On the fracture processes of cutting

The process of cutting is treated as a fracture mechanical process. For an elliptic rigid wedge pressed into an elastic material, fracture may occur as an autonomous process if the tip of the wedge is sufficiently blunt or is affected by the geometry of the wedge if the tip is sharp. The conditions leading to the former or the latter case is obtained as a relation between the wedge tip radius, the fracture toughness and the modulus of elasticity. These limits and the intermediate states are discussed. The implications of the drastic changes of the mechanical state of the near tip region when the wedge edge is sharp are also discussed.