Numerical modelling of elastohydrodynamic lubrication in soft contacts using non‐Newtonian fluids

Bohan, M. F. J.; Fox, Ian; Claypole, Tim; Gethin, D. T.

doi:10.1108/09615530210433297

Cited by 14 publications

(10 citation statements)

References 15 publications

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“…There has been no other published work that the model can be compared with directly since previous investigations have focused on blade squeegees and have excluded deformation effects. Therefore, to validate the numerical model, it was compared initially with results from simulating a roller pair in an SEHL junction [21]. The settings used are itemized in Table 1.…”

Section: Validation For An Impermeable Screenmentioning

confidence: 99%

See 1 more Smart Citation

Film thickness prediction in halftone screen-printing

Fox

Bohan

Claypole

et al. 2003

Proceedings of the Institution of Mechanical Engineers, Part E:

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The paper presents a numerical model of image transfer in screen-printing that is supported by experimental data. The model focuses on a roller squeegee system. It combines thin lm hydrodynamic behaviour with roller squeegee deformation and ow through a porous screen. The work within this investigation has, for the rst time, enabled an estimate of deposit thickness at different halftone coverage. For low coverage, ink transfer is governed by hydrodynamic behaviour in the nip contact, and deposited lm thickness is represented by an ink spread model. For larger open areas, dependent on squeegee load, the lm is removed from the top of the screen and therefore the deposit is likely to be controlled by the screen thickness. The work con rms that a roller squeegee system leads to higher nip pumping capacity in comparison with a sliding squeegee of nominally the same shape. The roller system is therefore appropriate when heavy ink deposits are required. The velocity gradients through the lm when ink ows through the screen are reduced as the open area increases. The consequent reduction in shear rate leads to a recovery in viscosity within the nip contact.

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Section: Validation For An Impermeable Screenmentioning

confidence: 99%

“…For the numerical model to be used to calculate the rheological properties within the nip contact region, it is necessary to carry out a validation study in order to con rm Fig. 6 [21].…”

Section: Validation For An Impermeable Screenmentioning

confidence: 99%

Film thickness prediction in halftone screen-printing

Fox

Bohan

Claypole

et al. 2003

Proceedings of the Institution of Mechanical Engineers, Part E:

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“…Besides, the soft elastohydrodynamic contacts are also concerned by some tribological researchers. Bohan et al 17 explored the non-Newtonian fluid behaviour in soft elastohydrodynamic nip contacts, and found the viscosity coefficient, power law index and sliding ratio all affect the nip flow rate and film thickness in a non-linear manner. Lim et al 18 adopted a shear rate cut-off model to predict the positive film pressure zone to analyse the EHL behaviour of soft rolling contacts.…”

Section: Introductionmentioning

confidence: 99%

Plasto‐elastohydrodynamic lubrication performance of greased ellipsoid contact

Zheng

Gong

et al. 2021

Lubrication Science

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The plasto-elastohydrodynamic lubrication (PEHL) model of the greased ellipsoid contact is established and solved numerically. In doing so, the increment theory of the plastic surface is adopted to solve the residual deformation, and the fast Fourier transform (FFT) method is employed to accelerate the deformation and stress calculations. Meanwhile, the effeteness of the PEHL model is verified through the residual stress experiment and finite element method. It is found that the plastic behaviour results in a reduction in the maximum grease film pressure. Under heavy load conditions, the grease with large rheology index, large tangential modulus or high entrainment speed of the lubricant is helpful to reducing the maximum residual deformation and maximum residual stress of the greased ellipsoid contact.

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“…36–40 The power law model takes into consideration the shear-thinning and shear-thickening behavior and, therefore, has been investigated by various researchers. 41–46 The non-Newtonian behavior of lubricants can be established by the consideration of power law fluid model characterized by the relation between shear stress and velocity gradient. The power law introduced by Ostwald and de Waele considers the characteristic constants “ m ” and “ n ” representing the consistency and flow index of the fluid.…”

Section: Introductionmentioning

confidence: 99%

A parametric investigation on the microelastohydrodynamic lubrication of power law fluid lubricated line contact

Thakre

Sharma

Harsha

et al. 2015

Proceedings of the Institution of Mechanical Engineers, Part J:

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A parametric study of microelastohydrodynamic lubrication contact between rough cylinder and plane lubricated with non-Newtonian power law fluid is carried out. A Gaussian rough surface is considered and modeled using stochastic approach. A theoretical solution of pressure distribution, fluid film thickness, and friction for given speeds, material properties, slide-to-roll ratio, and power law index, is obtained by solution of Reynolds equation using finite element method techniques. An isotropic roughness pattern is considered and results are obtained for wide range of operating parameters. The results indicate that the shear-thickening fluids provide thicker lubricant films as compared to shear-thinning fluids. The minimum fluid film thickness is observed to decrease with an increase of load and it increases with an increase of speed and material parameter. Slide-to-roll ratio has a marginal influence of the minimum film thickness. Under certain operating conditions, softer materials with shear-thickening lubricants yield thicker lubricant films than the harder materials lubricated with shear-thinning fluids. The coefficient of friction too is influenced by the rheology of lubricants with shear-thinning fluids providing larger values of coefficient of friction than the shear-thickening fluids.

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Numerical modelling of elastohydrodynamic lubrication in soft contacts using non‐Newtonian fluids

Cited by 14 publications

References 15 publications

Film thickness prediction in halftone screen-printing

Film thickness prediction in halftone screen-printing

Plasto‐elastohydrodynamic lubrication performance of greased ellipsoid contact

A parametric investigation on the microelastohydrodynamic lubrication of power law fluid lubricated line contact

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