Total fatigue lives, crack growth paths and cycles in cold expanded adjacent holes.

We need to predict the fatigue crack behavior for estimating the useful life of the components. Also, introducing the compressive residual stresses with some proper methods such as the cold expansion of holes can improve the fatigue life. Interaction of adjacent holes changes the values and distributions of created residual stresses and so their effects on the fatigue life. In this paper, we have studied the induced residual stress due to the cold expanding of two adjacent holes. Beneficial effects of the compressive residual stresses on the total fatigue lives and crack initiation cycles are investigated by using the numerical simulations and experimental tests. Some parameters as the hole geometries, expansion ratio and crack locations can affect the fatigue behavior. Results show that the expansion ratio has variable effects in comparison with other parameters. Reduction in distance between adjacent holes decreases the total and crack growth lives. 2D finite element model can precisely predict the fatigue growth of mixed mode through cracks in thin plates in the presence of the residual stress. [ABSTRACT FROM AUTHOR]