The investigation of fatigue crack initiation is important to get a fundamentally better insight in fatigue. It has been established experimentally that dislocations play a vital role in this context. We use discrete dislocation dynamics to build a model for fatigue crack initiation from a surface grain. Dislocations are modeled as line singularities in an elastic medium where they can be nucleated, glide or annihilate. The simulation reveals several features that could give rise to fracture initiation and dislocation structure formation. Three different, potential areas of fracture —surface, grain interior and grain boundary— are found which correspond to those found in experiments. The computational expenses currently limit the number of cycles that can be simulated, and therefore do not allow yet for a comparison with experimental results.
|University of Groningen, The Zernike Institute for Advanced Materials
|Published - 2003