Sub-components of Wind Turbine Blades: Proof of a Novel Trailing Edge Testing Concept

Abstract

Wind turbine rotor blade sub-component testing (SCT) confines the structural validation to design critical blade parts. Unlike full-scale blade testing, SCT can be adjusted to replicate the stress state of the local structure closer to field conditions and thus augment towards increasing the structural reliability. One of the blade regions often subjected to fatigue loads is the trailing edge bond line. In this work, the proof of concept of a novel trailing edge sub-component test is presented. An outboard specimen of 3 m length was cut out of a 34 m wind turbine rotor blade. The sub-component was installed on a customized test rig and loaded statically with an hydraulic actuator. The imposed strain field along the specimen length is found in a good agreement to the strain distribution in the corresponding area developed during the static full-scale blade test. The experimental setup was simulated by analytical and finite element models. Data recordings with electrical strain gauges and a four-camera digital image correlation system were obtained to validate the predicted structural response of the specimen.