Modélisation et simulation multi-échelles des contraintes d'élaboration et de service dans les matériaux composites PDF Download

Author: Emmanuel Lacoste
Publisher:
ISBN:
Category :
Languages : fr
Pages : 388

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Book Description
Dans cette thèse, les méthodes multi-echelles ont été utilisées afin de décrire le comportement d’un matériau composite à matrice organique, composé de bandes de renforts unidirectionnelles orientées aléatoirement dans le plan du pli. Une approche à champ moyen (modèles de Mori-Tanaka et autocoherent) a permis de calculer les propriétés mécaniques du composite via une procédure en deux étapes. Les difficultés liées a la coexistence dans le matériau de plusieurs morphologies d’inclusions ont été levées via a une généralisation du modèle autocohérent. Ce modèle a aussi permis de calculer les contraintes locales de service dans le composite. Les contraintes dans les bandes UD ont également été calculées via une approche à champ complet périodique utilisant les éléments finis, montrant ainsi les avantages et les limites des approches à champs moyens. En s’appuyant sur une description du comportement de la résine selon la température et le degré de réticulation, l'évolution des propriétés du composite et des contraintes résiduelles locales (dues au retrait thermochimique de la résine) a pu être déterminée tout au long du cycle de fabrication, pour différentes contraintes appliquées au composite. La problématique des déformations résiduelles de fabrication des pièces composites a également été abordée, en se focalisant notamment sur le phénomène de retrait angulaire des équerres du à l’anisotropie du matériau. Les éléments finis ont permis de simuler ce retrait ainsi que les interactions moule-piece, en tenant compte de l'évolution des propriétés mécaniques de l'équerre. La possibilité d’utiliser un moule composite pour cuire des pièces composites a également été évaluée

Author: Adjovi Abueno Kanika C-M. Koutsawa-Tchalla
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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We propose in this thesis several approaches for improving the multiscale modeling and simulation of composites' behavior. Accurate and reliable modeling of the mechanical response of composite materials remains a major challenge. The objective of this work is to develop simplified methodologies based on existing homogenization techniques (numerical and analytical) for efficient prediction of nonlinear behavior of these materials. First choice has been focused on the Mean-field homogenization methods to study the elasto-plastic behavior and ductile damage phenomena in composites. Although restrictive, these techniques remain the best in terms of computational cost and efficiency. Two methods were investigated for this purpose: the Incremental Scheme Micromechanics (IMS) in One-site modeling and the Mori-Tanaka model in multi-site modeling (MTMS). In the framework of elastoplasticity, we have shown and validated by finite element method that the IMS homogenization results are more accurate, when dealing with high volume fraction composites, than the Mori-Tanaka model, frequently used in the literature. Furthermore, we have extended the Mori-Tanaka's model (MT) generally formulated in One-site to the multi-site formulation for the study of elasto-plastic behavior of composites with ordered microstructure. This approach shows that the multi-site formulation produces consistent results with respect to finite element and experimental solutions. In the continuation of our research, the Lemaître-Chaboche ductile damage model has been included to the study of elasto-plastic behavior in composite through the IMS homogenization. This latest investigation demonstrates the capability of the IMS model to capture damage effects in the material. However, the issue on the loss of ellipticity was not addressed. Finally we develop a numerical homogenization tool based on computational homogenization. This novel numerical tool works with 2D and 3D structure and is fully integrated in the conventional finite element code ABAQUS through its subroutine UMAT. The (FE2) method offers the advantage of being extremely accurate and allows the handling of more complex physics and geometrical nonlinearities. Linear and non-linear cases were studied. In addition, its combination with ABAQUS allows the use of major resources provided by this software (a panel of toolbox for various mechanical, thermomechanical and electrical analysis) for the study of multi-physics problems. This work was validated in the linear case on a two-scale analysis in bending and compared to the multi-scale method ANM (Nezamabadi et al. (2009)). Extensive work will be needed later with applications on non-linear problems to highlight the value of the developed tool.

Author: Jean-Marie Berthelot
Publisher: Springer
ISBN: 9781461268031
Category : Technology & Engineering
Languages : en
Pages : 0

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Book Description
Mechanical engineering, an engineering discipline borne of the needs of the in dustrial revolution, is once again asked to do its substantial share in the call for industrial renewal. The general call is urgent as we face profound issues of produc tivity and competitiveness that require engineering solutions, among others. The Mechanical Engineering Series features graduate texts and research monographs intended to address the need for information in contemporary areas of mechanical engineering. The series is conceived as a comprehensive one that covers a broad range of concentrations important to mechanical engineering graduate education and re search. We are fortunate to have a distinguished roster of consulting editors on the advisory board, each an expert in one of the areas of concentration. The names of the consulting editors are listed on the next page of this volume. The areas of concentration are applied mechanics, biomechanics, computational mechan ics, dynamic systems and control, energetics, mechanics of materials, processing, thermal science, and tribology.

Author: Damien Marquis
Publisher:
ISBN:
Category :
Languages : fr
Pages : 618

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Book Description
Ce travail de thèse s’inscrit dans le cadre d’un projet de recherche partenariale, dédié à l’utilisation de matériaux composites dans la construction navale par une approche basée sur l’ingénierie de la sécurité incendie. La motivation de ce travail a été de vérifier, de caractériser et de modéliser le comportement au feu d’un sandwich composite, préalable incontournable pour l’introduction de ce produit dans la construction navale. Pour ce faire, une méthode basée sur une approche combinée expérience-simulation, à échelle et à complexité croissantes, a été mise en œuvre. L’analyse du comportement au feu du matériau étudié a été réalisée successivement par cinq niveaux d’échelle, de l’échelle de la matière jusqu’à une échelle représentative de l’utilisation finale. La caractérisation expérimentale a été réalisée au moyen de bancs d’essais normalisés et de bancs de référence métrologique. Parallèlement, un outil de simulation numérique avancé a été utilisé pour simuler les processus de dégradation thermique, de combustion et de propagation de flamme pour ce sandwich composite. L’application pratique de ce travail a consisté in fine en l’étude du développement d’un incendie dans le cadre de simulations de scenarii d’incendie à l’échelle réelle d’un navire en structure composite

Author: Ahmed Belasri
Publisher: Springer Nature
ISBN: 9811554447
Category : Technology & Engineering
Languages : en
Pages : 659

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Book Description
This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.

Author: Marco Gigliotti
Publisher: John Wiley & Sons
ISBN: 1119388848
Category : Science
Languages : en
Pages : 133

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Book Description
The book focuses on the effect of ageing (thermo-oxidation, humid ageing) on the mechanical properties of organic matrix composite materials, covering: Bibliographic issues and a detailed state-of-the-art; phenomenological and experimental issues; modelling issues and models parameter identification; illustration and interpretation of experimental tests and proposal for novel test design in the light of the model predictions.

Author: Canada. Department of Fisheries and Oceans
Publisher: Peches Et Oceans Direction Generale Des Communications = Fisheries and Oceans Communications Dir
ISBN:
Category : Science
Languages : fr
Pages : 376

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Book Description
Proceedings of a workshop, the scientific reviews and the contributed papers presented at the symposium. The document presents a brief historical summary of marine research in the Gulf; reports the discussions, conclusions and recommendations of the different working groups on oceanography (physics, biology, chemistry and sedimentology) and on the fishery (fish and invertebrates); then presents the discussions of each multidisciplinary working group, centered around how the St. Lawrence system may be used as a natural laboratory which will contribute to the solution of major long-term problems of conservation of natural resources and of the quality of the environment.

Author: Jean Daillant
Publisher: Springer Science & Business Media
ISBN: 3540486968
Category : Science
Languages : en
Pages : 347

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Book Description
The reflection of and neutrons from surfaces has existed as an x-rays exp- imental for almost it is in the last technique fifty Nevertheless, only years. decade that these methods have become as of enormously popular probes This the surfaces and interfaces. to be due to of several appears convergence of intense different circumstances. These include the more n- availability be measured orders tron and sources that can over (so reflectivity x-ray many of and the much weaker surface diffuse can now also be magnitude scattering of thin films and studied in some the detail); growing importance multil- basic the realization of the ers in both and technology research; important which in the of surfaces and and role roughness plays properties interfaces; the of statistical models to characterize the of finally development topology its and its characterization from on roughness, dependence growth processes The of and to surface scattering experiments. ability x-rays neutro4s study four five orders of in scale of surfaces over to magnitude length regardless their and also their to ability probe environment, temperature, pressure, etc. , makes these the choice for buried interfaces often probes preferred obtaining information about the microstructure of often in statistical a global surfaces, the local This is manner to complementary imaging microscopy techniques, of such studies in the literature witnessed the veritable by explosion published the last few Thus these lectures will useful for over a resource years.

Author: International Atomic Energy Agency
Publisher: International Atomic Energy Agency
ISBN: 9789201063205
Category : Technology & Engineering
Languages : en
Pages : 72

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Book Description
This publication results from a technical meeting on phenomenology and technologies relevant to in-vessel melt retention (IVMR) and ex-vessel corium cooling (EVCC). The purpose of the publication is to capture the state of knowledge, at the time of that meeting, related to phenomenology and technologies as well as the challenges and pending issues relevant to IVMR and EVCC for water cooled reactors by summarizing the information provided by the meeting participants in a form useful to practitioners in Member States.

Author: Mohamed Thariq Hameed Sultan
Publisher: CRC Press
ISBN: 1000634833
Category : Technology & Engineering
Languages : en
Pages : 339

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Book Description
This book bridges the gap between theoretical concepts and their implementations, especially for the high-performance structures/components related to advanced composite materials. This work focuses on the prediction of various structural responses such as deformations, natural frequencies etc. of advanced composites under complex environments and/or loading conditions. In addition, it discusses micro-mechanical material modeling of various advanced composite materials that involve different structures ranging from basic to advanced, such as beams, flat and curved panels, shells, skewed, corrugated, and other materials, as well as various solution techniques via analytical, semi-analytical, and numerical approaches. This book: Covers micro-mechanical material modeling of advanced composite materials Describes constitutive models of different composite materials and kinematic models of different structural configuration Discusses pertinent analytical, semi-analytical, and numerical techniques Focusses on structural responses relating to deformations, natural frequencies, and critical loads under complex environments Presents actual demonstrations of theoretical concepts as applied to real examples using Ansys APDL scripts This book is aimed at researchers, professionals, and graduate students in mechanical engineering, material science, material engineering, structural engineering, aerospace engineering, and composite materials.