Investigation of the Causes of Premature Rain Erosion Evolution in Rotor Blade-like GFRP Structures by Means of CT, XRM, and Active Thermography

November 08, 2022

Friederike Jensen (1), Elie Abi Aoun (2), Oliver Focke (2), Andreas Krenz (3), Christian Tornow (3), Mareike Schlag (3), Catherine Lester (4), Axel Herrmann (2) (5), Bernd Mayer (3) (5), Michael Sorg (1), Andreas Fischer (1)
Applied Sciences. Volume 12, issue 2 (8 November 2022). DOI:


Rain erosion, rotor blade leading edge, damage evolution, x-ray computed tomography, x-ray microscopy, active thermography, artificial intelligence


Premature rain erosion damage development at the leading edges of wind turbine rotor blades impair the efficiency of the turbines and should be detected as early as possible. To investigate the causes of premature erosion damage and the erosion evolution, test specimens similar to the leading edge of a rotor blade were modified with different initial defects, such as voids in the coating system, and impacted with waterdrops in a rain erosion test facility. Using CT and XRM with AI-based evaluation as non-destructive measurement methods showed that premature erosion arises from the initial material defects because they represent a weak point in the material composite. In addition, thermographic investigations were carried out. As it shows results similar to the two lab-based methods, active thermography has a promising potential for future in-situ monitoring of rotor blade leading edges.

How Our Software Was Used

The Segmentation Wizard was used to label pixels for classical machine learning and then used for training a deep model for segmentation.

Author Affiliation

(1) Bremen Institute for Metrology and Quality Science (BIMAQ), University of Bremen, Linzer Str. 13, 28359 Bremen, Germany
(2) FIBRE—Faserinstitut Bremen e.V., University of Bremen, Am Biologischen Garten 2, 28359 Bremen, Germany
(3) Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, 28359 Bremen, Germany
(4) Fraunhofer Institute for Wind Energy Systems IWES, 27572 Bremerhaven, Germany
(5) Faculty for Production Engineering, University of Bremen, Bibliothekstraße 1, 28359 Bremen, Germany