Real-time structural health monitoring of GFRCs using rGO-coated glass textile sensors

This paper presents a novel approach to structural health monitoring (SHM) of glass fibre reinforced polymer composites (GFRCs) by developing self-sensing capabilities through innovative chitosan-mediated reduced graphene oxide (rGO) coating techniques. A systematic application of biopolymer-enhanced dispersion on the non-conductive glass textile is described. To develop a piezoresistive sensor, two manufacturing techniques, a matrix-based dispersion and a chitosan-based coating dispersion, are employed on plain-woven E-glass textiles. Sensors are strategically placed at different through-thickness positions and gauge lengths within nine-layer GFRC laminates. Three-point bending tests measured the change in electrical resistance under flexural strain. Results showed that bottom-layer sensors with extended gauge lengths demonstrated superior sensitivity. The geometry of sensors, the structure of substrates (fabric versus tow), and the hybrid formulations of rGO-TiO2 were systematically analysed. Results revealed that narrower widths and tow substrates enhance the electrical resistance. The incorporation of TiO2 significantly enhances the piezoresistive response. Coating-based sensors demonstrated superior change in electrical resistance compared to matrix-based competitors. Mechanical testing verified that sensor implantation diminishes flexural strength when situated at various spatial locations. The findings offer design principles for incorporating high-sensitivity, lightweight, corrosion-resistant piezoresistive sensors into GFRCs by scalable methods suitable for industrial infusion and preform procedures.