PaSe2TestKonzept: Parallel Sequential Segmented Testing for Accelerated Lifetime Testing of Rotor Blades

At a glance

• The expansion goals for offshore wind energy require the development of wind turbines in the 20 MW+ class. However, the corresponding development and certification take considerable time: the accelerated lifetime testing for the rotor blades up to 120 meters in length alone can take up to three years.
• The PaSe2TestKonzept research project aims to shorten this period by up to 12 months. This should be made possible through the further development and implementation of the already patent-pending sequential segmented testing method developed at Fraunhofer IWES for industrial use.
• Fraunhofer IWES is coordinating the project and primarily responsible for its implementation.

The challenge

The German federal government’s expansion goals for offshore wind energy render the rapid development and certification of wind turbines with capacities of 20 MW and higher necessary. However, the accelerated lifetime testing of the rotor blades measuring up to 120 meters in length required for the certification tests alone can involve testing campaigns lasting several years in some cases using the methods currently available. In addition, the lacking availability of the requisite infrastructure results in a problematic bottleneck.

Fraunhofer IWES has already developed a patent-pending process to resolve this issue. The sequential segmented testing method is based on the accumulation of damage from multiple test sequences. Full blade, tip, and root segment tests are skillfully combined to achieve the required full damage precisely and avoid overloading. Extensive numerical preliminary studies on reference blade models have demonstrated the fundamental feasibility along with high potential for immense shortening of the test times for very long offshore rotor blades in particular. However, further development steps are still required for its specific implementation in an experimental test campaign to ensure universal applicability for different types of rotor blades.

The solution

This is where the PaSe2TestKonzept joint project comes in. The partners’ primary objective is to further develop the sequential segmented testing method for industrial use for the validation of future rotor blade generations. This requires expanded optimization and design tools capable of solving complex problems in an acceptable time frame. In addition, the scientists are investigating how the existing infrastructure at Fraunhofer IWES can be best utilized or optimized for this method, or whether additional infrastructure is required.

Fraunhofer IWES is coordinating the project and primarily responsible for its implementation.

The added value

The new testing method will make a decisive contribution to accelerating the expansion of offshore wind energy through immense shortening of the validation campaigns and the corresponding shortening of development times for wind turbines. This will help to reduce the levelized cost of energy (LCOE), strengthen the share of wind energy in the future energy mix, and guarantee a secure energy supply.