Transient mixed non-Newtonian thermo-elastohydrodynamics of vehicle differential hypoid gears with starved partial counter-flow inlet boundary

Mohammadpour, Mahdi; Theodossiades, Stephanos; Rahnejat, Homer

doi:10.1177/1350650114537805

Cited by 26 publications

(37 citation statements)

References 41 publications

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“…where, is the average asperity tip radius, is the composite RMS surface roughness, and the statistical function F5/2(λ) for a Gaussian distribution of asperities is obtained as [17]: …”

Section: Boundary Frictionmentioning

confidence: 99%

Efficiency and Durability Predictions of High Performance Racing Transmissions

Fatourehchi¹,

Elisaus²,

Mohammadpour³

et al. 2016

SAE Int. J. Passeng. Cars - Mech. Syst.

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Efficiency and durability are key areas of research and development in modern racing drivetrains. Stringent regulations necessitate the need for components capable of operating under highly loaded conditions whilst being efficient and reliable. Downsizing, increasing the powerto-weight ratio and modification of gear teeth geometry to reduce friction are some of the actions undertaken to achieve these objectives. These approaches can however result in reduced structural integrity and component durability. Achieving a balance between system reliability and optimal efficiency requires detailed integrated multidisciplinary analyses, with the consideration of system dynamics, contact mechanics/tribology and stress analysis/structural integrity.This paper presents an analytical model to predict quasi-static contact power losses in lubricated spur gear sets operating under the Elastohydrodynamic regime of lubrication. Tooth Contact Analysis (TCA) is used to predict variations in contact loads, local surface curvature and rolling and sliding velocities. This is combined with an extrapolated oil film thickness formula available in literature, to predict instantaneous lubricant film thickness and sub-surface stresses. Subsequently, viscous and boundary friction are estimated, enabling calculation of power losses.The presented methodology has been used to investigate the effects of parabolic tip relief on power loss and induced sub-surface stresses. The results of this investigation are also presented.

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“…where, is the average asperity tip radius, is the composite RMS surface roughness, and the statistical function F5/2(λ) for a Gaussian distribution of asperities is obtained as [17]: …”

Section: Boundary Frictionmentioning

confidence: 99%

Efficiency and Durability Predictions of High Performance Racing Transmissions

Fatourehchi¹,

Elisaus²,

Mohammadpour³

et al. 2016

SAE Int. J. Passeng. Cars - Mech. Syst.

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“…The resulting high contact pressures promote the formation of thin elatohydrodynamic films of the order of the root mean square (RMS) average surface roughness of the counter face surfaces [26]. This promotes mixed regime of lubrication, with friction generated according to two additive contributions; viscous shear of a thin lubricant film, and adhesive boundary friction as a result of direct interaction of asperities on the contiguous meshing surfaces.…”

Section: The Elastohydrodynamic Contact Modelmentioning

confidence: 99%

Transient thermal analysis of mixed-elastohydrodynamic contact of high performance transmission in a dry sump environment

Fatourehchi

Mohammadpour

Theodossiades

et al. 2018

Proceedings of the Institution of Mechanical Engineers, Part J:

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Fuel efficiency is one of the main concerns in the optimization of modern racing transmissions. The dry sump transmissions are the preferred choice for high performance racing applications. While it provides adequate lubricant for gear contacts, it minimises the system churning losses, and therefore enhances the system efficiency. An important aspect is assessing its thermal performance in removing the generated frictional heat. The generated heat in the highly loaded high shear contacts of racing transmissions should be dissipated through use of directed impinging oil jets and in an air-oil mist environment. The paper presents an integrated tribological and 3D computational fluid dynamics analysis for a spur gear pair, incorporated into an overall finite element model to evaluate the quantity of generated heat and its removal rate from the rotating gear surfaces. Furthermore, the temperature distribution in the circumferential direction is predicted and used to evaluate transient temperature distribution over representative race laps. Such an approach has not hitherto been reported in literature.

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“…These interactions establish the relationship between dynamics and tribology in hypoid gear pairs. Past research has focused on the necessity of solving tribology and dynamics of hypoid gears as a coupled multi-physics problem (4)(5). The necessity of the same approach has been used for other types of gears including spur and helical gears (6)(7).…”

mentioning

confidence: 98%

Tribodynamics of differential hypoid gears

Mohammadpour

Theodossiades

Rahnejat

2014

International Gear Conference 2014: 26th–28th August 2014, Lyon

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The paper presents a multi-physics approach for modelling the tribology and dynamics of hypoid gear pairs. The coupling between these disciplines is established through determination of flank friction as a source of damping source which alters in a transient manner. In order to improve upon time efficiency of simulation studies, an analytical tribological model has been used and integrated with system dynamics' analysis. On the other hand, a full numerical EHL model is employed after obtaining the dynamic response for a series of quasi-static snapshots during the steady-state meshing cycle. Finally, the effect of static transmission error is investigated.

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Transient mixed non-Newtonian thermo-elastohydrodynamics of vehicle differential hypoid gears with starved partial counter-flow inlet boundary

Cited by 26 publications

References 41 publications

Efficiency and Durability Predictions of High Performance Racing Transmissions

Efficiency and Durability Predictions of High Performance Racing Transmissions

Transient thermal analysis of mixed-elastohydrodynamic contact of high performance transmission in a dry sump environment

Tribodynamics of differential hypoid gears

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