Molecular Dynamics Simulations and Continuum Modeling of Temperature and Strain Rate Dependent Fracture Strength of Graphene

I would like to share with you our recent paper published in the Journal of Applied Mechanics: J. Appl. Mech. 81(8), 081010 (Jun 02, 2014)

Abstract

We investigated the temperature and strain rate dependent fracture
strength of defective graphene using molecular dynamics and an atomistic
model. This atomistic model was developed by introducing the influence
of strain rate and vacancy defects into the kinetics of graphene. We
also proposed a novel continuum based fracture mechanics framework to
characterize the temperature and strain rate dependent strength of
defective sheets. The strength of graphene highly depends on vacancy
concentration, temperature, and strain rate. Molecular dynamics
simulations, which are generally performed under high strain rates,
exceedingly overpredict the strength of graphene at elevated
temperatures. Graphene sheets with random vacancies demonstrate a
singular stress field as in continuum fracture mechanics. Molecular
dynamics simulations on the crack propagation reveal that the energy
dissipation rate indicates proportionality with the strength. These
findings provide a remarkable insight into the fracture strength of
defective graphene, which is critical in designing experimental and
instrumental applications