The energy approach to the formulation of the fatigue strength criterion is proposed. The criterion is based on the latent energy investigations. This conception has not been applied previously to the fatigue problem, but can be the most perspective one for fatigue strength predictions of high-strength metallic alloys which work in the high-cycle fatigue regime. On the basis of experimental investigations the logistic function is used to describe the kinetics of latent energy accumulation as a function of irreversible deformation. When the high-cycle fatigue criterion is formulated, it is assumed that the cyclic strength of metals is defined by the latent energy, stored in a specimen, when it is reached the critical value in accordance with the logistic curve in the saturation zone. Using the experimental results, the functions and parameters of logistic function and criterion are concretized, and fatigue strength in gigacycle regime is predicted.
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