Digital Twins-based deterioration prognosis of wind turbine tower under wind-wave-corrosion

The Modular Energy Islands (MEI) concept illustrates promising potential in exploiting the plentiful Aeolian source at deep-water ocean through wind turbines, combined with other types of sustainable energies as are e.g. solar and wave ones. At the same time, the innovation of MEIs encounters a list of structural challenges due to the strong wind-wave loads and escalating corrosivity. Especially, the wind turbine tower with a fast-growing height becomes highly prone to corrosion-fatigue (C-F) deterioration in such harsh conditions. The present work proposes a digital twins-based prognosis approach to offer novel insights into the C-F deterioration of wind turbine towers in MEIs exposed to wind-wave-corrosion. At first, a C-F deterioration model is constructed in a coupled manner at the mechanism level based on experimental findings. Then, multi-physics simulations are carried out to derive the fatigue stress from the measured wind-wave spectrum. Similarly, the environment corrosivity is estimated from the site conditions, with the help of test data. On this basis, the most deterioration sensitive detail, i.e., the bolts in tower flanges, is investigated in depth. The results highlight not only the prominent sensitivity of bolt deterioration to wind-wave distribution, but also the remarkable influence by the coupled C-F effect.