Micromechanics of Fracture in Generalized Spaces


Book Description

By the detailed analysis of the modern development of the mechanics of deformable media can be found the deep internal contradiction. From the one hand it is declared that the deformation and fracture are the hierarchical processes which are linked and unite several structural and scale levels. From the other hand the sequential investigation of the hierarchy of the deformation and destruction is not carried out. The book’s aim is filling this mentioned gap and investigates the hot topic of the fracture of non-ideal media. From the microscopic point of view in the book we study the hierarchy of the processes in fractured solid in the whole diapason of practically used scales. According the multilevel hierarchical system ideology under “microscopic we understand taking into account the processes on the level lower than relative present strata. From hierarchical point of view the conception of “microscopic fracture can be soundly applied to the traditionally macroscopic area, namely geomechanics or main crack propagation. At the same time microscopic fracture of the nanomaterials can be well-grounded too. This ground demands the investigation on the level of inter-atomic interaction and quantum mechanical description. The important feature of the book is the application of fibred manifolds and non-Euclidean spaces to the description of the processes of deformation and fracture in inhomogeneous and defected continua. The non-Euclidean spaces for the dislocations’ description were introduced by J.F. Nye, B.A. Bilby, E. Kröner, K. Kondo in fiftieth. In last decades this necessity was shown in geomechanics and theory of seismic signal propagation. The applications of non-Euclidean spaces to the plasticity allow us to construct the mathematically satisfying description of the processes. Taking into account this space expansion the media with microstructure are understood as Finsler space media. The bundle space technique is used for the description of the influence of microstructure on the continuum metrics. The crack propagation is studied as a process of movement in Finsler space. Reduction of the general description to the variational principle in engineering case is investigated and a new result for the crack trajectory in inhomogeneous media is obtained. Stability and stochastization of crack trajectory in layered composites is investigated. The gauge field is introduced on the basis of the structure representation of Lie group generated by defects without any additional assumption. Effective elastic and non-elastic media for nanomaterials and their geometrical description are discussed. The monograph provides the basis for more detailed and exact description of real processes in the material. The monograph will be interesting for the researchers in the field of fracture mechanics, solid state physics and geomechanics. It can be used as well by the last year students wishing to become more familiar with some modern approaches to the physics of fracture and continual theory of dislocations. In Supplement, written by V.V.Barkaline, quantum mechanical concept of physical body wholeness according to H. Primas is discussed with relation to fracture. Role of electronic subsystem in fracture dynamics in adiabatic and non-adiabatic approximations is clarified. Potential energy surface of ion subsystem accounting electron contribution is interpreted as master parameter of fracture dynamics. Its features and relation to non-euclidean metrics of defected solid body is discussed. Quantum mechanical criteria of fracture arising are proposed.




Micromechanics of Fracture and Damage


Book Description

This book deals with the mechanics and physics of fractures at various scales. Based on advanced continuum mechanics of heterogeneous media, it develops a rigorous mathematical framework for single macrocrack problems as well as for the effective properties of microcracked materials. In both cases, two geometrical models of cracks are examined and discussed: the idealized representation of the crack as two parallel faces (the Griffith crack model), and the representation of a crack as a flat elliptic or ellipsoidal cavity (the Eshelby inhomogeneity problem). The book is composed of two parts: The first part deals with solutions to 2D and 3D problems involving a single crack in linear elasticity. Elementary solutions of cracks problems in the different modes are fully worked. Various mathematical techniques are presented, including Neuber-Papkovitch displacement potentials, complex analysis with conformal mapping and Eshelby-based solutions. The second part is devoted to continuum micromechanics approaches of microcracked materials in relation to methods and results presented in the first part. Various estimates and bounds of the effective elastic properties are presented. They are considered for the formulation and application of continuum micromechanics-based damage models.




Field Theory of Multiscale Plasticity


Book Description

This unique book provides a concise and systematic treatment of foundational material on dislocations and metallurgy and an up-to-date discussion of multiscale modeling of materials, which ultimately leads to the field theory of multiscale plasticity (FTMP). Unlike conventional continuum models, this approach addresses the evolving inhomogeneities induced by deformation, typically as dislocation substructures like dislocation cells, as well as their interplay at more than one scale. This is an impressively visual text with many and varied examples and viewgraphs. In particular, the book presents a feasible constitutive model applicable to crystal plasticity-based finite element method (FEM) simulations. It will be an invaluable resource, accessible to undergraduate and graduate students as well as researchers in mechanical engineering, solid mechanics, applied physics, mathematics, materials science, and technology.




Fracture Mechanics


Book Description

- self-contained and well illustrated - complete and comprehensive derivation of mechanical/mathematical results with enphasis on issues of practical importance - combines classical subjects of fracture mechanics with modern topics such as microheterogeneous materials, piezoelectric materials, thin films, damage - mechanically and mathematically clear and complete derivations of results




Fracture of Solids with Microdefects


Book Description

The book covers some problems of fracture of solids with linear or penny-shaped cracks or rigid inclusions. The analysis of the interaction of a macrocrack with small defects or microcracks in the frame of linear fracture mechanics is the main topic of the book. The problem of the interaction of the macrocrack with microcracks has been intensively studied for almost two decades. One of the pioneering papers was published in 1984 by the authors of the present book. In the frame of linear elasticity a problem of interaction of the cracks, holes, or inclusions most often has been reduced to a system of singular integral equations. Although exact solutions to the system of singular integral equations. Although exact solutions to the system of singular integral equations exist in a few special cases, the problem, in general, is solved by various asymptotic methods. The series solution over a small parameter representing the ratio of the linear sizes of the microcrack to the macrocrack was first obtained by Tamuzs and Romalis in 1984. It was hown that the two dominant terms in the stress Intensity Factor (SIF) at the tip of the macrocrack do not depend on mutual interaction of the microcracks and only depend on the interaction of the macrocrack with arrays of small defects. This method is applied to various macrocrack-microdefect interaction problems of 2-D and 3-D elasticity and thermoelasticity. A review of other approached to the problem is given at the end of the book.




Damage Mechanics and Micromechanics of Localized Fracture Phenomena in Inelastic Solids


Book Description

This book resulted from a series of lecture notes presented in CISM, Udine in July 7 -11, 2008. The papers inform about recent advances in continuum damage mechanics for both metals and metal matrix composites as well as the micromechanics of localization in inelastic solids. Also many of the different constitutive damage models that have recently appeared in the literature and the different approaches to this topic are presented, making them easily accessible to researchers and graduate students in civil engineering, mechanical engineering, engineering mechanics, aerospace engineering, and material science.







Fracture Mechanics


Book Description

The proceedings of the 23rd National Symposium on Fracture Mechanics, held in College Station, Texas, June 1991, present a broad overview of the current state of the art in fracture mechanics research. Following the Swerdlow Lecture (Structural Problems in Search of Fracture Mechanics Solutions by




Fracture Micromechanics of Polymer Materials


Book Description

Within the last two decades fracture theory has been one of the most rapidly advancing fields of continuous media mechanics. Noteworthy suc cess has been achieved in linear fracture mechanics where the propagation of the macrocrack in elastic materials is under study. However, fracture of materials is by no means a simple process since it involves fracture of structural elements ranging from atomic sizes to macrocracks. To obtain all information about how and why materials fail, all stages of the process must be studied. For a long time both mechanical engineers and physicists have been concerned with the problem of the fracture of solids. Unfortunately, most of their work has been independent of the others. To solve the problem not only requires the minds and work of mechanical engineers and physicists but chemists and other specialists must be consulted as well. In this book we will consider some conclusions of the "physical" and "mechanical" schools acquired by the A. F. Joffe Physics-Technical Institute of the USSR Academy of Sciences in Leningrad and the Institute of Polymer Mechanics of Latvian SSR Academy of Sciences in Riga. The methods for studying the phenomena of fracture applied at both Institutes are different yet complimentary to one another; the materials tested are also sometimes different.