Additionally, the crack tip sharpens during fracture in water and an increased number of microscopic propagation events occur. Analysis of Si─O bonds in the process zone and calculations of dissipation energy associated with fracture indicated that water relaxes the entire process zone and not just the surface. The addition of water to silica fracture reduced the silica fracture toughness by ~25%, a trend consistent with experimentally reported results. The chemical and mechanical aspects were separated by simulating fracture in (a) a vacuum with dynamic loading, (b) an aqueous environment with dynamic loading, and (c) an aqueous environment with static subcritical mechanical loading to track silica dissolution. To investigate this effect, classical molecular dynamics simulations using the bond-order-based reactive force field (ReaxFF) were used to simulate silica fracture. Fracture toughness of silicates is reduced in aqueous environments due to water-silica interactions at the crack tip.

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