Some Regularities of Residual Stress Variation Under Cyclic Loading as Dependent on their Initial Level and Stress Concentrations.

Stress concentration and level of external load are studied for their effect on variation of residual stresses under cyclic loading. It is established that external loading leads to stabilization of the stress state of the specimen with and without initial residual stresses as early as at the first loading cycles. It is shown that effect of initial residual stresses on fatigue resistance of structural elements is determined by a difference in the levels of steady residual stresses in the zones of concentrators with and without initial stresses. Evaluation of the significance of residual stresses in fatigue processes proceeding from the obtained regularities and linearized ultimate stress diagrams of welded joints without residual stresses well agrees with results of fatigue tests performed on welded specimens with and without initial residual stresses.