Continuum approach to high-cycle fatigue modeling

A continuum approach to modeling of high-cycle fatigue is proposed. The approach takes a very simple and appealing form and is based on the concepts of a moving endurance surface in the stress space and an evolving damage variable. If the stress state is inside the endurance surface, no damage development occurs whereas damage may develop if the stress state is outside the surface. The endurance surface may move in the stress space as a function of the stress history. The theory is formulated within a proper continuum mechanics framework and it treats uniaxial and multiaxial stress states in a unified manner for arbitrary load histories. A unique feature of the theory is that it allows for the concepts of fatigue limits and accumulation of damage during the load history and thereby avoids cycle-counting techniques. Predictions of the theory are compared with experimental data and the agreement turns out to be close.