GRIFFITH'S THEORY OF RUPTURE,
Abstract:
Griffiths theory of rupture correctly portrays the mechanism of failure for brittle materials. Brittle fracture is due to high tensile stresses generated at the tips of the microscopic cracks which exist in all brittle materials. This high tensile stress exists near the tip of an elliptical crack regardless of the sign of the external stresses. Considerably more experimental research must be performed before the Griffith theory of rupture can be applied safely to engineering problems connected with rock mechanics. McClintock and Walsh modified Griffiths theory to take into account frictional forces which are developed when the crack is compressed. The modified Griffith theory is identical with the Coulomb law in the region of compression. After reviewing both Griffiths theory and the modified theories, it is concluded that Mohrs criteria t6 predict failure conditions in rock are the most applicable at the present time. Author