Validation of crack initiation model by means of cyclic full-scale blade test

Abstract Wind turbine rotor blades are subject to highly dynamic loads and designed for life cycles of at least 20 years, which means that materials subjected high-cycle fatigue. Fatigue is a design-driving loading current future blades. Bond lines exposed multi-axial stress-state due the anisotropic thin-walled blade structure curved, tapered, twisted, airfoil-shaped geometry. To eliminate undesirable failure modes thus increase reliability wind blades, standards guidelines recommend stress-states be taken into consideration limit state analysis. In addition, thermal residual stresses develop during manufacture can have significant impact on fatigue bond line. By cyclic full-scale test commercial 81.6m long offshore blade, we validate crack initiation model, takes account mechanical stress-states, as well probabilistic stress-life, predict edge in adhesive span-wise position. Both observations agreed with simulations. All normal stress components cross-sectional plane shear made up major part mean equivalent stress, while amplitude - longitudinal, peel, amplitude.