Article
Engineering, Mechanical
B. Wainwright, H. Takeuchi, T. Makino, A. Kadiric
Summary: Micropitting is a major failure mode in gears and rolling bearings. In this study, the individual effects of surface roughness amplitude and A-ratio on micropitting are investigated. It is found that surface roughness has a greater influence on micropitting than A-ratio, and the A-ratio alone is unable to accurately assess the risk of micropitting. Furthermore, there exists a sufficiently low surface roughness below which micropitting is unlikely to occur even at extremely low A-ratios.
Article
Engineering, Mechanical
W. M. Britton, A. Clarke, H. P. Evans
Summary: This paper presents a new algorithm for automated detection of micropitting in areal surface measurements of ground surfaces, demonstrating its effectiveness through examination of measurements from a test where early stages of micropitting developed. Comparison with previous methods based on linear surface profiles highlights the truly three-dimensional nature of incipient micropitting.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Engineering, Mechanical
Mao Ueda, Benjamin Wainwright, Hugh Spikes, Amir Kadiric
Summary: Micropitting is a surface fatigue damage that occurs in rolling-sliding contacts under thin oil film conditions and is poorly understood, Friction has a very significant impact on micropitting, reducing friction can mitigate crack initiation and propagation.
Article
Engineering, Mechanical
Sougata Roy, Jr Speed Lake, Michael Viola, Huimin Luo, Donovan Leonard, Jun Qu
Summary: This study demonstrated the feasibility of using a phosphonium phosphate ionic liquid as an anti-wear and anti-pitting additive for rear axle lubricant. The results showed effective surface protection for wear and micro-cracking, leading to the production of low-viscosity gear oils with superior rolling contact fatigue mitigation. Full-scale hub dynamometer tests further confirmed the improved power output and torque generation of the IL-containing gear oils compared to commercial benchmarks.
Article
Engineering, Mechanical
Guillermo E. Morales-Espejel
Summary: This paper extends a previously developed model for heavily loaded Elastohydrodynamically lubricated contacts with surface micro-geometry, including the effects of frictional heating and a new surface damage model. The study shows that the model can account for the detrimental effects of high temperature in rolling/sliding contacts and is applied to investigate the effects of loads, sliding speeds, and rolling bearings.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2021)
Article
Engineering, Mechanical
D. Mallipeddi, M. Norell, V. M. Subbaramaiah Naidu, X. Zhang, M. Naslund, L. Nyborg
Summary: The micropitting mechanism was elucidated by testing ground gears using FZG test rig, with the evolution of surface characteristics observed from initial 200 cycles to failure. Micropitting phenomenon was divided into three stages, mainly associated with plastic deformation of asperities, build-up of residual stresses, and increase in phosphorus content on gear surface.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Engineering, Mechanical
Xiang Yuan, Jun Wang, Zisheng Lian, Guofa Wang
Summary: An experimental and theoretical research on seal behavior was conducted in this work, using an innovative mixed lubrication model incorporating EHD theory. The computational procedure provided insight into the effects of seal pressure, rod velocity and compression ratio on sealing characteristics, accurately predicting friction force and providing a theoretical basis for EHL modeling.
TRIBOLOGY INTERNATIONAL
(2021)
Article
Engineering, Mechanical
Zhaoming Yin, Zhimin Fan, Feng Jiang
Summary: This paper investigates the calculation method of oil film stiffness for double involute gears and its influencing factors. The results show that the type of gears and operating conditions have a certain influence on the oil film stiffness.
CHINESE JOURNAL OF MECHANICAL ENGINEERING
(2021)
Article
Engineering, Mechanical
Youhua Li, Lubing Shi, Zhongming Liu, Xiaopeng Wang, Xuetao Qiao, Zhihong Zhang, Shidang Yan
Summary: For high-speed, heavy-load gear units, it is crucial to understand the effects of lubrication state on tooth pitting damage through numerical and experimental studies. A 3D line-contact elasto hydrodynamic lubrication model was developed to investigate the lubrication characteristics of involute gears, suggesting fluctuations in pressure and film thickness under different load and roughness conditions. The formation of gear pitting damage due to boundary lubrication state on highly rough surfaces was observed both through simulation and contact fatigue test.
JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Chemical
Jonny Hansen, Marcus Bjorling, Roland Larsson
Summary: A new film parameter Lambda* was proposed in this study, taking into account the elasto-hydrodynamic lubrication effects induced by surface irregularities on the microscopic scale. The new model was validated through tribological tests and found to accurately predict the experimentally measured true mixed and full-film EHL regimes. The ability to accurately predict the mode of lubrication represents a major advance in designing tribological interfaces for optimal efficiency and durability.
Article
Engineering, Mechanical
Jiang Zhao, Wei Sheng, Zhengminqing Li, Hong Zhang, Rupeng Zhu
Summary: The contact and lubrication characteristics of the gear pair are directly affected by the relative sliding at the meshing point. This study investigates a new type of low sliding ratio gear pair and establishes a 3D elastohydrodynamic lubrication line contact model. The results show that the LSR gears have increased film thickness, reduced friction coefficient compared to involute gears.
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2022)
Article
Engineering, Electrical & Electronic
Marko Tosic, Roland Larsson, Karsten Stahl, Thomas Lohner
Summary: This study investigates the elastohydrodynamic lubrication (EHL) between nonconjugate meshing tooth flanks of a worm gear. The contact is characterized by a slender elliptical shape and high sliding. A validated numerical EHL model considering non-Newtonian, thermal, and transient effects is used to analyze the complete contact area of the worm gear. The study identifies and discusses the design factors that influence EHL film formation in worm gears.
Article
Engineering, Mechanical
Xiuhua Zhang, Peitang Wei, Robert G. Parker, Guoliang Liu, Huaiju Liu, Shaojie Wu
Summary: This study investigates the relation between surface integrity and contact fatigue of gears. The results show that gears with high surface integrity exhibit the highest contact fatigue limit, which is 15.1% higher than gears with carburizing and grinding. Surface hardness, maximum compressive residual stress, and surface roughness are the most significant factors affecting contact fatigue life and fatigue limit. The proposed formulae have reasonable prediction accuracy for fatigue life and fatigue limit.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Chemical
Shuangbiao Liu, Q. Jane Wang, Yip-Wah Chung, Stephen Berkebile
Summary: The article discusses the lubrication-contact interface conditions (LCICs) and proposes mathematical LCICs to address the interface issue between fluid lubrication and solid contacts. Through practical testing, a new mixed/boundary elastohydrodynamic lubrication solver has been successfully developed, capable of accurately capturing film thickness and pressure behaviors involving solid contacts.
Article
Engineering, Mechanical
Jiang Zhao, Wei Sheng, Zhengminqing Li, Hong Zhang, Rupeng Zhu
Summary: Considering tooth surface micro-morphology, a coupling analysis model for wear characteristics of involute gear under mixed lubrication was established. The mixture of squalane base oil and polyisoprene showed higher film thickness and lower coefficient of friction compared to polyalphaolefin oil and mineral oil. Increasing lubricant viscosity was found to reduce direct rough contact area and load ratios, thereby reducing wear.
TRIBOLOGY INTERNATIONAL
(2022)
Article
Engineering, Mechanical
A. Clarke, H. U. Jamali, K. J. Sharif, H. P. Evans, R. Frazer, B. Shaw
TRIBOLOGY INTERNATIONAL
(2017)
Article
Chemistry, Physical
H. P. Evans, R. W. Snidle, K. J. Sharif, M. J. Bryant
FARADAY DISCUSSIONS
(2012)
Article
Engineering, Mechanical
K. J. Sharif, H. P. Evans, R. W. Snidle
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2012)
Article
Engineering, Mechanical
M. Carli, K. J. Sharif, E. Ciulli, H. R. Evans, R. W. Snidle
TRIBOLOGY INTERNATIONAL
(2009)
Article
Engineering, Mechanical
H. P. Evans, R. W. Snidle, K. J. Sharif
TRIBOLOGY INTERNATIONAL
(2009)
Article
Engineering, Mechanical
A. Fabre, H. P. Evans, L. Barrallier, K. J. Sharif, M. Desvignes
TRIBOLOGY INTERNATIONAL
(2013)
Article
Engineering, Mechanical
H. P. Evans, A. Clarke, K. J. Sharif, R. W. Snidle
TRIBOLOGY TRANSACTIONS
(2010)
Article
Engineering, Mechanical
Hazim U. Jamali, K. J. Sharif, H. P. Evans, R. W. Snidle
TRIBOLOGY TRANSACTIONS
(2015)
Article
Engineering, Chemical
M. F. AL-Mayali, S. Hutt, K. J. Sharif, A. Clarke, H. P. Evans
Proceedings Paper
Engineering, Electrical & Electronic
Maasi F. AL-Mayali, H. P. Evans, K. J. Sharif
2016 INTERNATIONAL CONFERENCE FOR STUDENTS ON APPLIED ENGINEERING (ICSAE)
(2016)
Article
Engineering, Mechanical
A. Clarke, K. J. Sharif, H. P. Evans, R. W. Snidle
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2007)
Article
Engineering, Mechanical
K. J. Sharif, H. P. Evans, R. W. Snidle
Article
Engineering, Mechanical
K. J. Sharif, H. P. Evans, R. W. Snidle, D. Barnett, I. M. Egorov
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART J-JOURNAL OF ENGINEERING TRIBOLOGY
(2006)
Article
Engineering, Mechanical
A Clarke, KJ Sharif, HP Evans, RW Snidle
JOURNAL OF TRIBOLOGY-TRANSACTIONS OF THE ASME
(2006)