A new multiscale modeling approach to unravel the influence of interlayer sp3 bonds on the nonlinear large-deformation and fracture behaviors of 2D carbon nanostructures under tension

TL;DR

This paper presents a multiscale modeling approach to analyze how interlayer sp3 bonds affect the nonlinear deformation and fracture of 2D carbon nanostructures under tension, providing insights into their mechanical behavior.

Contribution

It introduces the MAN multiscale auxiliary nodes method that accurately simulates large-deformation and fracture behaviors of 2D CNs by bridging atomic and continuum scales.

Findings

Diamane's elastic moduli are close to diamond's and higher than graphene's.

Interlayer sp3 bonds' quantity and distribution significantly affect fracture behavior.

Strategic placement of sp3 bonds enhances tensile strength.

Abstract

To delve deeply into the nonlinear large-deformation and fracture behaviors of 2D carbon nanostructures (2D CNs), including bilayer graphene, diamane, and their transitional structures, this paper introduces a multiscale auxiliary nodes (MAN) method rooted in atomic structures and potentials. This approach simulates 2D CNs by constructing two virtual continuum sheets with high-order continuity. The moving least squares (MLS) approximation is employed to facilitate the transformation between atomic displacements and nodal displacements, thereby converting atomic potential energy into strain energy within the continuum model. Through iterative solutions of nonlinear stiffness equations, the equilibrium configuration of the system under specified loading conditions can be obtained. The flexibility in the density and arrangement of nodes allows for a smooth and seamless cross-scale transition from discrete atomic structures to a continuum model. Numerical simulations demonstrate that MAN method accurately predicts the nonlinear large-deformation and fracture behaviors of 2D CNs. The Young's modulus and shear modulus of diamane in both zigzag and armchair directions closely approach those of diamond and are notably higher than those of graphene. Furthermore, the quantity and distribution of interlayer sp3 bonds significantly influence the fracture behavior of 2D CNs, with strategic placement of these bonds effectively enhancing the tensile strength of the structures.