Effect of Interatomic Potential Choice on Fracture Modes of Graphene with Parallel Cracks

TL;DR

This study compares how different interatomic potentials, AIREBO and ReaxFF, influence the predicted fracture behavior of defect-engineered graphene with parallel cracks, highlighting the importance of potential choice in simulations.

Contribution

It provides a direct comparison of AIREBO and ReaxFF potentials in modeling graphene fracture with parallel cracks, emphasizing potential-dependent differences in mechanical response.

Findings

AIREBO predicts lower peak stresses than ReaxFF.

Energy absorption and ductility are highly potential-dependent.

Potential choice significantly affects fracture simulation outcomes.

Abstract

Defect engineering via parallel cracks has been proposed as a route to tailor the fracture response of graphene. However, atomistic fracture predictions can be strongly sensitive to the interatomic potential. Here, we quantify the effect of potential choice by revisiting H-passivated graphene containing two parallel cracks separated by a gap $W_{\text{gap}}$ loaded in tension along the armchair (AC) and zigzag (ZZ) directions. Molecular dynamics simulations using the AIREBO potential under the same geometry and loading protocol previously studied with ReaxFF, are employed, so enabling a direct comparison. Stress-strain responses, Young's modulus, an effective mode-I stress intensity factor, and energy absorption are evaluated as functions of $W_{\text{gap}}$. Compared with ReaxFF, AIREBO predicts lower peak stresses and earlier catastrophic softening, leading to reduced post-peak deformation capacity and energy absorption. Ductility and energy absorption are shown to be highly potential-dependent, underscoring the need for careful potential selection in defect-engineered graphene fracture simulations.