Electrothermics

4.1. Introduction

Industrial processes and fabricated pieces have become increasingly complex and demanding in terms of quality and safety. These pieces’ failure can result in more or less important consequences. For example, in the aeronautic or nuclear fields, these consequences are expressed in terms of people’s safety or environmental damage. Often, many industries use destructive testing to verify their products’ safety. This type of control is slow, costly, and can only be performed on a limited number of components. Furthermore, it is only applicable for systems in operation. This is why non-destructive testing (NDT) has become an industrial necessity. It seeks to control the quality of the inspected components without damaging them. NDT also has an economical aspect: the speed and reliability of the techniques used are key to reducing maintenance costs and optimizing the life span of installations [WAR 89].

In view of the diversity and complexity of the systems and components undergoing the control, many NDT methods have been elaborated and remain a prestigious field of scientific research. These inspection techniques are very varied in their operating characteristics and performance. They each have their own advantages and drawbacks, and therefore have different (and sometimes complementary) fields of application. Depending on the constraints imposed for a typical inspection, some techniques are thus more suited than others for reasons of practicality, performance, economy, ...