A New Multi-Physics Molecular Dynamics Finite Element Method for Designing Graphene Composite Nano-Structures to Target Property Specifications

摘要

A new multi-physics and multi-scale Molecular Dynamics Finite Element Methodrn(MDFEM) is proposed, which allows for advanced mechanical and multi-physicsrncharge-dipole MD force fields to be implemented exactly in the computationallyrnmore favourable FEM. Moreover, new generalised Periodic Boundary Conditionsrn(PBC) are developed, which can be used to readily obtain homogenised electromechanicalrnproperties for low-dimensional nano-structures under generic rotationalrndeformations. The proposed model has produced novel mechanical, electrical chargedipolernas well as concurrently coupled MD-continuum FEM results. In particular,rnthe homogenised mechanical in-plane and bending properties of Pillared GraphenernStructures (PGS) as well as the fracture toughness properties of pristine graphenernhave been obtained. Additionally, eigenvalue-based analyses of nano-structures’ exactrnenergy Hessian allow for more in-depth and varied modelling opportunities (e.g.rnbuckling, frequency, modal dynamics). The presented MDFEM is well suited forrnthe optimised virtual design of a wide range of electro-mechanical nano-devices orrnnano-structures, e.g. PGS, to either given device property or macroscopic target specifications.