Predicting crack growth in specimens with overloads and cold-worked holes with residual stresses

• Fatigue crack growth in two aluminum alloys with residual stresses was analyzed.
• Effects of compressive residual stresses on crack growth due to overloads were modeled.
• Effects of compressive residual stresses on crack growth due to cold-worked holes were modeled.
• Plasticity-induced crack-closure model was able to predict effects of residual stresses on crack growth.
• Linear superposition greatly over predicted life on cold-worked holes specimens.

The FASTRAN life-prediction code was used to predict crack growth in specimens with compressive residual stresses on two aluminum alloys. All test data were obtained from the literature on middle-crack-tension or on specimens with a single through crack at an open hole. Specimens tested by Liu induced residual stresses by remote overloads, whereas the specimens tested by LaRue induced residual stresses by cold-expansion of the hole. Some modifications were made to FASTRAN to improve the residual-stress distribution and to simulate reaming of cold-worked holes. Overloads of specific magnitudes were applied to the FASTRAN strip-yield model to generate residual stresses that simulate those calculated from finite-element analyses from the literature. FASTRAN was then used to make fatigue-crack-growth predictions under residual-stress fields that compared fairly well with test results from the two aluminum alloys.