Fracture mechanics of monolayer molybdenum disulfide

Molecular dynamics (MD) modeling is used to study the fracture toughness and crack propagation path of monolayer molybdenum disulfide (MoS2) sheets under mixed modes I and II loading. Sheets with both initial armchair and zigzag cracks are studied. The MD simulations predict that crack edge chirality, tip configuration and the loading phase angle influence the fracture toughness and crack propagation path of monolayer MoS2 sheets. Furthermore, under all loading conditions, both armchair and zigzag cracks prefer to extend along a zigzag path, which is in agreement with the crack propagation path in graphene. A remarkable out-of-plane buckling can occur during mixed mode loading which can lead to the development of buckling cracks in addition to the propagation of the initial cracks.