Download or read book Comportement en fluage de composites renfort carbone et matrices poxyde et peek written by Tania Risson and published by . This book was released on 1998 with total page 244 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les excellentes propriétés mécaniques spécifiques (rapport performance / poids) des matériaux composites à fibres longues de carbone renforçant une matrice polymérique (CFRP) ont conduit depuis une vingtaine d'années à leur utilisation dans nombre d'applications de haute technologie. Néanmoins, les coûts de matière et de mise fin œuvre, leur faible résistance aux dommages et la méconnaissance de leur comportement à long terme sont les principales limitations à une diffusion encore plus importante. Plus particulièrement, dans le cas de pièces soumises à des conditions sévères de sollicitation (charges importantes et températures élevées), l'étude du comportement en fluage devient essentielle pour une conception optimale. L'enjeu scientifique se situe donc au niveau du développement de méthodes de caractérisation accélérée et de modélisation permettant une extrapolation fiable des résultats expérimentaux aux conditions réelles d'utilisation. Une bonne compréhension des mécanismes de dégradations intervenant sous sollicitation thermomécanique s'avère par conséquent nécessaire. Deux classes de composites sont considérées, l'une à matrice thermodurcissable (RTM), l'autre à matrice thermoplastique (APC-2). La première étape consiste à définir un domaine d'expérimentation pour les essais de fluage (en termes de température et de contrainte appliquée). Les différents aspects du comportement en fluage intervenant sous diverses conditions de sollicitations thermomécaniques sont ensuite analysés. Ces résultats sont complétés par une étude de l'évolution structurale des matériaux en cours d'essai. Pour la caractérisation de l'endommagement, deux types de méthodes sont employés : les techniques d'émission acoustique et de mesures de propriétés électriques sont utilisées pour le suivi de l'Initiation et de la propagation de dégradations en cours d'essai mécanique; une analyse par spectrométrie mécanique est réalisée afin de caractériser "l'état d'endommagement" des matériaux suite à l'application d'une sollicitation thermomécanique. L'ensemble des informations ainsi collectées permet l'élaboration d'une carte d'endommagement. La prévision du comportement à long terme peut finalement être abordée : une approche basée sur le principe de superposition Temps-Température-Contrainte est adoptée et complétée par une analyse plus physique inspirée du modèle microstructurai de PEREZ.

Download or read book Structural Health Monitoring written by Daniel Balageas and published by John Wiley & Sons. This book was released on 2010-01-05 with total page 496 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is organized around the various sensing techniques used to achieve structural health monitoring. Its main focus is on sensors, signal and data reduction methods and inverse techniques, which enable the identification of the physical parameters, affected by the presence of the damage, on which a diagnostic is established. Structural Health Monitoring is not oriented by the type of applications or linked to special classes of problems, but rather presents broader families of techniques: vibration and modal analysis; optical fibre sensing; acousto-ultrasonics, using piezoelectric transducers; and electric and electromagnetic techniques. Each chapter has been written by specialists in the subject area who possess a broad range of practical experience. The book will be accessible to students and those new to the field, but the exhaustive overview of present research and development, as well as the numerous references provided, also make it required reading for experienced researchers and engineers.

Download or read book Comportement m canique long terme et en temp rature d un composite inject matrice PEEK renforc de fibres de carbone courtes written by Sylvain Corveleyn and published by . This book was released on 2018 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les composites thermoplastiques hautes performances ont suscité l'intérêt de l'industrie aéronautique pour remplacer l'aluminium dans certaines pièces. Ils permettent la production de pièces moins lourdes et moins coûteuses. Parmi ces matériaux, le PEEK renforcé par des fibres de carbone courtes semble intéressant pour des applications nécessitant de hautes propriétés thermomécaniques. Ce matériau a déjà fait l'objet de travaux au Laboratoire ICA de l'IMT Mines Albi, dans le cadre de la thèse de Jérémy Crevel ainsi que les projets régionaux Midi-Pyrénées CINTHTE, CINTHTE2 et FUI INMAT2. En outre, des applications industrielles sont en cours de développement chez Liebherr Aerospace. Cependant, le comportement à long terme en température de ce matériau est mal connu. L'objectif de cette thèse est de déterminer la plage d'utilisation du matériau en fonction du temps, de la température et du chargement. Deux phénomènes intervenant à hautes températures et à long terme sont étudiés : le vieillissement et le fluage. L'étude du vieillissement sous air s'est concentrée sur l'évolution des propriétés mécaniques en traction après une longue exposition à haute température. L'influence du vieillissement sur les propriétés mécaniques usuelles (module, contrainte à rupture et allongement à rupture) ainsi que sur l'endommagement et la plasticité a été mesurée en dessous et au-dessus de la température de transition vitreuse et pour différentes orientations de fibres. L'évolution de la structure du matériau avec le vieillissement a été suivie pour faire le lien avec les propriétés mécaniques. L'étude du fluage s'est faite à des contraintes inférieures au seuil d'endommagement du matériau. Des essais à court terme et dynamiques fréquentiels ont été réalisés pour définir un modèle de comportement dépendant du temps et l'identifier sur le long terme. Ils ont en outre permis de prendre en compte la température, le vieillissement et l'anisotropie du matériau pour des durées longues. Ces deux études (vieillissement et fluage) ont été unifiées dans un critère de rupture pour prévoir le temps à rupture du matériau. Enfin, un modèle viscoélastique isotrope transverse et des indicateurs de rupture en fluage ont été implémentés dans Abaqus pour réaliser des calculs sur des pièces industrielles.

Download or read book FLUAGE EN TORSION DE COMPOSITES A RENFORTS FILAMENTAIRES ET AMTRICE POLYMERE written by MOHAND-TAYEB.. LACHI and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: CETTE ETUDE SE SITUE DANS LE CONTEXTE GENERAL DE LA CARACTERISATION DU COMPORTEMENT EN CISAILLEMENT DE COMPOSITES A FIBRES DE CARBONE OU VERRE ET MATRICE POLYMERE. LES EPROUVETTES PARALLELEPIPEDIQUES A FIBRES LONGITUDINALES OU TRANSVERSES SONT SOUMISES A DES ESSAIS DE FLUAGE EN TORSION AUX DIFFERENTS TAUX D'HUMIDITE RELATIVE 0, 60, 80 ET 96% A LA TEMPERATURE CONSTANTE DE 60#C. UNE ETUDE INTRODUCTIVE RAPPELLE LE PROBLEME DE LA CARACTERISATION DES PROPRIETES DE CISAILLEMENT ET LES BASES THEORIQUES DU PROBLEME DE TORSION. LES PHENOMENES D'ABSORPTION D'EAU DES COMPOSITES A MATRICE ORGANIQUE SONT EGALEMENT PRESENTES. LA CONCEPTION ET LA REALISATION DES MACHINES D'ESSAIS DE FLUAGE EN TORSION SIMPLES PEU ENCOMBRANTES ET DE COUT DE FABRICATION RAISONNABLE SONT ENSUITE DECRITES. CES MACHINES PERMETTENT D'EFFECTUER DES ESSAIS EN PARALLELE DANS LES ENCEINTES DE CONDITIONNEMENT. LES CINETIQUES D'ABSORPTION D'EAU SONT MODELISES A PRIORI PAR LA LOI DE FICK. LE CHOIX D'UN BARREAU COMPOSITE DE SECTION DROITE CARREE A FIBRES LONGITUDINALES OU TRANSVERSES PERMET EN PRINCIPE DE DETERMINER LES DIFFUSIVITES EFFECTIVES SUIVANT LES TROIS DIRECTIONS X, Y ET Z DE L'EPROUVETTE. TROIS COMPOSITES A MATRICE POLYMERE ONT ETE ETUDIES: DEUX MATERIAUX A BASE DE FIBRES DE VERRE E UNIDIRECTIONNELLES ET TISSEES ET UN MATERIAU A FIBRES DE CARBONE UNIDIRECTIONNELLES. L'ABSORPTION D'EAU SUIVANT LA DIRECTION DES FIBRES EST EN GENERAL PLUS RAPIDE QUE SUIVANT LA DIRECTION TRANSVERSE, ON CARACTERISE AINSI L'ANISOTROPIE DE LA DIFFUSION MACROSCOPIQUE DES COMPOSITES UNIDIRECTIONNELS. DE PLUS LES DIFFUSIVITES EXPERIMENTALES DU COMPOSITE RENFORCE PAR UN TISSU D VERRE EQUILIBRE SONT PRATIQUEMENT INDEPENDANTES DES HUMIDITES RELATIVES ET DE L'ORIENTATION CHAINE ET TRAME. LES ESSAIS DE FLUAGE D'ECHANTILLONS SATURES, TESTES A DIFFERENTS COUPLES, PERMETTENT L'ETUDE DE LA VARIATION DE LA COMPLAISANCE DE CISAILLEMENT DANS LE TEMPS EN FONCTION DE LA QUANTITE D'EAU ABSORBEE. LES COURBES DE COMPLAISANCE LES PLUS MARQUANTES SONT CELLES DES ECHANTILLONS VERRE/EPOXYDE CONDITIONNES A 80 ET 96% HR OU L'ON MET EN EVIDENCE LA GRANDE SENSIBILITE DU COMPORTEMENT EN CISAILLEMENT A LA CONCENTRATION EN EAU. EN OUTRE L'ENDOMMAGEMENT OBSERVE DES ECHANTILLONS A FIBRES LONGITUDINALES SE TRADUIT PAR DES FISSURES LONGITUDINALES SUIVANT LA DIRECTION DES FIBRES ALORS QUE LES TRANSVERSES SE ROMPENT EN TRACTION TRANSVERSE. ENFIN, LES COURBES MAITRESSES OBTENUES ET LA COURBE D'EVOLUTION DU FACTEUR DE GLISSEMENT EN FONCTION DE LA CONCENTRATION EN EAU PERMETTENT RAISONNABLEMENT DE PREVOIR LE COMPORTEMENT DU MATERIAU DANS UN LARGE DOMAINE TEMPS-CONCENTRATION EN EAU

Download or read book Caract risation du comportement en fluage de mat riaux composites carbonne expoxy written by Olivier Ceysson and published by . This book was released on 1996 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: LES MATERIAUX COMPOSITES DE TYPE FIBRES LONGUES DE CARBONE/MATRICE POLYMERE (CFRP) POSSEDENT D'EXCELLENTES CARACTERISTIQUES MECANIQUES SPECIFIQUES (RAPPORT PERFORMANCE/POIDS) QUI ONT CONDUIT, CES DERNIERES ANNEES, A LEUR UTILISATION DANS UN NOMBRE CROISSANT DE STRUCTURES TRAVAILLANTES, NOTAMMENT POUR DES APPLICATIONS AERONAUTIQUES. CEPENDANT, SI GENERALEMENT, L'INDUSTRIE CONSIDERE CES COMPOSITES COMME POTENTIELLEMENT INTERESSANTS, LA MECONNAISSANCE DE LEUR DURABILITE REND LEUR EMPLOI SOUVENT LIMITE. EN EFFET, LA CONCEPTION DE STRUCTURES COMPOSITES NECESSITE LE PLUS SOUVENT LA PRISE EN COMPTE DU COMPORTEMENT A LONG TERME SOUS DIVERS TYPES DE SOLLICITATIONS GENERES SIMULTANEMENT PAR LES CHARGEMENTS MECANIQUES ET L'ENVIRONNEMENT. CE TRAVAIL DE THESE EST BASE, D'UNE PART, SUR LE DEVELOPPEMENT D'UN MOYEN EXPERIMENTAL DE CARCTERISATION EN FLUAGE, ET, D'AUTRE PART, SUR LA MISE AU POINT D'UNE METHODOLOGIE PERMETTANT LA CARACTERISATION ET LA MODELISATION DU COMPORTEMENT A LONG TERME SOUS CHARGE CONSTANTE DE STRUCTURES COMPOSITES SOUMISES AUX EFFETS DU VIEILLISSEMENT (TEMPERATURE ET HUMIDITE). LES MATERIAUX COMPOSITES ETUDIES ETANT COMPLEXES (MATRICE POLYEPOXYDE MODIFIEE PAR UN TP), UNE ATTENTION TOUTE PARTICULIERE EST ACCORDEE A LEUR MICROSTRUCTURE (ETAT DE RETICULATION ET MORPHOLOGIE). DES RELATIONS MICROSTRUCTURES-PROPRIETES ONT AINSI PU ETRE ETABLIES. DES TESTS DE CARACTERISATION HYGRO-THERMO-MECANIQUE DES MATERIAUX ONT ETE CONDUITS. CES ESSAIS PERMETTENT NOTAMMENT DE PRECISER LES TEMPERATURES CARACTERISTIQUES DE NOS CFRP, D'ETUDIER L'EFFET DE L'EAU SUR LEURS PROPRIETES THERMO-MECANIQUES ET DE DETERMINER LEURS PROPRIETES MECANIQUES A RUPTURE POUR LES DIVERSES CONDITIONS ENVIRONNEMENTALES (TEMPERATURE ET HUMIDITE). CES DERNIERES PERMETTENT, ENTRE AUTRE, DE FIXER LE NIVEAU DE CONTRAINTE A APPLIQUER LORS DES ESSAIS DE FLUAGE. PUIS, UNE APPROCHE QUALITATIVE DU COMPORTEMENT EN FLUAGE A PERMIS DE METTRE EN EVIDENCE LES PRINCIPAUX PARAMETRES INFLUENCANT LA TENUE A LONG TERME DES CFRP. PARALLELEMENT, NOUS AVONS ETUDIES LES DIVERS MECANISMES DE DEGRADATION QUI CONDUISENT A LA RUINE DU MATERIAU. CETTE ETUDE A ETE EFFECTUEE A DIFFERENTES ECHELLES, GRACE A L'UTILISATION DE NOMBREUSES TECHNIQUES EXPERIMENTALES COMPLEMENTAIRES : A L'ECHELLE MACROMOLECULAIRE, GRACE A L'UTILISATION DE LA SPECTROMETRIE MECANIQUE, ET DE L'ECHELLE MICROSCOPIQUE A MACROSCOPIQUE, LE SUIVI IN-SITU DE L'ENDOMMAGEMENT (AU SENS DE CREATION DU SURFACE) A ETE REALISE PAR EMISSION ACOUSTIQUE ET PAR UNE TECHNIQUE NOUVELLE, DEVELOPPEE AU COURS DE CETTE ETUDE, BASEE SUR DES MESURES DE PROPRIETES ELECTRIQUES. DANS LA DERNIERE PARTIE, UNE APPROCHE QUANTITATIVE A PERMIS UNE MODELISATION PHENOMENOLOQIQUE ET AINSI UNE PREVISION DU COMPORTEMENT A LONG TERME SOUS CHARGE CONSTANTE DES CFRP.

Download or read book Dictionary of Building and Civil Engineering written by Don Montague and published by Taylor & Francis. This book was released on 1996 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dual-language dictionary lists over 20,000 specialist terms in both French and English, covering architecture, building, engineering and property terms. It meets the needs of all building professionals working on projects overseas. It has been comprehensively researched and compiled to provide an invaluable reference source in an increasingly European marketplace.

Download or read book Smart Structures and Materials written by B. Culshaw and published by Artech House Publishers. This book was released on 1996 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the enabling concepts that make up the so-called smart structure and presents a number of brief case studies to illustrate the applications of these concepts. It examines the domains of the individual technologies and defines the challenges faced by the integrator. The book is particularly effective for the potential system user who needs a good technical general background on the subject and is also useful for students and researchers in contributory technologies who want to better understand the context of their work. Consultants in civil and structural engineering will also find it of interest.

Download or read book Flexoelectricity in Liquid Crystals written by Agnes Buka and published by World Scientific. This book was released on 2013 with total page 299 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book intends to give a state-of-the-art overview of flexoelectricity, a linear physical coupling between mechanical (orientational) deformations and electric polarization, which is specific to systems with orientational order, such as liquid crystals. Chapters written by experts in the field shed light on theoretical as well as experimental aspects of research carried out since the discovery of flexoelectricity. Besides a common macroscopic (continuum) description the microscopic theory of flexoelectricity is also addressed. Electro-optic effects due to or modified by flexoelectricity as well as various (direct and indirect) measurement methods are discussed. Special emphasis is given to the role of flexoelectricity in pattern-forming instabilities. While the main focus of the book lies in flexoelectricity in nematic liquid crystals, peculiarities of other mesophases (bent-core systems, cholesterics, and smectics) are also reviewed. Flexoelectricity has relevance to biological (living) systems and can also offer possibilities for technical applications. The basics of these two interdisciplinary fields are also summarized.

Download or read book Encapsulations written by Alexandru Grumezescu and published by Academic Press. This book was released on 2016-05-27 with total page 926 pages. Available in PDF, EPUB and Kindle. Book excerpt: Encapsulations, a volume in the Nanotechnology in the Agri-Food Industry series,presents key elements in establishing food quality through the improvement of food flavor and aroma. The major benefits of nanoencapsulation for food ingredients include improvement in bioavailability of flavor and aroma ingredients, improvement in solubility of poor water-soluble ingredients, higher ingredient retention during production process, higher activity levels of encapsulated ingredients, improved shelf life, and controlled release of flavor and aroma. This volume discusses main nanoencapsulation processes such as spray drying, melt injection, extrusion, coacervation, and emulsification. The materials used in nanoencapsulation include lipids, proteins, carbohydrates, cellulose, gums, and food grade polymers. Applications and benefits of nanoencapsulation such as controlled release, protections, and taste masking will be explained in detail. Includes the most up-to-date information on nanoencapsulation and nanocontainer-based delivery of antimicrobials Presents nanomaterials for innovation based on scientific advancements in the field Provides control release strategies to enhance bioactivity, including methods and techniques for research and innovation Provides useful tools to improve the delivery of bioactive molecules and living cells into foods

Download or read book In Situ Gelling Polymers written by Xian Jun Loh and published by Springer. This book was released on 2014-10-01 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents the research involving in situ gelling polymers and can be used as a guidebook for academics, industrialists and postgraduates interested in this area. This work summaries the academic contributions from the top authorities in the field and explore the fundamental principles of in situ gelling polymeric networks, along with examples of their major applications. This book aims to provide an up-to-date resource of in situ gelling polymer research.

Download or read book Wood Adhesives written by Antonio Pizzi and published by CRC Press. This book was released on 2011-01-07 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wood adhesives are of tremendous industrial importance, as more than two-thirds of wood products in the world today are completely or partially bonded together using a variety of adhesives. Adhesive bonding offers many advantages over other joining methods for wood components, and there has been a great deal of R& D activity in devising new wood adhesives or improving the existing ones. The modern mantra in all industrial sectors is: "think green, go green," which has attracted much attention in the wood adhesive industry. Therefore, there is also a lot of research activity in synthesizing environmentally benign and human-friendly wood adhesives. This book is divided into four parts: Part 1: Fundamental Adhesion Aspects in Wood Bonding; Part 2: Synthetic Adhesives; Part 3: Environment-friendly adhesives; and Part 4: Wood Welding and General Paper. It addresses many different types of wood adhesives, as well as bonding (welding) of wood components without adhesives, a more recent development. The information contained in this book is valuable for individuals engaged in all aspects of wood adhesion and adhesives and, hopefully, will inspire new ideas in wood adhesives, a topic of vital industrial importance.

Download or read book Structural Health Monitoring 2000 written by Fu-Kuo Chang and published by CRC Press. This book was released on 1999-09-07 with total page 1104 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprising 102 papers presented by researchers from all over the world, the proceedings of this workshop contain current information about a variety of structural health monitoring technologies, as well as their current and potential applications in various fields. Emphasis is placed on those technologies that are promising for future applications in industry and government and the infrastructures that are needed to support such technological development. The content of the workshop is divided into keynote presentations (ten altogether), aerospace applications, general applications, civil applications, integration and systems, sensors, and signal processing and diagnostic methods. Includes the editor's summary report on the results of the panel discussions and presentations from the First International Workshop on Structural Health Monitoring held at Stanford U. in September 1997. Annotation c. Book News, Inc., Portland, OR (booknews.com)

Download or read book Nonlinear Optical Materials written by Jerome V. Moloney and published by Springer Science & Business Media. This book was released on 1998-08-13 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mathematical methods play a significant role in the rapidly growing field of nonlinear optical materials. This volume discusses a number of successful or promising contributions. The overall theme of this volume is twofold: (1) the challenges faced in computing and optimizing nonlinear optical material properties; and (2) the exploitation of these properties in important areas of application. These include the design of optical amplifiers and lasers, as well as novel optical switches. Research topics in this volume include how to exploit the magnetooptic effect, how to work with the nonlinear optical response of materials, how to predict laser-induced breakdown in efficient optical devices, and how to handle electron cloud distortion in femtosecond processes.

Download or read book Structural Health Monitoring 2006 written by Alfredo Güemes and published by DEStech Publications, Inc. This book was released on 2006 with total page 1458 pages. Available in PDF, EPUB and Kindle. Book excerpt: These proceedings of the Third European Workshop on Structural Health Monitoring held at the Conference Centre in Granada, Spain, in July of 2006 includes four keynote presentations and 170 technical papers written by an international group of contributors. Papers discuss technology and activities related to damage detection and evaluation in engin

Download or read book Advances in Polymer Science written by and published by . This book was released on 1985 with total page 165 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Diamond Based Composites written by Mark A. Prelas and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: Diamond-based composites, with their advantages of hardness, high Young's modulus and the like, have demonstrated new and unusual features, such as stability to high temperatures and pressure shocks and a large internal surface that can be controlled to offer customised electrical, magnetic and optical properties, leading to efficient filters, absorbents, sensors and other tools for environmental control and monitoring. The current book covers the synthesis of materials, their characterization and properties, trends in high pressure and high temperature technologies, low pressure technologies, basic principles of DBC material science, and future developments in electronics, optics, industrial tools and components, biotechnology, and medicine. Wide band-gap materials are considered, ranging from molecular clusters, nanophase materials, growth, processing and synthesis. The processing of composite based materials can be classified into six basic methods: in situ growth, high pressure/high temperature catalytic conversion; mix and sinter (c-BN plus metal-ceramic polymer mix); direct sintering; direct polymorphic conversion; shock detonation; and SHS sintering.

Download or read book Azoles written by Aleksey Kuznetsov and published by BoD – Books on Demand. This book was released on 2021-06-30 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: Azoles are a broad and promising class of five-membered heterocyclic compounds containing from one up to five nitrogen atom(s) that can also contain sulfur or oxygen atoms. Widely used as potent antifungal agents, various azole derivatives have also demonstrated many other promising biological properties. This book covers studies of several types of thiazole-based heterocyclic scaffolds, the development of 4-thiazolidinone and thiazole derivatives with heterocyclic fragments as potential candidates for new drugs against trypanosomiasis, numerous synthetic approaches for the synthesis of 1,2,3-triazoles, the application of N-azole, N,S-azole, and N,O-azole as well as their derivatives as retarders of metallic corrosion, and the integration of azoles in materials used for renewable energy processing and applications and wood treatment.