Analytical Concepts for Recent Development in Fatigue Crack Growth under Variable Amplitude Loading. Part I: Qualitative Interpretation

Understanding effective parameters in fatigue crack growth (FCG) model under variable amplitude loading (VAL) is of eminent importance theoretically as well as experimentally. In response to this necessity, a systematic study of different analytical concepts and loading sequences in order to gain a practical framework has been proposed. The theoretical background related to the fatigue life prediction by using FCG model has been presented. This has shown the rationale of why we need to calculate local stress-strain in the crack tip in developing FCG models which is the main subject of this research.