Effects of cyclic frequency and contact pressure on fretting fatigue under two‐level block loading

Abstract

Fretting fatigue tests involving the contact of flat and cylindrical titanium alloy Ti–6Al–4V surfaces, and constant‐ and two‐level block remote bulk stresses are described. The constant‐amplitude tests have been performed at cyclic frequencies of 1 and 200 Hz. The two‐level block spectra involve the superposition of a 1‐Hz, low‐cycle fatigue (LCF) constant‐amplitude component and a 200‐Hz, high‐cycle fatigue (HCF) component. Two values of contact pressure are considered. The cyclic frequency of 200 Hz is found to curtail the constant‐amplitude fretting fatigue life regardless of the contact pressure applied. Increasing the contact pressure reduces life at 1 Hz but does not have any effect at 200 Hz. Under two‐level block loading, the fretting fatigue life is determined primarily by the stress amplitude and high‐cyclic frequency of the HCF component of the load spectrum. The LCF component is found to play a secondary role in the determination of the two‐level block fretting fatigue life. Fracture topographies for the different test conditions are documented.