Atomistic Simulation of Anistropic Crystal Structures at Nanoscale

Abstract

The development of molecular modeling tools to describe and predict the mechanical properties of structural materials reveals an undeniable practical importance. It is now well recognized that such an objective can be achieved through the linking of the structure of materials at the nanoscale or with their performances. At the nanometer scale, anisotropic materials exhibit differences due to the directional arrangements of atomic structure, the force between atoms, such as van der Waals force, typical Coulomb force, and other forces. Nanoscale modeling and mechanical properties by using the density functional theory (DFT), a so-called atomic finite element method (AFEM), and the classical molecular dynamics (MD) method are especially concerned according to the modeling requirement of different crystal structures investigated. Omitting the description of these structures’ importance, elastic moduli are separately calculated by either homogenization or curve fitting of the linear portion of the stress-strain curve by the corresponding numerical simulations. This chapter is committed to introduce the modeling and simulation for calculating mechanical properties (Young’s modulus especially) of typical anisotropic crystal structures using three methods (DFT, AFEM, and MD) mentioned above. It is therefore asked to connect to the nanoscale modeling and continuous pattern of behavior by identifying the relevant output data at small scales and bringing the necessary information to higher scales.