graduate research assistantSenior research engineer, University of Illinois at Urbana ChampaignCaterpillar Inc., Technical Center, Peoria, IL
Professor, University of Illinois at Urbana-Champaign, Urbana, IL
Pages: 17 Published: Jan 1999
A 2-D analytical model of the combined effects of plasticity-induced crack closure (PICC) and roughness-induced crack closure (RICC) has been developed. A zigzag crack growth path was employed to simulate surface roughness. The two opposing fatigue crack surfaces were translated by the mixed-mode displacement occurring near the deflected crack tip. This translation caused a mechanical interference of the opposing crack surfaces as the crack closed, that is, caused RICC. The gradual transition from RICC- to PICC-dominated crack closure was handled naturally by this model. The influence of the geometrical features of the surface roughness, R-ratio, and the cyclic load range on RICC were examined using the PICC-RICC model. The effect of microstructure on the RICC was examined. Despite the simple, 2-D nature of the model, it predicted the trends of experimental data on near-threshold crack growth behavior reported in the literature.
fatigue, small crack, crack closure, roughness, plasticity, near-threshold crack growth, microstructure, grain size
Paper ID: STP14968S