Thermoelastic stress analysis as a method for the quantitative non-destructive evaluation of bonded CFRP T-joints

Adhesive bonding is a material joining process in which an adhesive, placed between the surfaces, solidifies to produce a strong bond. In this regard, adhesively bonded joints represent an interesting alternative to mechanical joints and provide many advantages over conventional mechanical fasteners: continuity of the structure, high strength-to-weight ratio, design flexibility, and easiness of fabrication. In the present research, the Thermoelastic Stress Analysis (TSA) technique has been used as a non-destructive tool for evaluating the mechanical behaviour of aeronautical adhesive bonded CFRP T-joints made by automated fibre placement process. Moreover, the thermoelastic signal was used for determining the debonded areas after the pull-off tests. The results in terms of the measured debonded area were compared to the well-established lock-in thermography technique. The capability of the Thermoelastic Stress Analysis to perform an in-depth study of the quality of T-joints has been demonstrated.