How did you decide on your topic? Had you already been working on wind turbines during your degree course?

I once dealt with the dynamic behavior of wind turbines as part of the seminar on measurement technology but wind turbines did not play a major role in my studies. For my master’s thesis, I wanted to work on a topic that had not been dealt with so intensively in the compulsory part of my studies and to familiarize myself with new areas. I had already taken a few modules on measurement technology at BIMAQ - the Bremen Institute for Measurement, Automation and Quality Science. Laser-Based Vibration and Deformation Measurement of Rotor Blades on Wind Turbines “Laserbasierte Schwingungs- und Deformationsmessung von Rotorblättern an Windenergieanlagen” was then one of several topics that were advertised at BIMAQ as a master’s thesis.

What role did sustainability play in your studies?

The main focus of my degree was on the fundamentals of mechanical engineering and production technology. As early as in the bachelor’s degree, but increasingly in the master’s degree, you have different elective options. I took advantage of the opportunities to also study sustainability-based modules. For example, electromobility, climate protection, and climate adaptation.

Can you explain in simple terms what exactly you researched and developed?

I have developed a laser-based method that can be used to determine the condition of a wind turbine rotor blade from a great distance, or more precisely: the vibration and deformation behavior of the rotor blades of a wind turbine. This then allows conclusions to be drawn about the condition of the rotor blades.

The study involved the use of a stationary 2D laser scanner for the detection of deformations. Normally, measurements taken from rotor blades of existing turbines are very complex. The special thing about my method compared to many other measurement methods is that it works at great distances and without modifying the turbine. That means you don’t need strain gauges or other sensors on the turbine. You can also measure during operation without stopping the plant.

How did you come up with that? Did you look at a wind turbine and think; somebody has to check those rotor blades?

In the area of engineering, work is advertised very specifically by the institutes – especially when it comes to corporate collaborations. It was already a given that the work would involve wind turbines. I decided to focus on the rotor blades because I thought it would be interesting to continue my research in this area. There had already been preliminary work on the tower, but I wanted to investigate something new, so I focused on the rotor, i.e. the hub, the nacelle, and especially the blades.

What kind of damage can you see on rotors? Do parts fall off or buckle?

There can be all kinds of things. Rotor blades can snap off or be torn off, that also happens. However, in most cases this happens in connection to storms or similar events. Such extreme damage is prevented by regular maintenance and care. A bigger problem, however, is the invisible damage. If you imagine that such a rotor blade vibrates a great deal, it is clear that the material will fatigue over the years and then changes in the material that cannot be seen will creep in.

So you need to be able to detect damage at an early stage?

Yes. It’s important for the safe operation of a turbine to know the condition of the rotor blades. That’s why there is such a great need for these detection methods. Regular maintenance costs a lot and causes loss of profit because the plant has to stop. My measurement system is designed so that this can be done during operation, without shutting down and costing money. If damage is detected in time, repair can extend the life of a wind turbine and ensure electricity yields.

How can we imagine this being carried out then? Did you stand in a field somewhere?

Yes, I did that regularly with my supervisor Paula Helming and Michael Sorg from BIMAQ. You point a laser scanner at the wind turbine and hope that the wind turbine doesn’t rotate out during the measurement. After all, it turns with the wind. That was always a big challenge during the measurements – to maintain a constant wind direction, as the measuring system remains fixed and the turbine will do what it wants and rotate out.

Companies are also interested in your results. What significance does that have for you?

During my degree, I worked on many interesting things from a theoretical point of view, so it is of course a nice acknowledgment that I have produced something that is relevant to practice. This was also extra motivation during the master’s thesis, when it became clear that the measurement technology I developed has practical applications and can enter the market.

Theme of the Month: Sustainability

Since its foundation in 1971, the University of Bremen has been committed to social responsibility. Climate protection and sustainability are fundamental principles guiding the university: in research, teaching, and operations. For this reason, up2date., the University of Bremen online magazine, will focus on the topic of sustainability in May. The theme of the month explores current projects, issues, and challenges.