STRESS CONCENTRATION APPROACH TO FRACTURE MECHANICS.

Describes a stress concentration approach to define the instability criterion of a stressed material containing a through thickness defect. The approach basically depends on simple considerations of static equilibrium in the plane of the crack. It is shown that the basic equation satisfies fracture data for widely varying materials. By postulating that failure at the crack tip occurs at a constant failure stress which is a basic material property and is proportional to the ultimate tensile strength in uniaxial tension, an equation is derived which gives the critical crack length in terms of nominal stress level, Charpy V energy, and conventional tensile properties.