Accurate self-damage detection by electrically conductive epoxy/graphene nanocomposite film

Detecting and locating accurately structure damages at an early stage is essential to minimization of catastrophic disasters, prevention of fatalities and provision of cost-effective maintenance. We herein report a facile approach to detect structure damages and to accurately identify their locations by using an electrically conductive epoxy/graphene nanocomposite film. A percolation threshold of electrical conductivity was observed at 0.58 vol% of graphene platelets (GnPs, ~3 nm in thickness and ~15 μm in length); electrical conductivity of 3.3 S/cm was obtained at 9.00 vol% of GnPs. The epoxy/GnP composite film containing 9.00 vol% of GnPs was employed as an array of electrically conductive paths in horizontal and vertical directions to detect and locate structure's damages. Thermal stability and temperature coefficient of the composite film were studied. Relative resistance change due to temperature effect was fitted into an exponential function, which showed strong correlation with the temperature change. This implies that an algorithm can be developed to compensate drift errors in resistance measurement due to temperature variation. With the help of Internet of Things, our self-sensing epoxy/graphene nanocomposite films have great potential for smart aerospace structural health monitoring.