Ragalwar, Ketan, William Heard, Brett Williams, Dhanendra Kumar et Ravi Ranade. On enhancing the mechanical behavior of ultra-high performance concrete through multi-scale fiber reinforcement. Engineer Research and Development Center (U.S.), septembre 2021. http://dx.doi.org/10.21079/11681/41940.
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Steel fibers are typically used in ultra-high performance concretes (UHPC) to impart flexural ductility and increase fracture toughness. However, the mechanical properties of the steel fibers are underutilized in UHPC, as evidenced by the fact that most of the steel fibers pull out of a UHPC matrix largely undamaged during tensile or flexural tests. This research aims to improve the bond between steel fibers and a UHPC matrix by using steel wool. The underlying mechanism for fiber-matrix bond improvement is the reinforcement of the matrix tunnel, surrounding the steel fibers, by steel wool. Single fiber pullout tests were performed to quantify the effect of steel wool content in UHPC on the fiber-matrix bond. Microscopic observations of pulled-out fibers were used to investigate the fiber-matrix interface. Compared to the control UHPC mixture with no steel wool, significant improvement in the flexural behavior was observed in the UHPC mixtures with steel wool. Thus, the addition of steel wool in steel fiber-reinforced UHPC provides multi-scale reinforcement that leads to significant improvement in fiber-matrix bond and mechanical properties of UHPC.
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Starr, T. L., D. L. Mohr, W. J. Lackey et J. A. Hanigofsky. Development of silicon nitride composites with continuous fiber reinforcement. Office of Scientific and Technical Information (OSTI), octobre 1993. http://dx.doi.org/10.2172/10192173.
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Tingle, Jeb S., Steve L. Webster et Rosa L. Santoni. Discrete Fiber Reinforcement of Sands for Expedient Road Construction. Fort Belvoir, VA : Defense Technical Information Center, mars 1999. http://dx.doi.org/10.21236/ada362057.
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Rafalko, Susan D., Thomas L. Brandon, George M. Filz et James K. Mitchell. Fiber Reinforcement for Rapid Stabilization of Soft Clay Soils. Fort Belvoir, VA : Defense Technical Information Center, novembre 2006. http://dx.doi.org/10.21236/ada521338.
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Zhu, Y. T., J. A. Valdez, N. Shi, M. L. Lovato, M. G. Stout, S. Zhou, W. R. Blumenthal et T. C. Lowe. Influence of reinforcement morphology on the mechanical properties of short-fiber composites. Office of Scientific and Technical Information (OSTI), décembre 1997. http://dx.doi.org/10.2172/564175.
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Zhu, Y. T., J. A. Valdez, I. J. Beyerlain, M. G. Stout, S. Zhou, N. Shi et T. C. Lowe. Innovative Composites Through Reinforcement Morphology Design - a Bone-Shaped-Short-Fiber Composite. Office of Scientific and Technical Information (OSTI), juin 1999. http://dx.doi.org/10.2172/763899.
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Spurgeon, William A. Thickness and Reinforcement Fiber Content Control in Composites by Vacuum-Assisted Resin Transfer Molding Fabrication Processes. Fort Belvoir, VA : Defense Technical Information Center, juin 2005. http://dx.doi.org/10.21236/ada436340.
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Weiss, Charles, William McGinley, Bradford Songer, Madeline Kuchinski et Frank Kuchinski. Performance of active porcelain enamel coated fibers for fiber-reinforced concrete : the performance of active porcelain enamel coatings for fiber-reinforced concrete and fiber tests at the University of Louisville. Engineer Research and Development Center (U.S.), mai 2021. http://dx.doi.org/10.21079/11681/40683.
Texte intégralRésumé :
A patented active porcelain enamel coating improves both the bond between the concrete and steel reinforcement as well as its corrosion resistance. A Small Business Innovation Research (SBIR) program to develop a commercial method for production of porcelain-coated fibers was developed in 2015. Market potential of this technology with its steel/concrete bond improvements and corrosion protection suggests that it can compete with other fiber reinforcing systems, with improvements in performance, durability, and cost, especially as compared to smooth fibers incorporated into concrete slabs and beams. Preliminary testing in a Phase 1 SBIR investigation indicated that active ceramic coatings on small diameter wire significantly improved the bond between the wires and the concrete to the point that the wires achieved yield before pullout without affecting the strength of the wire. As part of an SBIR Phase 2 effort, the University of Louisville under contract for Ceramics, Composites and Coatings Inc., proposed an investigation to evaluate active enamel-coated steel fibers in typical concrete applications and in masonry grouts in both tension and compression. Evaluation of the effect of the incorporation of coated fibers into Ultra-High Performance Concrete (UHPC) was examined using flexural and compressive strength testing as well as through nanoindentation.
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Bell, Matthew, Rob Ament, Damon Fick et Marcel Huijser. Improving Connectivity : Innovative Fiber-Reinforced Polymer Structures for Wildlife, Bicyclists, and/or Pedestrians. Nevada Department of Transportation, septembre 2022. http://dx.doi.org/10.15788/ndot2022.09.
Texte intégralRésumé :
Engineers and ecologists continue to explore new methods and adapt existing techniques to improve highway mitigation measures that increase motorist safety and conserve wildlife species. Crossing structures, overpasses and underpasses, combined with fences, are some of the most highly effective mitigation measures employed around the world to reduce wildlife-vehicle collisions (WVCs) with large animals, increase motorist safety, and maintain habitat connectivity across transportation networks for many other types and sizes of wildlife. Published research on structural designs and materials for wildlife crossings is limited and suggests relatively little innovation has occurred. Wildlife crossing structures for large mammals are crucial for many highway mitigation strategies, so there is a need for new, resourceful, and innovative techniques to construct these structures. This report explored the promising application of fiber-reinforced polymers (FRPs) to a wildlife crossing using an overpass. The use of FRP composites has increased due to their high strength and light weight characteristics, long service life, and low maintenance costs. They are highly customizable in shape and geometry and the materials used (e.g., resins and fibers) in their manufacture. This project explored what is known about FRP bridge structures and what commercial materials are available in North America that can be adapted for use in a wildlife crossing using an overpass structure. A 12-mile section of US Highway 97 (US-97) in Siskiyou County, California was selected as the design location. Working with the California Department of Transportation (Caltrans) and California Department of Fish and Wildlife (CDFW), a site was selected for the FRP overpass design where it would help reduce WVCs and provide habitat connectivity. The benefits of a variety of FRP materials have been incorporated into the US-97 crossing design, including in the superstructure, concrete reinforcement, fencing, and light/sound barriers on the overpass. Working with Caltrans helped identify the challenges and limitations of using FRP materials for bridge construction in California. The design was used to evaluate the life cycle costs (LCCs) of using FRP materials for wildlife infrastructure compared to traditional materials (e.g., concrete, steel, and wood). The preliminary design of an FRP wildlife overpass at the US-97 site provides an example of a feasible, efficient, and constructible alternative to the use of conventional steel and concrete materials. The LCC analysis indicated the preliminary design using FRP materials could be more cost effective over a 100-year service life than ones using traditional materials.