Nonlinear dynamical behaviour of jacket supported offshore wind turbines in loose sand

A spectrum of wind speeds are considered, increasing from the cut-in value of 3 m/s to an extreme case of 45 m/s. Response charts have been proposed in terms of rotations at various levels of the jacket, to serve as design-aids for similar structures. The effect of SSI becomes predominant for OWT in loose sands (with friction angle less than 30∘). Parametric resonant responses have been observed for the jacket in loose sands, in the region bounded by the rated and cut-out wind speeds.