FATIGUE-CRACK GROWTH IN RESIDUAL-STRESS FIELDS - EXPERIMENTAL RESULTSAND MODELING

The paper discusses the results of fatigue crack growth rate tests con ducted in the presence of residual stresses. Three different residual stress distributions, obtained by laser welds, were employed in order to characterize the crack propagation behavior under different conditi ons, producing either an increase or a reduction of the stress intensi ty factor due to external loads. Test results are analysed by means of a non-linear numerical model (based on the weight function method) an d a knowledge of the fatigue crack growth properties of the base mater ial, free from residual stresses. The results of the analysis are disc ussed with reference to experimental trends, in order to clarify the p redictive capabilities of the method and aspects needing further inves tigation.