Optimizing Wind Turbine Blade Operations & Maintenance: an experimental campaign in ETH Zurich
NexSys PhD student Theodorus Varouxis, based in UCD’s School of Civil Engineering, tells us about his recent research visit in ETH Zurich. This extended research visit was supported by the NexSys research programme. Dr. Abdollah Malekjafarian is Theo's supervisor, with Theo's research contributing to the Offshore Wind research investigating different aspects of "Structural Health Monitoring (SHM) and System Identification (SI) of Floating Wind Turbines."
At the end of 2023 , I had the privilege of taking part in pivotal and exciting research at ETH Zurich's prestigious laboratory facilities over several months. This journey was not just a personal achievement but a venture into advancing the methods for detecting structural damages in wind turbine blades—an essential step toward making renewable energy even more sustainable.
Detecting damage on turbine blades
Using the Aventa AV-7 wind turbine blade (part of the Aventa AV-7 wind turbine sold as the ‘Leichtwindanlagen©’ Light Wind Turbine), my research focused on employing data-driven and hybrid models to detect incremental structural damages on a full-scale blade. Exploring the potential of different sensing methodologies and excitation schemes. This will offer valuable insights into monitoring practices that can later by applied to any wind turbine that’s in operation.
An Immersive Experience
The research visit, spanning October to December 2023, was planned and executed under the guidance and support from Prof Eleni Chatzi the Chair of Structural Mechanics at the Institute of Structural Engineering, ETH Zurich, and her dedicated team. Dr Imad Abdallah, Dr Vasilis Dertimanis and Mr Dominik Werne, distinguished members in the Chair of Structural Mechanics supported me with excellent technical guidance as well. Dr Abdallah’s extensive experience working with wind turbines both in industry and academia was pivotal in formulating the experiments and Dr Dertimanis’ and Mr Werne’s contribution to setting up the experimental setups was invaluable.
The chair’s expertise in structural mechanics and health monitoring provided me with invaluable insights and elevated the quality of experimental outcomes. From the outset, the lab's sophisticated setting demanded rigorous preparation. Before I could dive into the practical aspects, I completed a laboratory safety course to familiarize myself with the stringent safety protocols and operational procedures of the lab—a testament to ETH Zurich's commitment to maintaining high standards as a leading institution globally.
Figure 1. A picture with Prof. Eleni Chatzi (left), myself (middle) and Dr Imad Abdallah (right) in front of the instrumented Wind Turbine Blade.
Challenges and Triumphs
The experimental setup involved securing the turbine blade on a sturdy wall-like structure and instrumenting it with state-of-the-art sensors - accelerometers, strain gauges and a real-time deflection measuring system. A significant challenge was adapting the blade's geometry to the electromechanical shaker used for exciting the blade. The process also involved the design and fabrication of a custom aluminium piece, that was later glued on the blade’s surface, to ensure compatibility.
Figure 2. Picture of the instrumented blade. The process of securing the custom aluminium piece, sturdily connecting the electromechanical shaker to the blade.
Key Outcomes and Future Directions
The data collected has been promising, showing distinct patterns that correlate with specific types of structural damage. These findings are crucial for developing more accurate predictive models for wind turbine blade maintenance. Looking ahead, the potential applications of this research are vast, with implications for improving the efficiency, reliability and sustainability of wind turbines. Moreover, this visit has paved the way for continued collaboration between my home institution and ETH Zurich, promising further advancements in our shared goals of enhancing renewable energy technologies
Reflecting back, my time in Zurich was not just about the rigors of research but also about personal and professional growth. Navigating through the complexities of experimental setups, resolving unexpected issues, and adapting to a high-calibre academic environment were all part of a journey that broadened my horizons as a researcher.