Multifunctional Crushing and Piezoresistive Self‐Sensing in Conductive Epoxy/CNT‐Coated Polyetherimide TPMS Lattices

This study experimentally demonstrates a multifunctional approach for architected lattices that couple structural reinforcement with autonomous sensing. Polyetherimide triply periodic minimal surface lattices – Gyroid, Diamond, Schwarz, Neovius and Split‐P – were fabricated via fused filament fabrication (15%–35% relative density) and subsequently coated with an epoxy nanocomposite containing 1 wt.% carbon nanotubes (CNTs). The conformal conductive coating (with an estimated average thickness of ≈0.5 mm, based on post‐processing measurements) significantly enhanced mechanical performance while imparting piezoresistive functionality. The elastic modulus increased by 140%, 192%, 182%, 99% and 282% and strength by 173%, 218%, 206%, 167% and 322% for the respective topologies. Coated lattices exhibited stiffer crushing responses with specific energy absorption gains up to 320%. The epoxy/CNT layer yielded reproducible and monotonic elastic strain‐dependent resistance changes up to the onset of structural collapse (gauge factor ≈1.8), beyond which the response became dominated by stochastic fracture and conductive network disruption. This scalable experimental route enables polymeric architected lattices with coupled mechanical‐sensing functionality and represents a first step towards the future development of self‐sensing architected structures for aerospace applications, with potential relevance to lightweight reinforcement and bird‐strike mitigation concepts.