Improved tensile and single-lap-shear mechanical-electrical response of epoxy composites reinforced with gridded nano-carbons

A new carbon nanotube (CNT)/graphene (GN) grid structure is prepared and used to reinforce and health-monitor the epoxy composites. Results reveal that with a 30–50% mesoscopic-porosity of the CNT/GN grid, tensile strength and single-lap-shear (SLS) strength of the CNT/GN/epoxy composites can be improved by 27–41% and 28–49%, respectively. Also, relative resistance change (ΔR/R₀%) at damage initiation would sudden change more than 10% for the tensile testing and 6% for the SLS testing. Meanwhile, during the damage evolution stage, the gauge factor obtained from tensile testing reaches 10.2–24.9 improved by 23–200%, and ΔR/R₀% from SLS testing achieves 47.4–60.4% increased by 69–116%, respectively, when compared to the baseline composite. Moreover, an equivalent resistance prediction mode for the CNT/GN grid composites is proposed and which can well explain the resistance response mechanism. The result reveals that the gridded CNT/GN sensor is potential in reinforcing and structural health monitoring the epoxy resin-based composites.