Quality control and nondestructive testing has emerged as an important part of industrial production. The well-known and widely used eddy current testing methods stand alone among several nondestructive testing methods in terms of quality control of conductive materials.

Eddy current testing problems depend in general on several parameters. We believe that the use of mathematical models along with the exact form of the solution facilitates the study of the influence of these parameters on the output characteristics of the signal and on the testing process. Such a task may be costly and difficult if not impossible to achieve experimentally.

This book is divided into two parts. In the first part (Chapters 1–5), the solutions of ldquo;classicrdquo; problems in eddy current testing are presented to the extent that they are useful for applications in the second part. Some new solutions related to the topics under consideration are included. In the second part (Chapters 6–9), perturbation techniques are used for solving two-dimensional and three-dimensional asymmetric eddy current testing problems. Both the Born approximation and the more recent layer approximation are considered.

### Table of Contents (abbreviated)

- LAYERED MEDIA
- Modelling Equations and Applications
- Multilayer with Constant Properties
- Multilayer with Variable Properties
- Cylindrical Problems
- Spherical Problems

- MEDIA WITH FLAWS
- Symmetric Problems with Flaws
- Asymmetric Problems with Flaws
- Asymmetric Double Line above a Flaw
- Layer Approximation