Effect of topography parameter, load, and surface roughness on friction coefficient in mixed lubrication regime

Prajapati, Deepak K.; Tiwari, Mayank

doi:10.1002/ls.1459

Cited by 13 publications

(13 citation statements)

References 19 publications

(42 reference statements)

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“…In mixed-EHL regime, film thickness is a function of operating conditions and scaling factor (fraction of total load carried by fluid film). This scaling factor increases with an increase in maximum contact load as reported previously by Prajapati and Tiwari [22]. An increase in scaling factor leads to an increase in film thickness which is the reason for getting lower traction coefficient at higher maximum contact load.…”

Section: The Effect Of Maximum Contact Load and Surface Roughnesssupporting

confidence: 79%

Study of mixed-EHL traction coefficient between cam-roller follower interface under different operating conditions

Prajapati

Prakash

2023

Eng. Res. Express

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In heavy duty vehicles, high power density (power throughput/ weight) is desired to achieve the high fuel efficiency. The increasing demand of high power output results in harsh operating conditions (high load, high surface temperature) in which tribological components such as cam/roller follower are enforced to operate. The traction between cam-roller interface highly depends on the contact conditions between roller-pin interface, and the slippage between roller-pin interface may leads to high friction coefficient between cam/roller follower. In this work, a simplified mixed-EHL model is developed to study the traction between the cam/roller follower interface by considering coupling between roller-pin and cam-roller contacts. The develop mixed-EHL model is validated with published results in order to verify the correctness of the model. It is found that slide-to-roll ratio (SRR) increases with an increase in load torque. The effect of surface roughness on performance parameters is presented. Surface maps of SRR, lambda ratio and asperity load ratio for feasible range of maximum contact load and cam speed are also discussed.

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Section: The Effect Of Maximum Contact Load and Surface Roughnesssupporting

confidence: 79%

Study of mixed-EHL traction coefficient between cam-roller follower interface under different operating conditions

Prajapati

Prakash

2023

Eng. Res. Express

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“…It is a conventional parameter extensively used for identifying the lubrication regimes. 4,34 The lubrication regimes are identified based on published literature by Prajapati et al 34 It can be seen from Fig. 9 that the condition of mixed-EHL is occurred in the vicinity of dead centres.…”

Section: Effect Of Skewness On Prclcmentioning

confidence: 99%

Research on tribological performance of piston ring/liner conjunction considering non-Gaussian roughness and cavitation

Prajapati

Ramkumar

Katiyar

2022

Proceedings of the Institution of Mechanical Engineers, Part J:

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The tribological performance of piston ring-cylinder liner conjunction (PRCLC) notably depends on the surface finish of cylinder liner. This study investigates the mixed lubrication condition near dead centres considering non-Gaussian roughness and cavitation. The non-Gaussian flow factors are incorporated in the average Reynold's equation to include the effect of non-Gaussian roughness. Whereas, the Weibull probability distribution function is employed to model the asymmetry in asperity heights. It is found that surfaces with more negative skewness exhibit lower engine total frictional force in the vicinity of the dead centres. No substantial effect of the skewness and surface roughness is observed in the mid-stroke of the piston. It is shown that PRCLC operates in mixed-EHL regime near the dead centres. The lambda ratio is found to increase with an increase in skewness of the rough surface.

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“…This study utilizes non-Newtonian Eyring shear stress model to calculate the fluid frictional force. The relation between shear stress and shear strain rate is given in equation ( 19) [6]:…”

Section: Rimentioning

confidence: 99%

“…where η 0 is the viscosity at ambient pressure and temperature, p h,eff is the effective hydrodynamic pressure calculated according to equation given in equation (21) [6].…”

Section: {( ) ( )mentioning

confidence: 99%

“…Gearbox in wind power turbines primarily operates under mixed-EHL regime due to low rolling speed of meshing gear teeth. In the mixed-EHL regime, total transmitted load is carried by asperities as well as the fluid film [6]. Firstly, Johnson et al [7] developed a stochastic mixed-EHL model by using load sharing concept, and a good match between numerical and experimental coefficient of friction was found.…”

Section: Introductionmentioning

confidence: 99%

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Prediction of coefficient of friction for different surface topography in mixed-EHL regime

Prajapati¹

2021

Surf. Topogr.: Metrol. Prop.

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The operation of concentrated contacts observed in gearboxes, rolling element bearings, and cams/followers of valve etc of several machinery and mechanical systems in the mixed-elastohydrodynamic lubrication (mixed-EHL) regime is one of the key reasons for occurring the incident of surface contact fatigue. Due to significant asperity interactions in the mixed-EHL regime, the friction coefficient is profoundly affected by the surface topography of mating bodies. Thus, exploration of role of surface topography on coefficient of friction in mixed-EHL regime is a vital issue. This work proposed a model for investigating the effect of different surface topography on the coefficient of friction of concentrated contacts under mixed-EHL regime. The results achieved with the proposed mixed-EHL model are validated by performing rolling/sliding experiments. A good match is found between experimental and predicted coefficient of friction. Based on the investigation, it is also concluded that a surface with small fraction of summits can operate in boundary lubrication regime at high-load and low-speed conditions. A surface with lower correlation length exhibit elastic-plastic deformation at higher coefficient of friction. High value of friction coefficient is observed for rough surface (S q > 0.5 μm) at even higher rolling speed (1 m s−1).

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Effect of topography parameter, load, and surface roughness on friction coefficient in mixed lubrication regime

Cited by 13 publications

References 19 publications

Study of mixed-EHL traction coefficient between cam-roller follower interface under different operating conditions

Study of mixed-EHL traction coefficient between cam-roller follower interface under different operating conditions

Research on tribological performance of piston ring/liner conjunction considering non-Gaussian roughness and cavitation

Prediction of coefficient of friction for different surface topography in mixed-EHL regime

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