Sacrificial Coating-Assisted Deformation Regulation in GO-Coated Kevlar Structures under Dynamic Bending

Kevlar-based flexible protective materials exhibit excellent tensile deformability and energy-dissipation capability under impact loading. However, under dynamic bending, the deformation response of Kevlar gradually evolves from distributed deformation toward highly localized structural failure with increasing loading velocity, which severely limits its resistance against catastrophic perforation. In this work, graphene oxide (GO) multilayer coatings were introduced onto Kevlar structures to regulate deformation localization and improve their dynamic bending tolerance. Molecular dynamics (MD) simulations were performed to investigate the quasi-static and dynamic bending behaviors of uncoated, single-layer-GO-coated, and bilayer-GO-coated Kevlar structures. The results reveal that the deformation behavior of Kevlar is governed by a velocity-dependent transition between distributed deformation and localized rupture. The introduction of GO coatings fundamentally modifies the stress redistribution and failure evolution of the Kevlar network. Under quasi-static bending, the GO layers enhance the load-bearing capability of the structure through coating-assisted stress transfer. Under dynamic bending, sacrificial fracture of the GO coatings delays severe Kevlar degradation and promotes broader deformation redistribution within the fibrous network. Compared with the uncoated structure, the critical perforation velocity increases by approximately 28.6 and 48.6% for the single-layer-coated and bilayer-coated systems, respectively. These findings provide mechanistic insight into coating-mediated deformation regulation in flexible fibrous networks and demonstrate the potential of GO-based interfacial engineering for improving dynamic bending resistance under extreme loading conditions.