Damage detection of FRP structures using the electrical resistance response of MWCNTs networks in a PDMS film substrate

To overcome the disadvantages such as local stiffness/strength reduction caused by the embedded sensors in composites structures used for structural health monitoring, we designed a surface pasting film sensor (SPFS) to locate the impact damage in glass-fiber reinforced polymer (GFRP) panels and composite overwrapped pressure vessel (COPV). The SPFS was made by printing MWCNTs/PDMS ink onto a PDMS film substrate. The relative resistance response (Delta R/R0) of the sensing networks was recorded during loading. Sensing performance of SPFSs was evaluated by monitoring damages in GFRP panels with three different thicknesses and assessing three typical positions within a COPV. The experimental results demonstrated that variations in the load magnitude and position can be estimated by Delta R/R0 shift of the SPFS. The newly designed SPFS shows superior accuracy in insitu detecting damages in FRP structures. The maximum root mean square error for damage localization is 4.45% in GFRP panels and 4.27% in COPV. The presented concept provides a novel approach for early detection of damages in FRP structures, offering advanced warning without disrupting their inherent integrity.