Evaluation of Graphene Oxide–Modified Repair Methodologies in Carbon Fiber Reinforced Polymer Composites for Aerospace Applications

ABSTRACT The structural design of damaged carbon fiber reinforced polymer (CFRP) components remains a major unresolved challenge, particularly under field conditions where processing quality cannot be rigorously controlled. Traditional wet lay‐up repairs, though widely employed, offer poor fiber–matrix consolidation and weak interfacial integrity, leading to markedly inferior mechanical performance compared with prepreg‐based systems. Here we demonstrate a targeted nanomodification strategy in which graphene oxide (GO) nanoparticles are integrated into an aerospace‐grade epoxy matrix to elevate wet lay‐up repair performance toward prepreg benchmarks. GO, synthesized via a modified Hummers method and dispersed at 0.3–2.5 wt%, enables a distinct, non‐linear reinforcement response: low loadings (0.3–0.5 wt%) significantly enhance tensile strength—from 282 MPa (unmodified) to 309 and 360 MPa—approaching the prepreg reference (≈391 MPa). At 2.5 wt% GO, however, severe nanoparticle agglomeration disrupts matrix continuity, reducing strength to 250 MPa. These results, for the first time, define an optimal GO concentration window capable of bridging the long‐standing mechanical performance gap between wet lay‐up and prepreg repair strategies. The study systematically and directly evaluates wet lay‐up and prepreg repair methods in a comparative framework, experimentally elucidating the mechanical performance differences between these two distinct repair approaches. Furthermore, it reveals the mechanistic basis of GO‐induced interfacial reinforcement and establishes a viable nanostructural design pathway for high‐fidelity, cost‐effective CFRP repair in aerospace maintenance applications.