# Failure and Scaling of Graphene Nanocomposites

## TL;DR

This study investigates how the structural strength of polymer/graphene nanocomposites scales with size, revealing deviations from classical fracture mechanics due to the fracture process zone's influence, especially at smaller scales.

## Contribution

It demonstrates that nanocomposite strength scaling deviates from LEFM predictions because of the fracture process zone, highlighting the importance of size effects in nanocomposite fracture analysis.

## Key findings

- Small specimens show increased ductility and deviate from LEFM.
- Larger specimens behave more brittle, aligning closer to LEFM predictions.
- Neglecting the fracture process zone can underestimate fracture energy by up to 113.

## Abstract

This work proposes an investigation on the scaling of the structural strength of polymer/graphene nanocomposites. To this end, fracture tests on geometrically scaled Single Edge Notch Bending (SENB) specimens with varying contents of graphene were conducted to study the effects of nanomodification on the scaling. It is shown that, while the strength of the pristine polymer scales according to Linear Elastic Fracture Mechanics (LEFM), this is not the case for nanocomposites, even for very low graphene contents. In fact, small specimens exhibited a more pronounced ductility with limited scaling and a significant deviation from LEFM whereas larger specimens behaved in a more brittle way, with scaling of nominal strength closer to the one predicted by LEFM. This behavior, due to the significant size of the Fracture Process Zone (FPZ) compared to the specimen size, needs to be taken into serious consideration. In facts, it is shown that, for the specimen sizes investigated in this work, neglecting the non-linear effects of the FPZ can lead to an underestimation of the fracture energy as high as 113%, this error decreasing for increasing specimen sizes.