Effects of various fairlead-connection parameters on chain-mooring OPB-induced failure

In this paper, the effects of underwater-chain-stopper (UCS) bearing friction at fairlead connection and time-varying interlink EI (bending stiffness) at the UCS exit on the OPB-fatigue-induced chain failure are investigated. To demonstrate their effects through numerical simulations, three different approaches, such as only considering time-varying EI, considering both time-varying EI and fairlead bearing friction, and neither considered, are modeled and the results are systematically compared. With fairlead bearing friction, the fairlead boundary condition is adjusted during the time-marching simulation according to the criterion between UCS angle and breakout angle. The numerical results show that the fairlead bearing friction plays much more important role than time-varying EI in significantly increasing OPB-induced fatigue damage, which is due to the significant increase of interlink angle and bending moment by the former especially at taut side. Furthermore, the present approach considering both time-varying EI and fairlead bearing friction is compared with widely adopted BV (Bureau Veritas) methodology. Also, since fairlead bearing friction effect is coupled with UCS bending stiffness, the bending moments and fatigue damages at UCS exit for various UCS bending stiffness are compared. Finally, the effects of residual stresses at hot-spots on OPB-induced fatigue damage are investigated.

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  • English

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  • Accession Number: 01762766
  • Record Type: Publication
  • Files: TRIS
  • Created Date: Dec 31 2020 3:21PM