A combined wear-fatigue design methodology for fretting in the pressure armour layer of flexible marine risers

This paper presents a combined experimental and computational methodology for fretting wear-fatigue prediction of pressure armour wire in flexible marine risers. Fretting wear, friction and fatigue parameters of pressure armour material have been characterised experimentally. A combined fretting wear-fatigue finite element model has been developed using an adaptive meshing technique and the effect of bending-induced tangential slip has been characterised. It has been shown that a surface damage parameter combined with a multiaxial fatigue parameter can accurately predict the beneficial effect of fretting wear on fatigue predictions. This provides a computationally efficient design tool for fretting in the pressure armour layer of flexible marine risers.The authors would like to thank the Irish Research Council and Wood Group for funding of this project through the Enterprise Partnership Scheme (EPSPG/2013/638), and the National University of Ireland for funding through an NUI Travelling Scholarship. We also wish to acknowledge the help and support we have received from Mr. Kieran Kavanagh (Wood Group Kenny), the NUI Galway Engineering Building technical staff; particularly Mr. Bonaventure Kennedy and Mr. Patrick Kelly and the Faculty of Engineering at the University of Nottingham