Author: Rachid El khaoulani El idrissi
Publisher:
ISBN:
Category :
Languages : fr
Pages : 148
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Book Description
L'objectif de cette thèse est le développement d'un modèle numérique fiable et précis pour prédire l'évolution de l'endommagement jusqu'à la rupture dans une structure soumise à des grandes déformations plastiques. Ces développements contribuent à l'enrichissement d'une librairie EF parallèle appelée CIMLib. Pour mieux traiter l'incompressibilité des déformations plastiques, une approximation éléments finis mixtes vitesse-pression avec une discrétisation stabilisée P1+/P1 est utilisée pour la résolution des équations mécaniques. L'intégration d'une loi de comportement élastoplastique endommageable dans cette approximation a été largement abordée. L'évolution de l'endommagement obéit à un modèle de Lemaitre enrichi, où les phénomènes dissipatifs sont couplés et qui prend en compte la nature des sollicitations et l'effet de refermeture des fissures en compression. L'approximation éléments finis avec un comportement adoucissant est fortement dépendante de la discrétisation spatiale dans la phase post-critique. Pour pallier à ce problème, nous avons adopté une méthode de régularisation non locale du gradient implicite. Nous avons choisi un exemple où la localisation est très marquée en bande de cisaillement pour montrer la fiabilité de notre modèle à prédire l'évolution de l'endommagement jusqu'à la rupture de la structure. Un autre axe principal de cette thèse est l'adaptation anisotrope de maillage au phénomène d'endommagement. Une stratégie d'adaptation anisotrope de maillage pilotée par un estimateur de l'erreur d'interpolation a été utilisée afin d'améliorer la précision pour l'endommagement avec un temps de calcul minimal. L'apport de l'adaptation de maillage permet de garantir une meilleure prédiction de l'évolution de l'endommagement jusqu'à la rupture. Son utilisation nous a permis de retrouver numériquement des modes de rupture observés expérimentalement. Dans le cadre de grands cas industriels irréductibles, par exemple à cause de la croissance de l'endommagement, le temps de calcul peut devenir pénalisant. Nous nous sommes donc intéressé à l'accélération de la résolution des grands systèmes linéaires issus d'une approximation éléments finis par les méthodes multigrilles. Un préconditionneur multigrille géométrique a été mis en place. Les premières validations ont montré que ce préconditionneur permet d'avoir une complexité quasi-linéaire en fonction des degrés de liberté. Le modèle numérique ainsi développé peut servir à la simulation des procédés de pose de points d'assemblage des tôles par déformations plastiques, à l'étude de leur tenue mécanique en les soumettant à des sollicitations variées, et à la simulation des procédés de mises en forme à froid des corps solides (emboutissage, forgeage, hydroformage, semi découpe ou découpe des tôles ...)
Author: Konstantin O. Papailiou
Publisher: Springer Science & Business Media
ISBN: 3642153208
Category : Technology & Engineering
Languages : en
Pages : 507
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Book Description
Composite insulators have been in service in electric power networks successfully for more than 40 years, and now up to the highest operating voltages. The present book extensively covers such insulators with a special focus on today’s prevalent material, which is silicone rubber. It includes a detailed description of the electrical and mechanical characteristics of composite insulators, their material properties, their design as well as typical applications and service experience. Particular attention is given to the mechanical behavior of long rod and post insulators, insulated cross-arms, interphase spacers and hollow core apparatus insulators. The state of the art on manufacturing procedures and the selection and dimensioning of the necessary power arc and corona fittings is presented as well as evaluation tests of “old” insulators, i.e. insulators after many years in service. The closing chapter deals with an up to date overview of test procedures and IEC standards. The selection and the contents of the various subjects covered in this book are based on the authors’ more than thirty years of experience with a renowned European manufacturer of composite insulators and string hardware. Their long and active participation in the relevant CIGRE and IEC working bodies adding to this experience. This book is therefore addressed to practicing engineers from electric utilities and the industry, as well as to academic professionals.
Author: Leslie Rainer
Publisher: Getty Publications
ISBN: 1606060430
Category : Architecture
Languages : fr
Pages : 438
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Book Description
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.
Author: Fabrice Pierron
Publisher: Springer Science & Business Media
ISBN: 1461418240
Category : Science
Languages : en
Pages : 531
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Book Description
The Virtual Fields Method: Extracting Constitutive Mechanical Parameters from Full-field Deformation Measurements is the first and only one on the Virtual Fields Method, a recent technique to identify materials mechanical properties from full-field measurements. It contains an extensive theoretical description of the method as well as numerous examples of application to a wide range of materials (composites, metals, welds, biomaterials etc.) and situations(static, vibration, high strain rate etc.). Finally, it contains a detailed training section with examples of progressive difficulty to lead the reader to program the VFM. This is accompanied with a set of commented Matlab programs as well as with a GUI Matlab based software for more general situations.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
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Author: Norman Jones
Publisher: Butterworth-Heinemann
ISBN:
Category : Science
Languages : en
Pages : 472
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Author: James E. Mark
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 430
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Book Description
The contents have been divided into sections on physical states of polymers and characterization techniques. Chapters on physical states include discussions of the rubber elastic state, the glassy state, melts and concentrated solutions, the crystalline state, and the mesomorphic state. Characterization techniques described are molecular spectroscopy and scattering techniques.
Author:
Publisher: Research Publishing Service
ISBN: 9810862180
Category : Building, Iron and steel
Languages : en
Pages : 145
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Book Description
Author: Bo Song
Publisher: Springer
ISBN: 3319224522
Category : Technology & Engineering
Languages : en
Pages : 265
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Book Description
Dynamic Behavior of Materials, Volume 1 represents the first of nine volumes of technical papers presented at the Society for Experimental Mechanics SEM 15th International Congress & Exposition on Experimental and Applied Mechanics, held at Costa Mesa, California, June 8-11, 2015. The full set of proceedings also includes volumes on: Challenges in Mechanics of Time Dependent Materials, Advancement of Optical Methods in Experimental Mechanics, Experimental and Applied Mechanics 16th International Symposium on MEMS and Nanotechnology, 5th International Symposium on the Mechanics of Biological Systems and Materials, International Symposium on the Mechanics of Composite and Multi-functional Materials, Fracture, Fatigue, Failure and Damage Evolution; and Residual Stress, Thermomechanics & Infrared Imaging, Hybrid Techniques and Inverse Problems.
Author: Jamie Kimberley
Publisher: Springer
ISBN: 9783319950884
Category : Science
Languages : en
Pages : 0
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Book Description
Dynamic Behavior of Materials, Volume 1 of the Proceedings of the 2018 SEM Annual Conference & Exposition on Experimental and Applied Mechanics, the first volume of eight from the Conference, brings together contributions to this important area of research and engineering. The collection presents early findings and case studies on fundamental and applied aspects of Experimental Mechanics, including papers on: Synchrotron Applications/Advanced Dynamic Imaging Quantitative Visualization of Dynamic Events Novel Experimental Techniques Dynamic Behavior of Geomaterials Dynamic Failure & Fragmentation Dynamic Response of Low Impedance Materials Hybrid Experimental/Computational Studies Shock and Blast Loading Advances in Material Modeling Industrial Applications
