Graphene and carbon nanotube-based high-sensitive film sensors for in-situ monitoring out-of-plane shear damage of epoxy composites

摘要

Graphene (GN) and carbon nanotube (CNT) have already been explored their potential crack-monitoring abilities in the field of composite materials, but a relatively low sensitivity to shear damage is still a practical problem. This work aims to improve the monitoring sensitivity to out-of-plane shear damage by constructing hybrid GN/ CNT film sensors with a GN weight loading of 0-10%. The prepared GN/CNT sensors are integrated into epoxy composites and both quasi-static and cyclic shear loads are carried out. It is found from quasi-static testing that once the out-of-plane shear damage initiates, relative electrical resistance variation suddenly jumps about 34-191% from the GN/CNT film sensors. Also, the sensitivity coefficient in the crack growth stage could reach 124-684. Namely, the GN/CNT sensors show high monitoring sensitivity to the initiation and growth of out-of -plane shear damage. Moreover, results from cyclic loading further reveal that the GN/CNT sensors possess stable sensitivity to the shear deformation and damage. Meanwhile, similar response trends from an acoustic emission sensor prove the monitoring reliability of the GN/CNT film sensors. The obtained high sensitivity demonstrates that the GN/CNT hybrid film sensors are prospective in the field of structural health monitoring of composite materials.