Elastic Waves: High Frequency Theory is concerned with mathematical aspects of the theory of high-frequency elastic waves, which is based on the ray method. The foundations of elastodynamics are presented along with the basic theory of plane and spherical waves. The ray method is then described in considerable detail for bulk waves in isotropic and anisotropic media, and also for the Rayleigh waves on the surface of inhomogeneous anisotropic elastic solids. Much attention is paid to analysis of higher-order terms and to generation of waves in inhomogeneous media. The aim of the book is to present a clear, systematic description of the ray method, and at the same time to emphasize its mathematical beauty. Luckily, this beauty is usually not accompanied by complexity and mathematical ornateness.
John G. Harris intended to explain in this book the special techniques required to model the radiation and diffraction of elastic and surface waves. Sadly, he died before he could fulfil this ambition, but his plan has been brought to fruition by a team of his distinguished collaborators. The book begins with the basic underlying equations for wave motion and then builds upon this foundation by solving a number of fundamental scattering problems. The remaining chapters provide a thorough introduction to modern techniques that have proven essential to understanding radiation and diffraction at high frequencies. Graduate students, researchers and professionals in applied mathematics, physics and engineering will find that the chapters increase in complexity, beginning with plane-wave propagation and spectral analyses. Other topics include elastic wave theory, the Wiener–Hopf technique, the effects of viscosity on acoustic diffraction, and the phenomenon of channelling of wave energy along guided structures.
Elastic waves possess some remarkable properties and have become ever more important to applications in fields such as telecommunications (signal processing), medicine (echography), and metallurgy (non-destructive testing). These volumes serve as a bridge between basic books on wave phenomena and more technically oriented books on specific applications of wave phenomena. The first volume studies the different mechanisms of propagation in isotropic and anisotropic media. The second volume describes the generation and applications of free and guided waves.
Ultrasound has found an increasing number of applications in recent years due to greatly increased computing power. Ultrasound devices are often preferred over other devices because of their lower cost, portability, and non-invasive nature. Patients using ultrasound can avoid the dangers of radiological imaging devices such as x-rays, CT scans, and radioactive media injections. Ultrasound is also a preferred and practical method of detecting material fatique and defects in metals, composites, semiconductors, wood, etc. - Detailed appendices contain useful formulas and their derivations, technical details of relevant theories - The FAQ format is used where a concept in one answer leads to a new Q
High Frequency and Pulse Scattering investigates high frequency and pulse scattering, with emphasis on the phenomenon of echoes from objects. Geometrical and catastrophe optics methods in scattering are discussed, along with the scattering of sound pulses and the ringing of target resonances. Caustics and associated diffraction catastrophes are also examined. Comprised of two chapters, this volume begins with a detailed account of geometrically based approximation methods in scattering theory, focusing on waves transmitted through fluid and elastic scatterers and glory scattering; surface ray representations of scattering by shells and other smooth objects; and caustics and associated diffraction catastrophes. The second chapter deals with the relation between sound pulses and the vibrational spectra of elastic submerged objects. The theory of the scattering of sound pulses from elastic and impenetrable objects is described, together with the theory of surface wave pulses. Target resonances and the singularity expansion method are also analyzed. This book will be of interest to physicists.
Integral Equation Methods for Electromagnetic and Elastic Waves is an outgrowth of several years of work. There have been no recent books on integral equation methods. There are books written on integral equations, but either they have been around for a while, or they were written by mathematicians. Much of the knowledge in integral equation methods still resides in journal papers. With this book, important relevant knowledge for integral equations are consolidated in one place and researchers need only read the pertinent chapters in this book to gain important knowledge needed for integral equation research. Also, learning the fundamentals of linear elastic wave theory does not require a quantum leap for electromagnetic practitioners. Integral equation methods have been around for several decades, and their introduction to electromagnetics has been due to the seminal works of Richmond and Harrington in the 1960s. There was a surge in the interest in this topic in the 1980s (notably the work of Wilton and his coworkers) due to increased computing power. The interest in this area was on the wane when it was demonstrated that differential equation methods, with their sparse matrices, can solve many problems more efficiently than integral equation methods. Recently, due to the advent of fast algorithms, there has been a revival in integral equation methods in electromagnetics. Much of our work in recent years has been in fast algorithms for integral equations, which prompted our interest in integral equation methods. While previously, only tens of thousands of unknowns could be solved by integral equation methods, now, tens of millions of unknowns can be solved with fast algorithms. This has prompted new enthusiasm in integral equation methods. Table of Contents: Introduction to Computational Electromagnetics / Linear Vector Space, Reciprocity, and Energy Conservation / Introduction to Integral Equations / Integral Equations for Penetrable Objects / Low-Frequency Problems in Integral Equations / Dyadic Green's Function for Layered Media and Integral Equations / Fast Inhomogeneous Plane Wave Algorithm for Layered Media / Electromagnetic Wave versus Elastic Wave / Glossary of Acronyms
Summary: This book presents necessary background knowledge on mechanics to understand and analyze elastic wave propagation in solids and fluids. This knowledge is necessary for elastic wave propagation modeling and for interpreting experimental data generated during ultrasonic nondestructive testing and evaluation (NDT&E). The book covers both linear and nonlinear analyses of ultrasonic NDT&E techniques. The materials presented here also include some exercise problems and solution manual. Therefore, this book can serve as a textbook or reference book for a graduate level course on elastic waves and/or ultrasonic nondestructive evaluation. It will be also useful for instructors who are interested in designing short courses on elastic wave propagation in solids or NDT&E. The materials covered in the first two chapters provide the fundamental knowledge on linear mechanics of deformable solids while Chapter 4 covers nonlinear mechanics. Thus, both linear and nonlinear ultrasonic techniques are covered here. Nonlinear ultrasonic techniques are becoming more popular in recent years for detecting very small defects and damages. However, this topic is hardly covered in currently available textbooks. Researchers mostly rely on published research papers and research monographs to learn about nonlinear ultrasonic techniques. Chapter 3 describes elastic wave propagation modeling techniques using DPSM. Chapter 5 is dedicated to an important and very active research field – acoustic source localization – that is essential for structural health monitoring and for localizing crack and other type of damage initiation regions. Features • Introduces Linear and Nonlinear ultrasonic techniques in a single book. • Commences with basic definitions of displacement, displacement gradient, traction and stress. • Provides step by step derivations of fundamental equations of mechanics as well as linear and nonlinear wave propagation analysis. • Discusses basic theory in addition to providing detailed NDE applications. • Provides extensive example and exercise problems along with an extensive solutions manual.
This volume contains a timely collection of research papers on the latest developments in the ever-increasing use of elastic waves in a variety of contexts. There are reports on wave-propagation in various types of media: in both isotropic and anisotropic bodies; in homogeneous and inhomogeneous media; in media with cracks or inclusions in random media; and in layered composites.The bulk of the papers are concerned with propagation in elastic media, but also included are viscoelastic, thermoelastic and magneto-electroelastic wave propagation, as well as waves in porous and piezo-electric bodies. Consideration is given to propagation in bodies as diverse as stretched elastic strings to surfaces such as thin walled cylinders, and thin films under stress. Applications considered include the determination of the depth of cracks; analysis of ground motions generated by a finite fault in seismology; surface wave spreading on piezo-electric solids; and dynamical stress intensity factors. Most of the papers are theoretical in nature, and many are complemented by numerical studies. Also included are a general survey on experimental techniques, and reports on experimental work.The volume will be of interest to those who do theoretical studies of elastic wave propagation and to those who apply elastic waves whether in seismology, non-destructive testing, the fabrication of devices or underwater acoustics, etc.
