The energy required to break glass is not a fixed number and actually increases by 33% if the crack is moving faster.
Fracture energy in silica glass depends on the velocity of the crack because of changes in the nanoscale surface structure. Engineering textbooks traditionally treat the toughness of a material as a constant property that never changes. This research proves that the faster a material breaks, the more energy it consumes during the process. This shift occurs because the atoms at the tip of the crack reorganize themselves differently at higher speeds. This finding will lead to more accurate safety ratings for glass used in high-speed vehicles and skyscraper windows. It changes how we design everything that needs to survive a violent impact.
Energy dissipation at the atomic scale explains how fracture energy depends on crack velocity in silica glass
arXiv · 2605.03457
The fracture energy of brittle materials rises with crack velocity, and this effect is typically attributed to surface roughening from path instabilities. Here we show, using molecular dynamics simulations of silica glass with a first-principles machine learned interatomic potential, that the structural fracture energy rises by up to 33 % already below the branching threshold, showing that fracture energy is not a constant material property. This rise in fracture energy is roughly equally partit