Damage evolution monitoring in GFRP riveted interfaces using CNT film-based electrical resistance tomography

Bolted connections are preferred over riveting for aerospace composite structures, as non-uniform rivet expansion during installation causes initial hole damage. This damage may propagate under in-service loading, threatening structural integrity; however, its quantitative assessment remains challenging, limiting the adoption of riveting. This study proposes a damage monitoring approach for riveted interfaces using electrical resistivity tomography (ERT). Carbon nanotube (CNT) films serve as sensing layers on the riveted interfaces of glass fibre reinforced polymer (GFRP) laminates. Boundary voltage data are collected during drilling, riveting, and subsequent loading to reconstruct the conductivity distribution within the damaged regions. The results demonstrate that ERT effectively captures compression damage induced during riveting and monitors damage propagation under static loading. Changes in conductivity correlate with observed physical damage mechanisms, including fibre fracture and matrix crushing. Despite a 6.64% deviation in the mean estimated damage area, the method validates the feasibility of ERT for monitoring damage in composite riveted interfaces. This approach offers a cost-effective and promising technique for aerospace structural health monitoring.