NDT-based design of joint material for the detection of bonding defects by infrared thermography

Non Destructive Testing (NDT) by active InfraRed Thermography (IRT) of bonded Carbon Fibers Reinforced Plastic (CFRP) laminates is a very challenging issue. Difficulties come from the weak contrast between the thermal properties of constitutive parts, the small thickness of the epoxy joint and also the depth of the bonded interface. The strategy considered in this work is to design a new joint material specially adapted to the NDT detection of bonding defects. Using a numerical model, it is suggested to reinforce the epoxy joint material with conductive boron nitride particles. Experimental investigation of defective assemblies confirms the interest of such approach through a clear improvement of the IRT defect detection capacity. •Bonded repaired composites are investigated by active Infrared Thermography.•Influence of the joint thermal behaviour is studied through a numerical model.•A new epoxy joint material with boron nitride additives is designed.•Improvement of defect detection by IRT is validated on experimental cases.