Download or read book A Report on the Use of Weak Shock Wave Profiles and 3 D Dislocation Dynamics Simulations for Validation of Dislocation Multiplication and Mobility in the Phonon Drag Regime written by D. Lassila and published by . This book was released on 2004 with total page 14 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dynamically loaded gas gun experiments were performed to validate the predictive capabilities of 3-D dislocation dynamics (DD) code simulations at very high strain rates and dislocation velocities where the phonon drag mechanism will be dominant. Experiments were performed in the weak-shock regime on high-purity Mo single crystals with [001] compression axes. We have also performed shock-recovery experiments and are in the process of analyzing the dislocation structure generated by the weak-shock using transmission electron microscopy (TEM), which will also be used to validate the dislocation structure predicted by the DD simulations. The DD simulations being performed at Washington State University by Prof. H. Zbib and co-workers will be compared to the experimentally measured wave profiles, thereby validating mechanisms of dislocation generation and motion. Some DD simulation results are presented to demonstrate the feasibility of using a combined experimental/simulation effort for the validation of dislocation generation and mobility physics issues in the phonon drag regime.

Download or read book Dislocations Mesoscale Simulations and Plastic Flow written by L. Kubin and published by Oxford University Press (UK). This book was released on 2013-04-18 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the past twenty years, new experimental approaches, improved models and progress in simulation techniques brought new insights into long-standing issues concerning dislocation-based plasticity in crystalline materials. Dislocation dynamics simulations are becoming accessible to a wide range of users. This book presents to students and researchers in materials science and mechanical engineering a comprehensive coverage of the physical body of knowledge on whichthey are based. This includes classical studies, which are too often ignored, recent experimental and theoretical advances, as well as a discussion of selected applications on various topics.

Download or read book Dislocation Dynamics written by Alan R. Rosenfield and published by . This book was released on 1968 with total page 806 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Single Crystal Deformation Experiments for Validation of Dislocation Dynamics Simulations written by and published by . This book was released on 2003 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: A new experimental apparatus has been developed for performing compression deformation experiments on high-purity Mo single crystals. These experiments provide data that can validate 3-D dislocation dynamics (DD) simulations. The experiments are performed under conditions that allow unconstrained deformation; thus, a relatively uniform state of axial stress is maintained during deformation. In the following sections, we describe the new experimental apparatus and our results from experiments performed at ambient temperature at a strain rate of s−1. Validation criteria based on the Mo experiments may include comparing the stress-strain response using 3-D strain information, the predicted slip-system yield, and work-hardening behavior.

Download or read book Computer Simulations of Dislocations written by Vasily Bulatov and published by OUP Oxford. This book was released on 2006-11-02 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book presents a variety of methods for computer simulations of crystal defects in the form of "numerical recipes", complete with computer codes and analysis tools. By working through numerous case studies and problems, this book provides a useful starter kit for further method development in the computational materials sciences.

Download or read book Dislocation Dynamics Simulations of Plasticity at Small Scales written by and published by . This book was released on 2010 with total page 179 pages. Available in PDF, EPUB and Kindle. Book excerpt: As metallic structures and devices are being created on a dimension comparable to the length scales of the underlying dislocation microstructures, the mechanical properties of them change drastically. Since such small structures are increasingly common in modern technologies, there is an emergent need to understand the critical roles of elasticity, plasticity, and fracture in small structures. Dislocation dynamics (DD) simulations, in which the dislocations are the simulated entities, offer a way to extend length scales beyond those of atomistic simulations and the results from DD simulations can be directly compared with the micromechanical tests. The primary objective of this research is to use 3-D DD simulations to study the plastic deformation of nano- and micro-scale materials and understand the correlation between dislocation motion, interactions and the mechanical response. Specifically, to identify what critical events (i.e., dislocation multiplication, cross-slip, storage, nucleation, junction and dipole formation, pinning etc.) determine the deformation response and how these change from bulk behavior as the system decreases in size and correlate and improve our current knowledge of bulk plasticity with the knowledge gained from the direct observations of small-scale plasticity. Our simulation results on single crystal micropillars and polycrystalline thin films can march the experiment results well and capture the essential features in small-scale plasticity. Furthermore, several simple and accurate models have been developed following our simulation results and can reasonably predict the plastic behavior of small scale materials.

Download or read book Continuum Scale Simulation of Engineering Materials written by Dierk Raabe and published by John Wiley & Sons. This book was released on 2006-03-06 with total page 885 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book fills a gap by presenting our current knowledge and understanding of continuum-based concepts behind computational methods used for microstructure and process simulation of engineering materials above the atomic scale. The volume provides an excellent overview on the different methods, comparing the different methods in terms of their respective particular weaknesses and advantages. This trains readers to identify appropriate approaches to the new challenges that emerge every day in this exciting domain. Divided into three main parts, the first is a basic overview covering fundamental key methods in the field of continuum scale materials simulation. The second one then goes on to look at applications of these methods to the prediction of microstructures, dealing with explicit simulation examples, while the third part discusses example applications in the field of process simulation. By presenting a spectrum of different computational approaches to materials, the book aims to initiate the development of corresponding virtual laboratories in the industry in which these methods are exploited. As such, it addresses graduates and undergraduates, lecturers, materials scientists and engineers, physicists, biologists, chemists, mathematicians, and mechanical engineers.

Download or read book Modeling Shockwave Deformation Via Molecular Dynamics written by and published by . This book was released on 1987 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular dynamics (MD), where the equations of motion of up to thousands of interacting atoms are solved on the computer, has proven to be a powerful tool for investigating a wide variety of nonequilibrium processes from the atomistic viewpoint. Simulations of shock waves in three-dimensional (3D) solids and fluids have shown conclusively that shear-stress relaxation is achieved through atomic rearrangement. In the case of fluids, the transverse motion is viscous, and the constitutive model of Navier-Stokes hydrodynamics has been shown to be accurate - even on the time and distance scales of MD experiments. For strong shocks in solids, the plastic flow that leads to shear-stress relaxation in MD is highly localized near the shock front, involving a slippage along close-packed planes. For shocks of intermediate strength, MD calculations exhibit an elastic precursor running out in front of the steady plastic wave, where slippage similar in character to that in the very strong shocks leads to shear-stress relaxation. An interesting correlation between the maximum shear stress and the Hugoniot pressure jump is observed for both 3D and fluid shockwave calculations, which may have some utility in modeling applications. At low shock strengths, the MD simulations show only elastic compression, with no permanent transverse atomic strains. The result for perfect 3D crystals is also seen in calculations for 1D chains. It is speculated that, if it were practical, a very large MD system containing dislocations could be expected to exhibit more realistic plastic flow for weak shock waves, too.

Download or read book An Introduction to Composite Materials written by D. Hull and published by Cambridge University Press. This book was released on 1996-08-13 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edition has been greatly enlarged and updated to provide both scientists and engineers with a clear and comprehensive understanding of composite materials. In describing both theoretical and practical aspects of their production, properties and usage, the book crosses the borders of many disciplines. Topics covered include: fibres, matrices, laminates and interfaces; elastic deformation, stress and strain, strength, fatigue crack propagation and creep resistance; toughness and thermal properties; fatigue and deterioration under environmental conditions; fabrication and applications. Coverage has been increased to include polymeric, metallic and ceramic matrices and reinforcement in the form of long fibres, short fibres and particles. Designed primarily as a teaching text for final-year undergraduates in materials science and engineering, this book will also interest undergraduates and postgraduates in chemistry, physics, and mechanical engineering. In addition, it will be an excellent source book for academic and technological researchers on materials.

Download or read book Semiconductor Laser Engineering Reliability and Diagnostics written by Peter W. Epperlein and published by John Wiley & Sons. This book was released on 2013-01-25 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: This reference book provides a fully integrated novel approach to the development of high-power, single-transverse mode, edge-emitting diode lasers by addressing the complementary topics of device engineering, reliability engineering and device diagnostics in the same book, and thus closes the gap in the current book literature. Diode laser fundamentals are discussed, followed by an elaborate discussion of problem-oriented design guidelines and techniques, and by a systematic treatment of the origins of laser degradation and a thorough exploration of the engineering means to enhance the optical strength of the laser. Stability criteria of critical laser characteristics and key laser robustness factors are discussed along with clear design considerations in the context of reliability engineering approaches and models, and typical programs for reliability tests and laser product qualifications. Novel, advanced diagnostic methods are reviewed to discuss, for the first time in detail in book literature, performance- and reliability-impacting factors such as temperature, stress and material instabilities. Further key features include: practical design guidelines that consider also reliability related effects, key laser robustness factors, basic laser fabrication and packaging issues; detailed discussion of diagnostic investigations of diode lasers, the fundamentals of the applied approaches and techniques, many of them pioneered by the author to be fit-for-purpose and novel in the application; systematic insight into laser degradation modes such as catastrophic optical damage, and a wide range of technologies to increase the optical strength of diode lasers; coverage of basic concepts and techniques of laser reliability engineering with details on a standard commercial high power laser reliability test program. Semiconductor Laser Engineering, Reliability and Diagnostics reflects the extensive expertise of the author in the diode laser field both as a top scientific researcher as well as a key developer of high-power highly reliable devices. With invaluable practical advice, this new reference book is suited to practising researchers in diode laser technologies, and to postgraduate engineering students.

Download or read book Physics of Solid Solution Strengthening written by E. Collings and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is the proceedings of a Symposium entitled "The Physics of Solid-Solution Strengthening in Alloys" which was held at McCormick Place, Chicago, on October 2, 1973, in association with a joint meeting of the American Society for Metals (ASM) and The Metallurgical Society (TMS) of the American Institute of Mining, Metallurgical, and Petroleum Engineers (AIME). The symposium, which was initiated and organized by the editors of this volume, was sponsored by the Committee on Alloy Phases, Institute of Metals Division, TMS, AIME, and the Flow and Fracture Section of the Materials Science Division, ASM. The discipline of Alloy Design has been very active in recent years, during which considerable stress has been placed on the roles of crystallography and microstructure in the rationalization and prediction of properties. Underestimated as a component of alloy design, however, has been the importance of physical property studies, even though physical property measurements have tradi tionally been employed to augment direct or x-ray observations in the determination of phase equilibrium (and, indeed, metastable equilibrium) boundaries.

Download or read book Nonlinear Finite Elements for Continua and Structures written by Ted Belytschko and published by John Wiley & Sons. This book was released on 2014-01-07 with total page 834 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nonlinear Finite Elements for Continua and Structures p>Nonlinear Finite Elements for Continua and Structures This updated and expanded edition of the bestselling textbook provides a comprehensive introduction to the methods and theory of nonlinear finite element analysis. New material provides a concise introduction to some of the cutting-edge methods that have evolved in recent years in the field of nonlinear finite element modeling, and includes the eXtended Finite Element Method (XFEM), multiresolution continuum theory for multiscale microstructures, and dislocation- density-based crystalline plasticity. Nonlinear Finite Elements for Continua and Structures, Second Edition focuses on the formulation and solution of discrete equations for various classes of problems that are of principal interest in applications to solid and structural mechanics. Topics covered include the discretization by finite elements of continua in one dimension and in multi-dimensions; the formulation of constitutive equations for nonlinear materials and large deformations; procedures for the solution of the discrete equations, including considerations of both numerical and multiscale physical instabilities; and the treatment of structural and contact-impact problems. Key features: Presents a detailed and rigorous treatment of nonlinear solid mechanics and how it can be implemented in finite element analysis Covers many of the material laws used in today’s software and research Introduces advanced topics in nonlinear finite element modelling of continua Introduction of multiresolution continuum theory and XFEM Accompanied by a website hosting a solution manual and MATLAB® and FORTRAN code Nonlinear Finite Elements for Continua and Structures, Second Edition is a must-have textbook for graduate students in mechanical engineering, civil engineering, applied mathematics, engineering mechanics, and materials science, and is also an excellent source of information for researchers and practitioners.

Download or read book Piezoelectric MEMS Resonators written by Harmeet Bhugra and published by Springer. This book was released on 2017-01-09 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces piezoelectric microelectromechanical (pMEMS) resonators to a broad audience by reviewing design techniques including use of finite element modeling, testing and qualification of resonators, and fabrication and large scale manufacturing techniques to help inspire future research and entrepreneurial activities in pMEMS. The authors discuss the most exciting developments in the area of materials and devices for the making of piezoelectric MEMS resonators, and offer direct examples of the technical challenges that need to be overcome in order to commercialize these types of devices. Some of the topics covered include: Widely-used piezoelectric materials, as well as materials in which there is emerging interest Principle of operation and design approaches for the making of flexural, contour-mode, thickness-mode, and shear-mode piezoelectric resonators, and examples of practical implementation of these devices Large scale manufacturing approaches, with a focus on the practical aspects associated with testing and qualification Examples of commercialization paths for piezoelectric MEMS resonators in the timing and the filter markets ...and more! The authors present industry and academic perspectives, making this book ideal for engineers, graduate students, and researchers.

Download or read book Continuum Mechanics and Applications in Geophysics and the Environment written by Brian Straughan and published by Springer Science & Business Media. This book was released on 2001-03-13 with total page 418 pages. Available in PDF, EPUB and Kindle. Book excerpt: The topics covered include soil mechanics and porous media, glacier and ice dynamics, climatology and lake physics, climate change as well as numerical algorithms. The book, written by well-known experts, addresses researchers and students interested in physical aspects of our environment.

Download or read book Computational Materials Engineering written by Koenraad George Frans Janssens and published by Academic Press. This book was released on 2010-07-26 with total page 359 pages. Available in PDF, EPUB and Kindle. Book excerpt: Computational Materials Engineering is an advanced introduction to the computer-aided modeling of essential material properties and behavior, including the physical, thermal and chemical parameters, as well as the mathematical tools used to perform simulations. Its emphasis will be on crystalline materials, which includes all metals. The basis of Computational Materials Engineering allows scientists and engineers to create virtual simulations of material behavior and properties, to better understand how a particular material works and performs and then use that knowledge to design improvements for particular material applications. The text displays knowledge of software designers, materials scientists and engineers, and those involved in materials applications like mechanical engineers, civil engineers, electrical engineers, and chemical engineers. Readers from students to practicing engineers to materials research scientists will find in this book a single source of the major elements that make up contemporary computer modeling of materials characteristics and behavior. The reader will gain an understanding of the underlying statistical and analytical tools that are the basis for modeling complex material interactions, including an understanding of computational thermodynamics and molecular kinetics; as well as various modeling systems. Finally, the book will offer the reader a variety of algorithms to use in solving typical modeling problems so that the theory presented herein can be put to real-world use. - Balanced coverage of fundamentals of materials modeling, as well as more advanced aspects of modeling, such as modeling at all scales from the atomic to the molecular to the macro-material - Concise, yet rigorous mathematical coverage of such analytical tools as the Potts type Monte Carlo method, cellular automata, phase field, dislocation dynamics and Finite Element Analysis in statistical and analytical modeling

Download or read book Superconducting Electronics written by Harold Weinstock and published by Springer Science & Business Media. This book was released on 2013-06-29 with total page 451 pages. Available in PDF, EPUB and Kindle. Book excerpt: The genesis of the NATO Advanced Study Institute (ASI) upon which this volume is based, occurred during the summer of 1986 when we came to the realization that there had been significant progress during the early 1980's in the field of superconducting electronics and in applications of this technology. Despite this progress, there was a perception among many engineers and scientists that, with the possible exception of a limited number of esoteric fundamental studies and applications (e.g., the Josephson voltage standard or the SQUID magnetometer), there was no significant future for electronic systems incorporating superconducting elements. One of the major reasons for this perception was the aversion to handling liquid helium or including a closed-cycle helium liquefier. In addition, many critics felt that IBM's cancellation of its superconducting computer project in 1983 was "proof" that superconductors could not possibly compete with semiconductors in high-speed signal processing. From our perspective, the need for liquid helium was outweighed by improved performance, i. e., higher speed, lower noise, greater sensitivity and much lower power dissipation. For many commercial, medical, scientific and military applications, these attributes can lead to either enhanced capability (e.g., compact real-time signal processing) or measurements that cannot be made using any other technology (e.g., SQUID magnetometry to detect neuromagnetic activity).

Download or read book Dynamic Behavior of Materials written by Marc A. Meyers and published by John Wiley & Sons. This book was released on 1994-10-28 with total page 694 pages. Available in PDF, EPUB and Kindle. Book excerpt: Addresses fundamentals and advanced topics relevant to the behavior of materials under in-service conditions such as impact, shock, stress and high-strain rate deformations. Deals extensively with materials from a microstructure perspective which is the future direction of research today.