Proceedings of the First International Symposium on Impact and Friction of Solids, Structures and Intelligent Machines


Book Description

This book deals with the dynamics of mechanical systems in presence of impact and friction. The contributors are an international group of engineers and scientists from industrial and academic institutions of more than 23 countries around the world concerned with the modeling, analysis, measurement and control of nonsmooth mechanical structures. Contact laws lead to mathematical models that are highly nonlinear and nonsmooth or discontinuous. Discontinuous and nonsmooth processes introduce problems with data processing techniques and analytical methods. Thanks to great advances in computer technology and computational analysis, as well as the introduction of new experimental devices such as the atomic-force microscope and the quartz-crystal-microbalance probe, the study of impact and friction ? one of the oldest problems in physics, is now in a phase of rapid and exciting development. The growing number of research breakthroughs have promoted the development of new technologies in the description and design of systems with impact and friction models to understand nature, structures, machines, transportation systems, and other processes. A fairly comprehensive picture of these new developments is presented in this book by researchers who are giving up-to-date accounts of the present state of the field in many aspects.The book is essential for introducing readers in mechanical engineering, material science, applied mathematics, aerospace engineering, ocean engineering, biomechanics, and civil engineering to recent developments in nonsmooth mechanics. It is also useful for self-study purposes by professionals and practitioners in the field.




Theory of Elasticity for Scientists and Engineers


Book Description

This book is intended to be an introduction to elasticity theory. It is as sumed that the student, before reading this book, has had courses in me chanics (statics, dynamics) and strength of materials (mechanics of mate rials). It is written at a level for undergraduate and beginning graduate engineering students in mechanical, civil, or aerospace engineering. As a background in mathematics, readers are expected to have had courses in ad vanced calculus, linear algebra, and differential equations. Our experience in teaching elasticity theory to engineering students leads us to believe that the course must be problem-solving oriented. We believe that formulation and solution of the problems is at the heart of elasticity theory. 1 Of course orientation to problem-solving philosophy does not exclude the need to study fundamentals. By fundamentals we mean both mechanical concepts such as stress, deformation and strain, compatibility conditions, constitu tive relations, energy of deformation, and mathematical methods, such as partial differential equations, complex variable and variational methods, and numerical techniques. We are aware of many excellent books on elasticity, some of which are listed in the References. If we are to state what differentiates our book from other similar texts we could, besides the already stated problem-solving ori entation, list the following: study of deformations that are not necessarily small, selection of problems that we treat, and the use of Cartesian tensors only.




Nonlinear Inclusions and Hemivariational Inequalities


Book Description

This book introduces the reader the theory of nonlinear inclusions and hemivariational inequalities with emphasis on the study of contact mechanics. The work covers both abstract results in the area of nonlinear inclusions, hemivariational inequalities as well as the study of specific contact problems, including their modelling and their variational analysis. Provided results are based on original research on the existence, uniqueness, regularity and behavior of the solution for various classes of nonlinear stationary and evolutionary inclusions. In carrying out the variational analysis of various contact models, one systematically uses results of hemivariational inequalities and, in this way, illustrates the applications of nonlinear analysis in contact mechanics. New mathematical methods are introduced and applied in the study of nonlinear problems, which describe the contact between a deformable body and a foundation. Contact problems arise in industry, engineering and geophysics. Their variational analysis presented in this book lies the background for their numerical analysis. This volume will interest mathematicians, applied mathematicians, engineers, and scientists as well as advanced graduate students.




Nonholonomic Mechanics and Control


Book Description

This book explores connections between control theory and geometric mechanics. The author links control theory with a geometric view of classical mechanics in both its Lagrangian and Hamiltonian formulations, and in particular with the theory of mechanical systems subject to motion constraints. The synthesis is appropriate as there is a rich connection between mechanics and nonlinear control theory. The book provides a unified treatment of nonlinear control theory and constrained mechanical systems that incorporates material not available in other recent texts. The book benefits graduate students and researchers in the area who want to enhance their understanding and enhance their techniques.




Normal Modes and Localization in Nonlinear Systems


Book Description

The nonlinear normal modes of a parametrically excited cantilever beam are constructed by directly applying the method of multiple scales to the governing integral-partial differential equation and associated boundary conditions. The effect of the inertia and curvature nonlin earities and the parametric excitation on the spatial distribution of the deflection is examined. The results are compared with those obtained by using a single-mode discretization. In the absence of linear viscous and quadratic damping, it is shown that there are nonlinear normal modes, as defined by Rosenberg, even in the presence of a principal parametric excitation. Furthermore, the nonlinear mode shape obtained with the direct approach is compared with that obtained with the discretization approach for some values of the excitation frequency. In the single-mode discretization, the spatial distribution of the deflection is assumed a priori to be given by the linear mode shape ¢n, which is parametrically excited, as Equation (41). Thus, the mode shape is not influenced by the nonlinear curvature and nonlinear damping. On the other hand, in the direct approach, the mode shape is not assumed a priori; the nonlinear effects modify the linear mode shape ¢n. Therefore, in the case of large-amplitude oscillations, the single-mode discretization may yield inaccurate mode shapes. References 1. Vakakis, A. F., Manevitch, L. I., Mikhlin, Y. v., Pilipchuk, V. N., and Zevin A. A., Nonnal Modes and Localization in Nonlinear Systems, Wiley, New York, 1996.




Dynamics with Friction


Book Description

Dynamics with friction: Modeling, analysis and experiments, part II. ch. 1. Interaction of vibration and friction at dry sliding contacts / Daniel P. Hess -- ch. 2. Vibrations and friction-induced instability in discs / John E. Mottershead -- ch. 3. Dynamics of flexible links in kinematic chains / Dan B. Marghitu and Ardeshir Guran -- ch. 4. Solitons, chaos and modal interactions in periodic structures / M.A. Davies and F.C. Moon -- ch. 5. Analysis and modeling of an experimental frictionally excited beam / R.V. Kappagantu and B.F. Feeny -- ch. 6. Transient waves in linear viscoelastic media / Francesco Mainardi -- ch. 7. Dynamic stability and nonlinear parametric vibrations of rectangular plates / G.L. Ostiguy -- ch. 8. Friction modelling and dynamic computation / J.P. Meijaard -- ch. 9. Damping through use of passive and semi-active dry friction forces / Aldo A. Ferri




Dynamics With Friction, Modeling, Analysis And Experiments, Part Ii


Book Description

The dynamics of dissipative mechanical and structural systems is being investigated at various institutions and laboratories worldwide with ever-increasing sophistication of modeling, analysis and experiments.This book offers a collection of contributions from these research centers that represent the state-of-the-art in the study of friction oscillators. It provides the reader with the fruits of a team effort by leaders in this fascinating field.The present part II of this volume on Dynamics with Friction is a continuation of the previous part I, and is designed to help synthesize our current knowledge regarding the role of friction in mechanical and structural systems as well as everyday life. The topics covered include interaction of vibration and friction at dry sliding contacts, friction-induced instability in disks, dynamics of lubricated flexible links in kinematic chains, modal interactions in periodic structures, dynamics of an experimentally excited beam, transient waves in viscoelastic materials, dynamic stability of plates with damping, friction modeling and dynamic computation, damping through use of passive and semi-active dry friction forces.This book gives a comprehensive picture of dynamics of dissipative mechanical and structural systems. It also gives an up-to-date account of the present state of the field. It will be of interest to engineers, rheologists, material scientists, applied mathematicians, physicists and historians of science and technology.




Annual Report


Book Description







Bulletin of the Atomic Scientists


Book Description

The Bulletin of the Atomic Scientists is the premier public resource on scientific and technological developments that impact global security. Founded by Manhattan Project Scientists, the Bulletin's iconic "Doomsday Clock" stimulates solutions for a safer world.