  We developed a combined atomistic-continuum hierarchical multiscale approach
to explore the effective thermal conductivity of graphene laminates. To this
aim, we first performed molecular dynamics simulations in order to study the
heat conduction at atomistic level. Using the non-equilibrium molecular
dynamics method, we evaluated the length dependent thermal conductivity of
graphene as well as the thermal contact conductance between two individual
graphene sheets. In the next step, based on the results provided by the
molecular dynamics simulations, we constructed finite element models of
graphene laminates to probe the effective thermal conductivity at macroscopic
level. A similar methodology was also developed to study the thermal
conductivity of laminates made from hexagonal boron-nitride (h-BN) films. In
agreement with recent experimental observations, our multiscale modeling
confirms that the flake size is the main factor that affects the thermal
conductivity of graphene and h-BN laminates. Provided information by the
proposed multiscale approach could be used to guide experimental studies to
fabricate laminates with tunable thermal conduction properties.
