Interaction between Short Surface Cracks and Residual Stress Field in Shot Peened Titanium Samples

To enhance the fatigue life of metal components, frequently compressive stress is introduced to the surface layer. Although procedures such as shot peening have been practiced for many decades in other industries, an improved understanding of the fundamental mechanics that leads to the improved performance is desired. From a continuum mechanical point of view, the interaction between the crack and the stress intensity field is the factor determining whether the crack will propagate. Of special interest for fatigue performance is the propagation behavior of microstructurally short cracks, where the energy release rate, G, is smaller than the threshold value, Gth. For this presentation Abaqus/Standard has been used to calculate J-integral values for different ratios of crack length and compressive residual stress depth, as well as different residual stress magnitudes.