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Estimating Fatigue in the Main Bearings of Wind Turbines Using Experimental Data

  • Giovanni M. FavaEmail author
  • Sauro Liberatore
  • Babak Moaveni
Conference paper
Part of the Conference Proceedings of the Society for Experimental Mechanics Series book series (CPSEMS)

Abstract

Axial bearing failures, in modern wind turbines, have been one of the major sources of unplanned maintenance expenses for the wind energy business. Although the causes of such failures are unclear, its statistics do increase in wind farms where the wind conditions range in considerably larger spans. It is common belief that torsional vibrations, combined with axial ones resulting from these extreme wind conditions are the major causes of high cycle, fatigue affecting the bearing. In this study, the strain measurements on blades are used to estimate the internal force time histories at the location of the main bearing. A rigid body equilibrium analysis was performed using moments and forces measured at the blades to estimate the force and moments acting on the low speed shaft. Experimental wind data was used to compare the difference between strong wind speed events and low wind speed events. The approach uses the blade bending-moments to isolate the axial excitations and is validated by measured data from an instrumented turbine with four interferometric strain sensors and four temperature sensors for each blade. The instrumented turbine is part of an onshore wind farm site, in Cohocton, NY, where wind conditions span in a large range and turbines are often placed in stop conditions. Preliminary data has shown some large excitations that could eventually lead to crack initiation.

Keywords

Wind turbines Stress estimation Fatigue analysis Main bearing monitoring 

Notes

Acknowledgements

The opinions, findings, and conclusions expressed in this paper are those of the authors and do not necessarily represent the views of the organizations involved in this project.

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Copyright information

© Society for Experimental Mechanics, Inc. 2020

Authors and Affiliations

  • Giovanni M. Fava
    • 1
    Email author
  • Sauro Liberatore
    • 1
  • Babak Moaveni
    • 2
  1. 1.Department of Mechanical EngineeringTufts UniversityNewtonUSA
  2. 2.Department of Civil and Environmental EngineeringSchool of Engineering, Tufts UniversityMedfordUSA

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