State of the art wind turbines place complex requirements on the corresponding foundations and support structures: In addition to external loads such as aerodynamic and hydrodynamic forces – both in terms of the standard operating regime and as experienced during extreme weather conditions – the dynamic interaction of all these components needs to be taken into consideration when planning and designing the system. For example, rigidities and damping effects have a decisive effect on the service life and efficiency of a wind turbine.
Nowadays, there are a whole range of tools available to the developer when designing a support structure, in other words the foundation piles and the adjacent elements such as the jacket and tower construction. Each tool is based on a theoretical model via which the individual elements of, for example, the foundations can be measured or even simply an initial decision concerning a certain technology can be taken.
Each model needs to be validated irrespective of the specific application scenario: the basic assumptions and output quantities need to be verified. An unvalidated model and an unvalidated dimensioning approach pose the risk that increased safety factors will be required on the one hand and the structure-critical components will not be able to withstand the real loads on the other.
Fraunhofer IWES offers the unique possibility for conducting model validations using large-scale tests. The following test environments can be made available in cooperation with the Leibniz Universität Hannover:
High-performance hydraulic load facilities for static, cyclic, and dynamic tests
Precise, reproducible model substrates (non-binding medium sand, waterlogged, density can be adjusted from medium to dense packing) in a foundations test pit with a depth of 10 m
Span for mechanical testing of components with individual forces of up to 2 MN, total flexural moments of up to 15 MN
Additional mechanical test facilities (e.g., resonance testing equipment) up to 4 MN, even with climate simulation.
Large-scale tests are always accompanied by sophisticated numerical methods and procedures, for example with our specifically designed “virtual test bench”.