Condition of High-Velocity Ductile Fracture

Abstract

The Griffith energy criterion, dW = −dU (dW = crack propagation work, −dU = released elastic energy), cannot be applied to essentially ductile fractures. In particular, it does not represent the condition of rapid ductile fracture propelled by the elastic energy of the specimen. The condition of such fractures is $d^2{\mathrm{W/dx}}^2{\mathrm{=-d}}^2{\mathrm{U/dx}}^2$ where x is the plastic extension accompanying the propagation of the crack.