Online in-situ monitoring of curing and impact damage of composite structure with embedded CNT sensors

The main purpose of structural health monitoring (SHM) is to detect damage at its earliest possible stage to prevent severe deterioration and reduce subsequent repair costs.Carbon nanotubes (CNTs) buckypaper (BP) was embedded into different cross-ply glass fibre composites to monitor the curing process and impact damage as an in situ sensor in this research.BP sensor can capture the four stages of the curing process, the gel point of the resin and residual stresses of the composite structure can be achieved by analysing the change of the resistance curve.Numerical and experimental analyses were performed to predict the damage in composite structures subjected to low-velocity impact.BP sensors' electrical resistance increases with repeated impact loading; composite structure elastic deformation and damage evolution can be identified from resistance change.Experiment results show that structure monitoring based on the BP sensors cannot only detect small, barely visible impact damage flaws and the damage evaluation of composite structures subjected to impact, but also provide a new method to monitor the curing process through the analysis of results.This work makes some constructive contributions to monitoring the manufacturing process of composites and long-term SHM to evaluate impact resistance and damage prediction of composite structures.