NDT characterisation of carbon-fibre and glass-fibre composites using non-invasive imaging techniques

The prerequisite for more competent and cost effective transport has led to the evolution of innovative testing and evaluation procedures. Non-destructive testing and evaluation (NDT & E) techniques for assessing the integrity of composite structures are essential to both reduce manufacturing costs and out of service time of transport means due to maintenance. Smart methods for assessing the integrity of a composite structure are essential to both reduce manufacturing costs and out of service time of the structure due to maintenance. Nowadays, thermal non-destructive testing (NDT) is commonly used for assessing composites. This research work evaluates the potential of various infrared thermography (IRT) approaches for assessing different types of fabricated defects (i.e. impact damage, inclusions for delaminations, etc) on Glass Fibre Reinforced Polymer (GFRP) and Carbon Fibre Reinforced Polymer (CFRP) plates. Measurements were performed using LWIR and three active approaches: a) pulsed thermography using the flash method (xenon flash lamps), b) transient themography using IR-heating pulse, and c) thermographic inspection for cooled sample by freezing in -20 °C and then use monitoring. Furthermore, integrated flash thermography by employing a MWIR system was also used. Finally, NIR imaging was also utilised for the inspection of the GFRP and CFRP plates.