~ Springer-Verlag Wien GmbH

~ Springer-Verlag Wien GmbH

CISM COURSES AND LECTURES Series Editors: The Rectors Manuel Garcia Velarde - Madrid Jean Salen<;on - Palaiseau Wilhelm Schneider - Wien The Secretary General Bernhard Schrefier - Padua Executive Editor Carlo Tasso- Udine The series presents lecture notes, monographs, edited works and proceedings in the field of Mechanics, Engineering, Computer Science and Applied Mathematics. Purpose of the series is to make known in the international scientific and technical community results obtained in some of the activities organized by CISM, the International Centre for Mechanical Sciences.

INTERNATIONAL CENTRE FOR MECHANICAL SCIENCES COURSES AND LECTURES - No. 464 MECHANICS OF MICROSTRUCTURED MATERIALS EDITED BY HELMUT J. BOHM VIENNA UNIVERSITY OF TECHNOLOGY Springer-Verlag Wien GmbH

The publication of this volume was co-sponsored and co-financed by the UNESCO Venice Office - Regional Bureau for Science in Europe (ROSTE) and its content corresponds to a CISM Advanced Course supported by the same UNESCO Regional Bureau. This volume contains 180 illustrations This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concemed specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. 2004 by Springer-Verlag Wien Originally published by CISM, Udine in 2004. SPIN 11370475 In order to make this volume available as economically and as rapidly as possible the authors' typescripts have been reproduced in their original forms. This method unfortunately has its typographicallimitations but it is hoped that they in no way distract the reader. ISBN 978-3-211-24154-7 ISBN 978-3-7091-2776-6 (ebook) DOI 10.1007/978-3-7091-2776-6

PREFACE The last decades have witnessed a strong thrust towards improving existing structural materials and to develop new ones, the long-term aim being a capability to tailor materials for specific applications. This environment - in combination with a remarkable increase in computing power - has been instrumental in giving rise to marked improvements in modeling capabilities and experimental methods aimed at obtaining a better understanding of the thermomechanical behavior of engineering materials. One field that has benefitted strongly from these trends is continuum mechanical methods for studying inhomogeneous materials. The CISM Course on "Mechanics of Microstructured Materials", which was held in U dine from July 7 to July 11, 2003, accordingly aimed at presenting selected state-of-the-art theoretical tools in this field of research in close integration with related experimental developments. Like the course, the present book is structured to consist of a short overview of modeling approaches in continuum micromechanics together with contributions on a number of research topics that are of current interest in the study of microstructured materials. Methods for modeling damage of and cracks in microstructured materials are a core issue, with the topics covered including descriptions of the fracture of brittle reinforcements in composites, thermomechanical cohesive zone models, and simulations of creep rupture in polycrystalline materials. A second focus lies in experimental and statistical methods for the description and classification of microstructures and statistically based methods for assessing the stress and strain fields. Advanced descriptions for the elastoplastic behavior of metals are a third point of emphasis, with contributions on crystal plasticity and discrete dislocation models. Finally, studies are provided that concentrate on modeling strategies for the thermomechanical behavior of specific microstructured materials, such as discontinuously reinforced composites and graded carbon-carbon composites. Together these contributions are intended to provide a framework for introducing the reader to current trends and different points of view in studying the mechanical behavior of microstructured materials. Finally, it is my pleasure to thank the lecturers at the CISM course and contributors to this book, Javier LLorca, Peter McHugh, Ryszard Pyrz, Thomas Siegmund and Erik van der Giessen. I would also like to express my appreciation of the active participation by the 31 attendees of the course, who came from 15 different countries. Last, but not least, the efficient support by the rectors and the staff of CISM is most gratefully acknowledged. Helmut J. Bohm

CONTENTS A Short Introduction to Continuum Micromechanics by H.J. Bohm... 1 Modeling the Mechanical Behavior of Short Fiber Reinforced Composites by H. J. Bohm...................................................... 41 Thermomechanical Cohesive Zone Models for the Analysis of Composite Failure under Thermal Gradients and Transients by A. Hattiangadi and T. Siegmund... 57 Deformation and Damage in Particle-Reinforced Composites: Experiments and Models by J. LLorca... 87 Introduction to Crystal Plasticity Theory by P.E. McHugh... 125 Microstructural Description of Composites, Statistical Methods by R. Pyrz.......................................................... 173 Processing-Microstructure-Property Relationships in Short Fiber Reinforced Carbon-Carbon Composite System by T. Siegmund, R. Cipra, J. Liakus, B. Wang, M. LaForest and A. Fatz... 235 Discrete Dislocation Plasticity by E. Van der Giessen.............................................. 259 Creep Rupture in Polycrystalline Materials by E. Van der Giessen.............................................. 283