Wave Propagation In Viscoelastic And Poroelastic Continua

Wave propagation is an important topic in engineering sciences, especially, in the field of solid mechanics. A description of wave propagation phenomena is given by Graff [98]: The effect of a sharply applied, localized disturbance in a medium soon transmits or 'spreads' to other parts of the medium. These effects are familiar to everyone, e.g., transmission of sound in air, the spreading of ripples on a pond of water, or the transmission of radio waves. From all wave types in nature, here, attention is focused only on waves in solids. Thus, solely mechanical disturbances in contrast to electro-magnetic or acoustic disturbances are considered. of waves - the compression wave similar to the In solids, there are two types pressure wave in fluids and, additionally, the shear wave. Due to continual reflec tions at boundaries and propagation of waves in bounded solids after some time a steady state is reached. Depending on the influence of the inertia terms, this state is governed by a static or dynamic equilibrium in frequency domain. However, if the rate of onset of the load is high compared to the time needed to reach this steady state, wave propagation phenomena have to be considered.

This book focuses on the mathematical potential and computational efficiency of the Boundary Element Method (BEM) for modeling seismic wave propagation in either continuous or discrete inhomogeneous elastic/viscoelastic, isotropic/anisotropic media containing multiple cavities, cracks, inclusions and surface topography. BEM models may take into account the entire seismic wave path from the seismic source through the geological deposits all the way up to the local site under consideration. The general presentation of the theoretical basis of elastodynamics for inhomogeneous and heterogeneous continua in the first part is followed by the analytical derivation of fundamental solutions and Green's functions for the governing field equations by the usage of Fourier and Radon transforms. The numerical implementation of the BEM is for antiplane in the second part as well as for plane strain boundary value problems in the third part. Verification studies and parametric analysis appear throughout the book, as do both recent references and seminal ones from the past. Since the background of the authors is in solid mechanics and mathematical physics, the presented BEM formulations are valid for many areas such as civil engineering, geophysics, material science and all others concerning elastic wave propagation through inhomogeneous and heterogeneous media. The material presented in this book is suitable for self-study. The book is written at a level suitable for advanced undergraduates or beginning graduate students in solid mechanics, computational mechanics and fracture mechanics.

The present volume offers a state-of-the-art report on the various recent sci entific developments in the Theory of Porous Media (TPM) comprehending the basic theoretical concepts in continuum mechanics on porous and mul tiphasic materials as well as the wide range of experimental and numerical applications. Following this, the volume does not only address the sophisti cated reader but also the interested beginner in the area of Porous Media by presenting a collection of articles. These articles written by experts in the field concern the fundamental approaches to multiphasic and porous materials as well as various applications to engineering problems. In many branches of engineering just as in applied natural sciences like bio- and chemomechanics, one often has to deal with continuum mechanical problems which cannot be uniquely classified within the well-known disci plines of either "solid mechanics" or "fluid mechanics". These problems, characterized by the fact that they require a unified treatment of volumetri cally coupled solid-fluid aggregates; basically fall into the categories of either mixtures or porous media. Following this, there is a broad variety of problems ranging in this category as for example the investigation of reacting fluid mix tures or solid-fluid suspensions as well as the investigation of the coupled solid deformation and pore-fluid flow behaviour of liquid- and gas-saturated porous solid skeleton materials like geomaterials (soil, rock, concrete, etc. ), polymeric and metallic foams or biomaterials (hard and soft tissues, etc).

This book presents 50 selected peer-reviewed reports from the 2016 International Conference on “Physics and Mechanics of New Materials and Their Applications”, PHENMA 2016 (Surabaya, Indonesia, 19–22 July, 2016). The Proceedings are devoted to processing techniques, physics, mechanics, and applications of advanced materials. As such, they examine a wide spectrum of nanostructures, ferroelectric crystals, materials and composites, as well as other promising materials with special properties. They present nanotechnology approaches, modern environmentally friendly piezoelectric and ferromagnetic techniques, and physical and mechanical studies of the structural and physical-mechanical properties of the materials discussed. Further, a broad range of original mathematical and numerical methods is applied to solve various technological, mechanical and physical problems, which are inte resting for applications. Great attention is devoted to novel devices with high accuracy, longevity and extended possibilities to work in wide temperature and pressure ranges, aggressive media, etc., which show improved characteristics, defined by the developed materials and composites, opening new possibilities to study different physico-mechanical processes and phenomena.

This book presents theoretical fundamentals and applications of a new numerical model that has the ability to simulate wave propagation. Coverage examines linear waves in ideal fluids and elastic domains. In addition, the book includes a numerical simulation of wave propagation based on scalar and vector wave equations, as well as fluid-structure interaction and soil-structure interaction.

Wave Fields in Real Media: Wave Propagation in Anisotropic, Anelastic, Porous and Electromagnetic Media examines the differences between an ideal and a real description of wave propagation, starting with the introduction of relevant constitutive relations. The differential formulation can be written in terms of memory variables, and Biot theory is used to describe wave propagation in porous media. For each constitutive relation, a plane-wave analysis is performed to illustrate the physics of wave propagation. New topics are the S-wave amplification function, Fermat principle and its relation to Snell law, bounds and averages of seismic Q, seismic attenuation in partially molten rocks, and more. This book contains a review of the main direct numerical methods for solving the equation of motion in the time and space domains. The emphasis is on geophysical applications for seismic exploration, but researchers in the fields of earthquake seismology, rock acoustics and material science - including many branches of acoustics of fluids and solids - may also find this text useful. Examines the fundamentals of wave propagation in anisotropic, anelastic and porous media Presents all equations and concepts necessary to understand the physics of wave propagation Emphasizes geophysics, particularly seismic exploration for hydrocarbon reservoirs, which is essential for the exploration and production of oil

This book contains the edited proceedings of the 29th World Conference on Boundary Elements and Other Mesh Reduction Methods, an internationally recognised forum for the dissemination of the latest advances on Mesh Reduction Techniques and their applications in sciences and engineering. The range of topics included in this volume are as follows: Advances in Mesh Reduction; Meshless Methods Techniques; Dual Reciprocity Method, Modified Trefftz Method; Fundamental Solution Method; Damage Mechanics and Fracture; Advanced Stress Analysis and Structural Applications; Plates and Shells; Dynamics and Vibrations; Material Characterisation; Acoustics; Heat and mass Transfer; Fluid Mechanics Applications; Wave Propagation; Inverse Problems and Computational Techniques.

The book provides a survey of numerical methods for acoustics, namely the finite element method (FEM) and the boundary element method (BEM). It is the first book summarizing FEM and BEM (and optimization) for acoustics. The book shows that both methods can be effectively used for many other cases, FEM even for open domains and BEM for closed ones. Emphasis of the book is put on numerical aspects and on treatment of the exterior problem in acoustics, i.e. noise radiation.