Differential Radar Imaging at 60GHz for Structural Health Monitoring of Wind Turbine Blades: Preliminary Experimental Results

This paper aims at sensor nodes that can be embedded in the laminate of wind turbine blades for structural health monitoring (SHM). Therefore, preliminary experimental results based on an FMCW-radar in the frequency band from 57-64GHz will be presented here showing the radars ability to detect, localize and quantify water inside of flat bottom holes of glass fibre composites. Accumulation of water inside rotor blades can be critical, because sudden evaporation during a lightning event can lead to a total failure of the blade. For this practically relevant scenario, we study a differential imaging approach where the dry plate serves as baseline and the filled cavaties are used as test cases. In the future, the same differential imaging concept can be applied for the detection of structural defects such as delaminations or debondings.