Fatigue Growth Analysis of a Surface Crack in a Solid Cylinder under Combined Cyclic Axial-Torsion Loading

In this paper, fatigue growth analyses of a surface crack in a solid cylinder under combined cyclic axial-torsion loadings through experimentation and numerical simulation are presented. The experimentation includes the preparation of inducing an initial surface crack in the specimens and the fatigue crack growth testing using a table top axial-torsion servo-hydraulic dynamic testing machine. The numerical modeling for the fatigue crack growths was simulated by using a dual boundary element method software package. The crack growth paths and the fatigue lives for different loading cases and crack aspect ratios obtained from the experiments were shown to be in good agreements with those by the numerical simulations. The changes of the angles of the crack growth direction predicted by the numerical simulations and the fracture surface condition of the specimens are also presented and discussed.