Fundamentals and Advances in Elastohydrodynamics: The Role of Ramsey Gohar

Johns-Rahnejat, P.M.; Karami, G.; Aini, R.; Rahnejat, Homer

doi:10.3390/lubricants9120120

Cited by 6 publications

(6 citation statements)

References 123 publications

(154 reference statements)

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“…However, due to the non-linear nature of the relationships, it is necessary to use an iterative numerical technique to solve the problem at any instant of time within a meshing cycle. The Effective Influence Newton-Raphson (EIN) method, which is well-established for the solution of EHL problems, especially at high loads [39,[59][60][61], is used within the following procedure:…”

Section: Methods Of Solutionmentioning

confidence: 99%

Non-Newtonian Thermo-Elastohydrodynamics and Sub-Surface Stress Field of High-Performance Racing Spur Gears

et al. 2022

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Meshing teeth pairs of involute spur gears often form the final drive of high-performance motorsport transmissions. They are subject to high normal and shear loading. Under transient conditions pertaining to a meshing cycle, the contact conditions alter from the onset of teeth pair engagement through to maximum normal loading, followed by contact separation. Sliding motion only ceases instantaneously at the pitch point. The regime of lubrication remains mostly in non-Newtonian thermo-elastohydrodynamic conditions. The results show that a starved inlet boundary is attained throughout most of the meshing cycle which leads to the diminution of the pressure spike at the exit from the contact conjunction. The reversing sub-surface shear stresses are the main source of the onset of any inelastic deformation, which is dominated by the primary pressure peak in compliance with the Hertzian maximum pressure. The shear stress field is supplemented by an induced field due to the presence of the pressure spike. Under starved conditions this secondary stress field is diminished. The combined solution of elastohydrodynamics with a thermal network model, non-Newtonian lubricant traction, and sub-surface stress evaluation provides for a comprehensive solution not hitherto reported in the literature.

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Section: Methods Of Solutionmentioning

confidence: 99%

Non-Newtonian Thermo-Elastohydrodynamics and Sub-Surface Stress Field of High-Performance Racing Spur Gears

et al. 2022

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“…Computational models and simulations play a pivotal role in the field of bio-tribology research as they enable the examination of intricate interactions across multiple dimensions [63,64]. These models facilitate the comprehension of the tribological characteristics of biological interfaces by researchers, including the atomic-level interactions that dictate friction and attrition in biomolecules.…”

Section: Role Of Computational Models In Optimizing Tribological Perf...mentioning

confidence: 99%

Recent Advances in Bio-Tribology From Joint Lubrication to Medical Implants: A Review

Akhai,

Wadhwa

2024

J. Mater. Eng.

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Bio-tribology, the study of lubrication, wear, and friction in biological systems, has made recent strides in the lubrication of medical implants and joints. This comprehensive review discusses the most recent developments in bio-tribology, with an emphasis on the transition from basic science to medical engineering applications. An overview of bio-tribology and its increasing significance in medicine commences the study. Following this, recent research on the composition of synovial fluid and its function in minimizing friction in natural joints is discussed. Medical implant tribology, including degradation issues in dental prostheses and joint replacements, is then addressed. This study investigates the manner in which surface modifications and coatings improve the tribological performance of medical implants. It emphasizes recent developments in material science and engineering. This article emphasizes the significance of minimizing implant material degradation in relation to the functionality and longevity of biomedical devices. Following this, digital models, simulations, and state-of-the-art imaging techniques that have propelled bio-tribology forward are highlighted. In addition to proposing potential research avenues to overcome the current obstacles, the article highlights the interdisciplinary nature of bio-tribology and urges collaboration among tribology, materials science, and biomechanics researchers.

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“…Additionally, another correction can be applied to account for pseudoplastic behaviour or shear-thinning [41]. The expression (4) is based on the Carreau model [53] and provides the shear-thinned central film thickness, also taking into account the thermal effects of Equation (3).…”

Section: Type Of Geometry Newtonian Film Thickness Hertzian Parametersmentioning

confidence: 99%

“…The significant prominence that tribology has gained in recent decades has contributed to technological progress in many sectors [1,2]. Continuous research in this field has led to the development of extensive knowledge, which is essential to face tribological challenges of the present and future [3,4].…”

Section: Introductionmentioning

confidence: 99%

An Analytical Approach for Predicting EHL Friction: Usefulness and Limitations

et al. 2022

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The article studies the friction coefficient in elastohydrodynamic lubrication (EHL) by means of analytically obtained equations for different contact geometries. The introduction of some simplifications allows for the simultaneous consideration of piezoviscous, pseudoplastic and thermal phenomena, resulting in complete and realistic models, which provide results in a quick and easy manner. The predictive potential of this analytical approach is analyzed by comparing the estimates of friction with full-EHL simulations and experimental data under different operating conditions. The results obtained allow us to discuss the influence of some assumptions taken into account and the scope of applicability of the models, in order to determine their usefulness and limitations.

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Fundamentals and Advances in Elastohydrodynamics: The Role of Ramsey Gohar

Cited by 6 publications

References 123 publications

Non-Newtonian Thermo-Elastohydrodynamics and Sub-Surface Stress Field of High-Performance Racing Spur Gears

Non-Newtonian Thermo-Elastohydrodynamics and Sub-Surface Stress Field of High-Performance Racing Spur Gears

Recent Advances in Bio-Tribology From Joint Lubrication to Medical Implants: A Review

An Analytical Approach for Predicting EHL Friction: Usefulness and Limitations

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