Computational modeling of the mechanics and fracture of 2D materials with defects and grain boundaries

Two dimensional materials including graphene, silicene, MoS2 and so forth represent ideal materials composed of a single layer of atoms organized in a lattice form. Their unique geometry and intriguing mechanical and thermal properties make them perfect candidates for nanoscale engineering applications. The robustness of the materials, especially for their tolerance with defects is important to prevent their catastrophic failure and contribute to their mechanical durability in usage. Here we have shown that our large-scale molecular dynamics modeling based on reactive force fields provides a useful tool to explore the mechanical response and fracture of different 2D materials under extreme mechanical loading conditions. Our research focuses on how defects and grain boundaries in 2D materials affect the critical conditions and the dynamics process of their fracture. We find good agreements between our simulations and experiments via transmission electron microscopy for MoS2 fracture as all experimental observations of crack propagation, deflection and the interaction between crack tip and defects have been observed in the simulation with similar boundary conditions, as shown in Figure 1.