Download or read book ETUDE DE LA RESISTANCE A LA PROPAGATION DES FISSURES DANS UN MILIEU HETEROGENE COHERENT written by Nadia Feknous and published by . This book was released on 1986 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: POUR LES STRUCTURES EN BETON ON CONNAIT MAL LES MECANISMES INTERNES DE LA PROPAGATION D'UNE FISSURE EN RELATION AVEC L'HETEROGENEITE DU MATERIAU, EN PARTICULIER LE ROLE JOUE PAR LES GRANULATS, D'OU LA RECHERCHE DE L'INFLUENCE DE CES DERNIERS SUR LA PROPAGATION D'UNE FISSURE. CONCEPTION ET REALISATION D'UNE MACHINE DE RUPTURE EN MODE I. ETUDE EXPERIMENTALE DE L'EVOLUTION DE L'ENERGIE SPECIFIQUE DE RUPTURE ET CELLE DE LA FORCE EXTERIEURE AU COURS DE LA PROPAGATION ET COMPARAISON DES ENERGIES MISES EN JEU SUIVANT QUE LE MODELE CONTIENT OU NON UN TROU OU UNE INCLUSION ADHERENTE OU NON DE LA MATRICE.
Download or read book tude de la r sistance la propagation d une fissure d un mat riau fragile granulaire coh rent written by Pierre Allevy (auteur d'une thèse de sciences.) and published by . This book was released on 1978 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: ON ETUDIE LA RESISTANCE A LA FISSURATION D'UN MATERIAU DE TYPE MORTIER OU BETON, EN UTILISANT UN MODELE DE MATERIAU HOMOGENE OU LE GRANULAT EST SCHEMATISE PAR UNE INCLUSION CIRCULAIRE. ON PRESENTE LES GRANDEURS CARACTERISTIQUES DE LA RESISTANCE A LA PROPAGATION D'UNE FISSURE ET LES METHODES PERMETTANT DE LA DETERMINER. PROBLEME DU CHOIX D'UN TYPE D'EPROUVETTE ET DES METHODES EXPERIMENTALES. ON ETUDIE LA RESISTANCE A LA PROPAGATION DE FISSURE D'UN MATERIAU EN FONCTION DE LA NATURE ET DE LA CONCENTRATION DES CONSTITUANTS. ON DONNE UN MODELE THEORIQUE
Download or read book Etude de la resistance la propagation d une fissure d un materiau fragile granulaire coherent written by Pierre Allevy and published by . This book was released on 1978 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book ETUDE DE LA RESISTANCE A LA PROPAGATION DE FISSURE DANS DES CERAMIQUES MONOLITHIQUES DE TYPE ALUMINE ET ZIRCONE written by MALIKA.. SAADAOUI and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: NOUS AVONS ETUDIE LA RESISTANCE A LA PROPAGATION DE FISSURE DE DEUX TYPES DE CERAMIQUES MONOLITHIQUES: UNE ALUMINE COMMERCIALE ET UNE ZIRCONE PARTIELLEMENT STABILISEE A LA MAGNESIE (MG-PSZ), CONSTITUEE D'UNE MATRICE CUBIQUE CONTENANT DES PRECIPITES DE PHASE TETRAGONALE ET MONOCLINIQUE. LES COURBES DE RESISTANCE A LA PROPAGATION DE FISSURE (COURBE R) DE CES MATERIAUX ONT ETE DETERMINEES DANS DIFFERENTES CONDITIONS D'ESSAI: ENVIRONNEMENT, VITESSE DE DEFORMATION, FORME DE LA PREFISSURE, TEMPERATURE (HAUTE ET BASSE TEMPERATURE). LES RESULTATS SONT DISCUTES PAR RAPPORT A LA MICROSTRUCTURE DES MATERIAUX ET AUX MECANISMES DE RENFORCEMENT MIS EN JEU: TRANSFORMATION DE PHASE, MICROFISSURATION OU PONTAGE DE FISSURE. UNE CORRELATION ENTRE L'INFLUENCE DES CONDITIONS D'ESSAI ET LA MICROSTRUCTURE A ETE MISE EN EVIDENCE AINSI QUE L'EFFET DE LA CROISSANCE SOUS CRITIQUE SUR LES COURBES R
Download or read book ETUDE DU PROCESSUS DE PROPAGATION DE FISSURES PAR FATIGUE DANS LE BETON written by Ahmed Toumi and published by . This book was released on 1998 with total page 169 pages. Available in PDF, EPUB and Kindle. Book excerpt: CE TRAVAIL, COUPLANT UNE PARTIE EXPERIMENTALE ET UNE PARTIE NUMERIQUE EST CENTRE SUR L'ETUDE DE LA PROPAGATION DE FISSURES DE FATIGUE DANS LE BETON. LA PARTIE EXPERIMENTALE S'INTERESSE A L'ETUDE DU PROCESSUS DE DEVELOPPEMENT DE FISSURES D'UN POINT DE VUE PHENOMENOLOGIQUE, TANDIS QUE L'ETUDE NUMERIQUE S'ATTACHE A MODELISER LE COMPORTEMENT REEL DES EPROUVETTES EN TENANT COMPTE DES PRINCIPAUX MECANISMES OBSERVES. L'ETUDE EST EFFECTUEE SUR DES EPROUVETTES DE MICRO-BETON, ENCOCHEES ET TESTEES EN MODE I DE RUPTURE PAR FLEXION TROIS POINTS. LES ESSAIS SONT CONDUITS SOUS ATMOSPHERE SATUREE, ET L'OBSERVATION DU PROCESSUS DE PROPAGATION EST REALISEE AU MICROSCOPE ELECTRONIQUE A BALAYAGE (MEB), MOYENNANT LA TECHNIQUE DE SIMPLE REPLIQUE. LES RESULTATS D'OBSERVATIONS MICROSCOPIQUES MONTRENT QUE, SOUS CHARGEMENT STATIQUE, L'AMORCE D'UNE FISSURE UNIQUE SE PRODUIT A UN SEUIL D'ENVIRON 60% DU PIC DE CHARGE. LES RESULTATS D'OBSERVATIONS MONTRENT QUE LES MECANISMES DE PROPAGATION DES FISSURES DE FATIGUE, SIMILAIRES EN SURFACE ET AU CUR DES ECHANTILLONS, SE CARACTERISENT ESSENTIELLEMENT PAR DES PHENOMENES DE BRANCHEMENTS. CONTRAIREMENT AUX ESSAIS STATIQUES, LE FRONT DE FISSURE EST PLAT DES LES PREMIERS CYCLES. LES BRANCHEMENTS SE SONT REVELES ETRE LE RESULTAT DE LA FORTE INTERACTION ENTRE LES SURFACES DE FRACTURE. LES LONGUEURS DE FISSURES EVALUEES PAR LA METHODE DE LA COMPLIANCE SONT EN EFFET TRES SOUS ESTIMEES EN COMPARAISON AVEC LES LONGUEURS MESUREES. LA CINETIQUE DE PROPAGATION EST CONFRONTEE AU MODELE DE PARIS. LES RESULTATS MONTRENT QUE LA VALIDITE DE CE MODELE EST ETROITEMENT LIEE AU TAUX DE CHARGE MAXIMAL DES CYCLES. LA MODELISATION NUMERIQUE PROPOSEE PAR ELEMENTS FINIS EST DE TYPE ELASTIQUE AVEC FISSURE COHESIVE, OU UN CRITERE EN CONTRAINTES DETERMINE LE CRITERE DE PROPAGATION. LA LOI DE COMPORTEMENT EN TRACTION INTRODUITE S'APPUIE D'UNE PART SUR LA RESISTANCE EN TRACTION ET L'ENERGIE DE FISSURATION MESUREES, ET D'AUTRE PART SUR LA LOI D'HYSTERESIS DETERMINEE PAR METHODE INVERSE. LE MODELE EST VALIDE SUR LES ESSAIS DE FLEXION STATIQUES ET CYCLIQUES.
Download or read book Etude de la r sistance au choc et des m canismes d amor age et de propagation rapide de fissures dans les P E H D written by Amar Kifani and published by . This book was released on 1987 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: L’objet de ce travail est d’examiner les mécanismes d’amorçage et d’instabilité de la propagation de fissures dans les P.E.H.D. Le comportement en fissuration très rapide a été étudié à l’aide d’essais en choc instrumenté sur des éprouvettes de flexion trois points entaillées. L4étude a porté sur l’influence de la vitesse d’impact, de la température et de l’épaisseur sur la ténacité et les modes de propagation stable et instable. Les mécanismes d’amorçage et d’instabilité ont été étudiés en évaluant les vitesses de propagation stable et instable et en examinant les faciès de rupture. A température ambiante, ces produits présentent une zone de propagation stable et des lèvres ductiles importantes. Il a été donc été nécessaire caractériser ces produits par une courbe R. Le modèle de T. VU-KHANH valable pour les matériaux semi-ductiles a été appliqué pour ces produits. Les conclusions suivantes peuvent être proposées : -La longueur de la propagation stable est indépendante de la longueur initiale de l’entaille. Elle diminue lorsque la vitesse de sollicitation augmente ou lorsque la température diminue. -La vitesse de propagation stable augmente peu avec l’avancée de la fissure. – La vitesse de propagation instable est constante pour chaque produit. –Dans la phase stable la fissure avance par rupture des craquelures. Dans cette zone la dimension des microvides et l’épaisseur des fibrilles diminuent avec la température. –La zone de propagation instable montre des étirements ductiles moins importants que ceux de la phase stable. En conclusion, le critère de choix des matériaux (de même famille) ayant un comportement semi-ductile en choc, comme les PEHD peut être basé sur la ténacité car le produit à ténacité élevée présente une énergie moyenne de propagation stable faible et une énergie de propagation instable importante se traduisant par une phase de propagation stable importante et une phase de propagation instable faible. Ainsi, le meilleur produit (le moins propageant) est celui qui présente une phase de propagation stable importante.
Download or read book Endommagement de milieux h t rog nes written by François Villette and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: La compréhension, la modélisation et la prévision de la rupture dans les matériaux hétérogènes sont des enjeux importants pour de nombreuses applications comme la résistance des structures de génie-civil ou les détachements de blocs rocheux par exemple. Actuellement, la modélisation de la fissuration dans les modèles d'endommagement fait intervenir une longueur interne qui n'est pas encore reliée explicitement aux longueurs caractéristiques du matériau. L'objectif de ce travail est d'étudier l'influence des hétérogénéités du matériau sur les processus de fissuration en utilisant le papier comme matériau d'étude. Ce matériau a en effet la propriété de révéler sa structure (fibres et agrégats de fibres) par transmission optique et permet ainsi de suivre l'évolution de l'endommagement au cours de la rupture à moindres coûts. Dans un premier temps, les propriétés structurales et mécaniques locales des agrégats de fibres ont été obtenues à partir d'images acquises par tomographie à rayons X et d'essais de tractions. Des essais de traction filmés ont ensuite permis de visualiser le développement de la zone d'endommagement et de relier ses dimensions au comportement post-pic de la courbe de traction. Sur la base de cette analyse, une méthode originale de calage de la longueur interne a été proposée sur un modèle d'endommagement continu non local. Le rôle des différentes longueurs caractéristiques du matériau a été mis en évidence par ces résultats qui ont été complétés par une étude de la statistique de propagation de fissure dans un matériau hétérogène en utilisant un Fiber Bundle Model (modèle à faisceaux de fibres), que nous avons dans le cadre de cette thèse étendu à des champs aléatoires de rupture corrélés dans l'espace.
Download or read book Spaces and Identities in Border Regions written by Christian Wille and published by transcript Verlag. This book was released on 2015-11-30 with total page 385 pages. Available in PDF, EPUB and Kindle. Book excerpt: Spatial and identity research operates with differentiations and relations. These are particularly useful heuristic tools when examining border regions where social and geopolitical demarcations diverge. Applying this approach, the authors of this volume investigate spatial and identity constructions in cross-border contexts as they appear in everyday, institutional and media practices. The results are discussed with a keen eye for obliquely aligned spaces and identities and relinked to governmental issues of normalization and subjectivation. The studies base upon empirical surveys conducted in Germany, France, Belgium and Luxembourg.
Download or read book Globalizing Race written by Dorian Bell and published by Northwestern University Press. This book was released on 2018-04-15 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: Globalizing Race explores how intersections between French antisemitism and imperialism shaped the development of European racial thought. Ranging from the African misadventures of the antisemitic Marquis de Morès to the Parisian novels and newspapers of late nineteenth-century professional antisemites, Dorian Bell argues that France’s colonial expansion helped antisemitism take its modern, racializing form—and that, conversely, antisemitism influenced the elaboration of the imperial project itself. Globalizing Race radiates from France to place authors like Guy de Maupassant and Émile Zola into sustained relation with thinkers from across the ideological spectrum, including Hannah Arendt, Friedrich Nietzsche, Frantz Fanon, Karl Marx, Max Horkheimer, and Theodor Adorno. Engaging with what has been called the “spatial turn” in social theory, the book offers new tools for thinking about how racisms interact across space and time. Among these is what Bell calls racial scalarity. Race, Bell argues, did not just become globalized when European racism and antisemitism accompanied imperial penetration into the farthest reaches of the world. Rather, race became most thoroughly global as a method for constructing and negotiating the different scales (national, global, etc.) necessary for the development of imperial capitalism. As France, Europe, and the world confront a rising tide of Islamophobia, Globalizing Race also brings into fascinating focus how present-day French responses to Muslim antisemitism hark back to older, problematic modes of representing the European colonial periphery.
Download or read book Terra 2008 written by Leslie Rainer and published by Getty Publications. This book was released on 2011-06-14 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: Earthen architecture constitutes one of the most diverse forms of cultural heritage and one of the most challenging to preserve. It dates from all periods and is found on all continents but is particularly prevalent in Africa, where it has been a building tradition for centuries. Sites range from ancestral cities in Mali to the palaces of Abomey in Benin, from monuments and mosques in Iran and Buddhist temples on the Silk Road to Spanish missions in California. This volume's sixty-four papers address such themes as earthen architecture in Mali, the conservation of living sites, local knowledge systems and intangible aspects, seismic and other natural forces, the conservation and management of archaeological sites, research advances, and training.
Download or read book Discrete Element Method to Model 3D Continuous Materials written by Mohamed Jebahi and published by John Wiley & Sons. This book was released on 2015-02-26 with total page 198 pages. Available in PDF, EPUB and Kindle. Book excerpt: Complex behavior models (plasticity, cracks, visco elascticity) face some theoretical difficulties for the determination of the behavior law at the continuous scale. When homogenization fails to give the right behavior law, a solution is to simulate the material at a meso scale in order to simulate directly a set of discrete properties that are responsible of the macroscopic behavior. The discrete element model has been developed for granular material. The proposed set shows how this method is capable to solve the problem of complex behavior that are linked to discrete meso scale effects.
Download or read book Deleuze s Philosophical Lineage written by Graham Jones and published by Edinburgh University Press. This book was released on 2009-03-31 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: The philosophy of Gilles Deleuze is increasingly gaining the prestige that its astonishing inventiveness calls for in the Anglo-American theoretical context. His wide-ranging works on the history of philosophy, cinema, painting, literature and politics are being taken up and put to work across disciplinary divides and in interesting and surprising ways. However, the backbone of Deleuze's philosophy - the many and varied sources from which he draws the material for his conceptual innovation - has until now remained relatively obscure and unexplored. This book takes as its goal the examination of this rich theoretical background. Presenting essays by a range of the world's foremost Deleuze scholars, and a number of up and coming theorists of his work, the book is composed of in-depth analyses of the key figures in Deleuze's lineage whose significance - as a result of either their obscurity or the complexity of their place in the Deleuzean text - has not previously been well understood. This work will prove indispensable to students and scholars seeking to understand the context from which Deleuze's ideas emerge.Included are essays on Deleuze's relationship to figures as varied as Marx, Simondon, Wronski, Hegel, Hume, Maimon, Ruyer, Kant, Heidegger, Husserl, Reimann, Leibniz, Bergson and Freud.
Download or read book Structural Conservation of Stone Masonry written by and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book UNESCO General History of Africa Vol I Abridged Edition written by Jacqueline Ki-Zerbo and published by Univ of California Press. This book was released on 1990 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This volume covers the period from the end of the Neolithic era to the beginning of the seventh century of our era. This lengthy period includes the civilization of Ancient Egypt, the history of Nubia, Ethiopia, North Africa and the Sahara, as well as of the other regions of the continent and its islands."--Publisher's description
Download or read book The Time of the City written by Michael Shapiro and published by Routledge. This book was released on 2010-06-17 with total page 227 pages. Available in PDF, EPUB and Kindle. Book excerpt: Engaging with critical theory, poststructuralist perspectives, cultural studies, film theory and urban studies, the book provides stunning insights into the micropolitics of ethnicity, identity, security, subjectivity and sovereignty.
Download or read book The Politics of Housing in Post Colonial Africa written by Kirsten Rüther and published by Walter de Gruyter GmbH & Co KG. This book was released on 2020-06-08 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: Housing matters, no matter when or where. This volume of collected essays on housing in colonial and postcolonial Africa seeks to elaborate the how and the why. Housing is much more than a living everyday practice. It unfolds in its disparate dimensions of time, space and agency. Context dependent, it acquires diverse, often ambivalent, meanings. Housing can be a promise, an unfulfilled dream, a tool of self- and class-assertion, a negotiation process, or a means to achieve other ends. Our focus lies in analyzing housing in its multifacetedness, be it a lens to offer insights into complex processes that shape societies; be it a tool of empire to exercise control over private relations of inhabitants; or be it a means to create good, obedient and productive citizens. Contributions to this volume range from the field of history, to architecture and urban planning, African Studies, linguistics, and literature. The individual case studies home in on specific aspects and dimensions of housing and seek to bring them into dialogue with each other. By doing so, the volume aims to add to the vibrant academic debate on studying urban practices and their significance for current social change.
Download or read book An Introduction to Islamic Cosmological Doctrines written by Seyyed Hossein Nasr and published by State University of New York Press. This book was released on 1993-07-01 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the only book to deal with classical Islamic cosmology as it was formulated by the Ikhwan al-S'afa al Biruni and Ibn Sina during the tenth and eleventh centuries. These figures influenced all the later centuries of Islamic history and in fact created the cosmological framework within which all later scientific activity in the Islamic world was carried out--the enduring image of the cosmos within which Muslims have lived during the past millennium. Nasr writes from within the Islamic tradition and demonstrates how, based on the teachings of the Quran and the Prophet, the figures treated in this work integrated elements drawn from various ancient schools of philosophy and the sciences. This book is unique in its treatment of classical Islamic cosmology as seen from within the Islamic world-view and provides a key for understanding of traditional Islamic thought.
