Recent Developments in Fracture Mechanics

Abstract

The lecture deals with new approaches to fracture mechanics which take account of damage of the material. The main assumption is that a stress-strain law is only assumed for tensile strain less than a critical value ɛ_R beyond which the stress a vanishes identically and irreversibly. It is shown with this model that a process zone of some characteristic size may exist. The dissipation rates by plastic deformation and by fracture, due to the release of stress, are introduced in the balance equation of energy. The dissipation analysis allows us to investigate the theoretical R-curves. Brittle and ductile fracture are discussed. The transition from damage fracture to classical fracture mechanics is shown by the limit ɛ_R→∞. Quite consistently, the dissipation rate by ductile fracture does not vanish.