THE STATISTICAL VARIATION OF MODAL PARAMETERS WITHIN PRODUCTION UNITS

摘要

Verifying the accuracy of a finite element model typically entails comparing the predicted modal frequencies to the results of an experimental modal survey. An inherent assumption is that the tested structure is representative of all production units. To evaluate this assumption, 20 wind turbines from a single production run were tested to determine the statistical variation of their modal frequencies and damping factors. For wind turbines it is particularly important to know the variation of the modal frequencies, as they must be known within 2% for current design practices. This report evaluates the stringency of this design requirement in light of the variation in modal parameters between production units.