Squeeze-film of unconformal, compliant and layered contacts

Pascovici, M. D.; Cicone, Traian

doi:10.1016/s0301-679x(03)00095-1

Cited by 26 publications

(21 citation statements)

References 6 publications

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“…The rate that the eyelid slides past the cornea during a blink as well as the upper limit on sliding speeds in articulating joints fall within this range. Considering the conformal geometries, numerical simulations suggest that hydrodynamic lubrication should separate the surfaces above ~ 100 mm s -1 [56][57][58]. In the future, using hydrogels as highly controllable tissue mimics, we can explore the role of polymer charge density and fluid viscosity in hydrogel friction to draw further connections between tissue and hydrogels.…”

Section: Resultsmentioning

confidence: 99%

Mesh Size Control of Polymer Fluctuation Lubrication in Gemini Hydrogels

et al. 2015

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Section: Resultsmentioning

confidence: 99%

Mesh Size Control of Polymer Fluctuation Lubrication in Gemini Hydrogels

et al. 2015

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“…Recent technological advances in surface treatment enable the introduction of such designs, with resolution accuracy in the micron scale [4]. The performance potential of texture patterns in improving bearing performance has been demonstrated in recent computational studies utilizing the Reynolds equation [5][6][7][8][9], as well as in recent CFD studies [9][10][11][12]. Lately, optimization studies of bearing texture patterns have been reported, aiming at an identification of proper texture geometry parameters, for optimal bearing performance [13][14][15][16][17].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Stiffness and Damping in Textured Sector Pad Micro Thrust Bearings Using Computational Fluid Dynamics

Papadopoulos

Nikolakopoulos

Kaiktsis

2012

Journal of Engineering for Gas Turbines and Power

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In the present paper, a study of stiffness and damping in sector-pad micro thrust bearings with artificial surface texturing is presented, based on computational fluid dynamics (CFD) simulations. The bearing pads are modeled as consecutive three-dimensional independent microchannels, each consisting of a smooth rotating wall (rotor) and a partially textured stationary wall (stator). CFD simulations are petformed, consisting in the numerical solution of the Navier-Stokes equations for incompressible isothermal flow. The goal of the present study is to characterize the dynamic behavior of favorable designs, identified in previous optimization studies, comprising parallel and convergent thrust bearings with rectangular texture patterns. To this end, a translational degree of freedom (DOF) along the thrust direction and a rotational (tilting) DOF of the rotor are considered. By implementing appropriate small perturbations around the equilibrium (steady-state) position and processing the simulation results, the stiffness and damping coefficients of the bearing are obtained for each DOF. The computed dynamic coefficients of textured thrust bearings are compared to those of conventional (smooth slider) designs. It is found that the dependence of bearing stiffness and damping on geometrical parameters exhibits the same trends for both DOFs. Both stiffness and damping are found to increase with bearing width. In general, increasing the bearing convergence ratio results in iticreased bearing stiffness and decreased damping. Finally, the present results demonstrate that properly textured parallel sliders are characterized by an overall dynamic performance that is superior to that of smooth converging sliders.

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“…The surface topography of these devices is a function of the material parameters and of molding conditions but have a typical R q of 5-10 nm [5]. Estimates of the contact pressure created by the eyelid during blinking range from 3.5 to 4.0 kPa and blinking speed average around 12 cm/s [6][7][8][9]. This combination of low contact pressure and moderate sliding speed are challenging to match with tribological instruments.…”

Section: Introductionmentioning

confidence: 99%

Friction Coefficient Measurement of Hydrogel Materials on Living Epithelial Cells

et al. 2008

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Soft biomaterials are often used in applications that involve contact and relative motion against biological tissues, as well as complicated and variable environments. The friction coefficient of these contacts involving living human cells is of key importance in the analysis and success of these devices. This work measures the contacting friction coefficient between soft hydrogel biomaterial surfaces against live human corneal epithelial cells using a custom micro-tribometer. The friction coefficients were of the order of l = 0.03 for contacts that did not cause gross destruction of the cell layer. Damage to the confluent cell layer was assessed using a Trypan blue stain with optical microscopy. This damage was quantified statistically using image-processing software. The damage was also correlated to in situ friction measurements, with the lowest friction values seen on undamaged cells and higher friction on damaged regions.

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Squeeze-film of unconformal, compliant and layered contacts

Cited by 26 publications

References 6 publications

Mesh Size Control of Polymer Fluctuation Lubrication in Gemini Hydrogels

Mesh Size Control of Polymer Fluctuation Lubrication in Gemini Hydrogels

Characterization of Stiffness and Damping in Textured Sector Pad Micro Thrust Bearings Using Computational Fluid Dynamics

Friction Coefficient Measurement of Hydrogel Materials on Living Epithelial Cells

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