Download or read book Analyse et optimisation des interfaces dans les composites carbone carbone renfort fibreux written by Béatrice Nguyen Van Sang-Trouvat and published by . This book was released on 1996 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: DANS LES MATERIAUX COMPOSITES CARBONE/CARBONE (C/C), LES INTERFACES ENTRE CONSTITUANTS JOUENT UN ROLE ESSENTIEL DANS LE COMPORTEMENT MECANIQUE. CE TRAVAIL A PORTE SUR LA MODIFICATION DES CARACTERISTIQUES INTERFACIALES FIBRE/MATRICE DE CES MATERIAUX PAR L'INTERPOSITION D'UNE INTERPHASE DE CARBONE DE MICROTEXTURE CONTROLEE. DES EXPERIENCES ONT ETE MENEES SUR DES COMPOSITES MODELES (MICRO ET MINICOMPOSITES) PREPARES PAR DEPOT CHIMIQUE EN PHASE VAPEUR (CVD/CVI). LEUR CARACTERISATION MICROSTRUCTURALE ET LEUR COMPORTEMENT MECANIQUE EN TRACTION A L'AMBIANTE ONT ETE ETUDIES EN PARALLELE AFIN DE MIEUX COMPRENDRE LE ROLE DE L'INTERPHASE. L'INFLUENCE DE TRAITEMENTS THERMIQUES A EGALEMENT ETE MISE EN EVIDENCE. LES RESULTATS ONT MONTRE QUE, SELON LES CARACTERISTIQUES INTERFACIALES, IL EST POSSIBLE D'AVOIR, POUR LES COMPOSITES CARBONE/CARBONE, LES DIFFERENTS COMPORTEMENTS MECANIQUES OBSERVES POUR LES AUTRES COMPOSITES A MATRICE CERAMIQUE (CMCS), A SAVOIR LA RUPTURE FRAGILE ET LE COMPORTEMENT TENACE PRESENTANT DE LA MULTIFISSURATION MATRICIELLE

Download or read book Sciences of Carbon Materials written by Harry Marsh and published by . This book was released on 2000 with total page 720 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sciences which are used to understand the properties and applications of carbons and graphites need to be described, comprehensively, in book format, at an up-to-date and introductory level. This book introduces the reader, comprehensively, to the sciences of structure of carbons, applications of carbon in nuclear energy, the chemistry of pitch carbonization, the spinnig of carbon fibres, carbon gasification reactions and oxidation protection, mechacnical properties, porosity and adsorption in carbons and coals, with chapters describing coal carbonization, coal liquefaction and the petrography of coal. The book serves both as a textbook and as a reference book and as a text for courses within educational institutions, worldwide.

Download or read book Optimisation des interfaces fibre matrice de composites renfort naturel written by Sofien Bouzouita and published by . This book was released on 2011 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les fibres naturelles ont réussi à acquérir un grand intérêt à l’échelle académique et industrielle. Ces fibres sont résistantes, possèdent des densités relativement basses, ont de faibles coûts et proviennent de ressources renouvelables abondantes. Les mêmes techniques classiques peuvent être utilisées pour la mise en œuvre des composites à base de fibres naturelles. Tous ces avantages ont fait que des constructeurs automobiles, par exemple, s’intéressent massivement à intégrer des pièces en ce type de composite dans plusieurs modèles de leurs véhicules. Cependant, les problèmes de compatibilité entre les fibres lignocellulosiques et les thermoplastiques limitent le transfert de charge entre fibre et matrice et ainsi les propriétés mécaniques des composites. La durabilité de ces matériaux en présence d’eau ou d’humidité est aussi problématique à cause de la haute hydrophilie des fibres naturelles. Le but de ce travail est de mieux comprendre les phénomènes relatifs à la mise en œuvre et à la l’utilisation de matériaux composites à base de polypropylène renforcé par des fibres de chanvre. L’influence d’un séchage préalable des fibres et d’une nouvelle technique de pré-imprégnation à sec, appelée Fibroline, ont été particulièrement étudiées. Cette dernière consiste à soumettre une poudre et un substrat fibreux à imprégner à un champ électrique de haute tension. Celui-ci provoque l'accélération des grains et crée une parfaite répartition de la résine dans le support fibreux. Au cours de ce traitement, des modifications chimiques et physiques peuvent se produire et entraîner l’amélioration de l'adhésion fibre/matrice. L’influence des techniques de préparation et de mise en œuvre sur les propriétés morphologiques, chimiques et mécaniques des fibres a été analysée. Des observations MEB ont permis de mettre en évidence des modifications de la surface par apparition de micro-craquelures après séchage, application du champ électrique et surtout après double traitement (séchage et Fibroline). Des analyses chimiques par XPS (spectroscopie photo-électronique aux rayons X) des fibres ont montré aussi des modifications de la chimie des surfaces. Principalement des phénomènes d’oxydation sont apparus. D’autre part, la caractérisation mécanique par traction sur mono-filaments dans différents états, a montré une dégradation des propriétés des fibres lors de leur préparation et lors de la phase d’imprégnation en utilisant la technique Fibroline, comparé au cas brut de réception. Les propriétés interfaciales ont été analysées en utilisant trois techniques. D’une part mécaniquement en utilisant le test de fragmentation et le test de déchaussement de micro-goutte, et d’autre part, par suivit de cristallisation isotherme à l’aide de platine chauffante et microscopie optique en lumière polarisée. Les essais mécaniques ont montré l’amélioration de la résistance interfaciale des fibres pré-séchées et celles traitées par la technique Fibroline. Celles doublement traitées ont vu leurs propriétés interfaciales chuter. L’analyse sous conditions isothermes des phénomènes de cristallisation ont permis d’observer l’apparition de zones transcristallines uniformes dans les deux cas ayant été imprégnés par la technique Fibroline. Ceci peut être expliqué par les modifications apportées par cette technique au niveau des surfaces des fibres.La durabilité des composites PP/chanvre a été étudiée à différentes températures sous atmosphères humides et en immersions dans de l’eau distillée. Les cinétiques d’absorption d’eau et d’humidité ont été suivies pendant une période de trois mois. Lescomposites vierges et vieillis ont été caractérisés par des essais statiques, en flexion trois points et dynamique, par spectroscopie mécanique (DMA). Pour les matériaux vierges, les améliorations observées au niveau des interfaces étaient synonymes d’améliorations dans le comportement global, mécanique et hygroscopique. Les composites imprégnés par la technique Fibroline sans séchage préalable ont montré les meilleures propriétés mécaniques, σ= 68,7MPa et E=5,4 GPa, ainsi que hygroscopiques avec des grains de masses plus faibles et des dégradations retardées. Les cinétiques d’absorption d’humidité des composites confirment la haute sensibilité à l’eau des composites à fibres naturelles. La température accentue les phénomènes de dégradation qui interviennent plutôt dans les processus de vieillissement. Les conditions en immersions sont plus sévères qu’en humidité relative (80%RH) avec des prises de masses plus élevées. Les modules de flexion et les contraintes à la rupture ont chuté et sont dépendants des quantités d’eau absorbées et des taux de la dégradation. La technique de DMA a montré que les modules élastiques ont chuté et a mis en évidence le décalage des relaxations vers les basses températures. Ceci est dû au caractère plastifiant de l’eau. L’évaluation des énergies d’activation relatives à la transition vitreuse du polypropylène confirme ces différentes observations.

Download or read book Material Characterisation and Interface Optimisation of Recycled Carbon Fibre Composites written by Jack Howarth and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Composites manufactured from a novel non-woven veil of recycled carbon fibre were tested in longitudinal tension, 3-point bend and short beam shear to assess their mechanical properties with respect to other commonly available materials. It was found that their mechanical properties were intermediate between 'high-end' unidirectional pre-preg and 'low-end' chopped strand mat, and similar to that of other short-fibre reinforced plastics. A range of oxygen plasma treatments were carried out on the fibres to improve interfacial performance of the composites. It was found that treatment at an intermediate plasma power of 20 W resulted in the greatest improvement in tensile strength of a 10° off-axis composite. Samples were manufactured from either 2 individual veils (IV) or from 2, 10-layer 'pre-forms' (PF). Both exhibited similar improvements in 10° off-axis strength. Thus shadowing of the fibre within the plasma did not appear to be significant. Overtreatment at higher plasma powers (35 and 50 W for IV and 50 W for PF) resulted in a significant reduction in tensile strength and failure strain. X-ray Photoelectron Spectroscopy (XPS) showed that plasma treatment at 20 W resulted in the highest level of oxygen functionality on the fibre surface, correlating with the best interfacial performance. Plasma treatment at 10 and 35 W resulted in slightly elevated surface oxygen content, however the off-axis tensile properties of 10 W treated samples were not significantly improved compared to the untreated control. The poor mechanical performance of the over-treated samples can be attributed to either an overly strong interface resulting from increased adhesion or damage to the fibres as a result of the treatment process. There were large variations in fibre wettability across treatments, such that no discernible pattern was present between wettability and interfacial performance. XPS and ToF-SIMS analysis showed that there was almost complete coverage of the veil by the binder in the veil-making process, and that silicon contamination on the fibre itself is likely silica based, and that silicon present in the binder is PDMS.

Download or read book Process Control and Interface Optimisation of Carbon Fibre PEEK Matrix Composites written by Shanglin Gao and published by . This book was released on 1999 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Mod lisation et optimisation du proc d de densificaton de composites carbone carbone par calefaction written by Jean-François Lines and published by . This book was released on 2003 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les matériaux composites carbone/carbone (C/C), constitués d'une architecture fibreuse en carbone et d'une matrice carbonée, font partie de cette classe de matériaux haute performance, avec d'intéressantes propriétés thermiques, mécaniques et tribologiques dans une large gamme de température (de -150°C à 4000°C), alliées à une faible densité. Le procédé de densification par caléfaction est une variante du procédé d'Infiltration Chimique à partir de la Phase Vapeur qui permet d'élaborer ces matériaux à partir d'une préforme fibreuse baignant dans un précurseur en ébullition, ce qui lui confère une vitesse de densification plus élevée que les autres variantes. En revanche, les puissances mises en jeu sont actuellement trop élevées pour exploiter industriellement ce procédé ; aussi une optimisation globale est-elle nécassaire. Dans cette perspective, una analyse et une modélisation à différentes échelles et une intégration de modèles sont présentées ici. Dans un premier temps, l'analyse phénoménologique et l'étude des couplages entre les différents phénomènes physiques et chimiques ont permis de proposer une modélisation basée sur l'assemblage de quatre sous-modèles. La chaîne de calcul est validée vis-àvis de résultats expérimentaux de laboratoire. Ensuite, une étude de sensibilité permet d'identifier les éléments cruciaux du procédé. L'étude du front de densification souligne la nécessité de la maîtrise de la température du front et met en évidence l'importance du gradient thermique sur la qualité du matériaux obtenu, ainsi que sur les temps et puissances de densification. Des solutions d'optimisation sont alors proposées,.

Download or read book Ceramic Matrix Composites written by Narottam P. Bansal and published by John Wiley & Sons. This book was released on 2014-10-27 with total page 725 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a comprehensive source of information on various aspects of ceramic matrix composites (CMC). It covers ceramic and carbon fibers; the fiber-matrix interface; processing, properties and industrial applications of various CMC systems; architecture, mechanical behavior at room and elevated temperatures, environmental effects and protective coatings, foreign object damage, modeling, life prediction, integration and joining. Each chapter in the book is written by specialists and internationally renowned researchers in the field. This book will provide state-of-the-art information on different aspects of CMCs. The book will be directed to researchers working in industry, academia, and national laboratories with interest and professional competence on CMCs. The book will also be useful to senior year and graduate students pursuing degrees in ceramic science and engineering, materials science and engineering, aeronautical, mechanical, and civil or aerospace engineering. Presents recent advances, new approaches and discusses new issues in the field, such as foreign object damage, life predictions, multiscale modeling based on probabilistic approaches, etc. Caters to the increasing interest in the application of ceramic matrix composites (CMC) materials in areas as diverse as aerospace, transport, energy, nuclear, and environment. CMCs are considered ans enabling technology for advanced aeropropulsion, space propulsion, space power, aerospace vehicles, space structures, as well as nuclear and chemical industries. Offers detailed descriptions of ceramic and carbon fibers; fiber-matrix interface; processing, properties and industrial applications of various CMC systems; architecture, mechanical behavior at room and elevated temperatures, environmental effects and protective coatings, foreign object damage, modeling, life prediction, integration/joining.

Download or read book Carbon Fiber Composites written by Deborah D.L. Chung and published by Butterworth-Heinemann. This book was released on 1994-09-23 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides introductory information on carbon fiber composites, including polymer-matrix, metal matrix, carbon-matrix, ceramic-matrix, and hybrid composites. Places emphasis on materials rather than mechanics.

Download or read book Polymer Crystallization written by Jerold M. Schultz and published by . This book was released on 2001 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt: Table of contents

Download or read book Government Reports Annual Index written by and published by . This book was released on 1990 with total page 1120 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Composites Forming Technologies written by A C Long and published by Elsevier. This book was released on 2014-01-23 with total page 345 pages. Available in PDF, EPUB and Kindle. Book excerpt: Composites are versatile engineered materials composed of two or more constituent materials which, when combined, lead to improved properties over the individual components whilst remaining separate on a macroscopic level. Due to their versatility, composite materials are used in a variety of areas ranging from healthcare and civil engineering to spacecraft technology. Composites forming technologies reviews the wealth of research in forming high-quality composite materials.The book begins with a concise explanation of the forming mechanisms and characterisation for composites, as well as covering modelling and analysis of forming techniques. Further chapters discuss the testing and simulation of composite materials forming. The book also considers forming technologies for various composite material forms including thermoset and thermoplastic prepreg, moulding compounds and composite/metal laminates.With its distinguished editor and array of international contributors, Composites forming technologies is an essential reference for engineers, researchers and academics involved with the production and use of composite materials. - Reviews the wealth of research in forming high-quality composite materials - Includes a concise explanation of the forming mechanisms and charaterisation for composites - Considers forming technologies for various composite material forms

Download or read book Status of Accelerator Driven Systems Research and Technology Development written by International Atomic Energy Agency and published by IAEA Tecdoc. This book was released on 2015 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the greatest challenges for nuclear energy is how to properly manage the highly radioactive waste generated during irradiation in nuclear reactors. Accelerator Driven Systems (ADSs) may offer new prospects and advantages for the transmutation of such high level nuclear waste. ADS or accelerator driven transmutation of waste (ATW) consists of a high power proton accelerator, a heavy metal spallation target that produces neutrons when bombarded by the high power beam, and a sub-critical core that is neutronically coupled to the spallation target. This publication provides a comprehensive state of the art of the ADS technology by representing the different ADS concepts proposed worldwide in the last 15 years, as well as the related R&D activities and demonstration initiatives carried out at national international level.

Download or read book Non Crimp Fabric Composites written by Stepan V Lomov and published by Elsevier. This book was released on 2011-04-19 with total page 557 pages. Available in PDF, EPUB and Kindle. Book excerpt: Non-crimp fabric (NCF) composites are reinforced with mats of straight (non-crimped) fibres, giving them such advantages as strength, ease of handling and low manufacturing costs. Non-crimp fabric composites provides a comprehensive review of the use of NCF composites, their manufacture and applications in engineering.Part one covers the manufacture of non-crimp fabrics, including also topics such as structural stitching and automated defect analysis. Part two goes on to discuss the manufacture of non-crimp fabric composites, with chapters covering such topics as deformability and permeability of NCF. Part three focuses on the properties of NCF composites, with chapters on stiffness and strength, damage progression and fatigue. Finally, part four covers the applications of NCF composites, including chapters on the aerospace and automotive industries as well as wind turbines and helicopter applications. The book concludes with a discussion of cost analysis of NCF composites in engineering applications.With its distinguished editor and international team of expert contributors, Non-crimp fabric composites is an essential reference for composite manufacturers and structural and mechanical engineers in industries using NCF composites, as well as academics with a research interest in the field. - Provides a comprehensive review of the use of NCF composites, their manufacture and applications in engineering - Reviews the manufacture of non-crimp fabrics, including also topics such as structural stitching and automated defect analysis - Examines the properties of NCF composites considering stiffness and strength, damage progression and fatigue

Download or read book Scientific Canadian Mechanics Magazine and Patent Office Record written by Canada. Patent Office and published by . This book was released on 1966-03 with total page 1070 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book American Fertilizers written by Perry Eugene Howard and published by . This book was released on 1932 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this publication is given a brief description of the production of commercial fertilizer. It is believed that this description, which complex technical discussion and statistics are avoided, will be of use to students, as well as farmers and gardeners.

Download or read book Thermoplastic written by Adel El-Sonbati and published by BoD – Books on Demand. This book was released on 2012-03-16 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Composite materials often demand a unique combination of properties, including high thermal and oxidative stability, toughness, solvent resistance and low dielectric constant. This book, "Thermoplastic - Composite Materials", is comprised of seven excellent chapters, written for all specialized scientists and engineers dealing with characterization, thermal, mechanical and technical properties, rheological, morphological and microstructure properties and processing design of composite materials.