Material characterisation and damage inspection of layered media using the Ultrasonic Polar Scan.

Non-destructive testing (NDT) refers to techniques that are used in the life-cycle of a structural component to investigate their quality, functionality and 'health' without destroying the object, nor affecting its properties. The development of NDT techniques is ever-evolving and needs continuous upgrading because of the emergence of new industrial materials, the increasing demand to more sensitive and more quantitative characterisation and quality control, and the need for earlier detection of defects. The implementation of an appropriate NDT system can save lives, time and costs. The Ultrasonic Polar Scan (UPS) is an advanced NDT method that analyses the reflected or transmitted ultrasonic signals for a wide range of azimuthal and polar angles. The recorded information (amplitude, phase, or time-of-flight) provides a fingerprint of the local material properties. The proposed project will extend the current status of UPS on three levels: 1) inverse determination of the true material properties (stiffness, attenuation, layering, orientation) for multilayered composites 2) design of a nonlinearity based UPS to inspect delaminations and microcracking, and 3) practical redesign of the laboratory set-up to obtain an efficient inspection tool. The goal is to quantify material parameters with an accuracy better than currently achievable, to identify damage with dimensions less than one millimetre, and to speed up the UPS recording to acceptable times.