Numerical Analysis of the Wind Turbine Pitch Bearing Raceway Tribo-contact due to Cyclic Loading Under Constant Pitch Angle

Cubillas, D.; Olave, Mireia; Llavori, Iñigo; Ulacia, I.; Larrañaga, Jon; Zurutuza, A.; Lopez, A.

doi:10.1007/978-981-15-9893-7_55

Cited by 5 publications

(2 citation statements)

References 13 publications

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“…In comparison to oil lubrication, the analysis of grease lubrication can require specialised treatment [1]. Furthermore, the wear and fatigue behaviour of these bearings is mostly discussed in the context of blade bearings in wind turbines especially for those operated with an individual pitch controller (IPC) [2][3][4][5]. Load-mitigating controller design leads to a highly increased pitch activity [6].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigations on Wear in Oscillating Grease-Lubricated Rolling Element Bearings of Different Size and Type

et al. 2023

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Grease-lubricated rolling element bearings can suffer from wear due to lubricant starvation under certain oscillating operating conditions. Especially for large-scale slewing bearings, such as blade bearings in wind turbines, experimental investigations are complex compared to small-scale reference testing. For an easier manner of testing, it is desirable to know whether the results of small-scale testing are applicable to larger-sized bearings. In this work, three different bearing types were tested and compared to already published results from a small-scale ACBB with a pitch diameter of 60 mm. The newly tested bearing types comprise a downscaled blade bearing (4-point contact double row ball bearing) with a pitch diameter of 673 mm, a small-scale CRTB with a pitch diameter of 77.5 mm and another ACBB with a pitch diameter of 95 mm. Qualitatively, all tested bearings show similar wear behaviour in terms of friction energy when operation parameters are varied. With higher oscillation frequency, damage becomes more severe. The oscillation amplitude shows three distinctive regimes. Within the range of small amplitudes, an increase in amplitude leads to more pronounced damage. We observe a threshold amplitude where this is no longer the case; a further increase in amplitude counteracts wear initiation until a final threshold is reached, beyond which no more wear is observed. These findings are in accordance with the reference results of the small-scale ACBB. Direct comparison between point and line contact shows that the latter is more prone to wear initiation under grease-lubricated, oscillating operating conditions. Furthermore, a previously introduced empirical number shows good performance in assessing critical operating parameters of the different bearing types. Specifically, harmful operating conditions can be classified for all studied bearing types with an accuracy of 78%. This method can be useful to assess operating conditions of greased, oscillating, rolling element bearings, e.g., to assess different pitch controllers or designs of slewing bearings.

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Section: Introductionmentioning

confidence: 99%

Experimental Investigations on Wear in Oscillating Grease-Lubricated Rolling Element Bearings of Different Size and Type

et al. 2023

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“…The 42CrMo4 type of steel is a medium carbon alloy structural steel that has high strength, hardenability, toughness, creep strength, and endurance strength at high temperatures [1][2][3][4][5]. It is commonly used to prepare pitch and yaw bearings in wind power steel.…”

Section: Introductionmentioning

confidence: 99%

Formation and Removal Mechanism of Nonmetallic Inclusions in 42CrMo4 Steel during the Steelmaking Process

Qiao

Cheng

Huang

et al. 2022

Metals

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Nonmetallic inclusions are harmful to the quality of 42CrMo4 steel. Therefore, the formation and removal mechanism of inclusions in 42CrMo4 steel during the steelmaking process is investigated by industrial trials. The characteristics of inclusions in specimens were analyzed by scanning electron microscopy and energy dispersive spectroscopy. The main type of inclusions in molten steel in the early stage of ladle furnace (LF) refining is MgO-Al2O3 inclusions of irregular shape. CaO begins to appear in MgO-Al2O3 inclusions in the middle and late stages of LF. In the vacuum degassing (VD) refining stage, the inclusions in molten steel completely change into low-melting-point CaO-MgO-Al2O3 inclusions. The existence of [Mg] in molten steel is the fundamental reason for the formation of a large number of MgO-Al2O3 inclusions. Thermodynamic calculation shows that the refractory mainly transfers [Mg] to the liquid steel in the LF refining stage, whereas the slag mainly transfers [Mg] to the liquid steel in the VD refining stage. Kinetic calculation indicates that MgO-Al2O3 inclusions could be removed from molten steel faster than low-melting-point CaO-MgO-Al2O3 inclusions. The fundamental reason for the different removal behavior of the two types of inclusions is that the interfacial tension between the low-melting-point CaO-MgO-Al2O3 inclusions and the liquid steel is 50% lower than that of the MgO-Al2O3 inclusions.

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On the critical amplitude in oscillating rolling element bearings

Schwack

Schneider

Wandel

et al. 2021

Tribology International

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Numerical Analysis of the Wind Turbine Pitch Bearing Raceway Tribo-contact due to Cyclic Loading Under Constant Pitch Angle

Cited by 5 publications

References 13 publications

Experimental Investigations on Wear in Oscillating Grease-Lubricated Rolling Element Bearings of Different Size and Type

Experimental Investigations on Wear in Oscillating Grease-Lubricated Rolling Element Bearings of Different Size and Type

Formation and Removal Mechanism of Nonmetallic Inclusions in 42CrMo4 Steel during the Steelmaking Process

On the critical amplitude in oscillating rolling element bearings

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