In a narrow sense, the term fatigue of materials and structural components means damage and fracture due to cyclic, repeatedly applied stresses. In a wide sense, it includes a large number of phenomena of delayed damage and fracture under loads and environmental conditions. The systematic study of fatigue was initiated by Wöhler, who in the period 1858–1860 performed the first systematic experimentation on damage of materials under cyclic loading. In particular, Wöhler introduced the concept of the fatigue curve, i.e., the diagram where a characteristic magnitude of cyclic stress is plotted against the cycle number until fatigue failure. Up to now, the Wöhler curve has been used widely in the applied structural analysis. At the same time, fatigue and related phenomena are considered as a subject of mechanics of solids, material science, as well as that of basic engineering.