Fretting failure of a pressure armour in an unbonded flexible riser

In the present paper, the failure of a pressure armour in a flexible riser under fretting wear loading is analysed. Fretting lifetime is evaluated through the multiaxial fatigue criterion by Carpinteri et al., implementing the critical direction method proposed by Araujo et al. to define the orientation of the critical plane. The fretting map (in terms of number of loading cycles to failure against displacement amplitude) is build starting from the simulation results of some fretting wear tests in partial slip regime. Then, such a map is compared with that determined by means of the results derived through a combined experimental and numerical methodology available in the literature.