Multiaxial fretting fatigue testing and prediction for splined couplings

This paper presents a combined experimental and computational methodology for fretting fatigue life prediction of aeroengine splined couplings under combined loading cycles involving cyclic torque and axial load, as well as rotating bending and fluctuating torque. The experimental method is based on the concept of a simplified representative test, which mimics the multiaxial fretting conditions between spline teeth via biaxial loading of specially-designed bridge pads and a fatigue specimen. The numerical method is based on a three-dimensional finite element model of the test rig assembly, including frictional contact effects, along with a multiaxial, critical-plane fatigue parameter for crack nucleation followed by crack growth prediction in the Paris regime using El Haddad small crack correction. The prediction methodology is shown to successfully capture the effect of the key fretting fatigue stress, which mimics the spline rotating bending moment, on total fatigue life.