Fracture Mechanics Of Electromagnetic Materials

This volume provides a comprehensive overview of fracture mechanics of conservative and dissipative materials, as well as a general formulation of nonlinear field theory of fracture mechanics and a rigorous treatment of dynamic crack problems involving coupled magnetic, electric, thermal and mechanical field quantities.

The mechanics of electromagnetic materials and structures has been developing rapidly with extensive applications in, e. g. , electronics industry, nuclear engineering, and smart materials and structures. Researchers in this interdisciplinary field are with diverse background and motivation. The Symposium on the Mechanics of Electromagnetic Materials and Structures of the Fourth International Conference on Nonlinear Mechanics in Shanghai, China in August 13-16, 2002 provided an opportunity for an intimate gathering of researchers and exchange of ideas. This volume contains papers based on most of the presentations at the symposium, and articles from a few invited contributors. These papers reflect some of the recent activities in the mechanics of electromagnetic materials and structures. The first twelve papers are in the order in which they were listed in the program of the conference. These are followed by six invited papers in alphabetical order of the last names of the first authors. We would like to extend our sincere thanks to Professor David Y. Gao of Virginia Tech for suggesting the symposium, and to the authors for their time and effort invested in preparing their manuscripts. We are also grateful to Professor Daining Fang of Tsinghua University for co-chairing the symposium with J. S. Yang. Our special thanks belong to Kluwer for preparing this book for publication. J. S. Yang G. A. Maugin PIEZOELECTRIC VIBRATORY GYROSCOPES J. S.

This volume contains papers presented at the Symposium on the Mechanics of Electromagnetic Materials and Structures of the 1999 ASME Summer Meeting in Blacksburg, Virginia, USA. Topics covered include continuum modelling of deformable electromagnetic materials, magnetoelasticity and electroelasticity. Experimental, computational, and theoretical results are presented. The Symposium and the book are enriched by the participation of contributors from industries and presentations related to device applications.

In recent years, the science of electro-magneto-mechanics has developed rapidly because of its possible extensive practical applications in fields such as smart material systems and structures, microelectromechanical systems (MEMS), bio-medical devices, superconducting devices, and magnetic fusion reactors. volume features a selection of papers presented at the Symposium on Electro-Magneto-Mechanics that formed part of the 14th US National Congress of Theoretical and Applied Mechanics (USNCTAM 14). state-of-the-art fundamental research to applied research and applications in emerging technologies. They are divided under the following main headings: magnetoelasticity; piezoelectric fracture and damage mechanics; piezoelectric buckling, stability and vibration; and smart sensors and actuators.

This book provides a comprehensive study of cracks situated at the interface of two piezoelectric materials. It discusses different electric boundary conditions along the crack faces, in particular the cases of electrically permeable, impermeable, partially permeable, and conducting cracks. The book also elaborates on a new technique for the determination of electromechanical fields at the tips of interface cracks in finite sized piezoceramic bodies of arbitrary shape under different load types. It solves scientific problems of solid mechanics in connection with the investigation of electromechanical fields in piezoceramic bodies with interface cracks, and develops calculation models and solution methods for plane fracture mechanical problems for piecewise homogeneous piezoceramic bodies with cracks at the interfaces. It discusses the “open” crack model, which leads to a physically unrealistic oscillating singularity at the crack tips, and the contact zone model for in-plane straight interface cracks between two dissimilar piezoelectric materials. It also investigates the model of a crack with electro-mechanical pre-fracture zones. The formulated problems are reduced to problems of linear relationship, which correspond to different crack models, and their exact analytical solutions are found. The book presents in detail the expressions for stress and electric displacement intensity factors, as well as for the energy release rate. The influence of the electric permittivity of the crack, the mechanical load and the electric field upon the electro-elastic state, as well as the main fracture mechanical parameters, are analyzed and clearly illustrated. This book addresses postgraduate students, university teachers and researchers dealing with the problems of fracture mechanics of piezoelectric materials, as well as engineers who are active in the analysis of strength and durability of piezoelectric constructions.

Scientific research on functionally graded materials (FGM's) looks at functions of gradients in materials comprising thermodynamic, mechanical, chemical, optical, electromagnetic, and/or biological aspects. This collection of technical papers represents current research interests with regard to the fracture behaviour of FGM's. The papers provide a balance between theoretical, computational, and experimental techniques. It also indicates areas for increased development, such as constraint effects, full experimental characterization of engineering FGM's under static and dynamic loading, development of fracture criteria with predictive capability, multiphysics and multiscale failure considerations, and connection of research with industrial applications.

This book is concerned with electrostructural systems, particularly the interaction between the control of the structural and electrical (electronic) components. Structronics is a new emerging area with many potential applications in the design of high-performance structures, adaptive structures, high-precision systems, and micro-systems. As structures are increasingly being controlled by electronics, the problems of structural engineering can be separated less and less from those of electronic engineering and control engineering. This graduate-level book fills a gap in the literature by considering these problems while giving an overview of the current state of analysis, modelling and control for structronic systems. It is a coherent compendium written by leading experts in this new research area and gives readers a sophisticated toolbox that will allow them to tackle the modelling and control of smart structures. The inclusion of an extensive, up-to-date bibliography and index makes this volume an invaluable standard for professional reference. Because of the large number of contributions to the present volume, it has been subdivided into two parts, of which this is Part I. This book will be of interest to engineers, materials scientists, physicists and applied mathematicians. The synergistic integration of active (smart) materials, structures, sensors, actuators, and control electronics has redefined the concept of structures from a conventional passive elastic system to an active (life-like) structronic (structure + electronic) system with inherent self-sensing, diagnosis, and control capabilities. Because of its multi-disciplinary nature, the development of structronic systems has attracted researchers and scientists from many disciplines, such as structures, materials, control, electronics, mathematics, manufacturing, electromechanics, and mechanics. In practical applications, this new structronic system can be used as a component of high-performance machines or structural systems, or be an integrated structure itself performing designated function(s). Most common active (smart) materials, such as piezoelectrics, shape-memory alloys, electro- and magneto-strictive materials, and polyelectrolyte gels have been reviewed in Part I. Application examples are also provided and research issues reported on. While the first part focuses primarily on materials and structures, Part II emphasizes control applications and intelligent systems. With the information provided in this two-volume book, scientists and researchers can easily grasp the state of the art of smart materials and structronic systems, and are ready to pursue their own research and development endeavors. Contents:Part I: Materials and StructuresThe Piezoelectric Vibration Absorber Systems (J Holkamp & T Starchville, Jr.)Self-Sensing Control Applied to Smart Material Systems (E Garcia & L D Jones)An Introduction to Active Constrained Layer Damping Treatments (S Shen)Static and Dynamic Behavior of Adaptive Wings Carrying Externally Mounted Stores (L Librescu & O Song)Adaptive Design and Active Composite Material Systems (J Tani & J-H Qiu)Microelectromechanics and Functionality of Segmented Cylindrical Transducers (H-S Tzou et al.)Thermomechanical Modeling of Shape Memory Alloys and Composites (D Lagoudas et al.)Active-Passive Hybrid Structural Vibration Controls Via Piezoelectrical Networks (K-W Wang & S Kahn)On-Line Structural Damage Detection (H Shen)On Material Degradation and Failure of Piezoelectric Ceramics (H Sosa)Part II: Systems and ControlNear-Minimum-Time Slewing and Vibration Control of Smart Structures(Y Kim et al.)Active Polyelectrolyte Gels as Electrically Controllable Artificial Muscles and Intelligent Network Structures(M Shahinpoor)Active Dynamic Absorbers — Theory and Application(S Tewani et al.)Active Vibration Sink for Flexible Structures(C-S Chou)Distributed Modal-Space Control and Estimation with Electroelastic Applications(H Öz)Markov Parameters in System Identification: Old and New Concepts(M Q Phan et al.)Effect of System Non-Linearities on the Modified Model Reference Adaptive Control Scheme(H M Sardar & M Ahmadian)Extending Teach-Repeat to Nonholonomic Robots(S B Skaar & J-D Yoder)Dynamic Analysis and Active Vibration Control of Chain Drive Systems(C-A Tan et al.)Basic Concepts of Fault-Tolerant Computing Design(C Aktouf et al.) Readership: Applied mathematicians, applied physicists and mechanical engineers. Keywords:Structronic Systems;Smart Structures;Devices;Systems;Materials;ControlReviews: “… Professors Guran and Tzou coined the word Structronics in the early 1990s as a new discipline describing the synergetic integration of active materials, structures, sensors, actuators, and control electronics. The present two-volume set is the first comprehensive book ever published on this newly emerging area of engineering. I believe anyone who would like to know what modern science and technology can offer for the design of better structures can learn a great deal from this book. Students and educators can use it as supplemental reading in an intermediate or advanced course on Structronics, or to gain a broader knowledge of systems thinking, model materials, and structural systems. Practicing engineers wishing to consolidate their knowledge in smart technology will also find this book an invaluable reference.” Dr Bernd Schaefer Director Institute of Robotics and Mechatronics, Wessling, Germany