Dynamic ice loads for offshore wind support structure design

For offshore wind farms which are planned in sub-arctic regions like the Baltic Sea and Bohai Bay, support structure design has to account for load effects from dynamic ice-structure interaction. There is relatively high uncertainty related ice loads as little no load- response data of turbines exposed drifting exists. In present study potential development ice-induced vibrations an turbine on monopile foundation experimentally investigated. The experiments aimed reproduce at scale interaction idling operational 14 MW with representative 50-year return period Southern conditions. A real-time hybrid test setup was used allow incorporation specific modal properties action point, well virtual loading. showed that all known regimes develop depending magnitude drift speed. At low speed this intermittent crushing intermediate speeds ‘frequency lock-in’ second global bending mode turbine. continuous brittle found. new finding regime a strongly amplified non-harmonic first-mode structure, combined higher modes after moments failure. develops between where frequency lock-in develop. can be turbine, third easily excited point. Preliminary numerical simulations phenomenological model coupled full show result largest large part structure. Frequency significantly smaller throughout