title: Ultrasonic fields radiated through matching layers with nonparallel boundaries.
abstract: In the case of ultrasonic measurements in aggressive media piezoelectric elements of ultrasonic transducers are separated from a medium by thick protective layers, which may posses nonparallel front and back surfaces. This enables to reduce significantly the amplitude of multiple reflections, but the structure of the ultrasonic field radiated through a layer with nonparallel boundaries becomes complicated. The main objective of this paper is to present a method suitable for simulation of ultrasonic fields radiated through a layer with nonparallel boundaries in a transient mode. The proposed simulation method is based on the transformation of a multilayered medium into a virtual one without internal boundaries, equivalent to the actual medium from the point of a view of the relative times of arrival of direct and edge waves. The simulated ultrasonic fields in water are compared with the measurement results and a good correspondence between calculated and measured fields is obtained.
authors.affiliation: Ultrasound Institute, Kaunas University of Technology, Studentu 50, Kaunas, Lithuania. rkazys@ktu.lt
authors.forename: R J
authors.initials: RJ
authors.lastname: Kazys
authors.forename: L
authors.initials: L
authors.lastname: Mazeika
authors.forename: E
authors.initials: E
authors.lastname: Jasiuniene