In-phase and out-of-phase combined bending-torsion fatigue of a notched specimen

An experimental study of the high-cycle biaxial fatigue behavior of notched specimens is reported. Solid round bars of 1%Cr-Mo-V steel having a circumferential semicircular groove were tested under fully reversed constant-amplitude bending, torsion, and combined bending and torsion, in-phase, and 90 degrees out-of-phase. Smooth specimens of the same material were also tested under bending as well as torsion to provide baseline data. Observed fatigue life data are used to evaluate several multiaxial fatigue life prediction models, including a critical plane method, a von Mises approach, and an energy-based approach. Crack growth behavior as observed on the surface in smooth and notched specimens is presented and discussed.