State the Griffith criterion for crack propagation in brittle solid.

Brittle fracture is that the failure of a fabric while not apparent plastic deformation. If the broken items when a brittle fracture area unit fitted along, lies the initial form and dimensions of specimen area unit repaired.

Griffith Criterion for crack has postulated a criterion for the propagation of pre-existing crack in brittle material (glass). filmmaker postulated that brittle fracture occurred once the energy unleash rate throughout crack growth exceeded the speed that energy was needed.