A Continuum Damage Model for Functionalized Graphene Membranes Based on Atomistic Simulations

A continuum model for GO membranes is developed in this study. The model is built representing the membrane as a two-dimensional, heterogeneous, two-phase continuum and the constitutive behavior of each phase (graphitic or oxidized) is built based on DFTB simulations of representative patches. A hyper-elastic continuum model is employed for the graphene areas, while a continuum damage model is more adequate for representing the behavior of oxidized regions. A finite element implementation for GO membranes subjected to degradation and failure is then implemented and, to avoid localization instabilities and spurious mesh sensitivity, a simple crack band model is adopted. The developed implementation is then used to investigate the existence of GO nano-representative volume elements.