Some insights into the remote strain versus fatigue life relationship

Quantification and physical explanation of empirical parameters of the Manson-Coffin (MC) rule has been an up-to-date question since it was first published in 1954. In the latest decades there have been extensive efforts to describe the micro-level processes controlling the LCF damage process using micromechanical models. This study aims at contributing to the current understanding of the nature and physical content of the empirical parameters of the Manson-Coffin rule. Some latest results of mathematical statistical analysis on the correlation between the fatigue ductility coefficient and ductility exponent are introduced. In addition, based on experimental procedures the validity of the MC rule for crack nucleation is substantiated, furthermore a distinction between crack initiation and propagation from the aspect of fatigue process “efficiency” is discussed, that has been proved to be cycle-dependent influencing directly the exponent c-value.