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Composite Structures 74 (2006) 332–342 /locate/compstruct Simulation of fatigue failure in a full composite wind turbine blade Mahmood M. Shokrieh *, Roham Rafiee Composites Research Laboratory, Mechanical Engineering Department, Iran University of Science and Technology, Narmak, Tehran 16844, Iran Available online 13 June 2005 Abstract Lifetime prediction of a horizontal axis wind turbine composite blade is considered. Load cases are identified, calculated and evaluated. Static analysis is performed with a full 3-D finite element method and the critical zone where fatigue failure begins is extracted. Accumulated fatigue damage modeling is employed as a damage estimation rule based on generalized material property degradation. Since wind flow (loading) is random, a stochastic approach is employed to develop a computer code in order to sim- ulate wind flow with randomness in its nature on the blade and subsequently each load case is weighted by its rate of occurrence using a Weibull wind speed distribution. 2005 Elsevier Ltd. All rights reserved. Keywords: Composites; Finite element; Stochastic; Wind turbine blade; Damage; Failure analysis 1. Introduction Generally, wind turbines are fatigue critical machines and the design of many of their components (especially Pollution free electricity generation, fast installation blades) are dictated by fatigue considerations. Several and commissioning capability, low operation and main- factors expose wind turbine blades to the fatigue phe- tenance cost and taking advantage of using free and