An experimental study on the key fretting variables for flexible marine risers

O�Halloran, S.M.; Harte, A.M.; Shipway, P.H.; Leen, S.B.

Abstract

This paper presents an experimental investigation into the effects of contact conformity, contact pressure and displacement amplitude on the gross-slip fretting behaviour grease-lubricated cylinder-on-flat contacts in the context of flexible marine riser pressure armour wire, and compares behaviour with that observed in unlubricated conditions. Characterisation of friction and wear is critical to fretting fatigue life prediction in flexible risers since friction directly controls trailing-edge fretting stresses and hence fatigue crack initiation, on the one hand, and on the other hand, directly affects wear via relative tangential slip (displacement). Wear can have a beneficial or detrimental effect on fatigue crack initiation and propagation, depending on relative slip and slip regime. It is shown that friction and wear are higher for dry conditions than for grease-lubricated conditions. For grease-lubricated conditions, behaviour is determined by whether grease can be retained in the contact (as opposed to being extruded out). Retention (or replenishment) of grease in the contact results in low rates of wear and low coefficients of friction; these conditions are favoured by fretting displacements above a critical value, by low contact conformity, and by low applied loads.

Citation

O’Halloran, S., Harte, A., Shipway, P., & Leen, S. (2018). An experimental study on the key fretting variables for flexible marine risers. Tribology International, 117, https://doi.org/10.1016/j.triboint.2017.07.032

• Journal Article Type: Article
• Acceptance Date: Jul 31, 2017
• Online Publication Date: Aug 2, 2017
• Publication Date: Jan 1, 2018
• Deposit Date: Aug 1, 2017
• Publicly Available Date: Aug 2, 2017
• Journal: Tribology International
• Print ISSN: 0301-679X
• Electronic ISSN: 1879-2464
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 117
• DOI: https://doi.org/10.1016/j.triboint.2017.07.032
• Keywords: Fretting wear, experimental, grease-lubrication, contact geometry, slip amplitude, flexible risers, pressure armour layer, nub-groove
• Public URL: https://nottingham-repository.worktribe.com/output/963466
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S0301679X1730378X
• Contract Date: Aug 1, 2017