Study on the Monitoring Method of Laminated Composites Molding Process Based on MWCNTs Coated Fiber Sensor

Carbon-based nanosensors, due to their excellent electromechanical sensing properties, have been prepared into composites by deposition and interlayer embedding methods, and have been widely used in the field of structural health monitoring during the fabrication process and in-service of composites. In this study, a high-performance self-sensing fiber sensor was developed to achieve the function of in situ online monitoring during the manufacturing process of composite materials. Carbon nanotubes were deposited onto glass fiber cloth by physical vapor deposition to obtain a carbon nanotube-coated glass fiber (MWCNT@GF) sensor. The fiber preform was obtained by embedding it between two original glass fiber layers, which was subjected to vacuum compaction and vacuum-assisted resin injection process (VARTM) experiments. The piezoresistive response of the sensor allows us to monitor the different states of the composite material. The reproducibility of the resistance change was confirmed by a series of vacuum-assisted cyclic compression tests. Moreover, the sensor shows superior performance in the resin injection stage, equilibration stage and curing stage. Therefore, the sensor can be applied to monitor the composite molding process and has the potential to monitor the structural health of composites.