Fretting fatigue crack growth for a spherical indenter with constant and cyclic bulk load

Fatigue growth of edge cracks subjected to non-proportional fretting loads was investigated experimentally and numerically. The cracks were produced during fretting experiments with a spherical contact between two α + β titanium alloys. Constant normal load was combined with cyclic tangential load and constant or cyclic bulk load. Crack propagation was detected during the experiments by strain gauges on the specimen surface and acoustic emission measurements. A parametric crack growth description procedure was used to model fatigue growth of the three-dimensional fretting cracks that were loaded with multiaxial and non-proportional stresses from the fretting contact. The predicted crack growth lives and crack shapes agreed with the experimental results. A crack path prediction based on the maximum principal value of the stress range tensor Δσij was evaluated.