On Fracture Mechanics A major objective of engineering design is the determination of the geometry and dimensions of machine or structural elements and the selection of material in such a way that the elements perform their operating function in an efficient, safe and economic manner. For this reason the results of stress analysis are coupled with an appropriate failure criterion. Traditional failure criteria based on maximum stress, strain or energy density cannot adequately explain many structural failures that occurred at stress levels considerably lower than the ultimate strength of the material. On the other hand, experiments performed by Griffith in 1921 on glass fibers led to the conclusion that the strength of real materials is much smaller, typically by two orders of magnitude, than the theoretical strength. The discipline of fracture mechanics has been created in an effort to explain these phenomena. It is based on the realistic assumption that all materials contain crack-like defects from which failure initiates. Defects can exist in a material due to its composition, as second-phase particles, debonds in composites, etc. , they can be introduced into a structure during fabrication, as welds, or can be created during the service life of a component like fatigue, environment-assisted or creep cracks. Fracture mechanics studies the loading-bearing capacity of structures in the presence of initial defects. A dominant crack is usually assumed to exist.

A vast majority of failures emanate from stress concentrators such as geometrical discontinuities. The role of stress concentration was first highlighted by Inglis (1912) who gives a stress concentration factor for an elliptical defect, and later by Neuber (1936). With the progress in computing, it is now possible to compute the real stress distribution at a notch tip. This distribution is not simple, but looks like pseudo-singularity as in principle the power dependence with distance remains. This distribution is governed by the notch stress intensity factor which is the basis of Notch Fracture Mechanics. Notch Fracture Mechanics is associated with the volumetric method which postulates that fracture requires a physical volume. Since fatigue also needs a physical process volume, Notch Fracture Mechanics can easily be extended to fatigue emanating from a stress concentration.

Have you ever wondered where the safety factors come from? Why is it that deterministic analysis has reached a very sophisticated level, but in the end empirical factors are still needed? Is there a way to select them, rather than assigning them arbitrarily as is often done? This book clearly shows that safety factors are closely related with the reliability of structures, giving yet another demonstration of Albert Einstein's maxim that "It is incomprehensible that Nature is comprehensible." The book shows that the safety factors are much more comprehensible if they are seen in a probabilistic context. Several definitions of the safety factors are given, analytical results on insightful numbers are presented, nonprobabilistic safety factors are shown, as well as their estimates derived by the inequalities of Bienayme, Markov, Chebushev and Camp-Meidell. A special chapter is devoted to important contributions by Japanese experts. This volume will help to critically re-think the issue of safety factors, which can create a false feeling of security. The deterministic paradigm can be enhanced by incorporating probabilistic concepts wisely where they are needed without treating all variables as probabilistic ones. The book shows that there is a need of their integration rather than separation. This book is intended for engineers, graduate students, lecturers and researchers.

Diffusion is a vital topic in solid-state physics and chemistry, physical metallurgy and materials science. Diffusion processes are ubiquitous in solids at elevated temperatures. A thorough understanding of diffusion in materials is crucial for materials development and engineering. This book first gives an account of the central aspects of diffusion in solids, for which the necessary background is a course in solid state physics. It then provides easy access to important information about diffusion in metals, alloys, semiconductors, ion-conducting materials, glasses and nanomaterials. Several diffusion-controlled phenomena, including ionic conduction, grain-boundary and dislocation pipe diffusion, are considered as well.

Graduate students in solid-state physics, physical metallurgy, materials science, physical and inorganic chemistry or geophysics will benefit from this book as will physicists, chemists, metallurgists, materials engineers in academic and industrial research laboratories.

From the reviews: "The book is excellent, and covers a very broad area (usually treated as separate topics) from a unified perspective. [ ] It will be very useful for both mathematicians and physicists." EMS Newsletter

This very comprehensive and practical textbook presents a clear, systematic and comprehensive introduction to the relevant mathematics and physics of linear and nonlinear oscillations and waves. It explains even the most complicated cases clearly, with numerous illustrations for further clarification.

This book provides complete coverage of the slitting method. It details new results in analysis, computation, and estimation and discusses different roles of residual stresses from the fracture mechanics perspective. It provides detailed formulations and examples of compliance functions, weighted least squares fit and convergence test in stress estimation, and computer programs to facilitate the implementation of the slitting method.

This is the first major compilation of new advances covering the current status and topics related to the processing and production of precisely controlled materials. It provides a unique source of information and guidance for specialists and non-specialists alike. This book represents an extended introductory treatise on the fundamental aspects, new methods for the precise control of morphology (size, shape, composition, structure etc.) and accurate materials characterization, from both the basic science and the applied engineering viewpoints.

This monograph presents an introduction into basic mechanical aspects of mechatronic systems for students, researchers and engineers from industrial practice. An overview over the theoretical background of rigid body mechanics is given as well as a systematic approach for deriving and solving model equations of general rigid body mechanisms in the form of differential-algebraic equations (DAE). The objective of this book is to prepare the reader for being capable of efficiently handling and applying general purpose rigid body programs to complex mechanisms. The reader will be able to set up symbolic mathematical models of planar and spatial mechanisms in DAE-form for computer simulations, often required in dynamic analysis and in control design.

Hard spheres and related objects (hard disks and mixtures of hard systems) are paradigmatic systems: indeed, they have served as a basis for the theoretical and numerical development of a number of fields, such as general liquids and fluids, amorphous solids, liquid crystals, colloids and granular matter, to name but a few. The present volume introduces and reviews some important basics and progress in the study of such systems. Their structure, thermodynamic properties, equations of state, as well as kinetic and transport properties are considered from different and complementary points of view. This book addresses graduate students, lecturers as well as researchers in statistical mechanics, physics of liquids, physical chemistry and chemical engineering.

The researchers in Aerodynamics know that there is not a unitary method of investigation in this field. The first mathematical model of the air plane wing, the model meaning the integral equation governing the phe nomenon, was proposed by L. Prandtl in 1918. The integral equation deduced by Prandtl, on the basis of some assumptions which will be specified in the sequeL furnishes the circulation C(y) (see Chapter 6). U sing the circulation, one calculates the lift and moment coefficients, which are very important in Aerodynamics. The first hypothesis made by Prandtl consists in replacing the wing by a distribution of vortices on the plan-form D of the wing (i. e. the projection of the wing on the plane determined by the direction of the uniform stream at infinity and t he direction of the span of the wing). Since such a distribution leads to a potential flow in the exterior of D and the experiences show that downstream the flow has not this character, Prandtl introduces as a sup plementary hypothesis another vortices distribution on the trace of the domain D in the uniform stream. The first kind of vortices are called tied vortices and the second kind of vortices are called free vortices."

The book systematically presents variational principles and methods of analysis for applied elasticity and structural mechanics. The variational approach is used consistently for both, constructing numerical procedures and deriving basic governing equations of applied mechanics of solids; it is the derivation of equations where this approach is most powerful and best grounded by mathematics.

The essential aim of this book is to consider a wide set of problems arising in the mathematical modeling of mechanical systems under unilateral constraints. In these investigations elastic and non-elastic deformations, friction and adhesion phenomena are taken into account. All the necessary mathematical tools are given: local boundary value problem formulations, construction of variational equations and inequalities and their transition to minimization problems, existence and uniqueness theorems, and variational transformations (Friedrichs and Young-Fenchel-Moreau) to dual and saddle-point search problems.

This work is devoted to an intensive study in contact mechanics, treating the nonsmooth dynamics of contacting bodies. Mathematical modeling is illustrated and discussed in numerous examples of engineering objects working in different kinematic and dynamic environments.

Topics covered in five self-contained chapters examine non-steady dynamic phenomena which are determined by key factors: i.e., heat conduction, thermal stresses, and the amount of wearing. New to this monograph is the importance of the inertia factor, which is considered on par with thermal stresses.

Nonsmooth Dynamics of Contacting Thermoelastic Bodies is an engaging accessible practical reference for engineers (civil, mechanical, industrial) and researchers in theoretical and applied mechanics, applied mathematics, physicists, and graduate students.

Size effects on material and structural behaviors are of great interest to physicists, material scientists, and engineers who need to understand and model the mechanical behavior of solids especially at micron- and nano-scales. This volume is a collection of twenty five written contributions by distinguished invited speakers from seven countries to the IUTAM Symposium on Size Effects on Material and Structural Behavior at Micron- and Nano-scales. It contains basic theoretical and experimental aspects of the recent advances in the mechanics research of various size effects. Main topics include: behaviors of materials and structures at micron- and nanometer-scales; physical bases of size effects; adaptive and multi-functional behaviors of materials at small scales; size effects in fracture and phase transformation of solids; multi-scale modeling and simulation; size effects in material instability and its propagation, etc. Due to the multidisciplinary nature of the research covered, this volume will be of interest to engineers, scientists, researchers, and graduate students in the field of theoretical and applied mechanics, materials science as well as technology.

Composite and heterogeneous materials play an important role in modern material engineering and technology. This volume is devoted to the theory of such materials. Static elastic, dielectric, thermo- and electroconductive properties of composite materials reinforced with ellipsoidal homogeneous and multi-layered inclusions, short and long multi-layered fibers, thin hard and soft inclusions, media with cracks and pores are considered. Self-consistent methods are used as the main theoretical tool for the calculation of static and dynamic properties of heterogeneous materials. This book is the first monograph to develop self-consistent methods and apply these to the solution of problems of electromagnetic and elastic wave propagation in matrix composites and polycrystals. Predictions of the methods are compared with experimental data and exact solutions. Explicit equations and efficient numerical algorithms for the calculation of velocities and attenuation coefficients of the mean (coherent) wave fields propagating in composites and polycrystals are presented.

The book helps materials engineers to predict properties of heterogeneous materials and to create new composite materials which physical properties are optimal to the exploitation conditions. The results of the book are useful for scholars who work on the theory of composite and heterogeneous media.

This book gives an overview of the research projects within the SFB 404 "Mehrfeldprobleme in der Kontinuumsmechanik." The book is for researchers and graduate students in applied mechanics and civil engineering.

This volume contains the proceedings of the IUTAM Symposium on Ela- ohydrodynamics and Microelastohydrodynamics held in Cardiff from 1st to 3rd September 2004. The symposium focused on theoretical, experimental and computational issues in elastohydrodynamic lubrication (EHL) both in relation to smooth surfaces and in situations where the ?lm is of the same order or th- ner than the surface roughness (micro-EHL). The last IUTAM Symposium in this general area of contact of deformable bodies was in 1974. The emphasis in the Symposium was upon fundamental issues such as: solution methods; lubricant rheological models, thermal effects; both low and high elastic m- ulus situations; human and replacement joints; ?uid traction; dynamic effects, asperity lubrication and the failure of lubrication; surface fatigue and thermal distress under EHL conditions. Delegates were welcomed to Wales and the Cardiff School of Engine- ing by the head of the School, Professor Hywel Thomas. The opening l- ture was given jointly by Professor Duncan Dowson, FRS and Sir Gordon Higginson, the distinguished partnership which produced some of the most important numerical solutions to the fundamental EHL problem which led to the ?rst reliable ?lm thickness formula for isothermal, Newtonian conditions. Their presentation reviewed the early developments in the subject and included some fascinating details of the dif?culties overcome and the scienti?c pers- alities involved. A total of 33 presentations were given over a period of three days.

These proceedings are a continuation of the series of International Conferences in Germany entitled "Mechanics of Unsaturated Soils." The objective is to discuss and understand unsaturated soil behaviour, so that engineered activities are improved in terms of judgement and quality. In addition to knowledge of classical concepts, it is a challenge to adapt convincing new concepts and present them in such a way that they can be used in engineering practices.

Mechanics as a fundamental science in Physics and in Engineering deals with interactions of forces resulting in motion and deformation of material bodies. Similar to other sciences Mechanics serves in the world of Physics and in that of Engineering in a di?erent way, in spite of many and increasing inter- pendencies. Machines and mechanisms are for physicists tools for cognition and research, for engineers they are the objectives of research, according to a famous statement of the Frankfurt physicist and biologist Friedrich Dessauer. Physicists apply machines to support their questions to Nature with the goal of new insights into our physical world. Engineers apply physical knowledge to support the realization process of their ideas and their intuition. Physics is an analytical Science searching for answers to questions concerning the world around us. Engineering is a synthetic Science, where the physical and ma- ematical fundamentals play the role of a kind of reinsurance with respect to a really functioning and e?ciently operating machine. Engineering is also an iterative Science resulting in typical long-time evolutions of their products, but also in terms of the relatively short-time developments of improving an existing product or in developing a new one. Every physical or mathematical Science has to face these properties by developing on their side new methods, new practice-proved algorithms up to new fundamentals adaptable to new technological developments. This is as a matter of fact also true for the ?eld of Mechanics.

Bonding in Microsystem Technology concerns the exciting field of microsystems (known under varying names as: MEMS, uTAS (analytical or chemical Microsystems), MOEMS: the micro-miniature devices, utilizing extremely miniaturized mechanical structures made usually from silicon by wet deep anisotropic etching. Such structures cannot be used directly, they must be designed and fabricated as a part of the three dimensional multi-layer sandwich built from silicon or silicon and glass. The procedures of formation of such a sandwich are known as bonding. The book contains the description of wet anisotropic micromachining of basic silicon micromechanical constructions and their utilization in microsystems followed by the detailed discussion of all of methods of bonding used for the formation of silicon and silicon-glass microsystems, with the special attention paid to the anodic bonding technique.

Bonding in Microsystem Technology starts with descriptions of terminology, kinds of microsystems and market analysis. Following this, presentation of mechanisms of wet etching, set of process parameters, description of micromachining methods, examples of procedures, process flow-charts and applications of basic micromechanical structures in microsystems are shown. Next, high-temperature, low temperature and room-temperature bonding and their applications in microsystem technology are presented. The following part of the book contains the detailed description of anodic bonding, starting from analysis of properties of glasses suitable for anodic bonding, and discussion of the nature of the process. Next all types of anodic bonding and sealing procedures used in microsystem technology are presented. This part of the book finishes with examples of applications of anodic bonding in microsystem technology taken from the literature but mainly based on the author s personal experience.

Bonding in Microsystem Technology is addressed to scientists and researchers, as well as to academic teachers and students, engineers active in the field of electric/electronics and microelectronics. It can serve as the encyclopaedia of wet etching and bonding for microsystem technology. Technological results presented in the book have been tested experimentally by the author and his team, and can be utilized in day-to-day laboratory practice. Special attention has been paid to the highest level of accessibility of the book by students. The book contains a large number of illustrations, algorithmic flow-charts and microsystems description and a rich index of literature sources.

This monograph examines the theoretical foundations of the spectral method for fatigue life determination. The authors discuss a rule of description of random loading states with the matrix of power spectral density functions of the stress/strain tensor components. Some chosen criteria of multiaxial fatigue failure are analyzed. The formula proposed in this book enables readers to determine power spectral density of the equivalent history directly from the components of the power spectral density matrix of the multidimensional stochastic process.

The Institute for Computer Applications in Science and Engineer ing (ICASE) and NASA Langley Research Center (LaRC) brought together on October 2-4, 1989 experts in the various areas of com bustion with a view to expose them to some combustion problems of technological interest to LaRC and possibly foster interaction with the academic community in these research areas. The top ics chosen for this purpose were flame structure, flame stability, flame holding/extinction, chemical kinetics, turbulence-kinetics in teraction, transition to detonation, and reacting free shear layers. The lead paper set the stage by discussing the status and issues of supersonic combustion relevant to scramjet engine. Then the ex perts were called upon i) to review the current status of knowledge in the aforementioned ;:I. reas, ii) to focus on how this knowledge can be extended and applied to high-speed combustion, and iii) to suggest future directions of research in these areas. Each topic was then dealt with in a position paper followed by formal discussion papers and a general discussion involving the participants. The position papers discussed the state-of-the-art with an emphasis on key issues that needed to be resolved in the near future. The discussion papers crit ically examined these issues and filled in any lacunae therein. The edited versions of the general discussions in the form of questions from the audience and answers from the speakers are included wher ever possible to give the reader the flavor of the lively interactions that took place.

Proceedings of the IUTAM Symposium on Fluid- Structure Interaction in Ocean Engineering, held in Hamburg, July 23-26, 2007. The study of gravity driven water waves interacting with fixed or freely floating objects is an active and important field of research in ocean engineering. The accurate prediction of large amplitude ship motions or of marine structures in severe seas is still a delicate problem in the field of fluid-structure interaction. While three-dimensional panel methods have reached the state of maturity in linear sea-keeping analysis, the original problem, governed by strongly nonlinear boundary conditions, is far from being solved efficiently. The principal nonlinearities are associated with the variable wetted surface of the ship hull or the floating body and with the nonlinear hydrodynamic conditions on the free surface. Moreover, marine structures often must be modelled as multibody systems rather than a single body. This causes additional problems due to wave slamming on floating and fixed structures. Furthermore, problems such as coupled structural behavior of submerged or floating systems as well as various wind effects have to be considered for the proper design of offshore systems. This book collects contributions from leading scientists working on the following topics: Ocean waves, probabilistic models of sea waves, fluid-loading on structures including pipes, cables, drill-strings etc., behavior of floating systems, stability and capsizing of ships, coupled structural behavior, sloshing in tanks, CFD validation and verification.

Capillary Forces in Microassembly discusses the use of capillary forces as a gripping principle in microscale assembly. Clearly written and well-organized, this text brings together physical concepts at the microscale with practical applications in micromanipulation. Throughout this work, the reader will find a review of the existing gripping principles, elements to model capillary forces as well as descriptions of the simulation and experimental test bench developed to study the design parameters. Using well-known concepts from surface science (such as surface tension, capillary effects, wettability, and contact angles) as inputs to mechanical models, the amount of effort required to handle micro-components is then predicted.

Researchers and engineers involved in micromanipulation and precision assembly will find this a highly useful reference for microassembly system design and analysis.