Theoretical Investigation of Transient Ultra-Thin Lubricant Film During Rapid Deceleration

Al-Samieh, M.F. Abd

doi:10.24874/ti.2018.40.03.02

Cited by 5 publications

(4 citation statements)

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“…Another layered model has been developed for assessing the effect of adsorption films on lubrication, and numerical results predict a film thicknessvelocity (h-v) dependence in a better agreement with that measured in thin film EHL [608]. In numerical solutions of thin film lubrication when film thickness decreases down to a few nanometers, surface forces due to the van de Waals interactions and electrostatic double layer have to be incorporated [589], and they are found to contribute significantly to the film formation that prevents surfaces from sticking at zero speed. In a recent attempt to model tribochemistry in mixed lubrication, Azam et al [609] have presented a formula that balances the tribofilm growth described in the Arrhenius equation with film removal obeying an exponential law.…”

Section: Incorporation Of Surface Interactionsmentioning

confidence: 99%

A review of recent advances in tribology

et al. 2020

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The reach of tribology has expanded in diverse fields and tribology related research activities have seen immense growth during the last decade. This review takes stock of the recent advances in research pertaining to different aspects of tribology within the last 2 to 3 years. Different aspects of tribology that have been reviewed including lubrication, wear and surface engineering, biotribology, high temperature tribology, and computational tribology. This review attempts to highlight recent research and also presents future outlook pertaining to these aspects. It may however be noted that there are limitations of this review. One of the most important of these is that tribology being a highly multidisciplinary field, the research results are widely spread across various disciplines and there can be omissions because of this. Secondly, the topics dealt with in the field of tribology include only some of the salient topics (such as lubrication, wear, surface engineering, biotribology, high temperature tribology, and computational tribology) but there are many more aspects of tribology that have not been covered in this review. Despite these limitations it is hoped that such a review will bring the most recent salient research in focus and will be beneficial for the growing community of tribology researchers.

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Section: Incorporation Of Surface Interactionsmentioning

confidence: 99%

A review of recent advances in tribology

et al. 2020

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“…Therefore, in such elements, the assumption of a steady-state solution is inappropriate to study both film thickness and contact pressure to protect such components form direct contact and damage. A series of theoretical and experimental studies of the effect of transient conditions on the behavior of lubricated elastohydrodynamic film have been reported in the past for different aspects of transient conditions such as variation due to surface velocity (Ehret et al, 1999;Vahid et al, 2001;Kushwaha and Rahnejat, 2004;Zhang and Glovnea, 2015;Petr et al, 2015;Al-Samieh, 2018) and variation due to surface geometry (Venner et al, 1997;Huang et al, 2015;Huang and Wang, 2016). Transient conditions of elastohydrodynamic lubrication subjected to vibration of load have received less attention because of the fact that the load has a small influence upon the steady-state film thickness and the difficult experimental setup.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of elastohydrodynamic contacts subjected to harmonic load variation

Alsamieh

2019

ILT

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Purpose The purpose of this paper is to study the behavior of elastohydrodynamic contacts subjected to forced harmonic vibrations including the effect of changing various working parameters such as frequency, load amplitude and entrainment speed. Design/methodology/approach The time-dependent Reynolds equation is solved using the Newton–Raphson technique. The film thickness and pressure distribution are obtained at every time step by simultaneous solution of the Reynolds equation and film thickness equation including elastic deformation. Findings The frequency of vibration, load amplitude and entrainment speed are directly related to the film thickness perturbation, which is formed during load increasing phase of the cycle. The film thickness formed during load increasing phase is larger than that formed during load decreasing phase with larger deviation at a higher frequency or load amplitude and vice versa for lower frequency or load amplitude. The entrainment speed of the contact has an opposite effect to that of the frequency of vibration or load amplitude. Originality/value Physical explanations for the behavior of elastohydrodynamic contact subjected to forced harmonic vibration are presented in this paper for various working parameters of frequency, load amplitude and entrainment speed.

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“…where δ(X,Y,T) is the total elastic deformation (Gohar and Rahnejat, 2008; Al-Samieh, 2018, 2019) and is given as: where:…”

Section: Background Theorymentioning

confidence: 99%

Effect of changing geometrical characteristics for different shapes of a single ridge passing through elastohydrodynamic of point contacts

Alsamieh

2021

ILT

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Purpose The purpose of this paper is to study the behavior of a single ridge passing through elastohydrodynamic lubrication of point contacts problem for different ridge shapes and sizes, including flat-top, triangular and cosine wave pattern to get an optimal ridge profile. Design/methodology/approach The time-dependent Reynolds’ equation is solved using Newton–Raphson technique. Several shapes of surface feature are simulated and the film thickness and pressure distribution are obtained at every time step by simultaneous solution of the Reynolds’ equation and film thickness equation, including elastic deformation. Film thickness and pressure distribution are chosen to be the criteria in the comparisons. Findings The geometrical characteristics of the ridge play an important role in the formation of lubricant film thickness profile and the pressure distribution through the contact zone. To minimize wear, friction and fatigue life, an optimal ridge profile should have smooth shape with small ridge size. Obtained results are compared with other published numerical results and show a good agreement. Originality/value The study evaluates the performance of different surface features of a single ridge with different shapes and sizes passing through elastohydrodynamic of point contact problem in relation to film thickness and pressure profile.

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Theoretical Investigation of Transient Ultra-Thin Lubricant Film During Rapid Deceleration

Cited by 5 publications

References 0 publications

A review of recent advances in tribology

A review of recent advances in tribology

Numerical investigation of elastohydrodynamic contacts subjected to harmonic load variation

Effect of changing geometrical characteristics for different shapes of a single ridge passing through elastohydrodynamic of point contacts

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