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Layer structure of Kraiburg LEP (Source: Gummiwerk Kraiburg)

28. July 2020

Gummiwerk Kraiburg: Long-term erosion protection for wind turbine rotor blades

The German company Gummiwerk Kraiburg GmbH & Co. KG has developed an elastomer-based solution to protect the leading edges of wind turbine rotor blades. According to the company, during their operations, the rotor blades are exposed to enormous loads. The leading edges of the blades, in particular, are subjected to a disproportionate degree of stress from raindrops and other particles.

The damage caused by erosion results in a loss of performance and entails complex and costly repairs. Kraiburg LEP (Leading Edge Protection) combines the robustness of ultra-high molecular weight polyethylene with the damping effect of an elastomer layer underneath and can prevent this erosion damage. The solution is therefore suitable for both onshore and offshore applications.

The company said the solution has been used by well-known manufacturers of wind turbines for many years to protect the fibre composite structure of rotor blades against damage. The fatigue and rain erosion tests carried out demonstrate the strong performance of Kraiburg LEP, in which the coating from Gummiwerk Kraiburg impressed due to its solid endurance and resistance. The fatigue test was carried out in both the lead and lag directions, and simulated a period of 20 years. Following the test, the connection between the erosion protection film and the rotor blade did not show any defects. Furthermore, the rain erosion test did not show any significant erosion of the Kraiburg LEP film after 2,000 hours of UV-B exposure. In an extensive and independent series of tests, the layers of the film were only removed partially and in small steps.

The elastomer-based film can be applied directly to the rotor blade as a two-layer system, and can be used in both a controlled production environment and under service conditions in the field. In this respect, two bonding options are available: The application with resin, in which the elastomer layer bonds with the infusion resin at room temperature during the curing process, and the application with adhesive. The use of an appropriate adhesive, which has been developed and tested in cooperation with an adhesive manufacturer, also enables the partial repair of blade protection films.

The use of Kraiburg LEP is said to offer significant advantages for the protection of rotor blades and is increasing the efficiency of wind turbines. The robust and UV-resistant material significantly reduces damage to the fibre composite structure of the leading edges of the blade, and provides the possibility for partial repair, known as splicing, in the affected areas. The high load-bearing capacity is particularly beneficial in the maintenance and repair cycles, as the use of Kraiburg LEP reduces the service and repair costs of the rotor blades, said the manufacturer.

www.kraiburg-rubber-compounds.com

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