FIBREGLASS WIND TURBINE ONE SHOT BLADE®: DAMAGE TOLERANT DESIGN

Nowadays, small wind turbines (SWTs) are designed according to specific regulations, which ensure the safety, the maintenance, and the operation under specified external loading conditions. Wind turbine One Shot Blade® manufacturing technology has been found compliant with the IEC 61400 and the Germanischer-Lloyd (GL) regulations for the SWTs. However, in order to ensure the safety, the requirements set by the regulations, based on uncertainty regarding the damage onset and evolution during service, lead to over-dimensioned blades design not fully realising the promising benefits in terms of weight of composite materials and, hence, in terms of blade energy efficiency. In this work, the results of a preliminary study finalised to the re-design of a 10-meter long fiberglass wind turbine blade, based on One Shot Blade® manufacturing technology are introduced. Indeed, the wing turbine blade, designed according to the above-mentioned regulations, has been modified in order to meet damage tolerance requirements with the aim to reduce the weight satisfying, at the same time, the strength, durability and stiffness requirements. Advanced non-linear structural Finite Elements based analyses have been performed to verify the capability of the structure to tolerate the damage under service loading conditions, by considering damage onset and evolution. Finally, comparisons between the proposed damage tolerant One Shot Blade® and the previous designs fully compliant to regulations are reported and discussed.