Nondestructive Testing of a Complex Aluminium-CFRP Hybrid Structure with EMAT and Thermography

A new concept of an aluminium-CFRP (carbon-fibre-reinforced-polymer) hybrid structure with integrated thermoplastic layer is introduced in this work. The occurring interfaces between the three materials are characterised with flash thermography and ultrasonic testing with electromagnetic acoustic transducer (EMAT). Thermography is able to detect artificial integrated defects in inner layers of the CFRP component and to characterise the bonding quality of the interface between the CFRP and the thermoplastic layer. Additionally a POD model (probability of detection) provides the smallest detectable size a(90/95) of gapping defects in the CFRP with 5.184mm diameter. This work shows that a characterisation of the deeper interface between the aluminium and the thermoplastic layer is possible despite the small and complex geometry. Furthermore the quality of this bonding can be investigated independently of the EMAT's position. By combining thermography and EMAT the whole complex hybrid structure with its interfaces can be characterised.