Data from: The interaction of fatigue cracks with a residual stress field using thermoelastic stress analysis and synchrotron x-ray diffraction experiments

This article presents an experimental study on the fatigue behaviour of
cracks emanating from cold-expanded holes utilising thermoelastic stress
analysis (TSA) and synchrotron x-ray diffraction (SXRD) techniques with
the aim of resolving the long-standing ambiguity in the literature
regarding potential relaxation, or modification, of beneficial compressive
residual stresses as a result of fatigue crack propagation. The crack
growth rates are found to be substantially lower as the crack tip moved
through the residual stress zone induced by cold expansion. The TSA
results demonstrated that the crack tip plastic zones were reduced in size
by the presence of the residual compressive stresses induced by cold
expansion. The crack tip plastic zones were found to be insignificant in
size in comparison to the residual stress zone resulting from cold
expansion, which implied that they were unlikely to have had a notable
impact on the surrounding residual stresses induced by cold expansion. The
residual stress distributions measured along the direction of crack
growth, using SXRD, showed no signs of any significant stress relaxation
or redistribution, which validates the conclusions drawn from the TSA
data. Fractographic analysis qualitatively confirmed the influence on
crack initiation of the residual stresses induced by the cold expansion.
It was found that the application of single compressive overload caused a
relaxation, or reduction in the residual stresses, which has wider
implications for improving the fatigue life.