Method and system for ultrasonic non-destructive evaluation of sheet composites

Abstract

The invention belongs to fields of aviation and non-destructive testing (NDT) industry. Specifically, it is a method and system for ultrasonic (US) NDT of sheet composite structures and products. The method employs a phased multi-element US contact array (20) to excite waves of specific higher-order Lamb modes, which are intended as most suitable for detecting and characterizing specific types of defects (5) inside and in inner layers (33) of sheet composites. By using this tuned US array (20) to generate the aforementioned modes, the method and system allow to obtain more information about material irregularities or defects (5) in the inner layers (33) of the sheet composite structure (8), to measure the distance to the defects and their size. The invention comprises digital models of guided Lamb waves excitation, propagation and interaction with defects (5), algorithms for reading measurement and modelling results, methods for signal filtering and calculating US velocities, and corresponding specialized.