Theoretical modeling of crack arrest by inserting interference fit fasteners

The repair technology under consideration involves drilling a number of holes along a crack in a metal part and inserting fasteners (bolts, rivets, or pins) into the holes with a predetermined interference fit. A fracture mechanics-based model is proposed to study the decrease in the crack growth rate after repair. A parametric analysis is performed to discover the effect of geometry and materials on crack retardation. Elastic-plastic contact stress distributions in the specimens during cyclic loading are determined by the finite element method. The results show that a significant enhancement of fatigue life until crack re-initiation can be achieved through an optimal set of parameters: number of fasteners, their material, and interference fit. The model is validated using a comparison of fatigue tests of the specimens.