Digital Twins for Life Prediction of Wind Turbine Pitch Bearings

Research projects

Project Description:

This PhD scholarship is offered by the Aura Centre for Doctoral Training in Offshore Wind Energy and the Environment; a partnership between the Universities of Durham, Hull, Newcastle and Sheffield. The successful applicant will undertake a PG-Dip training year at the University of Hull before completing their PhD research at the University of Sheffield.


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The Project

Modern large-scale wind turbines are equipped with individual pitch controllers to allow the blades to rotate under different wind speeds. The rotation of the blades is necessary to change the angle of attack as to control power production and loads acting on a wind turbine. Accurate positioning of blades of a wind turbine is essential to maximise energy production and ensure its operational safety therefore pitch bearings are critical components of a wind turbine.

As a wind turbine operates under variable wind speed conditions, this means that the blade pitch bearings can be constantly subjected to oscillating movements of small amplitudes and variable frequencies. Under these conditions, two critical wear damage modes of the pitch bearing raceways, false Brinelling and fretting corrosion, have been identified from wind turbine field operation [1].  For bearings operating under small oscillations, such as pitch bearings, currently there is no established international design standard to calculate their service life accurately. To address these issues, the current industrial solution is to design the full-scale pitch bearing test rig and to perform full-scale bearing life testing. These extremely costly full-scale tests are to identify key operating conditions on damage development and to test the service life of pitch bearings therefore to extend the bearing life as long as possible. This is because replacement and maintenance of pitch bearings of large-scale wind turbines are extremely expensive in offshore wind farms.

The aim of this project is to develop a digital twin life prediction method for pitch bearings of the large-scale wind turbines with individual blade pitch controllers. The project will develop a bespoke medium-scale laboratory tribometer and multi-scale numerical damage simulation models of roller-raceway surface contact for pitch bearings, with consideration of operation conditions by analysing the SCADA data of filed operating wind turbines. The project will seek answers to research questions if the wear coefficient derived from the experiment tests using the bespoke medium-scale laboratory tribometer, under the actual pitch bearing motion and loading profiles, could be used in numerical damage simulation to predict the service life of pitch bearings of various scales. The developed digital twin life prediction method could have potentials to replace the costly full-scale pitch bearing tests employed in the industry.

The project has two main themes and four areas of activities to develop physical and virtual twins of the damage development of pitch bearings to support the bearing life prediction. The development of the physical twin includes (1) a data analysis model for creating pitch bearing motion and loading profiles from the wind turbine SCADA data, and (2) a medium-scale laboratory test method of roller-on-surface contact to evaluate frictional behaviour and wear damage accumulation. The development of the virtual twin includes (3) a finite element wear simulation model of roller-on-surface contact of the medium-scale laboratory test and the roller-on-raceway surface contact of the pitch bearing of a large-scale wind turbine; and (4) a calculation method for pitch bearing life prediction based on simulation of wear damage accumulation under actual pitching bearing operation conditions.

The successful applicant will join the Department of Mechanical Engineering, working with researchers in Structural Integrity, Dynamics and Tribology Research Groups.  More information about the department research can be found at


For more information visit If you have a direct question about the project, you may email or the project supervisor.


Training and Skills

The student will receive training in use of relevant finite element software via the University of Sheffield and online courses. Extensive guidance will also be given through technical training in the University of Sheffield on experimental procedures for material wear damage test and measurement.

The student will be in a position to continue in academia or to move to a job in the wind energy industry.


Entry Requirements

This PhD research project is suitable for applicants with a background in Mechanical Engineering, Materials Sciences, or a closely related discipline. If you have received a First-class Honours degree OR a 2:1 Honours degree and a Masters OR a Distinction in a Masters Degree, with any Undergraduate Degree, in one of the above subjects, (or the international equivalents,) we would like to hear from you.

If your first language is not English, or you require Tier 4 student visa to study, you will be required to provide evidence of your English language proficiency level that meets the requirements of the Aura CDT’s academic partners. This course requires academic IELTS 7.0 overall, with no less than 6.0 in each skill.



The Aura CDT is funded by the EPSRC and NERC, allowing us to provide scholarships that cover fees plus a stipend set at the UKRI nationally agreed rates, circa £17,668 per annum at 2022/23 rates (subject to progress).



Research Council funding for postgraduate research has residence requirements. Our Aura CDT scholarships are available to Home (UK) Students. To be considered a Home student, and therefore eligible for a full award, a student must have no restrictions on how long they can stay in the UK and have been ordinarily resident in the UK for at least 3 years prior to the start of the scholarship (with some further constraint regarding residence for education). For full eligibility information, please refer to the EPSRC website. Please note, we have already allocated all our places for International Students to this cohort, so please do not apply unless you are a Home student.


How to apply

Recruitment is open until 16 April 2023 for Aura CDT PhD Scholarships beginning study in September 2023.

Applications are made via the University of Hull admissions system.

If you have not applied with the University of Hull before, you will need to set up an account to enable you to track the progress of your application and upload supporting documents.

With your application, you need to upload copies of the following supporting evidence:

  • complete transcripts (and final degree certificate(s) where possible). If your qualification documents are not in English, you will need to supply copies of your original language documents as well as their official translation into English.
  • A completed Supplementary Application Form (please upload when asked to add Personal Statement).

Guidance on completing your Supplementary Application Form: The Aura Centre for Doctoral Training is committed to generating a diverse and inclusive training programme. As part of our inclusive practices, the Centre adopts a process of assessing applications purely based on skills and attributes and does not consider any personal details. As such we ask applicants to remove any personal details from the Supplementary Form which is used by the Panel to assess and select applicants for interview. The form asks for details of your education, training and employment history as well as some specific questions about your motivations and research experience and interests. It is very important that you do not include any personally identifying information.

Applicants must:

Remove all personal references in their application. Specifically, do not include the following details: Names, age, country, sex, gender, religion, disability, race, sexual orientation

Complete all sections of the form in font and size Calibri 11pt

Indicate your interest in applying to a maximum of two Research Projects (you may apply for one or two, but no more than two)

Once fully completed, you should upload the form when asked for your Personal Statement, as part of your application through the University of Hull student application portal using the links below. (You will also be asked for your degree transcripts during the application process). Please do not send your form directly to the Aura CDT.

Application links:

Apply for a full-time PhD Scholarship with the Aura CDT.

Apply for a part-time PhD Scholarship with the Aura CDT.



[1] Schaeffler.

[2] Extend wind turbine life with pitch bearing upgrades.

[3] E. Hurtado and H. Long. Damage and Failure in Wind Turbine Pitch Bearings, Industrial Project Report, sponsored by the Powertrain Research Hub, the UK Offshore Renewable Energy Catapult, 2019-2020.

[4] T. Harris, J. H. Rumbarger, and C. P. Butterfield, Wind Turbine Design Guideline DG03: Yaw and Pitch Rolling Bearing Life, NREL, no. December, p. 63, 2009.

[5] F. Schwack, M. Stammler, G. Poll, and A. Reuter, Comparison of Life Calculations for Oscillating Bearings Considering Individual Pitch Control in Wind Turbines, Journal of Physics: Conference Series, vol. 753, no. 11, 2016.

[6] A. Sevinc, M. Rosemeier, M. Bätge, R. Braun, F. Meng, M. Shan, D. Horte, C. Balzani, and A. Reuter, IWES Wind Turbine IWT-7.5-164, no. June, p. 62, 2014.

[7] Powering Offshore Renewable Energy Research: Powertrain Research Hub.

[8] H. Long. Wind Turbine Pitch Bearings – Enhanced Test Strategy for a Large-scale Test Rig, sponsored by the EPSRC Impact Acceleration Award and the UK Offshore Renewable Energy Catapult, 2022-2023.

[9] E. Hurtado. False Brinelling and Fretting Wear in Wind Turbine Pitch Bearings. PhD Thesis, The University of Sheffield, 2022.

[10] M. Stammler, A. Reuter, and G. Poll, Cycle counting of roller bearing oscillations – case study of wind turbine individual pitching system, Renewable Energy Focus, vol. 25, no. June, pp. 40–47, 2018

[11] M. H. Zhu and Z. R. Zhou. On the mechanisms of various fretting wear modes, Tribology International, vol. 44, no. 11, pp. 1378–1388, 2011.

View our webinar recording from 29 November
for information on our 2023 PhD Scholarships

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