IEA 22 MW Semi model redesigned for fatigue.
The IEA 22 MW Semi-submersible is a key reference model for floating wind and reflects the industry’s upscaling trend toward larger rotors and taller towers. Its original release did not include a tower configuration evaluated under fatigue constraints.
This repository provides the first fatigue-oriented redesign of the IEA 22 MW floating tower, FLOAT-22-280-RWT-Semi, enabled entirely by FLOAT, our lightweight fatigue-aware design optimization framework.
- João Alves Ribeiro (MIT & University of Porto) — jpar@mit.edu
- Francisco Pimenta (University of Porto)
- Bruno Alves Ribeiro (TU Delft & Brown University)
- Sérgio M. O. Tavares (University of Aveiro)
- Faez Ahmed (MIT) — faez@mit.edu
The FLOAT-22-280-RWT-Semi is documented in full detail in the scientific paper FLOAT: Fatigue-Aware Design Optimization of Wind Turbine Towers, where the tower, the optimization process, and the validation are presented.
Using FLOAT, the IEA 22 MW floating reference tower was redesigned under fatigue constraints, achieving:
- Fatigue damage reduction: at the tower base, damage decreases from 32.1 → 0.8 (~98% reduction); at the tower top, from 3.5 → 0.9 (~73% reduction)
- Fatigue lifetime extension: from ~9 months to 25 years (~33× increase)
- Geometry change: tower base diameter increases from 10 m → 12 m, which raises the tower mass from 1,574 t to 2,656 t (~69% increase) to satisfy fatigue requirements
- Validation: redesign verified through 6,468 coupled wind–wave high-fidelity OpenFAST simulations
The redesigned tower introduces a new geometric profile driven by fatigue requirements:
The figure below shows how the fatigue damage distribution decreases when moving from the original IEA-22-280-RWT-Semi tower to the fatigue-optimized FLOAT-22-280-RWT-Semi design:
This repository includes for the FLOAT-22-280-RWT-Semi:
- OpenFAST aeroelasic model inputs (OpenFAST version 3.5.2): see OpenFAST.
- WindIO turbine ontology file: see WindIO.
This repository introduces a new fatigue-oriented tower for the *IEA-22-280-RWT-Semi and updates the platform mass to remain dynamically consistent with the baseline model. The following input files are modified:
- FLOAT-22-280-RWT-Semi_ElastoDyn_tower.dat: Updated tower properties (TMassDen, TwFAStif, TwSSStif) while retaining the original mode shapes.
- FLOAT-22-280-RWT-Semi_ElastoDyn.dat: Updated platform mass (PtfmMass) and adjusted it by subtracting the additional weight introduced by the new tower.
- FLOAT-22-280-RWT-Semi.fst: Updated OpenFAST primary file to reference the new tower and ElastoDyn inputs.
All remaining OpenFAST input files remain unchanged and follow the original model.
The theoretical background and validation of the tower are fully presented in the FLOAT paper.
This project is licensed under the Apache License 2.0.
See the LICENSE file for full details or view it online at: Apache License 2.0.
If you use FLOAT-22-280-RWT-Semi in your work, please cite:
FLOAT: Fatigue-Aware Design Optimization of Wind Turbine Towers.
João Alves Ribeiro, Francisco Pimenta, Bruno Alves Ribeiro, Sérgio M. O. Tavares, Faez Ahmed.
arXiv:2502.02594, 2025.
https://arxiv.org/abs/2502.02594
BibTeX
@article{ribeiro2025float,
title = {FLOAT: Fatigue-Aware Design Optimization of Wind Turbine Towers},
author = {Ribeiro, Jo{\~a}o Alves and Pimenta, Francisco and Ribeiro, Bruno Alves and Tavares, S{\'e}rgio M. O. and Ahmed, Faez},
journal = {arXiv preprint arXiv:2502.02594},
year = {2025}
}For issues, questions, or feature requests related to FLOAT-22-280-RWT-Semi: FLOAT-22-280-RWT-Semi Issues.
We thank Garrett Barter, Pietro Bortolotti, and Daniel Zalkind from the National Renewable Energy Laboratory (NREL) for their insightful discussions and technical guidance.
This project builds upon the IEA-22-280-RWT reference wind turbine. We acknowledge the IEA Wind Task 55 REFWIND team for developing and openly releasing the foundational open-source model that enabled this work.