# Combined molecular dynamics and phase-field modelling of crack propagation in defective graphene

## TL;DR

This paper presents a combined molecular dynamics and phase-field modeling approach to study crack propagation in defective graphene, linking atomistic and continuum fracture processes and validating with experimental data.

## Contribution

It introduces an integrated MD and phase-field methodology to determine defect-dependent fracture properties in graphene.

## Key findings

- Elastic properties and fracture toughness influenced by point defects.
- Values of fracture toughness align with experimental results.
- Effective fracture toughness concept links atomistic and continuum fracture models.

## Abstract

In this work, a combined modelling approach for crack propagation in defective graphene is presented. Molecular dynamics (MD) simulations are used to obtain material parameters (Young's modulus and Poisson ratio) and to determine the energy contributions during the crack evolution. The elastic properties are then applied in phase-field continuum simulations which are based on the Griffith energy criterion for fracture. In particular, the influence of point defects on elastic properties and the fracture toughness are investigated. For the latter, we obtain values consistent with recent experimental findings. Further, we discuss alternative definitions of an effective fracture toughness, which accounts for the conditions of crack propagation and establishes a link between dynamic, discrete and continuous, quasi-static fracture processes on MD level and continuum level, respectively. It is demonstrated that the combination of MD and phase-field simulations is a well-founded approach to identify defect-dependent material parameters.