Architecture-controlled resistance–mechanics response in carbon nanotube coated and carbon veil functionalised glass fibre composites under low velocity impact

This study establishes an architecture-dependent framework linking high-frequency electrical resistance response to mechanical damage severity in functionalised glass fibre reinforced polymer laminates subjected to low-velocity impact. Two conductive architectures based on multi-walled carbon nanotube coated glass fibres and carbon fibre non-woven veils were benchmarked under identical laminate configurations and impact energies of 5, 12 and 20 J. Electrical resistance was recorded at 25 kHz during 3–5 ms impact events. At 20 J, maximum resistance changes reached approximately 8–9 % for both configurations, while residual resistance changes in the bottom sensing layers increased to approximately 6–7.5 %. Compression-after-impact strength decreased by nearly 50 % at the highest impact energy. Residual resistance change exhibited a direct correlation with strength reduction and ultrasonic damage area across both architectures, demonstrating that transient electrical response provides a quantitative indicator of residual structural integrity. To interpret these trends, an experiment-anchored Monte Carlo percolation model was developed using dense three-dimensional random rod networks. A Gaussian deformation field calibrated from measured damage footprints enabled direct mapping between network disruption, indentation severity and macroscopic mechanical response without introducing free fitting parameters. The model quantitatively reproduced the experimentally observed resistance–mechanics scaling across impact energies.