Twin disc micropitting tests

Ahlroos, Tiina; Ronkainen, Helena; Helle, Aino; Parikka, Risto; Virta, Jouko; Varjus, Simo

doi:10.1016/j.triboint.2009.05.023

Cited by 38 publications

(6 citation statements)

References 7 publications

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“…When the surface roughness of the discs was reduced with polishing process no micropitting was observed due to more evenly distributes contact loads. This is in correlation with the previous twin disc studies [23]. The discs with K0.1 polishing had the lowest surface roughness and completely smooth surfaces with no grinding marks, indicating thus a more efficient polishing process.…”

Section: Discussionsupporting

confidence: 91%

“…The twin disc test setup enables rolling contact with different slide-to-roll ratios and therefore is one of the rare test arrangements that can simulate the gear contact [22,23]. Different coatings evaluated in twin disc tests show that a-C:H coating provides friction reduction and superior wear performance, particularly for thick films [24].…”

Section: Introductionmentioning

confidence: 99%

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The influence of carbon based coatings and surface finish on the tribological performance in high-load contacts

Ronkainen

Elomaa

Varjus

et al. 2016

Tribology International

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

The influence of carbon based coatings and surface finish on the tribological performance in high-load contacts

Ronkainen

Elomaa

Varjus

et al. 2016

Tribology International

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“…The review also shows how small hard inclusions can, when loaded, generate bumps, which behave similar to ridges in EHL contacts. Other studies, such as experiments by Ahlroos et al [47] and the 2 dimensional numerical simulations of cylindrical gear contacts with ridges and slip by Sharif et al [48] and Qiao et al [38] show that the damage increases with decreased lambda-ratio. These studies highlight surface roughness as important for rolling contact fatigue initiation.…”

Section: Damage Simulations In Ehlmentioning

confidence: 93%

Contact fatigue initiation and tensile surface stresses at a point asperity which passes an elastohydrodynamic contact

Everitt

Alfredsson

2018

Tribology International

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Contact mechanics and tribology was combined with fundamental fatigue and fracture mechanics to form a new mechanism for surface initiated rolling contact fatigue. Following, fatigue was investigated numerically for single asperities and craters in lubricated rolling contact surfaces. The hypothesis suggests that asperity point contacts can create sufficiently large tensile stresses for fatigue. The investigated case corresponded to a heavily loaded truck gear with ground surfaces. Reynolds equation resolved the elastohydrodynamic effect of the asperity in the transient three dimensional contacts. The Findley critical plane criterion was used for multiaxial and non-proportional fatigue evaluation. The simulations confirmed the new mechanism for rolling contact fatigue and showed how asperities can create contact fatigue in the lubricated contacts even without slip.

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“…The factors that influence the severity of the surface stresses and consequently the fatigue life are diverse, primarily including the operating conditions (surface velocities, sliding direction, normal load, temperature) [1][2][3][4]15], the surface conditions (surface roughness, texture) [2,[16][17][18][19][20], and the lubricant properties (viscosity, non-Newtonian behavior) [9,20]. The other potential factors such as surface hardness [20], residual stresses [14], material micro-structures [21], and lubricant additives [20,22,23] may also affect the fatigue crack formation, while not through the direct alteration of the stress distributions.…”

Section: Introductionmentioning

confidence: 99%

Determination of the accelerated RCF operating condition of the sun-planet contact of a tractor final drive using a computational method

Wagner

2016

Meccanica

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This study proposes a computational approach to determine the operating condition, under which the rolling contact fatigue (RCF) crack nucleation of the sun-planet mesh of a tractor final drive is accelerated. Although the experimental RCF time period can be reduced by increasing the rotational velocity, the resultant increase in the film thickness promotes the lubrication condition and thus lengthens the fatigue life. To counteract this fatigue performance variation, it is proposed to increase the lubricant temperature at the same time. In the process, the lubricant viscosity decreases and offsets lubrication film thickness increase introduced by the rotational velocity increase. A physics-based gear contact fatigue model that includes the descriptions of the mixed elastohydrodynamic lubrication, the multiaxial stresses and the multi-axial fatigue is used to quantify the impacts of the lubricant temperature and the rotational velocity on the crack formation, allowing the fine tune of the temperature and velocity parameters.

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Twin disc micropitting tests

Cited by 38 publications

References 7 publications

The influence of carbon based coatings and surface finish on the tribological performance in high-load contacts

The influence of carbon based coatings and surface finish on the tribological performance in high-load contacts

Contact fatigue initiation and tensile surface stresses at a point asperity which passes an elastohydrodynamic contact

Determination of the accelerated RCF operating condition of the sun-planet contact of a tractor final drive using a computational method

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