Linear elastic fracture mechanics is the study of the response and failure of structures as a consequence of crack initiation and propagation. It is a method of characterizing the fracture behavior in structural parameters that can be used directly by the engineer, namely stress and flaw size. The science of fracture mechanics can be used to describe quantitatively the trade-offs among three factors (stress, materials toughness and flaw size) so that the designer can determine the relative importance of each of them during design rather than during failure analysis.