Download or read book Application de m thodes avanc es de calcul num rique dans la mod lisation et la simulation num rique de l emboutissage written by Julian Rosu and published by . This book was released on 1996 with total page 163 pages. Available in PDF, EPUB and Kindle. Book excerpt: La modélisation mécanique de l'emboutissage conduit a des problèmes aux limites très compliques, a cause de la non-linéarité de la loi de comportement, de la présence des grandes déformations et rotations et de l'évolution des conditions de contact avec frottement. De plus, la réussite d'une opération d'emboutissage impose en général des marges assez étroites de variation de la géométrie de l'outillage et des paramètres technologiques. C'est pourquoi, la simulation numérique de tels processus demande des algorithmes robustes et stables, afin d'éviter des problèmes de convergence jusqu'a la fin du processus de déformation et de pouvoir déterminer les contraintes résiduelles et le retour élastique après enlèvement des outils. Le modèle utilisé dans ce travail considère l'emboutissage 2-d comme un processus de grandes transformations élastoplastiques. Pour le comportement élastique, on considère le matériau isotrope, avec des petites déformations élastiques et un module de Young constant ou variable avec la déformation plastique cumulée. Le comportement plastique est suppose non-visqueux et décrit par un critère de Hill avec anisotropie plastique initiale, par une loi d'écrouissage isotrope, une loi d'écrouissage cinématique linéaire et une loi d'écoulement associée. Le modèle prend en compte la flexion et les déformations de cisaillement a travers l'épaisseur de la tôle et n'introduit donc aucune simplification cinématique de type membrane ou coque mince, la tôle étant considérée comme une coque épaisse. La loi de frottement adoptée est de type coulomb. La tôle est discrétisée en éléments finis volumiques isoparamétriques, la partie sphérique de la déformation étant interpolée par la méthode b-bar. La déformation de la tôle est décrite par un schéma lagrangien réactualisé, le processus étant pilote en déplacements. Le schéma d'intégration temporelle utilise pour chaque pas de temps un prédicateur explicite et un correcteur implicite. La taille du pas est choisie par plusieurs conditions imposées sur la solution obtenue par le prédicateur, en limitant notamment les incréments des déformations, des rotations et des contraintes et la norme des forces non-équilibrées. L'algorithme retenu pour la simulation numérique combine l'utilisation de boucles de contact et d'équilibre, avec la détermination des statuts de contact des nuds selon les forces d'essai selon un algorithme de type lagrangien augmente. Ainsi, l'algorithme général est compose de deux boucles imbriquées. La première boucle est utilisée pour gérer le contact avec frottement, plus précisément pour changer les statuts des nuds et les conditions aux limites. La deuxième, inclue dans la première, assure l'équilibre de la tôle, tout en gardant inchangés les statuts des nuds. Les outils sont décrits par des courbes de Bézier. A chaque outil est associe un statut selon son rôle pendant chaque phase du processus. On distingue ainsi des outils a déplacement impose ou a force imposée. Le déplacement des outils n'est autorise que dans la direction verticale, les déplacements horizontaux étant bloques. Le résultat de cette étude est concrétisé dans un code de calcul permettant la simulation numérique des processus de mise en forme rencontres dans l'industrie automobile. Le code a été soumis à des validations numériques et expérimentales. Les résultats obtenus montrent une très bonne stabilité numérique et une concordance satisfaisante entre le calcul et les données expérimentales
Download or read book MODELISATION MECANIQUE ET SIMULATION NUMERIQUE DU RETOUR ELASTIQUE EN EMBOUTISSAGE DES TOLES MINCES ET OPTIMISATION PARAMETRIQUE written by David Joannic and published by . This book was released on 1998 with total page 175 pages. Available in PDF, EPUB and Kindle. Book excerpt: LA MODELISATION MECANIQUE ET NUMERIQUE DU RETOUR ELASTIQUE APRES EMBOUTISSAGE DES TOLES MINCES EST ENVISAGEE SELON DIFFERENTES STRATEGIES : IMPLICITE QUASI-STATIQUE ET DYNAMIQUE EXPLICITE. LA FORMULATION EST BASEE SUR DES ELEMENTS FINIS DE COQUES MINCES AVEC INTERPOLATION MIXTE DES COMPOSANTES DE CISAILLEMENT TRANSVERSE, DONT L'INTERET POUR LA PREVISION DU RETOUR ELASTIQUE EST DEMONTRE. OUTRE UNE DESCRIPTION PRECISE DU COMPORTEMENT MATERIEL DES TOLES, DIFFERENTES POSSIBILITES SONT ENVISAGEES POUR LA SIMULATION DE LA PHASE DE RETRAIT DES OUTILLAGES. ON DISTINGUE NOTAMMENT UN MODELE SIMPLIFIE CORRESPONDANT AU REMPLACEMENT DES OUTILLAGES PAR LES ACTIONS DE CONTACT QU'ILS EXERCENT ET UN MODELE PLUS REALISTE OU LES OUTILLAGES SONT CONSERVES AVEC UNE CINEMATIQUE CORRESPONDANT AU DECHARGEMENT. DES ESSAIS DE PLIAGE EN U OU V, CARACTERISES PAR UN FORT RETOUR ELASTIQUE, MONTRENT LA PRECISION DONNEE PAR LES METHODES PROPOSEES, PAR RAPPORT A DES RESULTATS NUMERIQUES OU EXPERIMENTAUX. UNE ANALYSE DE SENSIBILITE A ETE DEVELOPPEE POUR L'ANALYSE ET LA COMPREHENSION DU PROCEDE. BASEE SUR UNE METHODE DE DIFFERENCIATION DIRECTE DU SCHEMA DE RESOLUTION DU PROBLEME DIRECT, CETTE ANALYSE EST REALISEE DE MANIERE COHERENTE AVEC LA FORMULATION ELEMENTS FINIS. LES RESULTATS PRESENTES ILLUSTRENT AINSI L'INFLUENCE DES PARAMETRES DE PROCEDE SUR DES GRANDEURS REPRESENTATIVES DU RETOUR ELASTIQUE ET FOURNISSENT DES INDICATIONS TECHNOLOGIQUES UTILES DANS LE CADRE DU CONTROLE DE FORME. LE PROBLEME D'OPTIMISATION DE FORMES DES OUTILLAGES EST ICI TRAITE COMME UN PROBLEME DE MINIMISATION DE L'ERREUR DE FORME ENTRE PIECE REELLE APRES RETOUR ELASTIQUE ET PIECE DESIREE ET UTILISE LE CARACTERE INVERSE DU RETOUR ELASTIQUE. UN EXEMPLE NUMERIQUE EST PRESENTE ET DONNE DES RESULTATS SATISFAISANTS.
Download or read book Etude en grandes transformations d une nouvelle famille d l ments finis coque triangulaire trois degr s de libert par noeud Application la simulation num rique de l emboutissage written by Hervé Laurent and published by . This book was released on 1996 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'OBJECTIF DE CETTE ETUDE EST D'APPORTER DES SOLUTIONS ORIGINALES AUX PROBLEMES D'ORDRE CINEMATIQUE RENCONTRES DANS LA MODELISATION NUMERIQUE DES GRANDES TRANSFORMATIONS. L'APPLICATION PRINCIPALE DES DIFFERENTES METHODES DEVELOPPEES CONCERNE LA SIMULATION NUMERIQUE DU PROCEDE D'EMBOUTISSAGE DES TOLES MINCES. LA PRISE EN COMPTE DES GRANDES TRANSFORMATIONS EST REALISEE A PARTIR DE LA NOTION DE COORDONNEES MATERIELLES ENTRAINEES. DANS CE CONTEXTE, DANS UNE PREMIERE PARTIE, UNE FAMILLE D'ELEMENT FINI DE COQUE TRIANGULAIRE, APPELEE SFE, AVEC TROIS DEGRES DE LIBERTE EN DEPLACEMENT PAR NUD EST PRESENTEE. A PARTIR D'UNE TECHNIQUE DE TYPE DIFFERENCE FINIE, PAR L'INTERMEDIAIRE DES ELEMENTS ADJACENTS A L'ELEMENT CONSIDERE, LA COURBURE EST APPROCHEE ET LES PHENOMENES DE FLEXION SONT PRIS EN COMPTE. LES GAINS DE TEMPS DE CALCUL MAIS AUSSI LA CONSERVATION D'UNE CONTINUITE C#0, TOUT EN RESPECTANT LES HYPOTHESES DE LOVE-KIRCHHOFF, FONT DE CETTE FAMILLE UNE ALTERNATIVE INTERESSANTE AUX ELEMENTS FINIS DE COQUE CLASSIQUE. DANS UNE SECONDE PARTIE, UNE TECHNIQUE ORIGINALE DE MAILLAGE ADAPTATIF DE TYPE-R, PAR RELOCALISATION, EST EXPOSEE. IMPLANTEE DANS LE LOGICIEL DE SIMULATION NUMERIQUE DE L'EMBOUTISSAGE SIMEM3 DE RENAULT, ELLE ASSURE UNE OPTIMISATION EN CONTINU DE LA POSITION DES NUDS EN FONCTION D'UN CRITERE GEOMETRIQUE. LES NUDS DU MAILLAGE, DE NOMBRE FIXE AU COURS DU PROCESSUS, SONT ATTIRES VERS LES REGIONS DE FORTE COURBURE DE MANIERE A MIEUX APPREHENDER LA FORME FINALE DE LA PIECE DEFORMEE. POUR EVITER UNE DISTORSION DES ELEMENTS, PLUSIEURS METHODES SONT INTRODUITES. LE TRANSFERT DES INFORMATIONS DE L'ANCIEN MAILLAGE VERS LE NOUVEAU MAILLAGE EST REALISE A TRAVERS UNE TECHNIQUE NUMERIQUE ORIGINALE. DES CALCULS D'EMBOUTISSAGE INDUSTRIELS, DE COMPLEXITES VARIEES, ILLUSTRENT LES DIFFERENTS AVANTAGES ET INCONVENIENTS DES ELEMENTS FINIS DE COQUE SFE MAIS AUSSI L'INTERET DE LA TECHNIQUE DE MAILLAGE ADAPTATIF PROPOSEE
Download or read book Simulation num rique de l emboutissage M thode a grand incr ment de temps written by Baosheng Liu and published by . This book was released on 1992 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: La simulation numérique de l'emboutissage conduit a des temps de calcul très élevés par les méthodes classiques de newton-raphson a cause de grandes non-linearites physiques, géométriques et de phénomènes surfaciques (contact et frottement). La méthode a grand incrément de temps (magit) ouvre une voie différente en se détachant du cadre incrémental habituel. Cette méthode est établie en vue de rechercher une convergence vers la solution en peu d'itérations. Cette thèse concerne l'application de la magit, avec la réalisation d'un logiciel, pour la simulation des problèmes d'emboutissage. La simulation pratique en 2 dimensions est atteinte et on est optimiste quant à une prochaine application industrielle
Download or read book Engines and Powertrains written by Ronald K Jurgen and published by SAE International. This book was released on 2010-11-29 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: With production and planning for new electric vehicles gaining momentum worldwide, this book – the third in a series of five volumes on this subject – provides engineers and researchers with perspectives on the most current and innovative developments regarding electric and hybrid-electric vehicle technology, design considerations, and components. This book features 13 SAE technical papers, published from 2008 through 2010, that provide an overview of research on electric vehicle engines and powertrains. Topics include: Hybrid-electric vehicle transmissions and propulsion systems The development of a new 1.8-liter engine for hybrid vehicles Vehicle system control software validation The impact of hybrid-electric powertrains on chassis systems and vehicle dynamics High-torque density motors, and interior permanent magnet synchronous motors
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 Food Fray written by Lisa H. WEASEL Ph.D. and published by AMACOM Div American Mgmt Assn. This book was released on 2008-12-10 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: More than ten years ago, the first genetically modified foods took their place on the shelves of American supermarkets. But while American consumers remained blissfully unconcerned with the new products that suddenly filled their kitchens, Europeans were much more wary of these “Frankenfoods.” When famine struck Africa in 2002, several nations refused shipments of genetically modified foods, fueling a controversy that put the issue on the world's political agenda for good. In Food Fray, esteemed molecular biologist Dr. Lisa H. Weasel brings readers into the center of this debate, capturing the real-life experiences of the scientists, farmers, policymakers and grassroots activists on the front lines. Here she combines solid scientific knowledge and a gripping narrative to tell the real story behind the headlines and the hype. Seminal and cutting-edge, Food Fray enlightens and informs and will allow readers to make up their own minds about one of the most important issues facing us today.
Download or read book Modeling Uncertainty in the Earth Sciences written by Jef Caers and published by John Wiley & Sons. This book was released on 2011-05-25 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: Modeling Uncertainty in the Earth Sciences highlights the various issues, techniques and practical modeling tools available for modeling the uncertainty of complex Earth systems and the impact that it has on practical situations. The aim of the book is to provide an introductory overview which covers a broad range of tried-and-tested tools. Descriptions of concepts, philosophies, challenges, methodologies and workflows give the reader an understanding of the best way to make decisions under uncertainty for Earth Science problems. The book covers key issues such as: Spatial and time aspect; large complexity and dimensionality; computation power; costs of 'engineering' the Earth; uncertainty in the modeling and decision process. Focusing on reliable and practical methods this book provides an invaluable primer for the complex area of decision making with uncertainty in the Earth Sciences.
Download or read book Clean Energy Nation written by Gerald McNerney and published by AMACOM Div American Mgmt Assn. This book was released on 2012 with total page 321 pages. Available in PDF, EPUB and Kindle. Book excerpt: Americans are already feeling the pressures of the current energy situation, and many of us are ready to make a change. Clean Energy Nation is a timely and hopeful look at an issue we can't afford to ignore. --Book Jacket.
Download or read book Grammar and Proofreading Course written by Pam Helling and published by AMACOM Div American Mgmt Assn. This book was released on 1992-08-21 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Positive, practical techniques for achieving a more professional writing style. Here are the "how to" keys of writing-from putting the first words on paper to the final polishing and proofreading. Readers will learn how to edit their writing for improved clarity, cut excess words, use transitional phrases, recognize and correct run-on sentences and overcome procrastination and impulsive writing. Readers will learn how to: Identify the key components of any well-written business document Cut excess words and phrases from your writing Use transitional words and phrases Avoid misplaced and dangling modifiers and split infinitives Use commas, semicolons, colons, dashes, and parentheses Use slash marks, ellipsis marks, quotation marks, italics, and brackets Recognize and correct run-on sentences Proofread your writing for clarity of meaning Overcome the two common writing problems that waste time and money-procrastination and impulsive writing. This is an ebook version of the AMA Self-Study course. If you want to take the course for credit you need to either purchase a hard copy of the course through amaselfstudy.org or purchase an online version of the course through www.flexstudy.com.
Download or read book Green Tech written by Lawrence WEBBER and published by AMACOM Div American Mgmt Assn. This book was released on 2009-07-28 with total page 306 pages. Available in PDF, EPUB and Kindle. Book excerpt: With today’s electronic systems consuming massive amounts of energy, and improper disposal of old equipment threatening to release dangerous toxicity into the atmosphere, any company whose IT department isn’t actively working to shrink its carbon footprint isn’t just hurting the environment...it is also probably wasting money. Green Tech provides readers with practical, easily implemented strategies for sustainable computing, showing them how to: • build a business case to influence their organization's green strategy • reduce costs and improve equipment utilization while maintaining current customer service levels • identify old equipment at all levels, as well as suitable green replacements • virtualize servers • find alternative methods for data center cooling • conduct an energy audit and establish an energy baseline • determine the best options for recycling or donating old equipment Filled with realistic, cost-efficient ideas, this book shows that going green isn’t just the right thing to do, but also a good business strategy.
Download or read book Theory Building in Applied Disciplines written by Richard A. Swanson and published by Berrett-Koehler Publishers. This book was released on 2013-08-05 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theory matters in applied disciplines—fields that apply scholarly research to professional practice, such as management, social work, health care, human resource development, education, and many others. Because these disciplines deal with human beings in the real world, a flawed theory can result in actual harm to people and institutions. When faced with a professional problem, practitioners resort to the latest fad or simply throw everything and anything at it because of the lack of sound theory. Scholars deal with problems by slicing them into small segments to study them but fail to address the practical implications. What's needed is a way to unite research and practice to create robust theory. This is exactly what Richard Swanson and Thomas Chermack offer here: a complete, five-step method for developing sound, field-tested theory in applied disciplines. Unlike many existing methods, which cover only the initial conceptualization of a theory, the authors offer a complete approach, from conceptualizing a theory to creating relevant assessment criteria, establishing a research agenda to test the theory's validity, applying the theoretical concepts in the real world, and using that experience to further refine and improve the theory. The method is not restricted to any single discipline, nor is it beholden to any research ideology. Swanson and Chermack provide a set of tools for each phase of the process, making this book accessible and applicable to a wide audience. And in addition to examples in each chapter, they offer two extended case examples of complete theory building. With flawed theories impeding the development of many applied disciplines, this book is desperately needed.
Download or read book Overfished Ocean Strategy written by Nadya Zhexembayeva and published by Berrett-Koehler Publishers. This book was released on 2014-06-02 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Business is waking up to a global shortage of resources of every kind. Raw materials are running out, whether in Tokyo or Quito. While businesses have toyed with the idea of sustainability as a means to market to eco-minded consumers, this book shows that scarcity must become central to their thinking and the key driver of strategic innovation"--
Download or read book Management and Mitigation of Acid Mine Drainage in South Africa written by Mujuru, Munyaradzi and published by Africa Institute of South Africa. This book was released on 2017-02-03 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: South Africa is facing the increasing challenge of acid mine drainage (AMD) whose genesis is the country’s mining history, which paid limited attention to post-mining mine site management. In mineral resource-rich Africa, this has emerged as one of the most daunting challenges of our time. South Africa has been bold in its approach to mitigating this problem, although the challenge is multi-faceted. On a positive note, substantial research has been conducted to confront the challenge. However, thus far, the research has been largely fragmented. This book builds on the work that has been done, but also provides a refreshing multi-disciplinary approach that is useful in addressing the AMD challenges that South Africa and the continent face. Whilst addressing the problem as a scientific and engineering challenge, the book also exposes the economic, policy and legal challenges involved in addressing the problem. The book concludes, quite uniquely, that AMD is an opportunity that can be used by South Africa and Africa to solve problems, such as acute water shortage, as well as mineral recovery operations.
Download or read book Absolutely Small written by Michael D. Fayer and published by HarperChristian + ORM. This book was released on 2010-06-16 with total page 397 pages. Available in PDF, EPUB and Kindle. Book excerpt: Absolutely Small presents (and demystifies) the world of quantum science like no book before. Physics is a complex, daunting topic, but it is also deeply satisfying?even thrilling. When liberated from its mathematical underpinnings, physics suddenly becomes accessible to anyone with the curiosity and imagination to explore its beauty. Science without math? It’s not that unusual. For example, we can understand the concept of gravity without solving a single equation. So for all those who may have pondered what makes blueberries blue and strawberries red; for those who have wondered if sound really travels in waves; and why light behaves so differently from any other phenomenon in the universe, it’s all a matter of quantum physics. This book explores in considerable depth scientific concepts using examples from everyday life, such as: particles of light, probability, states of matter, what makes greenhouse gases bad Challenging without being intimidating, accessible but not condescending, Absolutely Small develops your intuition for the very nature of things at their most basic and intriguing levels.
Download or read book Rooftop Revolution written by Danny Kennedy and published by Berrett-Koehler Publishers. This book was released on 2012-09-03 with total page 209 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here is the truth that the powerful Dirty Energy public relations machine doesn't want you to know: the ascent of solar energy is upon us. Solar-generated electricity has risen exponentially in the last few years and employment in the solar industry has doubled since 2009. Meanwhile, electricity from coal has declined to pre-World War II levels as the fossil fuel industry continues to shed jobs. Danny Kennedy systematically refutes the lies spread by solar's opponents—that it is expensive, inefficient, and unreliable; that it is kept alive only by subsidies; that it can't be scaled; and many other untruths. He shows that we need a rooftop revolution to break the entrenched power of the coal, oil, nuclear, and gas industries Solar energy can create more jobs, return our nation to prosperity, and ensure the sustainability and safety of our planet. Now is the time to move away from the dangerous energy sources of the past and unleash the amazing potential of the sun.
Download or read book It s Not the Size of the Data It s How You Use It written by Koen Pauwels and published by AMACOM. This book was released on 2014-03-26 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this invaluable resource, discover how to conduct smarter marketing strategies using analytics and dashboards to get the most out of your data. Did you know that your business already has the world’s greatest information-tracking team working tirelessly for you 24/7 to gather all the info you could possibly need to find your next customers? Between brand tracking, CRM programs, and online behavior tracking, as well as the always-dependable trade shows and satisfaction studies, mounds of marketing metrics are being generated for you across various touchpoints and channels. Locked in the vast quantity of information are accurate, data-driven answers to every marketing question--and analytic dashboards are the key to finding it all. In It’s Not the Size of the Data--It’s How You Use It, marketing expert Koen Pauwels introduces you to these transformative web-based tools that gather, synthesize, and visually display essential data in real time, directly connecting marketing with performance. He then supplies a simple yet rigorous methodology that explains step by step how to: Gain crucial IT support Build a rock-solid database Select key leading performance indicators Design the optimal dashboard layout Use marketing analytics to improve decisions and reap rewards There is simply too much customer-produced information out there today for marketing teams to go with gut decisions or the same old standbys. Dashboard analytics will bring scientific precision and insight to the marketing efforts of any size organization, in any industry, and turn this eye-popping data into a specific plan of attack.
