EXTENSIONS OF A STATISTICAL APPROACH TO FRACTURE

It is shown how the cumulative failure probability of an inhomogeneously stressed structure may be estimated when the material contains N different types of defect, each having its own fracture criterion. The theory is applied to: a) materials containing a distribution of randomly oriented cracks having various sizes, b) materials containing a distribution of cracks, the tips of which lie in material of differing fracture toughness. It is also shown how to account for defects which grow in size because of fatigue and/or creep mechanisms. As an example the fatigue crack growth of defects, in a material having an inhomogeneous distribution of fracture toughness, is discussed. A method of accounting for defect nucleation during service is described. © 1979 Sijthoff & Noordhoff International Publishers.