Measurement of thickness of layer and sound velocity in multi-layered structure by the use of angular ultrasonic transducers

Abstract

The possibilities of measurement of thickness of layer and the velocity propagation of ultrasound signals in layered structures by the use of the angular electroacoustical transducers with known parameters are analyzed. It is shown that, when the velocity propagation of ultrasound signals in the separate layer of structure is unknown, the thickness and the velocity propagation of signals in them may be measured by the use of the single measuring channel with angular ultrasonic transducers. The algorithms for determination of thickness of separate layers and ultrasound velocity in them are developed, when the layered structure is iradiated at a known angle to the surface of structure. The modeling of measuring channel with the angular ultrasonic transducers is performed. When modeling the propagation and reflection of ultrasound signals in duralumin – plexiglass layered structure and the spatial and temporal distributions of them on the surface of layered structure are revealed. The variation of temporal and spatial distributions of received signals is investigated when the angle of incidence to the layered structure is changed. It is shown that temporal and spatial distributions of shear and longitudinal waves do not coincide to each other and alter differently, when the angle of incidence is changed. The results of experimental investigation are presented.