Advanced 3D Ultrasonic Non-destructive Evaluation Technique for CFRP aeronautical applications

Nowadays, carbon fiber reinforced plastic (CFRP) composite materials are massively used in a very large number of aeronautical applications such the construction of light weight aircrafts. In aeronautical field, the ultrasonic (UT) non-destructive evaluation NDE technique is are largely used for materials inspection and part quality control because it permits to examine aircraft structures without disassembling them. Damages can occur, at several scales, within this composite material (e.g. delamination) without an external indication. Consequently, each produced composite structure needs to be inspected in order to evaluate the presence of possible defects and to prevent a catastrophic failure of the airplane. In this thesis work an advanced UT NDE system was utilized to perform a reliable and repeatable UT Full Volume (FV) scanning based on pulse-echo immersion testing on three different CFRP aeronautical components that represent three case studies. The resulting ultrasonic data were processed by a custom made software, developed in Labview environment, in order to obtain a metrological characterization and a quality assessment of non-crimp fabric composite laminates (first case study) and by a second custom made software, developed in Matlab environment, in order to provide a 3D thickness reconstruction of the defects of a CFRP bonded joint laminates and of a CFRP drilled laminates (second and the third case respectively).