An Experimental Approach for Investigating Fatigue-Induced Debonding Propagation in Composite Stiffened Panels Using Thermographic Phase Mapping.

This work introduces an experimental approach focused on investigating fatigue-driven debonding in a composite structure designed to simulate the complexity of a typical aeronautical panel. The debonding is placed between the skin and the stringer, and the structure has been tested under fatigue compression conditions. Using lock-in thermography, the damage evolution during fatigue cycles has been detailed monitored. Indeed, thermographic phase maps obtained after a predetermined number of cycles during the whole fatigue test have been graphically analysed and have allowed us to obtain an accurate measurement of the delaminated area extent and shape. Our approach advances the understanding of damage propagation in composite materials, contributing to the development of damage-tolerant structural designs and supplying valuable data to validate numerical fatigue prediction models. Furthermore, the use of non-destructive testing techniques, such as thermography, has been found crucial for accurately quantifying the extent and the shape of the debonding after a given number of fatigue cycles.