Disarrangements in Continua and the Geometry of Microstructure


Book Description

Abstract: "The term 'disarrangement' is proposed here to describe geometrical changes either at the macroscale or at the microscale that are not accounted for by the classical deformations employed in continuum mechanics. Collections of non-classical deformations studied by Del Piero and Owen (1993) are then described in order to give a more precise context for the term 'disarrangement'. Examples of disarrangements both at the microscale and at the macroscale are presented, including disarrangements in liquid crystals, metallic crystals, and mixtures of continua. It is shown that volume-preserving deformations that are limits of discrete translations in crystallographically preferred directions necessarily are 'piecewise-shearing deformations'."




Differential Geometry and Continuum Mechanics


Book Description

This book examines the exciting interface between differential geometry and continuum mechanics, now recognised as being of increasing technological significance. Topics discussed include isometric embeddings in differential geometry and the relation with microstructure in nonlinear elasticity, the use of manifolds in the description of microstructure in continuum mechanics, experimental measurement of microstructure, defects, dislocations, surface energies, and nematic liquid crystals. Compensated compactness in partial differential equations is also treated. The volume is intended for specialists and non-specialists in pure and applied geometry, continuum mechanics, theoretical physics, materials and engineering sciences, and partial differential equations. It will also be of interest to postdoctoral scientists and advanced postgraduate research students. These proceedings include revised written versions of the majority of papers presented by leading experts at the ICMS Edinburgh Workshop on Differential Geometry and Continuum Mechanics held in June 2013. All papers have been peer reviewed.




Mechanics of Generalized Continua


Book Description

In their 1909 publication Théorie des corps déformables, Eugène and François Cosserat made a historic contribution to materials science by establishing the fundamental principles of the mechanics of generalized continua. The chapters collected in this volume showcase the many areas of continuum mechanics that grew out of the foundational work of the Cosserat brothers. The included contributions provide a detailed survey of the most recent theoretical developments in the field of generalized continuum mechanics and can serve as a useful reference for graduate students and researchers in mechanical engineering, materials science, applied physics and applied mathematics.







Advances in Extended and Multifield Theories for Continua


Book Description

Modern computational techniques, such as the Finite Element Method, have, since their development several decades ago, successfully exploited continuum theories for numerous applications in science and technology. Although standard continuum methods based upon the Cauchy-Boltzmann continuum are still of great importance and are widely used, it increasingly appears that material properties stemming from microstructural phenomena have to be considered. This is particularly true for inhomogeneous load and deformation states, where lower-scale size effects begin to affect the macroscopic material response; something standard continuum theories fail to account for. Following this idea, it is evident that standard continuum mechanics has to be augmented to capture lower-scale structural and compositional phenomena, and to make this information accessible to macroscopic numerical simulations.




Generalized Continua and Dislocation Theory


Book Description

Defects, dislocations and the general theory.- Approaches to generalized continua.- Generalized continuum modelling of crystal plasticity.- Introduction to discrete dislocation dynamics. The book contains four lectures on generalized continua and dislocation theory, reflecting the treatment of the subject at different scales. G. Maugin provides a continuum formulation of defects at the heart of which lies the notion of the material configuration and the material driving forces of in-homogeneities such as dislocations, disclinations, point defects, cracks, phase-transition fronts and shock waves. C. Sansour and S. Skatulla start with a compact treatment of linear transformation groups with subsequent excursion into the continuum theory of generalized continua. After a critical assessment a unified framework of the same is presented. The next contribution by S. Forest gives an account on generalized crystal plasticity. Finally, H. Zbib provides an account of dislocation dynamics and illustrates its fundamental importance at the smallest scale. In three contributions extensive computational results of many examples are presented.




Continuum Models And Discrete Systems - Proceedings Of The Eighth International Symposium


Book Description

The purpose of this symposium is to bring together scientists working on continuum theories of discrete mechanical and thermodynamical systems in the realm of mathematics, theoretical and applied mechanics, physics, material science and engineering. It aims to join together the divergent languages, questions and methods developed in the respective disciplines and to stimulate broad interdisciplinary exchange of ideas and results. The main topics, discussed in the lectures, concern thermodynamics, transport theory, statistical mechanics; continuum mechanics of complex fluids and deformable solids with microstructure; continuum theory of living structures; defect dynamics, synergetics, solitons, coherent structures; dislocations and plasticity; fundamentals of fracture mechanics.




Continua with Microstructure


Book Description

This book proposes a new general setting for theories of bodies with microstructure when they are described within the scheme of the con tinuum: besides the usual fields of classical thermomechanics (dis placement, stress, temperature, etc.) some new fields enter the picture (order parameters, microstress, etc.). The book can be used in a semester course for students who have already followed lectures on the classical theory of continua and is intended as an introduction to special topics: materials with voids, liquid crystals, meromorphic con tinua. In fact, the content is essentially that of a series of lectures given in 1986 at the Scuola Estiva di Fisica Matematica in Ravello (Italy). I would like to thank the Scientific Committee of the Gruppo di Fisica Matematica of the Italian National Council of Research (CNR) for the invitation to teach in the School. I also thank the Committee for Mathematics of CNR and the National Science Foundation: they have supported my research over many years and given me the opportunity to study the topics presented in this book, in particular through a USA-Italy program initiated by Professor Clifford A. Truesdell. My interest in the field dates back to a period of collaboration with Paolo Podio-Guidugli and some of the basic ideas came up during our discussions.