Self-sensing of CNT-Doped GFRP Panels During Impact and Compression After Impact Tests

In the last decades, the interest on fiber reinforced polymers (FRPs) has increased due to their mechanical properties and weight saving potential. This has led to the development of novel inspection techniques, being the failure modes of composite structures complex to identify. In this regard, carbon nanotube (CNT) have been widely used for Structure Health Monitoring (SHM) purpose, thanks to their excellent electrical properties and piezoresistive behavior. In this framework, some studies in the literature prove the sensitivity of the CNT percolating network to potential impact damage, rarely exploiting the real-time potential for signal acquisition and never attempting the monitoring during compression after impact (CAI) tests. In this study, the signals from multiple channels on a single GFRP plate specimen doped with multi-walled CNTs have been acquired in real-time and then correlated with simultaneous measures of displacement and forces, aimed at identifying the occurrence of impact damage. In a second phase, the signals from the CNT percolating network have been acquired during CAI tests, identifying precursors of specimen failure.