Impact of surface topography on torsional fretting wear of the blade bearing interface under different lubrication conditions

Torsional fretting wear properties of the blade bearing interface were studied with varying initial surface morphologies. Tests were carried out with flat on flat contact, in the gross slip regime and under different lubrication conditions. Results show that with the increase of surface roughness, the friction torque decreases and increases respectively under the lubricated and dry fretting conditions. The wear volume was higher for the rougher surface in all the tests. In oil and artificial seawater, the wear mechanism was mainly abrasive wear; under dry fretting, it was a combination of abrasion, adhesion and oxidation. Based on the surface topography effect on the pitch adjustment flexibility and dynamic sealing performance of the CPP, surface topography of the blade bearing interface was optimized to be with the texture direction perpendicular to the relative movement direction, and S _a in the range of 0.8 to 1.2 μm.