Size Dependent Fracture Mechanics in Nano-Reinforced Thin Composite Structures

Abstract

Nano-reinforced thin composite structures, such as laminates and plates, are increasingly used in aerospace, microelectronics, and biomedical applications due to their high strength-to-weight ratio and multifunctionality. However, as structural thickness decreases to micro- or nanoscale dimensions, conventional fracture mechanics assumptions fail, and size dependent effects dominate crack initiation and propagation. This paper investigates the size dependent fracture mechanics of thin composite structures reinforced with nanoparticles such as carbon nanotubes (CNTs), graphene oxide (GO), and nanosilica. Both experimental and computational approaches are employed to quantify how specimen thickness, nanoparticle content, dispersion, and interfacial properties affect fracture toughness and energy dissipation. Results indicate that nanoscale reinforcements not only improve strength and toughness but also modify crack tip stress fields and energy release rates, introducing a clear size effect in thin composites. Cohesive zone modeling, multiscale simulations, and fractographic analysis reveal mechanisms such as crack bridging, pull-out, and matrix plasticization that dominate at small scales. The findings provide critical insights for the design and optimization of nanoscale thin composite structures with predictable fracture behavior.