ABSTRACT
This chapter aims to demonstrate the flexibility of the theory and its availability to fit various, sometimes vague and controversial experimental data. The tip sharpens during the crack growth, and begins to blunt during the growth retardation. The crack behavior is predicable: the longer the initial crack, the shorter the durations of the initiation stage and of the total fatigue life. The influence of crack closure on crack growth enters the fatigue problems with global deformations of a specimen or structural component. The influence of dilatant strains on fatigue crack growth may also be considerable; these strains may affect, at least indirectly, via the stress-strain field. The stability condition of the system cracked body-loading contains the differences between the driving and resistance generalized forces. For the opening mode crack, assume that microdamage is represented by an array of a large number of microcracks coplanar to the main, macroscopic crack.
