Numerical implementation and feasibility of DYNEEMA® HMPE tendons for floating offshore wind tension leg platforms and the effect of viscoelasticity

• Novel methodology to calibrate a synthetic based mooring system. • Demonstrated the capability to model intrinsic material properties of Dyneema. • Fibre’s intrinsic damping property shows potential benefits for structural fatigue. • Comparison shows feasibility of synthetic mooring for a tension leg platform. Bluewater Energy Services B.V. (BES) and Dyneema®, owned by Avient, investigated the feasibility of using Dyneema®high modulus polyethylene (HMPE) tendons for tension leg platforms (TLP) for floating offshore wind applications (FOW). To do so, time domain simulations are performed using OrcaFlex, where the behaviour of HMPE is modelled by an external function named D3TRM that allows to properly capture its viscoelastic behaviour, with the involved dependence on time, temperature, and tension (3T). For the time domain simulations, a combination of Fatigue Limit State (FLS) and Ultimate Limit State (ULS) environmental loading conditions are applied to the floating platform and wind turbine generator and the performance of HMPE is quantified by comparing it to the performance of the mooring system using steel strand wire (SSW). This work provides background on the viscoelastic model, and discusses the analysis of the TLP in full detail, showing that the use of HMPE parallel wound tendons is feasible for mooring of TLPs.