Destructive and nondestructive remaining fatigue life prediction methods of metals: a review

Metals’ remaining fatigue life (RFL) forecast is considered to be an overly complicated process among engineers in practical applications, especially since a fast and acceptable level of safety operation and trust assessment are needed to avoid fatigue risks in worksites. The internal damage that the material suffers under fatigue stress results in invisible changes in the microstructure, which may lead to its failure below the intended design life of the material. Therefore, predictive calculations of RFL are very important for personnel safety and design quality. Here, the RFL prediction models and material-dependent characteristic components are reviewed via two approaches: the destructive (DT) and nondestructive (NDT) methods. Typical measurements and data associated with their relationships, such as stress, strain and effective contact at different stages of fatigue failure were explored. Moreover, the effectiveness of the DT and NDT evaluation methods was compared to obtain the information and description of the material fatigue response. Subsequently, the best models were selected.