3D FE dynamic modelling of offshore wind turbines in sand: natural frequency evolution in the pre– to after-storm transition

3D FE dynamic modelling of offshore wind turbines in sand: natural frequency evolution in the pre– to after-storm transition

Kementzetzidis, E. (TU Delft Offshore Engineering)
Versteijlen, Willem Geert (Siemens Gamesa Renewable Energy)
Nernheim, Axel (Siemens Gamesa Renewable Energy)
Pisano, F. (TU Delft Geo-engineering)

Cardoso, António S. (editor)
Borges, José L. (editor)
Costa, Pedro A. (editor)
Gomes, António T. (editor)
Marques, José C. (editor)
Vieira, Castorina S. (editor)

2018-06-27

3D non-linear finite element analyses are proving increasingly beneficial to analyse the foundations of offshore wind turbines (OWTs) in combination with advanced soil modelling. For this purpose, the well-known SANISAND04 bounding surface plasticity model (Dafalias & Manzari 2004) is adopted in this work to incorporate key aspects of critical state soil mechanics into the analysis of monopile foundations in sand. The final 3D soil-foundation-OWT model is exploited to simulate the response of an 8 MW OWT to a long loading history of approximately 2 hours duration. The scope is to investigate/explain the drops in natural frequency observed in the field during storms, as well as its subsequent recovery. The numerical results point out a strong connection between transient frequency drops and pore pressure accumulation, whereas the original OWT natural frequency seems to be restored as a consequence of post-storm re-consolidation.

http://resolver.tudelft.nl/uuid:be363010-02d9-4896-bab6-161e4e85f9ff

9781138544468

9th European Conference on Numerical Methods in Geotechnical Engineering, 2

NUMGE 2018: 9th European Conference on Numerical Methods in Geotechnical Engineering, 2018-06-25 → 2018-06-27, Porto, Portugal

Institutional Repository

conference paper

© 2018 E. Kementzetzidis, Willem Geert Versteijlen, Axel Nernheim, F. Pisano