A generalized theory of fracture mechanics

A fracture-mechanics theory is developed which gives fracture criteria for solids in general, without limitations as to their linearity, elastic behaviour or infinitesimal strain. Besides the “standard” results of the theory which reduce to familiar forms like the Griffith equation for linear, elastic solids, several new results emerge from the theory. These include a relationship between the surface work and the true surface energy of the solid, an explanation of certain departures from standard fracture mechanics obtained with inelastic materials, and a prediction and explanation of the phenomenon of notch brittleness. Further applications of the theory, such as adhesive failure and fatigue, will be explored in a subsequent paper.