An Experimental Investigation into the Onset of Smearing Damage in Nonconformal Contacts with Application to Roller Bearings

Fowell, Mark; Ioannides, Stathis; Kadiric, Amir

doi:10.1080/10402004.2013.875607

Cited by 32 publications

(26 citation statements)

References 22 publications

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“…The kinematics of each roller in combination with the loading will be used for the evaluation of the risk of smearing by calculation of a smearing criterion. There are different state of the art smearing criterions [6,7,[17][18][19] that are all based on energetic equations. Fundamental to these equations is the friction power intensity [17].…”

Section: Discussionmentioning

confidence: 99%

“….t/ describes the friction coefficient for the contact between the roller and the raceway, p max is the maximum Hertzian contact pressure and u 1 .t/ − u 2 .t/ describes the sliding speed between the roller and the raceway. In order to estimate the risk of smearing the value of the criterion can be compared to state of the art thresholds which range from 1.05 10 8 to 1.4 10 8 [19], to 1.5 10 8 [18] to 2.6 10 8 W m -2 [7]. By comparing the simulation results to these thresholds, it is possible to evaluate the smearing risk within WT bearings for three phase short circuit converter faults.…”

Section: Discussionmentioning

confidence: 99%

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Simulative investigation of wind turbine gearbox loads during power converter fault

Röder

Jacobs

Duda

et al. 2021

Forsch Ingenieurwes

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Three phase short circuit power converter faults in wind turbines (WT) result in highly dynamic generator torque reversals, which lead to load reversals within the drivetrain. Dynamic load reversals in combination with changing rotational speeds are, for example, critical for smearing within roller bearings. Therefore, an investigation of the correlation between three phase short circuit converter faults and drivetrain component failures is necessary.Due to the risk of damage and the resulting costs, it is not economically feasible to extensively investigate three phase short circuit converter faults on test benches. Valid WT drivetrain models can be used instead. A WT drivetrain model, which has been developed and validated in a national project at the CWD, is used and a three phase short circuit converter fault is implemented. In this paper, the resulting torque load on the drivetrain for a three phase short circuit converter fault in rated power production is presented. This converter fault leads to a highly dynamic reversing electromagnetic torque which exceeds the rated torque by a factor of three. As a result the load on the rotor side high speed shaft (HSS) bearing oscillates and increases by around 15 per cent compared to rated power production. Simultaneously the rotational velocity of the HSS oscillates with an amplitude of 10 rpm. Therefore an increase in the risk of smearing is expected.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Simulative investigation of wind turbine gearbox loads during power converter fault

Röder

Jacobs

Duda

et al. 2021

Forsch Ingenieurwes

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“…Given this general mechanism, random variations in surface roughness or local friction can trigger a sudden and unexpected onset of scuffing, and in practice, it is not unusual to observe two seemingly identical machines have very different scuffing performance. Some practical examples of scuffing include those in gears, large slow rotating bearings, where the rolling elements undergo significant slowdown in the unloaded zone and so experience high sliding speeds at the re-entry to the loaded zone [6], for example in wind turbine gearbox bearings [7], piston ring liner contacts in combustion engines [8] and cam-followers. If left unchecked, scuffing can lead to the affected components losing their surface integrity and functionality, resulting in a shutdown of the affected system with associated downtime costs.…”

Section: Introductionmentioning

confidence: 99%

The Development and Application of a Scuffing Test Based on Contra-rotation

2019

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Scuffing is a surface failure mode that occurs in sliding-rolling contacts subjected to high loads and high sliding speeds, such as those in gears and cam-followers. Owing to its sudden onset, rapid progression and dependence on both fluid and boundary lubricant films, scuffing is difficult to study in a repeatable manner. This paper describes further development of a recently proposed scuffing test method based on contra-rotation, its extension to higher loads using a new experimental setup and its application to study the onset of scuffing with a selection of model and fully-formulated oils. The method employs two surfaces moving in opposite directions under rolling-sliding conditions, with a fixed load and step-wise increasing sliding speed. By decoupling the entrainment and sliding speeds, the method allows the effects of lubricant formulation on scuffing performance to be isolated from the influence of viscosity. The approach achieves high sliding speeds in parallel with low entrainment speeds, while minimising the undesirable effects of surface wear and frictional heating. The proposed test is relatively fast and economical, with total test time of about 30 min including specimen cleaning and setup. Results show that the newly implemented modifications have improved the repeatability of the test method, so that the number of repeat tests required for reliable oil ranking results is minimal. Tests with model and fully-formulated oils show that the onset of scuffing is characterised by a sharp and unrecoverable increase in friction and accompanied by the destruction of any boundary films. All tests show that the relationship load × speed n = constant holds at scuffing, with the exact value of the exponent n being dependent on the oil formulation. Additivised oils were shown to have enhanced scuffing resistance, which arises from their ability to postpone the uncontrollable rise in friction to higher sliding speeds. Finally, the critical maximum contact temperature scuffing criterion was shown to predict the onset of scuffing in our tests better than the frictional power intensity criterion.

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“…The larger the preload, the more intense is the vibration. When the preload is rather large, the lubrication between the roller and the raceway changes from oil film lubrication to boundary lubrication [39][40][41] and the vibration increases sharply.…”

Section: Effect Of External Loadsmentioning

confidence: 99%

Effect of grease on bearing vibration performance caused by short-time high-temperature exposure

Xiong

et al. 2019

J Braz. Soc. Mech. Sci. Eng.

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A short-time high-temperature environment is a common working condition in the use of bearings; it can occur as rapid heating before interference assembly of a bearing, or in a quick shutdown due to failure and heating of other parts of equipment. However, the current research mainly focuses on the influence of long-term high temperatures on bearing lubrication. In this paper, the 6204DDU ball bearing with lithium soap/mineral oil (paraffin base type) grease and fatty acid soap/mineral oil (refined white oil) grease (white grease) is investigated. The recovery performance of the two greases after a short-time high temperature is studied. It is found that a large number of fractures occur in the soap fibre of the white grease after 20 min exposure in 140 °C temperature environments, while lithium grease remains in a good working condition. The vibration velocity with white grease decreases during a temperature falls from 110 °C to the heated balanced temperature, while the vibration velocities with lithium grease is without significant fluctuations. Before and after heating, the vibration velocities in middle frequency band of rolling bearings with lithium grease and white grease increase with the increase in preload, but it is the opposite in the high frequency band except for white grease after heating condition. Infiltration with a small amount of water or oil can greatly affect the performance of white grease. Water can emulsify the white oil and accelerates the oxidation of white grease. The structure of the L-AN32 oil contaminant is different from that of white oil, resulting in uneven dispersion of saponified crystals and obvious flocculent agglomeration is presented.

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An Experimental Investigation into the Onset of Smearing Damage in Nonconformal Contacts with Application to Roller Bearings

Cited by 32 publications

References 22 publications

Simulative investigation of wind turbine gearbox loads during power converter fault

Simulative investigation of wind turbine gearbox loads during power converter fault

The Development and Application of a Scuffing Test Based on Contra-rotation

Effect of grease on bearing vibration performance caused by short-time high-temperature exposure

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