Mechanics of fracture in large structures

Abstract

A dislocation theory of cracks, which takes account of elastic-plastic and other non-linear modes of deformation, is used to discuss the geometrical and physical conditions for unstable fracture. The importance of discontinuous cracking in providing an unstable mode of plane strain, semi-brittle, tensile fracture is emphasized. The general formulae reduce to those of Griffith, Orowan, and Irwin, at low stresses. Size effects and their relation to microscopic processes of deformation and fracture, especially twinning, are discussed and the concept of the crack arrest temperature is considered.