Review of the damage mechanism in wind turbine gearbox bearings under rolling contact fatigue

Rolling bearings in wind turbine gearboxes occasionally fail prematurely by so-called white etching cracks. The appearance of the damage indicates brittle spontaneous tensile stress induced surface cracking followed by corrosion fatigue driven crack growth. An X-ray diffraction based residual stress analysis reveals vibrations in service as the root cause. The occurrence of high local friction coefficients in the rolling contact is described by a tribological model. Depth profiles of the equivalent shear and normal stresses are compared with residual stress patterns and a relevant fracture strength, respectively. White etching crack failures are reproduced on a rolling contact fatigue test rig under increased mixed friction. Causative vibration loading is evident from residual stress measurements. Cold working compressive residual stresses are an effective countermeasure.

Download Full-text

Predicting Micro-Pitting Occurrence in Wind Turbine Gearbox Roller Bearings

STLE/ASME 2010 International Joint Tribology Conference ◽

10.1115/ijtc2010-41136 ◽

2010 ◽

Author(s):

Tedric A. Harris ◽

Michael N. Kotzalas

Keyword(s):

Wind Turbine ◽

Rolling Contact Fatigue ◽

Roller Bearing ◽

Contact Fatigue ◽

Rolling Bearing ◽

Rolling Contact ◽

Test Scheme ◽

Wind Turbine Gearbox ◽

Roller Bearings ◽

Contact Fatigue Life

The standard rolling contact fatigue life calculations currently in use by the rolling bearing industry is based on the first occurrence of subsurface-initiated spalling of a raceway or roller surface. However, wind turbine gearbox roller bearings have been suffering from another damage mode, which manifests itself as micro-pitting. The micro-pitting, which is spalling on a micro scale, by itself can be tolerated in its early stages; i.e. the roller bearing will still function properly. As the damaged bearing continues to operate, the micro-pitting propagates and at the later stages, often termed peeling, the pitting becomes deep enough to reach the appearance of traditional subsurface-initiated spalling. To better understand the phenomenon micro-pitting and its causes, this study was conducted to review published literature on the topic as it relates to bearing operation. The key findings were the need for a low specific lubricant film thickness parameter, and some component of sliding velocity in the contacting surface. With this knowledge, a proposed test scheme including these variables could be created from which a method to predict the risk of micro-pitting may be determined.

Download Full-text

Effects of microstructure on rolling contact fatigue of a wind turbine gear based on crystal plasticity modeling

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2018.10.022 ◽

2019 ◽

Vol 120 ◽

pp. 73-86 ◽

Cited By ~ 16

Author(s):

Wei Wang ◽

Huaiju Liu ◽

Caichao Zhu ◽

Peitang Wei ◽

Jinyuan Tang

Keyword(s):

Wind Turbine ◽

Crystal Plasticity ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact

Download Full-text

A New Multiscale Modeling and Simulation of Rolling Contact Fatigue for Wind Turbine Bearings

Advanced Wind Turbine Technology ◽

10.1007/978-3-319-78166-2_4 ◽

2018 ◽

pp. 119-142

Author(s):

Mir Ali Ghaffari ◽

Shaoping Xiao

Keyword(s):

Modeling And Simulation ◽

Wind Turbine ◽

Multiscale Modeling ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Rolling Contact

Download Full-text

Rolling bearing seizure and sliding effects on fatigue life

Proceedings of the Institution of Mechanical Engineers Part J Journal of Engineering Tribology ◽

10.1177/1350650118779174 ◽

2018 ◽

Vol 233 (2) ◽

pp. 339-354 ◽

Cited By ~ 3

Author(s):

Guillermo E Morales-Espejel ◽

Antonio Gabelli

Keyword(s):

Fatigue Life ◽

Numerical Models ◽

Rolling Contact Fatigue ◽

Contact Fatigue ◽

Damage Mechanism ◽

Rolling Bearing ◽

Rolling Contact ◽

Frictional Stress ◽

Lubricated Contacts ◽

Contact Fatigue Life

The effects of kinematic sliding on rolling contact fatigue life have been discussed in many occasions, often with some disregard of the fundamental principles of tribology. In this paper, the authors’ intention is to discuss this issue with a perspective as objective as possible and performing a study on factual and known scientific knowledge, applying tribology modelling and methods. The effects of kinematic sliding of Hertzian contacts are studied from three different standpoints: (1) by analysing the combination of sliding speed and contact pressure giving rise to seizure, that is high instantaneous contact temperatures leading to film collapse, (2) by assessing the possible effects of sliding to surface traction and fatigue, (3) by discussing other possible effects of sliding in heavily loaded lubricated contacts as the concurrent damage mechanism caused by wear and rolling contact fatigue. Throughout the paper, different numerical models are presented and discussed alongside with some experimental data. This approach provides a comprehensive assessment of the various phenomena related to the kinematic sliding of rolling bearings. The different mechanisms involved and the interaction of sliding with the elastohydrodynamic lubricant film, frictional stress, wear and fatigue are discussed, and their significance to the performance of the bearing is qualified.

Download Full-text