Role of the process zone in fatigue macrocrack initiation and propagation is
considered. An examples of the assessment of the fatigue macrocrack initiation period, Ni,
and the failure period, Nf, of a notched specimens on the base of unified model using fatigue
macrocrack growth rates only are shown. Some backgrounds and well-known fatigue
phenomena (Kitagawa's and Smith's diagrams, etc) are discussed
