Lock-in thermography as a tool for fatigue damage monitoring of composite structures

International audienceFatigue dimensioning of composite structures has become a great challenge in the aeronautic industry. The estimation of the fatigue limit requires time-consuming experimental campaigns: millions of mechanical cycles are applied to one studied sample until failure, for several load levels. The alternative discussed in the present paper is to monitor the self-heating of carbon/epoxy composites under a significantly reduced number of load cycles, in order to define fatigue damage indicators. The chosen approach is to use lock-in thermography, which makes it possible to analyse the first harmonics of the heating signal, not matter how noisy it might be