The “BeLeb - development of a method for determining the service life of rotor blade coatings” project aims to significantly increase the level of protection of rotor blades on wind energy turbines against rain erosion. In particular, the goal is to develop a reliable erosion damage prognosis model.

For this purpose, the research association headed by the Fraunhofer Institute for Wind Energy Systems (IWES) is using tests in its own in-house rain erosion test facility. This is made possible by the use of a laser-based, automatic inspection system, which permits a higher throughput of material samples, which in turn considerably improves the quality of the test results. The test results obtained are then compared with the measurement data from a long-term study on different coated wind turbines.

In order to be able to conduct a comprehensive study of the damaging effect of the raindrops, a droplet impact system is being used on the test bed. With its help, the researchers can precisely control parameters such as the quantity and size of the droplets, as well as the point in time and frequency of their occurrence on the surface of the test rotor. A laser-based inspection system and the 3D recordings of a high-speed camera document the damage caused in each case on a micrometre level. On this basis, the aim is to develop a material and damage model in order to better understand what happens at the material level.

In cases where damage has occurred on a wind turbine, repairs of damaged material samples are conducted in a climate chamber under ambient environmental conditions. By testing different methods, the researchers hope to be able to derive ways to optimise repair work in the field.