Fatigue Estimation for a Rotating Blade of a Wind Turbine

Mahri, Z.l.; Rouabah, M.s.

Rеvuе des Energies Renouvelables
Volume 5, Numéro 1, Pages 39-47
2002-06-30

Fatigue Estimation For A Rotating Blade Of A Wind Turbine

Authors : Mahri Z.l. . Rouabah M.s. .

Abstract

The fatigue estimation of a rotating blade can be useful for preventing blade breakage, which is a very frequent problem in the use of wind turbine. The estimation of fatigue for a rotating blade must go through several steps of calculation: among them the calculation of mode shapes and frequencies and the computation of displacements and stresses acting on the blades. In this work two methods are used in the calculation of the mode shapes, the first one is based on the discretization of the blade element, whereas the second method is based on the resolution of the differential equation of the blade as a continuous system. This later method is more advantageous in determining mode shapes as well as stresses acting on the blades because it doesn’t require the use of a powerful computer. Once the stresses are calculated, the fatigue is estimated using the theory of « cumulative damage in fatigue ». This estimation must be based on the statistical distribution of wind speed for the site in use.