GreT: Integral tower concept for wind turbines with large hub heights for onshore sites with low winds involving the efficient use of resources

The project aims at the development of an integral tower concept which both facilitates cost reduction at today's typical hub heights and permits the cost-efficient increase in hub heights for onshore wind turbines.

When it comes to tower dimensioning, one aspect that plays a key role in defining the required wall thicknesses is shell buckling. This indicates the amount of material required and ultimately the cost of manufacture. Another aim is to develop novel bracing concepts for steel towers and to determine the buckling behavior of tower segments under highly realistic conditions in order to achieve optimizations. To this end, extensive experiments will be conducted in the support structure test center: for one the buckling behavior will be tested on small- and large-scale braced test specimens subject to static axial and bending loads on the span field; in addition, the structural durability will be tested by means of accelerated life tests. For this, fatigue tests will be conducted on braced flat steel specimens in the resonance test machine for the fatigue strength region.

Fraunhofer IWES is developing the test program for the structure tests and is analyzing them with the aim of validating support structure and damage models.