FRACTURE CRITERION FOR THE AXISYMMETRICAL DISKING PROCESS

Disking is a process designed to cut brittle plates and rods. In axisy mmetric disking, a pre-cracked cylindrical rod is placed in an elastic , annular sheath and the composite is subjected to biaxial fluid press ure. At a critical pressure the crack runs across the circular section of the rod producing a clean cut. A linear elastic fracture mechanics analysis is used to develop a fracture criterion for the process. A c oncentric circular cylinders model is assumed with perfect bonding at the interface. The flaw that initiates fracture in the rod is modeled as an annular crack perpendicular to the interface with one crack tip at the interface. The problem is formulated as a singular integral equ ation of the first kind with a Cauchy type kernel. The stress intensit y factors are determined as a function of crack size and shear moduli.