When a beam of ultrasound interacts with a flaw in a material, additional scattered waves are generated by the flaw; these waves travel in all directions. The distribution of scattered waves of course, depends strongly on the geometric and material properties of the flaw. In this chapter we characterize scattering responses of flaws in terms of their far-field scattering amplitudes, and we describe both exact and approximate methods of calculating scattering amplitudes. The scattering amplitude is a quantity of fundamental interest, since as shown later this quantity completely characterizes the flaw response in an LTI model of an ultrasonic system.
KeywordsImpulse Response Incident Wave Scattered Wave Born Approximation Incident Plane Wave
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