Study on self-sensing properties of carbon nanofiber-graphene sheet hybrids modified CFRP composites with high sensitivity

Abstract

This study is devoted to the doping of carbon nanomaterials (CNF-graphene) with two dimensions into carbon fiber-reinforced polymers (CFRP) in order to implement the optimization of them in terms of limited mechanical properties and low self-sensing sensitivity. CFRP composites modified with hybrid nanomaterials (CNF-graphene) with three-dimensional structure, as well as CFRP composites modified by carbon nanofibers (CNFs) and graphene, respectively, were prepared through experiments. The mechanical, electrical, and self-perception properties of these composites were comparatively investigated. The electrical conductivity mechanism of the nanocomposites was explored based on the theory of conductive channels and quantum tunneling effect, and the relationship between the electrical conductivity of CFRP and CNM (carbon nanomaterials) doping was constructed based on the law of mixtures. The results show that CNM can greatly enhance the tensile strength and modulus of elasticity of CFRP, and the strength reaches the maximum value when the mixed CNM doping is 1.5 wt%. The addition of CNM did not reduce the electrical resistance significantly compared with the control group, although the dispersion of the electrical resistance was improved. The electrical resistance rate-of-change–strain curves of the CNM/CFRP composites were roughly divided into three phases, which corresponded to the different damage modes, and the sensitivity of CNM/CFRP composites varies in different stages, which should be selected according to the actual application requirements.