Resilient Offshore Wind Turbine Tower Segment with Enhanced Ductility: Hybrid Modelling and Seismic Performance
摘要
The installation of jacket-type offshore wind turbines (JOWTs) in seismically active regions has rapidly increased in recent years, raising concerns regarding their seismic safety in both industry and academia. To improve the seismic performance of JOWTs, this study proposes a resilient tower segment design based on the widely used ductile seismic design philosophy. The enhanced ductility and energy dissipation of the proposed design are achieved by introducing a ductile tower segment (DTS) with reduced section and stiffeners, which concentrates nonlinear deformations, combined with self-centring viscous dampers (SCVD) for meeting resilient objectives. A hybrid numerical model is developed by combining hysteretic model of the DTS based on detailed finite element simulations and the simplified JOWT model to facilitate the nonlinear dynamic analysis of the resilient JOWT, and the accuracy and efficiency of the proposed model are confirmed. Nonlinear dynamic analyses are performed based on a suite of long-period ground motions at two intensity levels. The benefits of the resilient JOWT in seismic mitigation over the 10-MW JOWT prototype are evaluated through a comparative study. The results show that the resilient JOWT design can improve the seismic performance of JOWTs in terms of serviceability under low-intensity earthquakes and collapse prevention under major earthquakes. Moreover, the hysteretic behaviour of the DTS-SCVD assembly has a significant influence on the seismic performance of JOWTs, showing the prospect of performance optimisation by modulating the structural parameters.