Fractography, NDE, and fracture mechanics applications in failure analysis studies

Residual Stress Measurement and the Slitting Method

“…Thus, shot-peening in this case is harmful and the opening of the flaw tip makes it more susceptible to cyclic loading. Furthermore, the detection of the surface flaw by dye penetrant techniques [83] becomes very difficult due to closed flaw faces under compressive residual stress. Residual stress not only affects the initiation and onset of the propagation of surface cracks but also changes the path/growth of a crack as it grows below the surface.…”

“…Also, if parts containing surface cracks are exposed to processes, such as shot peening, which induce high, near surface compressive stresses, the internal end of the crack will experience tensile loading. What is often ignored is that the compressive stresses close the crack at the surface and make it more difficult to detect by dye penetrant techniques [83]. An attempt is made here to quantify these observations using procedures based on linear elastic fracture mechanics (LEFM).…”