In-situ Strain and Damage Sensing in Glass Fiber Laminates Using Embedded CNT

Carbon nanotube (CNT) membranes manufactured by a novel slurry compression process have been used to introduce self-sensing capability in glass fiber reinforced polymer matrix (GFRP) laminates. The CNT membranes were embedded in the interlaminar region of the laminates and piezoresistive characterization studies were conducted under monotonic and cyclic loading. High sensitivity to strain was observed. A measurement model, developed using the resistance measurements obtained under fatigue loading, was used to quantify fatigue crack length in real time. The fatigue crack growth rates and the nature of crack propagation in baseline and self-sensing GFRP (SGFRP) specimens were compared. The results show that the average crack growth rate reduced by an order of magnitude by the introduction of CNT membrane. The SGFRP laminates developed in this study exhibited crack tip blunting during fatigue, while facilitating real time strain and damage sensing.