Measurement Models and Scattering Models for Predicting the Ultrasonic Pulse-Echo Response From Side-Drilled Holes

A side-drilled hole (SDH) is a commonly used reference reflector in ultrasonic nondestructive evaluation. In this paper, we will develop reciprocity-based measurement models along with scattering models that allow us to predict the ultrasonic response from a SDH in a pulse-echo immersion setup. Two measurement models will be derived, one suitable for large SDHs where variations of the incident fields over the cross section area of the SDH are considered, and a second model which neglects those variations. Two scattering models are also used along with these measurement models. These include an explicit model based on the Kirchhoff approximation, as well as an exact model obtained using the separation of variables method. Examples of the model-based received waveforms and peak-to-peak voltage responses are presented for a number of SDHs of different sizes and compared with experimentally determined SDH responses.