Bondlines – Online blade measurements (October 2012 and January 2013)

Some local deformations in an operating Wind Turbine blade (V80) have been measured during October 2012. Displacement and load values generated between the trailing edge panels at blade radius R9.2m, R10,2m, and R11,2m were obtained. A fluctuating loading of between 100 - 200N existed when the two panels were connected, and with a displacement of between 6.5 - 10mm when the panels were free to flex as they do in normal operating conditions. Shear distortion within the main loading spar of the blade (at approximately R10m) showed a fluctuating cross beam shear distortion of about 9mm.
The trailing edge displacement was re-measured (during January 2013) following a reinforcement of the blade to prevent trailing edge distortion. This trial showed that the new displacement values were below 1mm during similar operating conditions.
This report describes the planning for and procurement of hardware for the on-site measurements. The data output is then summarised. The full data files will be used to improve models and sub-component testing of these structures, as well as the continuing development of the reinforcement approaches designed to prolong structural life.