ABSTRACT
The chapter is divided into four parts. We begin Section 6.1 with a consideration of the fundamental principles of œnite amplitude ultrasonics with an emphasis on the connection of nonlinear ultrasonics generally to the basic atomic structures of the material and to thermodynamics. This connection is also emphasized in Section 6.2 where the fundamental aspects of acoustoelasticity are developed. The application of nonlinear ultrasonics to materials characterization is developed in Section 6.3 with an emphasis on establishing the fundamental relationships between nonlinear ultrasonic parameters, both for œnite amplitude ultrasonics and for acoustoelasticity, and basic microstructural features, including defects, in materials. Section 6.4 concludes the chapter with a brief discussion of general measurement considerations.
