▎ 摘　　要

2D materials such as graphene, boron nitride (BN) and molybdenum disulphide (MoS2) nanoplatelets have found wide applications in energy generation and storage, catalysis, flexible electronics, tissue engineering and nanocomposites. For practical applications, their mechanical behaviour needs to be understood. Here we use molecular dynamics (MD) simulations to investigate the deformation and failure of graphene, hBN and MoS2 nanosheets under tension. A model was built to highlight the contribution of 'critical bonds' in the loading di-rection to the fracture strength, which can explain the anisotropy observed in graphene and hBN. As compared to graphene and hBN, different mechanical behaviour was observed in MoS2. The effects of atomic defects on the strength were also investigated and compared with classic fracture mechanics theory.