Dislocation-Cracks Interaction During Fatigue: A Discrete Dislocation Dynamics Simulation

摘要

In this article, the effect of different shape cracks on fatigue behavior in metals is investigated with the help of the discrete dislocation dynamics technique. The cracks are represented as distributions of infinitesimal dislocation loops. The distribution is determined by an integral equation satisfying stress-free boundary conditions and containing a singular kernel of the third type. The stress field in the cracked domain is calculated using a superposition principle coupled with an iterative technique. The derived stress fields describe the interaction between the cracks and the dislocations into the framework of dislocation dynamics. The simulation results provide an insight on the three-dimensional character of the dislocation structure around the cracks and its relation to the crack shapes. The effect of the cracks on the macroscopic yield stress is also determined for various crack sizes and shapes.