Damage monitoring in fiber-reinforced composites under fatigue loading using carbon nanotube networks

The formation of carbon nanotube networks around the structural reinforcement in fiber composites has enabled in situ monitoring of matrix damage accumulation. Real-time monitoring of damage development under fatigue loading was studied. The electrical response of the fatigue specimens change synchronously with the applied fatigue loading and enable a quantitative measure of the damage state. The fatigue response of the nanotube network was examined and the damage accumulation validated using microscopic technique. Various damage stages in composite cross-ply laminates under fatigue loading can be clearly detected by adopting the quantitative parameter, damaged resistance change. The sensitivity of the technique to the onset and accumulation of damage may enable future life prediction methodologies.