Dynamic response analysis and vibration reduction of a 10-MW jacket offshore wind turbines under the combined wind and ice loads

This study investigates the structural dynamics of a 10 MW jacket-type offshore wind turbine (OWT) subjected to combined sea ice and wind loads. Utilizing the LS-DYNA software, the OWT model is constructed with aerodynamic loads computed through the blade element momentum (BEM) method and stochastic ice loads derived from the KARNA ice force spectrum. These forces are exerted externally on the OWT model. Various wind-ice scenarios are simulated to uncover the dynamic response patterns of the OWT in areas susceptible to ice. The research introduces an innovative structure employing concrete-filled double-skin steel tubes (CFDST) instead of the original hollow legs to reduce vibrations in icy conditions. An analysis of displacement and acceleration at three critical locations (the tower top, the platform top, and the pile leg top) indicated that under combined wind-ice conditions, the innovative structure diminishes peak displacements and accelerations by at least 30%. The entire structure demonstrates a notable reduction in vibrations, offering a theoretical foundation for implementing CFDST composite structures in offshore wind turbines located in ice-prone areas.