New experimental research facility to identify the weakest points of wind turbine blades

On 25 November a new research facility at Risø DTU will be inaugurated. Here, scientists will be able to experiment with different physical loads on wind turbine blades, corresponding exactly to what the wind does to the blades during a lifetime. The advanced measurements will make it possible to work more focused on design and structure, thus contributing to the development of larger and stronger blades.

With the explosive growth within wind energy and several turbines with blades of 60 meters or more, there is a greater need for research into the design and structure of blades. If you just upgrade the blades without simultaneously optimizing them, the weight will increase faster than the wind turbine performance. The huge blades get relatively very heavy and therefore uneconomic if you only improve their strength by adding more material. Therefore the scientists are now working with other forms of reinforcement, for example, change of structure and support of the blade precisely where it is weakest.

"By using the latest knowledge and reinforcing the blades, we expect that the weight of tomorrow's blades can be reduced substantially," says Find Mølholt Jensen who is head of the new research test facility. Find Mølholt's PhD thesis focused on this issue, and based on his inventions Risø DTU has patented several reinforcements. One of the inventions, for instance, has proved to increase buckling strength by 30-40 percent. The implementation in the manufacturing process still remains, but Risø DTU hopes that this can be solved together with the manufactures.

Experimental Research Facility for Blade Structure
There is room for a 30-40 meter wind turbine blade in the big hall which now opens with the name Experimental Research Facility for Blade Structure. SSP Technology A/S has donated a 34m blade and the blade has been mounted with different kinds of measuring equipment, which differ significantly from the way traditionally commercial tests are performed today. 3D measuring equipment is funded by DTU globalization funds based on a joint application from Risø DTU, DTU Mechanical Engineering and DTU Civil Engineering.

The many tests and measurements are going to be used to validate seven patents on various structural reinforcements which have been taken out by Risø DTU during the past 3-5 years. They will also make it possible to evaluate and improve the methods which are being used to approve wind turbine blades

The official inauguration will be the festive end of Wind Day 2008 held by the Danish Research Consortium for Wind Energy. Director Henrik Bindslev will be present and there will be lectures on research into blade design.

Source : RISO