Computationally efficient modelling of short fatigue crack growth using dislocation formulations

In an attempt to develop a computationally efficient model for simulation of fatigue crack growth of microstructurally short cracks two dislocation based models have been compared. In both models, the geometry of the boundary and the crack is described using dislocation dipole elements, whereas the plasticity is described either by discrete dislocations or by distributed dipole elements. The two models were found to agree qualitatively as well as quantitatively. It was concluded that modelling the plasticity by dipole elements becomes comparatively increasingly more time efficient with increasing grain size plastic zone size. However, plasticity modelling by dipole elements showed to provide somewhat higher crack growth rates.