04.1 - Aerospace Grade Materials, Structural Analysis, Fatigue and Damage Tolerance
ENHANCEMENT AND DEGRADATION: THE DUAL ROLE OF GRAPHENE NANOPLATELETS ON THE STRUCTURAL PERFORMANCE OF COMPOSITE T-JOINTS AND MECHANISTIC INSIGHTS
M. Bhasin¹, A.P. Mouritz¹; ¹RMIT University, Australia
This paper reports an experimental investigation into the effect of graphene nanoplatelet (GNP) inclusion on the structural properties of carbon-epoxy T-joints under stiffener pull-off loading. T-joints with 0.0–2.0 wt.% GNPs (five concentrations; ≥9 specimens each) were tested. GNP addition significantly improved toughness- reliant properties: load drop after damage initiation reduced by up to 93%, absorbed energy capacity increased by up to 17%, and fracture propagation transformed from unstable stick-slip to stable distributed cracking. DIC characterisation revealed progressive strain field diffusion with GNP content. Conversely, joint stiffness decreased by up to 36%, damage initiation load by up to 24%, and ultimate strength by up to 25% at high GNP concentrations. The study identifies the effective dispersion window for balanced performance. Mechanisms responsible for both enhancement and degradation are identified and linked not only to continuum mechanics scale factors but also at the quantum mechanical forces scale. This study yields two pivotal insights: (a) the filler–matrix interface emerges as the true performance ceiling and primary design lever for T-joint composites, (b) graphene's reinforcement potential hinges on de-stacking GNPs into individual monolayers due to the weak van der Waals interlayer properties—a perspective that supersedes the conventional dispersion– agglomeration phenomenological model treating platelets as intact multi-layer units.
DOI: 10.71945/icas2026_0868