Wind turbine bearings




Greater Copenhagen area

This project proposal is focused on investigating subsurface cracks in wind turbine bearings called White Etching Cracks (WEC), which is probably the single most critical and least understood failure mode experienced in wind turbines. This project can be carried out in cooperation with a major wind turbine manufacturer, depending on the content.


In order for wind power to compete without subsidies against other cheaper energy sources such as coal, a higher reliability is needed for lowering downtime and maintenance expenses. Bearings are one of the critical components for the wind turbine drivetrain, being present at the main shaft, gearbox and generator. Although bearings are designed for a 20 year life span, failure after 1 or 2 years from WEC is not uncommon. Maintenance and repair of bearing related failures are very costly and some turbine manufacturers consider WEC to be the most expensive technical issue for wind turbines.


This project focuses on comparing several types of bearing materials acquired from different bearing manufacturers, as well as new experimental alloys. The bearings will be tested using accelerated WEC bearing tests rigs to find the best suitable material and failure analysis will be performed for investigating the damage mechanism for each material. Light optical microscopy will be used for identifying crack networks and Scanning Electron Microscopy (SEM) will be used for high resolution characterization of WEC and chemical analysis of inclusions. The project could be expanded to include state-of-the-art high resolution 3D X-ray CT scanning for mapping crack networks in three dimensions.

The project should help clarify how to avoid White Etch Cracks formation in bearings, which has arguably been the all-time single most expensive failure mode out of all wind turbine components. More specific goals should be defined between the project student and the supervisor, depending on which areas of research the student finds interesting.


Some background in materials or mechanical engineering.

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Company / Organization

DTU Vindenergi


Hilmar Kjartansson Danielsen




Supervisor info

MSc in Wind Energy


Hilmar Kjartansson Danielsen

ECTS credits

15 - 45


Final project, BSc project, MSc thesis

Technical University of Denmark

For almost two centuries DTU, Technical University of Denmark, has been dedicated to fulfilling the vision of H.C. Ørsted – the father of electromagnetism – who founded the university in 1829 to develop and create value using the natural sciences and the technical sciences to benefit society.

Today, DTU is ranked as one of the foremost technical universities in Europe, continues to set new records in the number of publications, and persistently increases and develops our partnerships with industry, and assignments accomplished by DTU’s public sector consultancy.

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