This study investigates how FE models of different fidelity affect the damage identification in a 31 m wind turbine rotor blade tested under edgewise fatigue loading. Different design variable configurations are compared, whereby the FE model updating is based on modal parameters identified from measured vibration data.

In this work, for the first time, a Kriging meta-model is detailed analysed to replace the simulation model of an idling offshore wind turbine. It becomes clear that the findings regarding meta-modelling of the idling wind turbine are generally similar to the findings regarding meta-modelling of the same wind turbine in operation. Only for the approximation of the rotor blade root bending moments, two additional input parameters have to be included compared to the same wind turbine in operation.

This study investigates dynamic displacement estimation using double-time-integrated acceleration signals for future application in load monitoring based on accelerometers. To estimate displacements without amplitude distortion, a tilt error compensation method for low-frequency vibrations of tower structures using the static bending line without the need for additional sensors is presented. The method is validated using a full-scale onshore wind turbine tower and a terrestrial laser scanner.

Extensive measurements in the area of wind turbines were performed in order to validate a sound propagation model. The measurements were carried out under various environmental conditions and included the acquisition of acoustical, meteorological and wind turbine performance data. By processing and analysing the measurement data, validation cases and input parameters for the propagation model were derived. Comparing measured and modelled propagation losses, generally good agreement is observed.

Offshore wind turbines are beginning to reach their design lifetimes. Hence, lifetime extensions are becoming relevant. To make well-founded decisions on possible lifetime extensions, fatigue damage predictions are required. Measurement-based assessments instead of simulation-based analyses have rarely been conducted so far, since data are limited. Therefore, this work focuses on the temporal extrapolation of measurement data. It is shown that fatigue damage can be extrapolated accurately.