Download or read book ENDOMMAGEMENT ET FISSURATION EN FLUAGE DE POLYETHYLENES EXTRUDES written by HEDI.. BEN HADJ HAMOUDA and published by . This book was released on 2000 with total page 267 pages. Available in PDF, EPUB and Kindle. Book excerpt: CE TRAVAIL A POUR BUT LE DEVELOPPEMENT ET LA VALIDATION D'OUTILS PERMETTANT LA PREVISION DES DUREES DE VIE EN FLUAGE DES CANALISATIONS DE GAZ EN POLYETHYLENE. TOUS LES ESSAIS MECANIQUES, PRESENTES DANS LE PREMIER CHAPITRE, ONT ETE MENES A HAUTES TEMPERATURES (40, 60 ET 80\C) AFIN D'ACCELERER LES PROCESSUS D'ENDOMMAGEMENT ET DE RUPTURE ET D'ECOURTER AINSI LES DUREES DES TESTS. LE DEUXIEME CHAPITRE CONCERNE L'ETUDE DE L'ENDOMMAGEMENT. LES MECANISMES D'AMORCAGE ET DE PROPAGATION DE MICRO ET MACRO-FISSURES ONT ETE MIS EN EVIDENCE ET INTERPRETES EN TENANT COMPTE DE LA STRUCTURE SEMI-CRISTALLINE DU MATERIAU. IL A ETE NOTAMMENT MONTRE QUE LES STRUCTURES EN PE PEUVENT S'ENDOMMAGER DANS LA GLOBALITE DE LEURS VOLUMES. CET ENDOMMAGEMENT S'AMORCE SOIT SUR UN DEFAUT EXTERNE (FISSURE) SOIT SUR DES PARTICULES DE RESIDUS CATALYTIQUES DISPERSEES DANS LE MATERIAU. DANS LE PREMIER CAS LA FISSURE SE PROPAGE PAR BANDES DISCONTINUES. DANS LE SECOND, UNE PHASE DE CROISSANCE DE ZONE MIROIR AUTOUR DU SITE D'AMORCAGE PRECEDE LA PROPAGATION PAR BANDES DISCONTINUES. LE TROISIEME CHAPITRE EST CONSACRE A L'APPLICATION DE L'APPROCHE LOCALE A CE PROBLEME DE FISSURATION. LE DEVELOPPEMENT DES OUTILS NECESSAIRES A LA QUANTIFICATION DE L'ENDOMMAGEMENT A PERMIS DE PREDIRE L'AMORCAGE ET LA PROPAGATION DE DEFAUTS MACROSCOPIQUES. DANS CETTE OPTIQUE UNE LOI DE COMPORTEMENT VISCOPLASTIQUE NONLINEAIRE ET UNE LOI INCREMENTALE D'ENDOMMAGEMENT ONT ETE PROPOSEES. DANS LE QUATRIEME CHAPITRE LE PROBLEME A ETE ABORDE PAR L'APPROCHE GLOBALE. LA DEMARCHE REPOSE SUR LA MECANIQUE NON LINEAIRE DE LA RUPTURE. ELLE CONSISTE A DETERMINER LES PARAMETRES PERTINENTS CONTROLANT LA RHEOLOGIE ET L'ENDOMMAGEMENT DU MATERIAU. DANS NOTRE CAS LA CORRELATION DU PARAMETRE DE CHARGEMENT C* A LA DUREE DE VIE DE STRUCTURES SOLLICITEES EN FLUAGE A PERMIS D'ETABLIR UNE COURBE MAITRESSE VALABLE SUR UNE LARGE PLAGE DE TEMPERATURE.

Download or read book Deformation and Fracture Behaviour of High density Polyethylene Pipe Materials written by Mehdi Mehdizadeh-Kafash and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: L'utilisation des matériaux polvmères dans les applications de l'ingénierie augmente de plus en plus de part le monde. L'utilisation du polyéthvlène (PE) dans la construction de canalisations est l'un des exemples les plus courant. Ceci exige de nouvelles méthodes afin d'évaluer la capacité du matériau à supporter des chargements mecamques. Dans la présente thèse, le comportement contrainte-déformation en grandes dètformations du PE haute densité (PEHD) a été examinée dans différentes configurations de triaxialité. Un large domaine de conditions de chargements (traction. compression et cisaillement simple) a été exploré. L'investigation a été réalisée à partir d'échantillons découpés dans des canalisations en PEHD. Les essais de traction ont été faits à partir d'échantillons sabliers présentant plusieurs rayons de courbure afin de fixer différents états de contrainte dans la section médiane Une attention particulière a été portée à l'évolution de la déformation volumique résultant de l'endommagement par cavitation. L'effet de la triaxialité sur la déformation à rupture a pu également être dégagé. La méthode des éléments fims (EF) a été utilisée pour simuler le comportement en grandes déformations du PEHD. De plus. le phénoméne d'endommagement par croissance de vide a été étudié à partir de cellules unitaires soumises à différentes conditions de triaxialité. Afin d'évaluer le comportement à la rupture du PEHD. une méthode expérimentale basée sur l'hypothèse de la séparation de la charge a èté élaborée. En outre une analyse numérique par EF a été réalisée pour le calcul des paramètres de rupture. L'investigation a été réalisée dans les dIrections longitudinale et radiale. d'évaluer le comportement à la rupture du PEHD. une méthode expérimentale basée sur l'hypothèse de la séparation de la charge a èté élaborée. En ! outre. une analyse numérique par EF a été réalisée pour le calcul des paramètres de rupture. L'investigation a été réalisée dans les directions longitudinale et radiale.

Download or read book Creep and Relaxation of Nonlinear Viscoelastic Materials written by William N. Findley and published by Courier Corporation. This book was released on 2013-01-15 with total page 402 pages. Available in PDF, EPUB and Kindle. Book excerpt: This pioneering book presents the basic theory, experimental methods, experimental results and solution of boundary value problems in a readable, useful way to designers as well as research workers and students. The mathematical background required has been kept to a minimum and supplemented by explanations where it has been necessary to introduce specialized mathematics. Also, appendices have been included to provide sufficient background in Laplace transforms and in step functions. Chapters 1 and 2 contain an introduction and historic review of creep. As an aid to the reader a background on stress, strain, and stress analysis is provided in Chapters 3 and 4, an introduction to linear viscoelasticity is found in Chapter 5 and linear viscoelastic stress analysis in Chapter 6. In the next six chapters the multiple integral representation of nonlinear creep and relaxation, and simplifications to single integral forms and incompressibility, are examined at length. After a consideration of other representations, general relations are derived, then expanded to components of stress or strain for special cases. Both constant stress (or strain) and variable states are described, together with methods of determining material constants. Conversion from creep to relaxation, effects of temperature and stress analysis problems in nonlinear materials are also treated here. Finally, Chapter 13 discusses experimental methods for creep and stress relaxation under combined stress. This chapter considers especially those experimental problems which must be solved properly when reliable experimental results of high precision are required. Six appendices present the necessary mathematical background, conversion tables, and more rigorous derivations than employed in the text. An extensive updated bibliography completes the book.

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 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 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 The Phenomenological Theory of Linear Viscoelastic Behavior written by Nicholas W. Tschoegl and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 791 pages. Available in PDF, EPUB and Kindle. Book excerpt: One of the principal objects of theoretical research in any department of knowledge is to find the point of view from which the subject appears in its greatest simplicity. J. Willard Gibbs This book is an outgrowth of lectures I have given, on and off over some sixteen years, in graduate courses at the California Institute of Technology, and, in abbreviated form, elsewhere. It is, nevertheless, not meant to be a textbook. I have aimed at a full exposition of the phenomenological theory of linear viscoelastic behavior for the use of the practicing scientist or engineer as well as the academic teacher or student. The book is thus primarily a reference work. In accord with the motto above, I have chosen to describe the theory of linear viscoelastic behavior through the use of the Laplace transformation. The treatment oflinear time-dependent systems in terms of the Laplace transforms of the relations between the excitation add response variables has by now become commonplace in other fields. With some notable exceptions, it has not been widely used in viscoelasticity. I hope that the reader will find this approach useful.

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 Physical Networks written by Walther Burchard and published by Springer Science & Business Media. This book was released on 1990-05-31 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Creep and Fracture of Engineering Materials and Structures written by T. Sakuma and published by Trans Tech Publications Ltd. This book was released on 1999-10-12 with total page 888 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume is indexed by Thomson Reuters CPCI-S (WoS). Recent research on the creep and fracture of engineering materials is presented, with particular emphasis being placed on: mechanisms of high-temperature deformation and fracture, materials for high-temperature service, the behavior of single and polycrystals, components and structures, grain boundaries and interfaces, and superplasticity.

Download or read book Reliability of Reactor Pressure Components written by International Atomic Energy Agency and published by Bernan Press(PA). This book was released on 1983 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 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 Niobium Science and Technology written by International Symposium Niobium and published by . This book was released on 2002 with total page 1162 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Micro Mesoporous Materials written by K. Hadjiivanov and published by Heron Press. This book was released on 2008-10-31 with total page 391 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modelling and Simulation in Thermal and Chemical Engineering written by J. Thoma and published by Springer Science & Business Media. This book was released on 2000 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main object of this book is modeling and simulation of energetic processes by bond graphs. But even without knowledge of this powerful method it can be used to a certain extent as an introduction to simulation in thermodynamics. The book addresses advanced students, lecturers and researchers in mechanical engineering and automation as well as experienced engineers in process industries.