A new approach to predicting fatigue life behavior under the action of mean stresses

Abstract Modern methods of predicting fatigue life behavior under the action of mean stresses are briefly reviewed. These methods reflect a gradual evolution from the old-fashioned S-N approach to one based on strain cycling and cyclic deformation. This development is here carried further. We show that cyclic response under mean stress is closely correlated with that under zero mean stress and we suggest that life data under mean stress conditions can be described adequately by the Coffin-Manson law. The concept of an “isolongevity” diagram is proposed for fatigue life behavior under mean stresses.