A New Multiscale Modeling Approach to Unravel the Influence of Interlayer sp 3 Bonds on the Nonlinear Large‐Deformation and Fracture Behaviors of 2D Carbon Nanostructures Under Tension

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. Different from traditional atomistic and multiscale solvers, the proposed framework builds a pair of decoupled, C 2 ‐continuous virtual continuum sheets separated from the physical atomic lattice as independent solution domains. Atomic geometric information, interatomic distances, and REBO bond‐order potentials are mapped onto the dual sheets via moving least squares (MLS) shape functions, reformulating the full atomic potential functional purely in terms of auxiliary nodal displacements rather than atomic coordinates. The derived equilibrium equations follow order‐N linear complexity with respect to auxiliary nodes, whose positions are unrestricted by lattice periodicity; flexible adjustment of node density enables smooth atom‐to‐continuum transitions without artificial interfacial forces. Through iterative solutions of nonlinear stiffness equations, the equilibrium configuration of the system under specified loading conditions can be obtained. Numerical simulations suggest that the MAN method can reasonably capture the nonlinear large‐deformation responses 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 sp 3 bonds significantly influence the fracture behavior of 2D CNs, with uniform dispersion of these bonds effectively mitigating strain localization and improving structural tensile strength.