Cumulative Fatigue Damage Mechanisms And Quantifying Parameters

Cumulative fatigue damage analysis plays an important role in fatigue life prediction of components and structures which are subjected to field loading histories. Understanding of cumulative damage mechanisms is essential since it provides the necessary physical bases for modeling the cumulative damage process. A damage measure that can reflect and quantify the real damage state the material undergoes is also a key issue for successful modeling of cumulative fatigue damage. This review paper provides a comprehensive overview of research activities highlighting the recent findings and progress on phenomenological observations and mechanisms, as well as quantification measures of cumulative fatigue damage. Depending on the definition of failure or the characteristics of failure experienced in a material, the effectiveness of a damage parameter could vary from case to case. Many damage parameters have been proposed and many of them are in use. Those to be reviewed are sorted into categories of metallurgical parameters, surface crack quantifications, mechanical measures, and physical parameters. Early studies on cumulative damage mechanisms and quantifying measures are reviewed only briefly, since they have been covered in the existing literature.