Download or read book Mod lisation m canique et simulation num rique de la mise en forme des structures en tr s faibles dimensions written by Jean-François Michel and published by . This book was released on 2002 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les travaux de recherche concernent le développement et la mise en œuvre de nouveaux critères de détection des défauts de striction localisée/éclatement et de plissement/flambage lors de procédés d'emboutissage et d'hydroformage de structures minces. La striction est considérée comme une instabilité du flux de matière. Elle est modélisée via une Analyse Linéaire de Stabilité (ALS) par méthode de perturbation étendue à un état tridimensionnel. Ainsi, de nouveaux modes de striction sont repérés. De plus, le critère initial est amélioré par la détermination rigoureuse du seuil d'instabilité différenciant l'instabilité effective de l'instabilité absolue. Des Courbes Limites de Formage sont construites pour étudier l'influence de paramètres de comportement matériel sur l'apparition de la striction/éclatement. Enfin l'ALS appliquée à une plaque e flexion pure montre que les défauts observés ne sont pas dus à un phénomène de striction. Concernant le plissement, ce défaut semble plus correspondre à un problème de bifurcation qu'à un problème d'instabilité. Dans cet ouvrage, une nouvelle analyse basée sur l'équilibre d'une plaque est développée. De plus, l'analyse qualitative de Nordlund et Häggblad est reprise. Enfin, un nouveau critère basé sur une méthode de perturbation est développé en annexe. Les modélisations présentées pour la détection de striction/éclatement et de plissement/flambage ont été intégrées dans le code POLYFORMâ de simulation par éléments finis des procédés d'emboutissage et d'hydroformage. L'influence des paramètres de procédés et de comportement matériel sur la prédiction des défauts lors de simulations est présentée. La validation expérimentale des prédictions est réalisée pour un procédé d'hydroformage oscillant. L'influence des paramètres de ce procédé sur l'apparition de défauts est également observée.
Download or read book Mod lisation du comportement des structures souples written by Ilyes Ben Naceur and published by Presses Academiques Francophones. This book was released on 2014-11-18 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: La mise en forme des structures souples, tel que les etoffes, necessite la connaissance de leurs comportements mecanique et thermique. Une etude experimentale permet de caracteriser le comportement mecanique en traction simple et biaxiale et l'aptitude a la deformation de l'etoffe. De meme une etude thermique permet de modeliser l'influence des parametres temps et temperature par rapport a la thermofixation de l'etoffe tout en tenant compte de l'effet du lavage sur le retour elastique. Pour la modelisation de la capacite de deformation de l'etoffe, une approche mesoscopique discrete est proposee avec un comportement elastique non lineaire. Pour cette approche, l'etoffe est discretisee par des elements finis barres et membranes pour tenir compte de l'heterogeneite. La deuxieme approche proposee est basee sur la methode des elements finis UEL developpes pour tenir compte de l'effet biaxial. Enfin, des simulations de mise en forme sont proposees pour valider les modeles et tester la capacite de deformation tridimensionnelle de l'etoffe.
Download or read book Contribution la modelisation et la simulation num rique des effets d chelle en mise en forme written by Nicolas Pernin and published by . This book was released on 2005 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: La modélisation des procédés de mise en forme de pièces métalliques en faibles dimensions nécessite de tenir compte de phénomènes appelés effets d'échelle. Après une revue bibliographique des technologies liées aux procédés de micro-formage de pièces minces et massives, deux principaux effets d'échelle sont mis en évidence : un effet tribologique et un effet rhéologique. Afin de prendre en compte les effets rhéologiques, trois approches sont proposées. Le premier modèle développé est un modèle cœur-peau qui consiste à modéliser le comportement du matériau en distinguant le cœur et la peau du matériau. Ce modèle permet de traduire l'effet de grains moins écrouissable en surface qu'à cœur de la pièce. Le second modèle est un modèle à gradient de plasticité : un terme en laplacien de la déformation plastique équivalente est ajouté dans la relation d'écrouissage qui figure dans le critère de plasticité. Le Laplacien de la déformation plastique équivalente à un certain point d'intégration est déterminé à partir des dérivées d'un polynôme, qui est interpolé en utilisant les valeurs du multiplicateur plastique aux points d'intégration voisins. Le dernier modèle est un modèle d'endommagement non local au sens de Gurson-Tvergaard-Needleman. La fraction volumique de cavité est régularisée par une équation intégrale sur un certain voisinage de chaque point d'intégration de Gauss. Les trois modèles ont été implémentés dans le code de calculs par éléments finis POLYFORM dédié aux grandes déformations. Cette intégration est réalisée dans le cadre d'une approche quasi statique implicite. Un ensemble de tests numériques valide l'intégration numérique des modélisations proposées.
Download or read book Symmetric Galerkin Boundary Element Method written by Alok Sutradhar and published by Springer Science & Business Media. This book was released on 2008-09-26 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: Symmetric Galerkin Boundary Element Method presents an introduction as well as recent developments of this accurate, powerful, and versatile method. The formulation possesses the attractive feature of producing a symmetric coefficient matrix. In addition, the Galerkin approximation allows standard continuous elements to be used for evaluation of hypersingular integrals. FEATURES • Written in a form suitable for a graduate level textbook as well as a self-learning tutorial in the field. • Covers applications in two-dimensional and three-dimensional problems of potential theory and elasticity. Additional basic topics involve axisymmetry, multi-zone and interface formulations. More advanced topics include fluid flow (wave breaking over a sloping beach), non-homogeneous media, functionally graded materials (FGMs), anisotropic elasticity, error estimation, adaptivity, and fracture mechanics. • Presents integral equations as a basis for the formulation of general symmetric Galerkin boundary element methods and their corresponding numerical implementation. • Designed to convey effective unified procedures for the treatment of singular and hypersingular integrals that naturally arise in the method. Symbolic codes using Maple® for singular-type integrations are provided and discussed in detail. • The user-friendly adaptive computer code BEAN (Boundary Element ANalysis), fully written in Matlab®, is available as a companion to the text. The complete source code, including the graphical user-interface (GUI), can be downloaded from the web site http://www.ghpaulino.com/SGBEM_book. The source code can be used as the basis for building new applications, and should also function as an effective teaching tool. To facilitate the use of BEAN, a video tutorial and a library of practical examples are provided.
Download or read book Adhesion Between Polymers and Concrete Adh sion Entre Polym res Et B ton written by H. R. Sasse and published by Springer. This book was released on 1986 with total page 792 pages. Available in PDF, EPUB and Kindle. Book excerpt: Preface Adhesion is a phenomenon architects and civil engineers are not very familiar with. In other disciplines knowledge about surface properties and the background of bonding energies is also far from satisfactory; nevertheless there are many important· applications in concrete engineering, where adhesion is necessary for success and durability. These include: - coating and painting - repair of concrete surfaces - bonding of fresh to old concrete - crack injection - glueing of precast elements - glueing of steel to concrete, etc. In 1981 RILEM established the technical committee 52-RAC 'Resin Adherence to Concrete'. The main aims of the committee's work were - to collect research results and practical experiences - to initiate and coordinate research programs - to develop, on a scientific base, test methods for field and for laboratory purposes. One of the results of the committee's work is a state-of-the-art report, which will be presented orally as a General Report at the International Symposium ISAP '86, and will be printed either in the RILEM journal Materials and Structures or separately. Several test recommendations have been elaborated and will be prepared as drafts for the participants ofISAP '86. These are: - direct tensile test - pull-off test - direct shear test - slant shear test - four-point bending test - dynamic loading test - thermal compatibility test (two versions) - injectibility test.
Download or read book Charges Et Les Sp cifications Des Avions Militaires written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Structures and Materials Panel. Meeting and published by . This book was released on 1997 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dynamique Non lin aire Et Le Chaos written by and published by . This book was released on 1993 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanics of Porous Media written by Philippe Charlez and published by CRC Press. This book was released on 1995-01-01 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work presents the lecture notes of the 1994 Mechanics of Porous Media Summer School. Chapters cover theoretical basics, methods for measuring poroelastic coefficients, numerical implementation and applications.
Download or read book Neighbourhoods in Transition written by Emmanuel Rey and published by Springer Nature. This book was released on 2021-09-25 with total page 257 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book is focused on the intersection between urban brownfields and the sustainability transitions of metreopolitan areas, cities and neighbourhoods. It provides both a theoretical and practical approach to the topic, offering a thorough introduction to urban brownfields and regeneration projects as well as an operational monitoring tool. Neighbourhoods in Transition begins with an overview of historic urban development and strategic areas in the hearts of towns to be developed. It then defines several key issues related to the topic, including urban brownfields, regeneration projects, and sustainability issues related to neighbourhood development. The second part of this book is focused on support tools, explaining the challenges faced, the steps involved in a regeneration process, and offering an operational monitoring tool. It applies the unique tool to case studies in three selected neighbourhoods and the outcomes of one case study are also presented and discussed, highlighting its benefits. The audience for this book will be both professional and academic. It will support researchers as an up-to-date reference book on urban brownfield regeneration projects, and also the work of architects, urban designers, urban planners and engineers involved in sustainability transitions of the built environment.
Download or read book Solid Propellant Rocket Research written by Martin Summerfield and published by Elsevier. This book was released on 2013-11-11 with total page 713 pages. Available in PDF, EPUB and Kindle. Book excerpt: Solid Propellant Rocket Research
Download or read book Product Life Cycle Management written by Max Giordano and published by John Wiley & Sons. This book was released on 2012-12-17 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives a comprehensive view of the most recent major international research in the field of tolerancing, and is an excellent resource for anyone interested in Computer Aided Tolerating. It is organized into 4 parts. Part 1 focuses on the more general problems of tolerance analysis and synthesis, for tolerancing in mechanical design and manufacturing processes. Part 2 specifically highlights the simulation of assembly with defects, and the influence of tolerances on the quality of the assembly. Part 3 deals with measurement aspects, and quality control throughout the life cycle. Different measurement technologies and methods for estimating uncertainty are considered. In Part 4, different aspects of tolerancing and their interactions are explored, from the definition of functional requirement to measurement processes in a PLM approach.
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 Advances in Hydroinformatics written by Philippe Gourbesville and published by Springer. This book was released on 2015-08-21 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a collection of extended papers based on presentations given during the SIMHYDRO 2014 conference, held in Sophia Antipolis in June 2014. It focuses on the modeling and simulation of fast hydraulic transients, on 3D modeling, and on uncertainties and multiphase flows. The book explores both the limitations and performance of current models and presents the latest developments based on new numerical schemes, high-performance computing, multiphysics and multiscale methods, and better interaction with field or scale model data. It addresses the interests of practitioners, stakeholders, researchers and engineers active in this field.
Download or read book AGARD Conference Proceedings written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development and published by . This book was released on 1994 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Physics on Manifolds written by M. Flato and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 365 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains the proceedings of the Colloquium "Analysis, Manifolds and Physics" organized in honour of Yvonne Choquet-Bruhat by her friends, collaborators and former students, on June 3, 4 and 5, 1992 in Paris. Its title accurately reflects the domains to which Yvonne Choquet-Bruhat has made essential contributions. Since the rise of General Relativity, the geometry of Manifolds has become a non-trivial part of space-time physics. At the same time, Functional Analysis has been of enormous importance in Quantum Mechanics, and Quantum Field Theory. Its role becomes decisive when one considers the global behaviour of solutions of differential systems on manifolds. In this sense, General Relativity is an exceptional theory in which the solutions of a highly non-linear system of partial differential equations define by themselves the very manifold on which they are supposed to exist. This is why a solution of Einstein's equations cannot be physically interpreted before its global behaviour is known, taking into account the entire hypothetical underlying manifold. In her youth, Yvonne Choquet-Bruhat contributed in a spectacular way to this domain stretching between physics and mathematics, when she gave the proof of the existence of solutions to Einstein's equations on differential manifolds of a quite general type. The methods she created have been worked out by the French school of mathematics, principally by Jean Leray. Her first proof of the local existence and uniqueness of solutions of Einstein's equations inspired Jean Leray's theory of general hyperbolic systems.
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 Mechanical Vibration written by William John Palm and published by . This book was released on 2007 with total page 728 pages. Available in PDF, EPUB and Kindle. Book excerpt: Model, analyze, and solve vibration problems, using modern computer tools. Featuring clear explanations, worked examples, applications, and modern computer tools, William Palm's Mechanical Vibration provides a firm foundation in vibratory systems. You'll learn how to apply knowledge of mathematics and science to model and analyze systems ranging from a single degree of freedom to complex systems with two and more degrees of freedom. Separate MATLAB sections at the end of most chapters show how to use the most recent features of this standard engineering tool, in the context of solving vibration problems. The text introduces Simulink where solutions may be difficult to program in MATLAB, such as modeling Coulomb friction effects and simulating systems that contain non-linearities. Ample problems throughout the text provide opportunities to practice identifying, formulating, and solving vibration problems. KEY FEATURES Strong pedagogical approach, including chapter objectives and summaries Extensive worked examples illustrating applications Numerous realistic homework problems Up-to-date MATLAB coverage The first vibration textbook to cover Simulink Self-contained introduction to MATLAB in Appendix A Special section dealing with active vibration control in sports equipment Special sections devoted to obtaining parameter values from experimental data
