An approach for prediction of fatigue strength of shot peened components

In this paper the problem of predicting and optimising the fatigue strength of shot peened specimens is dealt with. A series of notched cylindrical specimens, peened by using different parameters, was fatigue tested, being the aim to determine the improvement of the fatigue limit of the treated specimens. After the tests, the specimens were observed at the SE microscope and non-propagating microcracks were found. On the basis of this experimental evidence it was considered that the fatigue alleviation due to shot peening is mainly due to the ability of stopping crack propagation. A finite element procedure of the cracked notched specimens was established, with the aim of calculating the stress intensity factor including the applied load, the residual stresses and the contact between the crack faces. The results enable the prediction of the improvement of fatigue strength due to shot peening.