EMATs for Science and Industry comprises the physical principles of
electromagnetic acoustic transducers (EMATs) and the applications to
scientific and industrial ultrasonic measurements on materials. The text
is arranged in four parts:
-PART I is intended to be a self-contained description of the basic
elements of coupling mechanism along with practical designing of EMATs
for various purposes. There are several implementations to compensate
for the low transfer efficiency of the EMATs. Useful tips to make an
EMAT are also presented.
-PART II describes the principle of electromagnetic acoustic resonance
(EMAR), which makes the most of contactless nature of EMATs and is the
most successful amplification mechanism for precise velocity and
attenuation measurements.
-PART III applies EMAR to studying the physical acoustics. New
measurements emerged on three major subjects; in situ monitoring of
dislocation behavior, determination of anisotropic elastic constants,
and acoustic nonlinearity evolution.
-PART IV deals with a variety of individual topics encountered in
industrial applications, for which the EMATs are believed to the best
solutions.
The authors' work in this area has shown Electromagnetic acoustic
resonance (EMAR) to be applicable not only to the acoustoelastic stress
measurements, but also to many other nondestructive evaluation issues,
including the determination of attenuation in solids. Noncontact
measurement with high enough signal intensity was striking. Basic
preconditions of theoretical approaches were realized by eliminating
artifacts caused by the contact transducers. EMAR thus illuminated
antiquated theories, which were accepted to be of little use or limited
to qualitative interpretation of observations. It also uncovered
interesting phenomena. Continuous monitoring of attenuation and acoustic
nonlinearity resulted in the detection of ongoing microstructure
evolutions in deforming or fatiguing metals.
The aim of this book is to provide practical answers to the needs of
ultrasonic measurements as well as an understanding of a novel
methodology.
