Theory And Methodology Of Electromagnetic Ultrasonic Guided Wave Imaging

Written by respected experts, this book highlights the latest findings on the electromagnetic ultrasonic guided wave (UGW) imaging method. It introduces main topics as the Time of Flight (TOF) extraction method for the guided wave signal, tomography and scattering imaging methods which can be used to improve the imaging accuracy of defects. Further, it offers essential insights into how electromagnetic UGW can be used in nondestructive testing (NDT) and defect imaging. As such, the book provides valuable information, useful methods and practical experiments that will benefit researchers, scientists and engineers in the field of NDT.

This book introduces the fundamental theory of electromagnetic ultrasonic guided waves, together with its applications. It includes the dispersion characteristics and matching theory of guided waves; the mechanism of production and theoretical model of electromagnetic ultrasonic guided waves; the effect mechanism between guided waves and defects; the simulation method for the entire process of electromagnetic ultrasonic guided wave propagation; electromagnetic ultrasonic thickness measurement; pipeline axial guided wave defect detection; and electromagnetic ultrasonic guided wave detection of gas pipeline cracks. This theory and findings on applications draw on the author’s intensive research over the past eight years. The book can be used for nondestructive testing technology and as an engineering reference work. The specific implementation of the electromagnetic ultrasonic guided wave system presented here will also be of value for other nondestructive test developers.

Focusing on the theory and state-of-the-art technologies of ultrasonic testing (UT), this book examines ultrasonic propagation in solids and its detection applications, and explores the intersection of UT technology with various fields of electromagnetics, optics and physics. UT is one of the most widely used nondestructive testing techniques due to its high performance in terms of detection efficiency and safety. The rapid development of modern industrial products and technologies has created a new challenge and demand for ultrasonic nondestructive testing technology. This book introduces the fundamentals of UT, including sound wave and sound field, interface wave theory and liquid-solid coupled sound field. It then discusses various types of UT methods, ranging from the critically refracted longitudinal wave method to ultrasonic surface wave and ultrasonic guided wave detection methods. Some newly developed UT techniques are also discussed, including phased-array UT, high-frequency UT and non-contact UT. This title will appeal to engineering students and technicians in the field of ultrasonic nondestructive testing.

The propagation of ultrasonic guided waves in solids is an important area of scientific inquiry, primarily due to their practical applications for nondestructive characterization of materials, such as nondestructive inspection, quality assurance testing, structural health monitoring, and providing a material state awareness. This Special Issue of Applied Sciences covers all aspects of ultrasonic guided waves (e.g., phased array transducers, meta-materials to control wave propagation characteristics, scattering, attenuation, and signal processing techniques) from the perspective of modeling, simulation, laboratory experiments, or field testing. In order to fully utilize ultrasonic guided waves for these applications, it is necessary to have a firm grasp of their requisite characteristics, which include that they are multimodal, dispersive, and are comprised of unique displacement profiles through the thickness of the waveguide.

In this era of technological progress and given the need for welfare and safety, everything that is manufactured and maintained must comply with such needs. We would all like to live in a safe house that will not collapse on us. We would all like to walk on a safe road and never see a chasm open in front of us. We would all like to cross a bridge and reach the other side safely. We all would like to feel safe and secure when taking a plane, ship, train, or using any equipment. All this may be possible with the adoption of adequate manufacturing processes, with non-destructive inspection of final parts and monitoring during the in-service life of components. Above all, maintenance should be imperative. This requires effective non-destructive testing techniques and procedures. This Special Issue is a collection of some of the latest research in these areas, aiming to highlight new ideas and ways to deal with challenging issues worldwide. Different types of materials and structures are considered, different non-destructive testing techniques are employed with new approaches for data treatment proposed as well as numerical simulations. This can serve as food for thought for the community involved in the inspection of materials and structures as well as condition monitoring.

This thesis discusses ultrasonic testing by means of numerical modeling and image reconstruction techniques using elastic and acoustic wave fields. Numerical modeling of elastic waves (part one of the thesis) is used to understand the elastic wave scattering due to material defects and the propagation of surface waves in inhomogeneous isotropic and anisotropic media, with special emphasis on transversely isotropic and orthotropic media. Different imaging techniques (part two of the thesis) are investigated to develop a software, implemented in Matlab, which can give imaging results immediately after the measurement almost in real time as it can read and process the data obtained directly from the measurement. Acoustic wave scattering using analytical techniques and imaging techniques based on Radon transform are investigated. The data obtained from the Radon transform are subjected for imaging utilizing the filtered back projection algorithm and the Fourier slice theorem. The fundamentals of elastic wave propagation in solids are extensively elaborated. The point source synthesis to compute the Green’s functions for anisotropic media and the plane wave synthesis to compute slowness, phase and group velocity surfaces are studied. The elastic integral equations for the so called stretched coordinate system are derived. Based on these equations the numerical tool ’Three-dimensional Elastodynamic Finite Integration Technique’ (3D-EFIT) has been enhanced to treat not only isotropic media but also anisotropic media. For fast computation, the 3D-EFIT code using the Message Passing Interface (MPI) is used by which processing on massive parallel computers is made possible. In 3D-EFIT the Convolutional Perfectly Matched Layers (CPML) can also be applied to absorb the elastic body waves as well as the surface and evanescent waves. 3D-EFIT for homogeneous anisotropic media is validated by comparing computed Green’s functions with an analytical solution. After the validation, the applications of EFIT such as elastic wave modeling in inhomogeneous austenitic steel welds and inhomogeneous orthotropic wooden structures are presented. The results of the 2D-EFIT and 3D-EFIT modeling are compared against measurements performed at Federal Institute for Materials Research and Testing (BAM). After the modeling part of the thesis, inverse scattering techniques for fast imaging of inhomogeneities are studied. For three-dimensional imaging of defects in concrete, the Synthetic Aperture and Focusing Technique (SAFT) and Fourier Transformed Synthetic aperture Focusing Technique (FT-SAFT) are applied to data measured using a transducer array. The seismic Dip-Moveout (DMO) method has been utilized to convert measured bistatic data into monostatic data. A special treatment of SAFT as a technique for back propagation of the wave fields using time reversal, utilizing the knowledge of the geometry, is presented. Finally, time domain anisotropic SAFT (AnSAFT) is studied for image reconstruction of defects in inhomogeneous geometry with orthotropic crystal structure of the embedding medium.

Most books on nondestructive evaluation (NDE) focus either on the theoretical background or on advanced applications. Bridging the gap between the two, Ultrasonic and Electromagnetic NDE for Structure and Material Characterization: Engineering and Biomedical Applications brings together the principles, equations, and applications of ultrasonic and electromagnetic NDE in a single, authoritative resource. This is also one of the first books to incorporate a number of popular NDE methods based on electromagnetic techniques. Combines Engineering and Biological Material Characterization Techniques in One Book The book begins with the relevant fundamentals of mechanics and electromagnetic theory, derives the basic equations, and then, step by step, covers state-of-the-art topics and applications of ultrasonic and electromagnetic NDE that are at the forefront of research. These include engineering, biological, and clinical applications such as structural health monitoring, acoustic microscopy, the characterization of biological cells, and terahertz imaging. Covers Numerous Applications of Ultrasonic and Electromagnetic Techniques—from the Traditional to the Advanced Written in plain language by some of the world’s leading experts, the book includes worked-out examples and exercises that make this an outstanding resource for coursework. The coverage of traditional and advanced NDE applications also appeals to practicing engineers and researchers.