Crack propagation in silica from reactive classical molecular dynamics simulations

Mechanistic insight into the process of crack growth can be obtained through molecular dynamics ( MD ) simulations. In this investigation of fracture propagation, a slit crack was introduced into an atomistic amorphous silica model and mode I stress was applied through far‐field loading until the crack propagates. Atomic displacements and forces and an Irving–Kirkwood method with a Lagrangian kernel estimator were used to calculate the J ‐integral of classical fracture mechanics around the crack tip. The resulting fracture toughness ( K IC ), 0.76 ± 0.16 MP a√m, agrees with experimental values. In addition, the stress fields and dissipation energies around the slit crack indicate the development of an inelastic region ~30Å in diameter. This is one of the first reports of K IC values obtained from up‐scaled atomic‐level energies and stresses through the J ‐integral. The application of the Reax FF classical MD force field in this study provides the basis for future research into crack growth in multicomponent oxides in a variety of environmental conditions.