On the Effect of Contact Geometry on Fretting Fatigue Life Under Cyclic Contact Loading

Most of the previous studies on fretting fatigue have been accomplished under constant contact load condition, and a less attention has been paid to cyclic contact load. That is the case in many engineering applications such as bearing cap bolted joints of the V-type engines and dovetail joint of turbines. In this study, the effect of contact geometry on fretting fatigue behavior of Al7075-T6 under cyclic normal contact loading is investigated by experiment, numerical simulation and analysis. Two contact types including flat-on-flat and cylinder-on-flat are considered in this study. The crack initiated at a lower cycle for cylinder-on-flat contacts. It was found that in comparison with the constant contact loading condition, the cyclic contact loadings have more damaging effect on fretting fatigue life, particularly for cylinder-on-flat contact. With the increase in the pad width, fretting fatigue life increased for flat and cylindrical pads, particularly for high cycle fatigue (HCF) conditions. Examination of the fretting scars was performed using optical microscopy. Crack propagation life was determined by numerical simulation using the commercial FE codes ABAQUS® and FRANC2D/L®. Crack initiation life was calculated by a combination of numerical simulation and experiment.