Structure-property relationship of graphene/carbon nanotube enabled embeddable fiber sensors for <i>in-situ</i> monitoring of composites

Abstract

Carbon nanomaterials based sensing technology has become a promising technology in the field of structural health monitoring of composites. Self-sensing composites were achieved with varied sensing elements, including carbon nanotube (CNT) coated fibers (CNTF) and reduced graphene oxide (RGO) coated fibers (RGOF), to compare their sensing performance and mechanism. Piezoresistive response of varied sensors show that RGOF has higher piezoresistive sensitivity and clearly exhibits two-stage behavior from linear to non-linear; whereas, CNTF always exhibits a smooth and orderly electrical signal before fracture occurs. This strong structure-property relationship can be explained by resin infiltration theory. For CNTF, resin molecules can penetrate its porous network structure, forming a complete CNT/resin nanocomposite structure integrated on the fiber surface. In contrast, RGOs with large lateral dimensions and surface consistency can form non-invasive network structure that impedes resin penetration. Further analysis and study show that CNTF is more suitable for long-term monitoring and mechanical state recognition, while RGOF is more practical for the early warning of structural damage.

Keywords

• carbon nanotube
• reduced graphene oxide
• fiber sensor
• composites
• structural health mon-itoring