Investigation of multi-layer structures by the use of angular ultrasonic transducers

Abstract

Practical aspects of application of angular ultrasonic transducers for measurement parameters of multi-layered structures are analyzed. The algorithms for determination of thickness of every separate layer in the multi-layered structure, by the use of angular ultrasonic transducers as well as by the use of longitudinal or shear waves, are proposed. It is shown that the ratio of thickness of the first layer to the transversal dimensions of angular ultrasonic transducers is very important when the angle of incidence is selected and the parameters of multi-layered structures are determined. The algorithms for determination of minimal thickness of the first layer, which may be determined by the use of angular ultrasonic transducers with a given transversal dimensions, are developed. The modeling of dependence of the ratio of minimal thickness of the first layer to the transversal dimensions of angular transducers in the plane of incidence was performed, when the angle of incidence and propagation velocity of ultrasound signals in the first layer of structure are changed. The results of modeling are presented and analyzed.