This combined experimental and analytical study was directed at determining the growth and shape change of surface flaws under axial loading as compared with crack growth data obtained from simple compact tension specimens. The experimental effort aimed at measuring surface flaw crack growth rates for 2219-T851 aluminum specimens. Tests were conducted using constant-amplitude loading with marker bands to measure crack front shape changes.
The analytical effort evaluated available crack growth models and stress-intensity solutions and their ability to predict the growth and shape change of surface flaws. The characterization of surface flaws as semiellipses and the independence of crack growth rate and direction were addressed. The resulting model was successful in predicting growth and shape changes under most conditions. However, due to the variation between surface and depth crack growth rates for surface flaws, it was determined that crack growth data from compact tension specimens could not generally be used to characterize the growth of surface flaws.