Development of the world’s first regenerative hydraulic tidal blade test centre: FASTBLADE

The structural lifetime fatigue testing of tidal turbine blades is currently a challenge faced by the tidal industry. Due to the high stiffness and short length of composite tidal blades, it is not possible to perform resonant fatigue testing in the same way as wind turbine blades. Tidal blades have too high a natural frequency which, if tested resonantly, would result in internal heating of the composite and lead to premature failure. The aerospace industry uses conventional hydraulic systems to fatigue test composite structures such as wings. Although this approach would technically work for tidal blades, testing using this method is economically unviable for an emerging sector. FASTBLADE has been designed to specifically address the challenge of providing lifetime fatigue testing of tidal turbine blades in a cost effective and timely manner. The
facility uses a Digital Displacement® hydraulic system to enable energy recovery between loading cycles at high flow rates without compromising on the quality, control or confidence in certification of tidal blades. The paper evaluate the choice of instrumentation and facility equipment designed to enable the fast and yet robust fatigue testing of tidal blades. The 70 tonne reaction frame, capable of 1 MN fatigue loads and 2 MN static loads, combined with 800 lpm of reversible hydraulic flow, will revolutionise the structural testing capabilities within the UK. FASTBLADE will provide training for students and apprentices, deliver cutting edge research outputs, and enable the tidal sector to make the next step toward commercial success with the delivery of larger and certified blades.