New concepts of homogenization applied in rough surface hydrodynamic lubrication

Almqvist, Andreas; Lukkassen, Dag; Meidell, Annette; Wall, Peter

doi:10.1016/j.ijengsci.2006.09.005

Cited by 35 publications

(16 citation statements)

References 17 publications

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“…A series of works have been published by Almqvist which contributed to the consolidation and widespread use of homogenization methods in lubrication applications [176][177][178][179][180][181]. The homogenization method proposed by Almqvist has been used to investigate the effect of roughness and surface texture on the tribological performance of different machine elements, such as piston-ring cylinder liner contact and rotating devices [179,[182][183][184][185][186][187].…”

Section: Homogenization Methodsmentioning

confidence: 99%

Multi-Scale Surface Texturing in Tribology—Current Knowledge and Future Perspectives

2019

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Surface texturing has been frequently used for tribological purposes in the last three decades due to its great potential to reduce friction and wear. Although biological systems advocate the use of hierarchical, multi-scale surface textures, most of the published experimental and numerical works have mainly addressed effects induced by single-scale surface textures. Therefore, it can be assumed that the potential of multi-scale surface texturing to further optimize friction and wear is underexplored. The aim of this review article is to shed some light on the current knowledge in the field of multi-scale surface textures applied to tribological systems from an experimental and numerical point of view. Initially, fabrication techniques with their respective advantages and disadvantages regarding the ability to create multi-scale surface textures are summarized. Afterwards, the existing state-of-the-art regarding experimental work performed to explore the potential, as well as the underlying effects of multi-scale textures under dry and lubricated conditions, is presented. Subsequently, numerical approaches to predict the behavior of multi-scale surface texturing under lubricated conditions are elucidated. Finally, the existing knowledge and hypotheses about the underlying driven mechanisms responsible for the improved tribological performance of multi-scale textures are summarized, and future trends in this research direction are emphasized.

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Section: Homogenization Methodsmentioning

confidence: 99%

Multi-Scale Surface Texturing in Tribology—Current Knowledge and Future Perspectives

2019

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“…For a micro‐texture with grooves, A is diagonal with components

A_{⊥} = {(⟨⟩, a^{– 1})}^{– 1}, A_{false‖} = ⟨ a ⟩,

where ‖ (⊥) indicates the direction that is parallel (perpendicular) to the grooves. Denoting the analytical estimates for NOF values via

\overset{η}{true}

, one then concludes

\begin{matrix} right {\bar{η}}_{\min}^{A} = A_{⊥} / a_{0} \leq 1, {\bar{η}}_{\max}^{A} = A_{‖} / a_{0} \geq 1 . \end{matrix}

The reader is referred to the works of Almqvist et al and Lukkassen et al for an analysis of bounds associated with the flow factor tensors.…”

Section: Micro‐texture Optimalitymentioning

confidence: 99%

“…The reader is referred to the works of Almqvist et al 66 and Lukkassen et al 67 for an analysis of bounds associated with the flow factor tensors.…”

Section: Flow Factor Tensormentioning

confidence: 99%

Microscopic design and optimization of hydrodynamically lubricated dissipative interfaces

Çakal

Temizer

Terada

et al. 2019

Numerical Meth Engineering

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Summary A homogenization‐based topology optimization framework is developed, which can endow hydrodynamically lubricated interfaces with a micro‐texture, to achieve optimal macroscopic responses by addressing both dissipative and nondissipative physics at the interface. With respect to the homogenization aspects of the problem, the thermodynamic consistency of the two‐scale formulation is explicitly analyzed and verified. With respect to the topology optimization aspects, a variational approach to sensitivity analysis is pursued. Subsequently, these are employed in micro‐texture design studies, which address microscopic and macroscopic objectives. The influence of dissipation on the optimization results is demonstrated through extensive numerical investigations, which also highlight the importance of working in a sufficiently flexible design space that can deliver nearly optimal micro‐texture geometries.

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“…Cavitation has also been considered, accounting for both inter-asperity cavitation and a macroscopic cavitation zone resulting from a diverging geometry of the bearing. 28,29 More recently, the homogenization method, used for the numerical solution of partial differential equations with rapidly changing coefficients, 30 has been implemented to solve lubrication problems that involve surface roughness. [31][32][33][34][35][36] These studies have significantly improved the understanding of surface topography effects in lubrication films in nominally smooth bearings.…”

Section: Andmentioning

confidence: 99%

The load-carrying capacity and friction coefficient of incompressible textured parallel slider bearings with surface roughness inside the texture features

Qiu

Raeymaekers

2014

Proceedings of the Institution of Mechanical Engineers, Part J:

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Surface texturing is used to increase hydrodynamic pressure and reduce friction and wear between parallel sliding surfaces in a variety of applications. The shape, geometry, and density of the patterned microtexture features play a key role in the tribological performance of such textured slider bearings. Lubrication models are used to predict the load-carrying capacity, friction coefficient, and volume flow rate of textured bearings, assuming a smooth surface and ideal shape of the texture features. However, experimental evidence shows that manufacturing techniques such as laser surface texturing only approach the ideal shape of the texture features. Moreover, the manufacturing process typically creates roughness inside the texture features. In this paper, we numerically evaluate the effect of roughness inside the texture features on the load-carrying capacity, friction coefficient, and volume flow rate of the textured parallel slider bearing. We consider the cases of sinusoidal roughness and isotropic random roughness with Gaussian distribution of surface heights and find that the effect of roughness inside the texture features on the bearing load-carrying capacity and friction coefficient increases with increasing roughness height and increasing wavelength of the roughness. In addition, the effect of sinusoidal roughness is larger than the effect of isotropic random roughness with Gaussian distribution of surface heights. We also find that the roughness inside the texture features has negligible impact on the volume flow rate of the textured bearing.

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New concepts of homogenization applied in rough surface hydrodynamic lubrication

Cited by 35 publications

References 17 publications

Multi-Scale Surface Texturing in Tribology—Current Knowledge and Future Perspectives

Multi-Scale Surface Texturing in Tribology—Current Knowledge and Future Perspectives

Microscopic design and optimization of hydrodynamically lubricated dissipative interfaces

The load-carrying capacity and friction coefficient of incompressible textured parallel slider bearings with surface roughness inside the texture features

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