Partial Slip Contact of Materials with Vertically Aligned Cracks Near Surface

Abstract This study developed a numerical model for partial slip contact of fractured substrates with embedded cracks aligned vertically. Each crack is assumed in mixed modes I and II, and crack faces remain separated with their tips closed. The discrete dislocation technique is adopted to simulate the crack by a distribution of climb and glide dislocations with unknown densities, which are iteratively determined in a subroutine based on the conjugate gradient method. Tangential displacements induced by dislocations are integrated into the model to investigate the crack effects on the tractions in slip and stick regions. The stress intensity factors (SIFs) are determined based on the solutions of dislocation densities. The model is capable of solving problems concerning multiple cracks with the consideration of interactions among cracks and contact bodies, and the effects of cracks on the loading distribution and stress fields are discussed in detail. It is found out that the contact loading produces a tendency of closing crack faces and a vertical crack prevents surfaces from deforming. The interactions of the normal and tangential forces lead to the shift of the stresses along the frictional direction. The conclusions may provide fundamentals for fretting fatigue damage and offer insightful ideas for fracture behaviors.