Fatigue and inelasticity of metals under nonuniform stressed state

Based on the review of the available publications and the findings of the original studies, the author demonstrates that with cyclic stresses in the maximum-stressed surface layer being equal the inelastic strains in the presence of stress gradients are smaller than those in the material under uniform stressed state. As a result, there is a difference in the cyclic stress–strain diagrams between these cases. An equation for the cyclic stress–strain diagram is put forward, which allows for the stress gradient effect. A model is substantiated, which provides an explanation for the difference between fatigue strength characteristics under uniform and nonuniform stressed states.