Synergy of Viscosity Wedge and Squeeze Under Zero Entrainment Velocity in EHL Contacts

Meziane, Bilel; Fillot, Nicolas; Morales-Espejel, Guillermo E.

doi:10.1007/s11249-020-01311-y

Cited by 3 publications

(4 citation statements)

References 34 publications

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“…The convergence criterion for load balancing is: journal.ump.edu.my/ijame ◄ (10) where, U and V are the whole grid points in X and Y directions.…”

Section: Background Theorymentioning

confidence: 99%

“…The difference between the results for smooth and wavy surface contacts is the appearance of fluctuations in film and pressure profiles, as well as the reduction of the film thickness and increase in pressure for the wavy surface when compared to contact with a smooth surface. journal.ump.edu.my/ijame ◄ [4], Ming et al [5], Ohno [6], Sperka [7], Alsamieh [8], Meziane et al [9,10], and Sivayogan et al [11]. All previous studies, both theoretically and experimentally, have shown that the thickness of the film observed during the transient action is contrary to the predicted values using the theory of steady-state elastohydrodynamics at instantaneous speed since the thickness of the film will be zero as the speed of entraining motion reaches a zero value, which contradicts the results of both experimental and numerical transient action.…”

Section: Introductionmentioning

confidence: 99%

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Transient Elastohydrodynamic Lubrication of Rough Contact Surface for Intermittent Motion

Al-Samieh

2022

Int. J. Automot. Mech. Eng.

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The current study aims to study the characteristics of transient elastohydrodynamic lubrication of smooth and rough surface contacts subjected to intermittent motion for different inactive periods of motion and deceleration/acceleration periods to fulfill an identified need for such conjunction. In this case, the non-steady Reynolds’ equation, the film thickness equation with elastic deformation and taking into account the influence of surface roughness, and the load balance equation are simultaneously solved using the Newton-Raphson with Gauss-Seidel iterations method to determine the film profile and pressure distribution at various time steps. Surface contact of sinusoidal waves is presented with different amplitudes and wavelengths. The results indicated that surface waviness causes random oscillations in pressure and film profiles at different time steps. The greater the amplitude of the waviness, the more pressure and film profile variations occur. The magnitude of the pressure and film profile fluctuations becomes little noticeable as the wavelength of a wavy surface rises. The findings of this investigation also revealed that increasing the inactive duration for wavy surfaces results in zero minimum film thickness and surface contact. Squeezing action is ineffective in conveying loading capacity in this circumstance. The central and maximum pressure heights increase during the stop time interval as stop time increases. The centre film thickness increases at the end of the deceleration phase when the deceleration/acceleration period is reduced, but the minimum film thickness is unaffected. In fact, the minimum film thickness tends to be zero at the end of the deceleration phase, regardless of the deceleration/acceleration period. The central and maximum pressure increase during the stop time interval with the decrease of the deceleration/acceleration period. The difference between the results for smooth and wavy surface contacts is the appearance of fluctuations in film and pressure profiles, as well as the reduction of the film thickness and increase in pressure for the wavy surface when compared to contact with a smooth surface.

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“…The convergence criterion for load balancing is: journal.ump.edu.my/ijame ◄ (10) where, U and V are the whole grid points in X and Y directions.…”

Section: Background Theorymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transient Elastohydrodynamic Lubrication of Rough Contact Surface for Intermittent Motion

Al-Samieh

2022

Int. J. Automot. Mech. Eng.

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“…Yang et al (2016) investigated the starvation effect on non-Newtonian EHL using the distance of a meniscus inlet boundary as a pre-known parameter to predict the film thickness. Meziane et al (2020) studied the viscosity wedge deduced by the thermal effect and squeeze effect of an infinitely long cylinder in a transient non-Newtonian EHL problem. Bai et al (2021a) developed the TEHL model for impact motion conditions integrates the non-Newtonian, thermal and other effects together in a strongly nonlinear equation system.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigations on the lubrication characteristics of involute harmonic gears

Shen,

He,

Gong

2023

ILT

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Purpose Harmonic gears always work under different operating conditions and may usually break down due to lubrication failures, while its lubrication mechanism is still not clearly understood. This paper aims to present a lubrication model comprehensively considering the influence of contact geometry, lubrication properties and three-dimensional (3D) real surface roughness to analyze the lubrication performance under different conditions. Design/methodology/approach Based on the discrete convolution-fast Fourier transformation with duplicated padding and quasi-system numerical methods, the lubrication model for harmonic gears is developed, which is verified by comparing results with available lubrication data. Findings The effects of meshing process, working conditions and 3D roughness on the lubrication characteristics are discussed. From the calculated cases, the increase in rotational speed and decrease of applied torque may increase the film thickness, enhancing the lubrication performance of harmonic gears. It is also observed that proper surface roughness can be used for lubrication design. Originality/value The research results can provide theoretical guidance for improving lubrication performance and reducing friction/wear of the harmonic gear interfaces. This study can be promoted to various engineering scenarios of harmonic gears, such as industrial robots, space-driven agencies and precision measuring instruments.

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“…Later, Yang et al [16,17] put forward a separation flow method to derive analytical lubricant shear rate and velocity, which assumed the lubricant flow as the superposition of the Poiseuille flow and Couette flow. Mezlane et al [18] studied the viscosity wedge deduced by the thermal effect and squeeze effect of an infinitely long cylinder in a transient non-Newtonian EHL problem by applying the Carreau-Yasuda rheological model. Recently, some experimental studies were conducted to investigate the rheological behaviours of non-Newtonian lubricants under the impact load [19,20].…”

Section: Introductionmentioning

confidence: 99%

Modelling of Non-Newtonian Starved Thermal-elastohydrodynamic Lubrication of Heterogeneous Materials in Impact Motion

Bai

Dong

Zheng

et al. 2021

Acta Mech. Solida Sin.

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This study presents a numerical model for the thermal-elastohydrodynamic lubrication of heterogeneous materials in impact motion, in which a rigid ball bounces on a starved non-Newtonian oil-covered plane surface of an elastic semi-infinite heterogeneous solid with inhomogeneous inclusions. The impact–rebound process and the microscopic response of the subsurface inhomogeneous inclusions are investigated. The inclusions are homogenized according to Eshelby’s equivalent inclusion method. The Elrod algorithm is adopted to determine the lubrication starvation based on the solutions of pressure and film thickness, while the lubricant velocity and shear rate of the non-Newtonian lubricant are derived by using the separation flow method. The dynamic response of the cases subjected to constant impact mass, momentum, and energy is discussed to reveal the influence of the initial drop height on the impact–rebound process. The results imply that the inclusion disturbs the subsurface stress field and affects the dynamic response of the contact system when the surface pressure is high. The impact energy is the decisive factor for the stress peak, maximum hydrodynamic force, and restitution coefficient, while the dynamic response during the early approaching process is controlled by the drop height.

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Synergy of Viscosity Wedge and Squeeze Under Zero Entrainment Velocity in EHL Contacts

Cited by 3 publications

References 34 publications

Transient Elastohydrodynamic Lubrication of Rough Contact Surface for Intermittent Motion

Transient Elastohydrodynamic Lubrication of Rough Contact Surface for Intermittent Motion

Numerical investigations on the lubrication characteristics of involute harmonic gears

Modelling of Non-Newtonian Starved Thermal-elastohydrodynamic Lubrication of Heterogeneous Materials in Impact Motion

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