Advances in Ceramic-matrix Composites PDF Download

Author:
Publisher:
ISBN:
Category : Ceramic-matrix composites
Languages : en
Pages : 634

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Author: Michael C. Halbig
Publisher:
ISBN:
Category :
Languages : en
Pages : 18

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Carbon fiber reinforced silicon carbide matrix composites (C/SiC) are a ceramic matrix composite (CMC) material that offers benefits for use in a wide range of high temperature structural applications. However the susceptibility of the carbon fibers to degradation in oxidizing environments has hindered the material's use in certain applications requiring long lives under oxidizing conditions. The susceptibility of carbon fibers to oxidation will be discussed as well as the enhancement (improvement in oxidation resistance) of C/SiC materials. Thermogravimetric analysis of carbon fibers shows susceptibility to oxidation in two distinct kinetic regimes. However, in the thermogravimetric (wt. loss) analysis of unstressed, unenhanced, seal coated C/SiC coupons, the two regimes were not observed due to crack closure and matrix effects, which inhibited the oxidation process. Stressed oxidation (creep rupture) tests put the material under a stress, which is a more realistic condition for many applications. In stressed oxidation tests, the two oxidation kinetics regimes were observed. These tests can provide better insight into how the material will perform in applications involving stress. Stressed oxidation of enhanced materials containing oxidation inhibitors showed significantly improved lives at the specific test conditions considered, although there was susceptibility to oxidation at intermediate temperatures.

Author: Marco Gigliotti
Publisher: ISTE Group
ISBN: 1784052833
Category : Composite materials
Languages : fr
Pages : 123

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L’utilisation des composites à matrice organique pour des applications structurales à haute température est de plus en plus souvent envisagée, notamment dans certaines zones de turbomachines aéronautiques. A cette fin, il devient nécessaire d’analyser les effets du vieillissement thermo-oxydant sur le comportement mécanique d’un polymère et des composites associés. Cet ouvrage met en relief des méthodologies expérimentales originales qui permettent, par analyse inverse, de développer et d’identifier une loi de comportement du polymère dépendant du vieillissement ainsi que les déformations d’origine chimique. Ces informations sont utilisées pour le calcul des contraintes internes induites par un vieillissement thermo-oxydant dans des composites unidirectionnels à fibres continues de carbone. Comportement mécanique des composites à matrice organique se différencie des autres ouvrages par son approche. Il examine des lois de comportement thermomécaniques locales dépendant de l’oxydation grâce à l’emploi d’essais couplés et non couplés à l’échelle microscopique. Il présente des modèles originaux afin d'intégrer toute la richesse de la phénoménologie observée expérimentalement, grâce à l'emploi de variables internes correctement choisies.

Author: L. Remy
Publisher: Elsevier
ISBN: 0080542328
Category : Technology & Engineering
Languages : en
Pages : 397

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This volume contains a selection of peer-reviewed papers presented at the International Conference on Temperature-Fatigue Interaction, held in Paris, May 29-31, 2001, organised by the Fatigue Committee of the Societé Française de Métallurgie et de Matériaux (SF2M), under the auspices of the European Structural Integrity Society. The conference disseminated recent research results and promoting the interaction and collaboration amongst materials scientists, mechanical engineers and design engineers. Many engineering components and structures used in the automotive, aerospace, power generation and many other industries experience cyclic mechanical loads at high temperature or temperature transients causing thermally induced stresses. The increase of operating temperature and thermal mechanical loading trigger the interaction with time-dependent phenomena such as creep and environmental effects (oxidation, corrosion). A large number of metallic materials were investigated including aluminium alloys for the automotive industry, steels and cast iron for the automotive industry and materials forming, stainless steels for power plants, titanium, composites, intermetallic alloys and nickel base superalloys for aircraft industry, polymers. Important progress was observed in testing practice for high temperature behaviour, including environment and thermo-mechanical loading as well as in observation techniques. A large problem which was emphasized is to know precisely service loading cycles under non-isothermal conditions. This was considered critical for numerous thermal fatigue problems discussed in this conference.

Author: Nathalie Godin
Publisher: ISTE Group
ISBN: 1784054348
Category : Acoustic emission
Languages : fr
Pages : 191

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L’un des enjeux en contrôle de santé des structures est la détection précoce de l’endommagement avant que ce dernier ne conduise à la ruine. Dans ce contexte, l’émission acoustique est une technique bien adaptée afin de suivre, en temps réel, l’état de santé d’une structure ou des matériaux qui la constituent. En effet, les mécanismes d’endommagement s’accompagnent de libération d’énergie sous forme d’ondes acoustiques. Des capteurs disposés à la surface de structures ou d’éprouvettes de laboratoire permettent d’enregistrer les signaux d’EA. Cet ouvrage est dédié à l’identification de la signature acoustique des différents mécanismes d’endommagement se produisant dans les matériaux composites à matrice organique, mais aussi dans les matériaux composites à matrice céramique. Les apports de cette approche sont présentés, ainsi que les principales difficultés et les limites. Aussi, la prévision de la durée de vie à l’aide de l’EA pour des essais de longues durées est discutée.

Author: J. Bressers
Publisher: Springer Science & Business Media
ISBN: 9401586365
Category : Technology & Engineering
Languages : en
Pages : 497

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The International Symposium "Fatigue under Thermal and Mechanical Loading", held at Petten (The Netherlands) on May 22-24, 1995, was jointly organized by the Institute for Advanced Materials of The Joint Research Centre, E. C. , and by the Societe Fran~se de Metallurgie et de Materiaux. The fast heating and cooling cycles experienced by many high temperature components cause thermally induced stresses, which often operate in combination with mechanical loads. The resulting thermal / mechanical fatigue cycle leads to material degradation mechanisms and failure modes typical of service cycles. The growing awareness that the synergism between the combined thermal and mechanical loads can not be reproduced by means of isothermal tests, has resulted in an increasing interest in thermal and thermo-mechanical fatigue testing. This trend has been reinforced by the constant pull by industry for more performant, yet safer high temperature systems, pushing the materials to the limit of their properties. Dedicated ASTM meetings in particular have set the scene for this area of research. The proceedings of the symposium organized by D. A. Spera and D. F. Mowbray in 1975 provided a reference book on thermal fatigue which reflects the knowledge and experimental capabilities of the mid-seventies.

Author: Huseyin Sehitoglu
Publisher: ASTM International
ISBN: 0803128533
Category : Alloys
Languages : en
Pages : 339

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Author: Anastasios P. Vassilopoulos
Publisher: Woodhead Publishing
ISBN: 0081025769
Category : Technology & Engineering
Languages : en
Pages : 766

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Fatigue Life Prediction of Composites and Composite Structures, Second Edition, is a comprehensive review of fatigue damage and fatigue life modeling and prediction methodologies for composites and their use in practice. In this new edition, existing chapters are fully updated, while new chapters are introduced to cover the most recent developments in the field. The use of composites is growing in structural applications in many industries, including aerospace, marine, wind turbine and civil engineering. However, there are uncertainties about their long-term performance, including performance issues relating to cyclic fatigue loading that hinder the adoption of a commonly accepted credible fatigue design methodology for the life prediction of composite engineering structures. With its distinguished editor and international team of contributors, this book is a standard reference for industry professionals and researchers alike. - Examines past, present and future trends associated with the fatigue life prediction of composite materials and structures - Assesses novel computational methods for fatigue life modeling and prediction of composite materials under constant amplitude loading - Covers a wide range of techniques for predicting fatigue, including their theoretical background and practical applications - Addresses new topics and covers contemporary research developments in the field

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 56

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A theory of local and global mechanisms of heat generation and distribution in carbon-fiber-based composites subjected to an alternating magnetic field has been proposed. A model that predicts the strength and distribution of thermal generation through the thickness of carbon-fiber-based laminated composites has been developed. Earlier work has established the distribution of point voltages in the plane of the laminate that exist in the form of potential differences between fibers in adjacent plies in a cross-ply or angle-ply laminate system. In this work a capacitive-layer microstructure that models the actual fiber-reinforced-polymer microstructure from a square-packing assumption to a series of conductive parallel plates is formulated. An effective parameter of heating, gamma, that establishes the distribution of heating through the thickness is defined. Extreme gradients in this thermal source can exist with peaks occurring at the interfaces of ply-ply orientation changes. An optimization study establishes the effect of various microstructural and macrostructural parameters on the heating parameter, gamma. Several parametric studies are performed on the computer algorithm, which calculates gamma to further analyze these effects.

Author: Bruce Fink
Publisher:
ISBN:
Category : Carbon
Languages : en
Pages : 48

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Heating of continuous carbon-fiber-reinforced polymers (CFRP's) by the application of an alternating magnetic field has been shown to be due to dielectric losses in the polymer. Models that predict thermal generation in these composites are input to a finite element heat-transfer analysis, providing the predicted transient thermal profile in the plane of the laminate. The validity of the global thermal generation model is established through an experimental test matrix in which various specimen configurations are evaluated and compared with theoretical predictions of transient surface temperatures.