Strength and Fatigue Experiments and Modelling

The wind turbine rotor is an important part of the connection between the moving air (containing the wind energy) and the generator (used to capture this energy). The rotor consists of (usually) three blades, which are almost entirely made of fibre-reinforced plastic. These blades experience a large number of load cycles during their economic life. The magnitude of the load cycles is not at all constant. The rotor materials and structure need to withstand all these loads, great and small. Extensive research is devoted to predicting strength and life for rotor blades. For this research, numerous tests are done, exposing small fibre-reinforced coupons (specimens) to realistic loading conditions. Based on this data, fatigue models can be made predicting blade life. But, of course, ‘the proof of the pudding is in the eating'. Full-scale blade tests are required to see if reality matches expectations.

By Rogier Nijssen, WMC, The Netherlands