Bøger i CISM International Centre for Mechanical Sciences serien

The volume provides a comprehensive understanding of the macroscopic failure behavior of solids from the description of the microscopic failure processes and their coupling with the microstructure. Several fundamental questions were addressed: the relation between the microstructural features of materials and their fracture properties and crack trajectories; the role of damage mechanisms and non-linear deformations near the crack tip on the failure behavior of solids; and finally the role of dynamic inertial effects during fast fracture was more briefly evoked. The chapters provide a pedagogical overview of recently developed concepts and tools, that permit to perform the transition from small scales to large ones in fracture problems, thus introducing basic rules for the rational design of tough solids.

The book provides basic and recent research insights concerning the small scale modeling and simulation of turbulent multi-phase flows. By small scale, it has to be understood that the grid size for the simulation is smaller than most of the physical time and space scales of the problem. Small scale modeling of multi-phase flows is a very popular topic since the capabilities of massively parallel computers allows to go deeper into the comprehension and characterization of realistic flow configurations and at the same time, many environmental and industrial applications are concerned such as nuclear industry, material processing, chemical reactors, engine design, ocean dynamics, pollution and erosion in rivers or on beaches. The work proposes a complete and exhaustive presentation of models and numerical methods devoted to small scale simulation of incompressible turbulent multi-phase flows from specialists of the research community. Attention has also been paid to promote illustrations and applications, multi-phase flows and collaborations with industry. The idea is also to bring together developers and users of different numerical approaches and codes to share their experience in the development and validation of the algorithms and discuss the difficulties and limitations of the different methods and their pros and cons. The focus will be mainly on fixed-grid methods, however adaptive grids will be also partly broached, with the aim to compare and validate the different approaches and models.

The book introduces advanced theories for deformation, damage, and failure in materials. The overall continuum mechanical framework was marked out and added by creep and damage mechanics of materials at elevated temperatures. The time-dependent and time-independent models of cyclic plasticity for low cycle and thermomechanical fatigue life assessment were specified in a very special manner: instead of three-dimensional statements, only one-dimensional rheological models were discussed. Anisotropic plasticity during non-proportional loading and anisotropy of yield/failure criteria is more and more important in modern applications. It is showing how the limit states of materials can be estimated. In addition, the damage and failure of composite materials demonstrate the possibility to extend continuum mechanics to continuum damage mechanics of composite materials.

This book gathers contributions on analytical, numerical, and application aspects of time-delay systems, under the paradigm of control theory, and discusses recent advances in these different contexts, also highlighting the interdisciplinary connections. The book will serve as a useful tool for graduate students and researchers in the fields of dynamical systems, automatic control, numerical methods, and functional analysis.

This volume is a special Issue on "e;Dynamical Systems, Wave based computation and neuro inspired robots'^ based on a Course carried out at the CISM in Udine (Italy), the last week of September, 2003. From the topics treated within that Course, several new ideas were f- mulated, which led to a new kind of approach to locomotion and p- ception, grounded both on biologically inspired issues and on nonlinear dynamics. The Course was characterised by a high degree of multi disciplinarity. In fact, in order to conceive, design and build neuro inspired machines, it is necessary to deeply scan into different d- ciplines, including neuroscience. Artificial Intelligence, Biorobotics, Dynamical Systems theory and Electronics. New types of moving machines should be more closely related to the biological rules, not discarding the real implementation issues. The recipe has to include neurobiological paradigms as well as behavioral aspects from the one hand, new circuit paradigms, able of real time control of multi joint robots on the other hand. These new circuit paradigms are based on the theory of complex nonlinear dynamical systems, where aggregates of simple non linear units into ensembles of lattices, have the pr- erty that the solution set is much richer than that one shown by the single units. As a consequence, new solutions ^'emerge'\ which are often characterized by order and harmony.

This is the first book which exploits concepts and tools of global nonlinear dynamics for bridging the gap between theoretical and practical stability of systems/structures, and for possibly enhancing the engineering design in macro-, micro- and nano-mechanics. Addressed topics include complementing theoretical and practical stability to achieve load carrying capacity; dynamical integrity for analyzing global dynamics, for interpreting/predicting experimental behavior, for getting hints towards engineering design; techniques for control of chaos; response of uncontrolled and controlled system/models in applied mechanics and structural dynamics by also considerung the effect of system imperfections; from relatively simple systems to multidimensional models representative of real world applications; potential and expected impact of global dynamics for engineering design.

This course with 6 lecturers intends to present a systematic survey of recent re- search results of well-known scientists on error-controlled adaptive finite element methods in solid and structural mechanics with emphasis to problem-dependent concepts for adaptivity, error analysis as well as h- and p-adaptive refinement techniques including meshing and remeshing. Challenging applications are of equal importance, including elastic and elastoplastic deformations of solids, con- tact problems and thin-walled structures. Some major topics should be pointed out, namely: (i) The growing importance of goal-oriented and local error estimates for quan- tities of interest-in comparison with global error estimates-based on dual finite element solutions; (a) The importance of the p-version of the finite element method in conjunction with parameter-dependent hierarchical approximations of the mathematical model, for example in boundary layers of elastic plates; (Hi) The choice of problem-oriented error measures in suitable norms, consider- ing residual, averaging and hierarchical error estimates in conjunction with the efficiency of the associated adaptive computations; (iv) The importance of implicit local postprocessing with enhanced test spaces in order to get constant-free, i. e. absolute-not only relative-discretizati- error estimates; (v) The coupling of error-controlled adaptive discretizations and the mathemat- ical modeling in related subdomains, such as boundary layers. The main goals of adaptivity are reliability and efficiency, combined with in- sight and access to controls which are independent of the applied discretization methods. By these efforts, new paradigms in Computational Mechanics should be realized, namely verifications and even validations of engineering models.

The quest for more reliable, more environment-friendly, more fuel-efficient, and more affordable products in an extremely competitive market appear as the driving forces behind the need for an integrated approach to mechanical design, analysis, and control. In this context, aircraft is being designed currently with novel electromechanical systems for the steering of its control surfaces - ailerons, rudders, and the like - while terrestrial vehicles are nowadays designed with active suspensions, to name but a few of the plethora of mechanical systems whereby an integration of disciplines is unavoidable. This book is intended to fill the gap among kinematics, dynamics, and control, as pertaining to complex mechanical systems, with the aim to ease the task of the design and control engineers as well as to assist the researchers in related disciplines in the analysis and synthesis of novel mechanical systems.

The volume collects the contributions presented at the second meeting on Unilateral Problems, organized by CISM and held near Udine in June 1985. It gives an updated account of the state-of-the-art in the field of unilateral problems, with an outlook on open problems and on perspectives of application to structural analysis. The topic is presently the object of growing interest and is undergoing very rapid development. One of the most noticeable characteristics of unilateral problems is their interdisciplinary nature; they involve sophisticated mathematics, fundamental questions in mechanics, modern techniques in numerical analysis, re-inspection of the present knowledge of physical phenomena, and engineering applications. This volume succeeds in collecting and coordinating contributions from all these areas. For this reason, it is an excellent source of information for researchers working in the field.

The solution of stress analysis problems through numerical, computer oriented techniques is becoming more and more popular in soil and rock engineering. This is due to the ability of these methods to handle geometrically complex problems even in the presence of highly nonlinear material behaviour, characterizing the majority of soils and rocks, and of media consisting of two or more phases, like saturated and partially saturated soils. Aim of this book is to present to researchers and engineers working in the various branches of geomechanics an updated state of the research on the development and application of numerical methods in geotechnical and foundation engineering. Particular attention is devoted to the formulation of nonlinear material models and to their use for the analysis of complex engineering problems. In addition to the constitutive modelling, other topics discussed concern the use of the finite element and boundary element methods in geomechanics; the dynamic analysis of inelastic and saturated soils; the solution of seepage, consolidation and coupled problems; the analysis of soil-structure interaction problems; the numerical procedures for the interpretation of field measurements; the analysis of tunnels and underground openings.

This book, based on the Fourth International Conference on Advanced Manufacturing Systems and Technology - AMST '96 aims at presenting trend and up-to-date information on the latest developments - research results and industrial experience in the field of machining processes, optimization and process planning, forming, flexible machining systems, non conventional machining, robotics and control, measuring and quality, thus providing an international forum for a beneficial exchange of ideas, and furthering a favourable cooperation between research and industry.

This book presents, as a single package, three semingly contradictory and often competitive approaches to deal with ever present uncertainty in science and engineering. The book describes, as a unique view, probabilistic, fuzzy sets based and antioptimization based approaches, in order to remedy the present "e;tower ob Babel"e; situation, in which researchers in competing fields do not communicate. Integrative approach will attract scientists and engineers alike and provide a strong impetus towards integrative, hybrid approaches.

The book deals with modern methods of nonlinear stability theory applied to problems of continuous media mechanics in the presence of interfaces, with applications to materials science, chemical engineering, heat transfer technologies, as well as in combustion and other reaction-diffusion systems. Interfaces play a dominant role at small scales, and their correct modeling is therefore also crucial in the rapidly expanding fields of microfluidics and nanotechnologies. To this aim, the book combines contributions of eminent specialists in the field, with a special emphasis on rigorous and predictive approaches. Other goals of this volume are to allow the reader to identify key problems of high scientific value, and to see the similarity between a variety of seemingly different physical problems.

This book examines the fundamentals of vehicle dynamics, as well as the recent trends in the field, such as torque vectoring control, vehicle state estimation, and autonomous vehicles.

The book introduces modern high-order methods for computational fluid dynamics. As compared to low order finite volumes predominant in today's production codes, higher order discretizations significantly reduce dispersion errors, the main source of error in long-time simulations of flow at higher Reynolds numbers. A major goal of this book is to teach the basics of the discontinuous Galerkin (DG) method in terms of its finite volume and finite element ingredients. It also discusses the computational efficiency of high-order methods versus state-of-the-art low order methods in the finite difference context, given that accuracy requirements in engineering are often not overly strict.The book mainly addresses researchers and doctoral students in engineering, applied mathematics, physics and high-performance computing with a strong interest in the interdisciplinary aspects of computational fluid dynamics. It is also well-suited for practicing computational engineers who would like to gain an overview of discontinuous Galerkin methods, modern algorithmic realizations, and high-performance implementations.

This book highlights the latest innovations and applications in robotics, as presented by leading international researchers and engineers at the ROMANSY 2020, the 23rd CISM IFToMM Symposium on Theory and Practice of Robots and Manipulators.