A New NDT Method for the study of composite bonded repair

Abstract

This paper deals with the non destructive analysis of bonded repaired CFRP laminates by means of an active Infrared Thermography (IT) approach. The challenging issue comes from the weak property contrast between parts of repaired assemblies (carbon-epoxy composites bonded by an epoxy glue) and thickness of the joint. A specific experimental device has been set up to strongly control tests conditions (heat load, boundary conditions) and be able to develop a physically consistent numerical model of the thermal problem. Comparison between measured and simulated surface temperature fields shows very good agreement regarding temporal and spatial evolutions and provides new solutions for the non destructive testing (NDT) of bonded repaired composites. Specially is investigated here the opportunity to incorporate relevant additives with specific infrared signatures into the adhesive to improve thermal contrast between different parts and thus to improve the defects detection.