Experiments have been performed on a series of 2024-T351 Aluminum alloy uniaxiaf, tension specimens loaded under R = 0 conditions to grow a low cycle fatigue crack to a predetermined length. One half of the specimens were given a 33% single pulse overload at the conclusion of the test. All specimens were sectioned along the plane of the crack and measurements made of the residual displacements occurring at this location due to the relief of the internal stresses produced during crack propagation and overload. The data was used as the boundary condition in a Displacement Boundary Value Problem solving an Airy Stress Function for the residual stress distribution in the vicinity of the crack.
The results indicate a significant degree of tensile stress ahead of the crack tip and compressive stresses both at the crack tip and in the wake of the crack reaching magnitudes as high as 34% of the yield stress.
The results are consistent in both the overload and no overload cases however the magnitude and extent of the compressive stress regron appears to be increased by the action of the overload. These results are consistent with the concept of crack closure as proposed by Elber.