Metrological Analysis of High Performance Composite Laminates through Advanced Ultrasonic Nondestructive Inspection

In this work, the study of the influence of impact conditions on damage generation in high performance composite materials is carried out through the application of an advanced ultrasonic (UT) non-destructive inspection (NDI) technique known as UT full waveform scanning. This technique is based on the pulse-echo immersion testing method and allows for the quantitative analysis of the internal material structure in the entire composite laminate volume (2 1/2 D evaluation). The composite material under examination consists of 20 µm diameter carbon fibre reinforced plastic (CFRP) laminates fabricated by superimposing 150 µm unidirectional (+45° or -45°) tape layers and 210 µm bi-directional (0°, 90°) fabric layers. A 15 MHz focused UT probe was used to scan CFRP composite laminate samples subjected to impact testing conditions. The scope of the UT NDI metrological analysis is the quality assurance of the CFRP composite laminates (actual laminate thickness evaluation, correct stacking sequence verification) and the characterisation and measurement of impact damage development in the entire composite material volume (in-plane delamination damage extension, damage position in the thickness direction, and damage transition in the laminate stacking sequence)