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Keywords: parallel thrust bearing, surface texturing, friction coefficient.

Summary

The aim of the work described in this paper is to provide an effective numerical tool to examine through a parametric analysis how texture might influence tribological characteristics in a mixed lubrication regime.

A simplified geometrical model of a single pad in the form of a rectangular parallel slider is considered in this paper. It is well known, in fact, that each pad, when properly textured, develops the same hydrodynamic force. Hence, in order to evaluate the load carrying capacity of the complete parallel thrust bearing it is sufficient to determine the hydrodynamic pressure distribution over a single pad. The Reynolds equation in two-dimensional form, that governs the problem studied is applied to problems in finite geometry, does not permit exact analyticalsolution but requires a resolution of the numerical type. Moreover, obtaining the solution is further complicated by the equation of balance of the loads arising from both the fluid and the multi asperity contacts. Furthermore, the discretization with a fixed grid has led to large numbers of nodes, in order to reconstruct with accuracy the pressure distribution inside the cavities.

Therefore a numerical study of a thrust bearing with a series of dimples created on the stationary surface was carried out in order to evaluate the influence of the texture parameters. Simulations were performed varying the parameters of, width, depth and density of the dimples. The results obtained are presented in terms of pressure distribution, friction coefficient, minimum film thickness and load carrying capacity. The main conclusions that can be drawn are:

the partial laser texturing seems to be much more suitable than the full laser texturing to the formation of a pressure that can support external loads
the existence of dimples on the steel surface was observed to reduce the friction coefficient substantially, when compared with un-textured surfaces
the positive effect of the dimples does not depend linearly by their number; the dimple influence is affected by working conditions and the width of the dimples
one of the key parameters appears to be the aspect ratio, it is not possible to uniquely identify an optimum value as this depends on the mutual distance between the dimples

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Front Page Browse CCP CSETS CTR IJRT Other Authors Search Purchase Guide FAQ Contact us	Civil-Comp Proceedings ISSN 1759-3433 CCP: 100 PROCEEDINGS OF THE EIGHTH INTERNATIONAL CONFERENCE ON ENGINEERING COMPUTATIONAL TECHNOLOGY Edited by: B.H.V. Topping Paper 78 A Numerical Approach to the Effect of Surface Texturing on Parallel Thrust Bearings F. Abate, V. D'Agostino and R. Di Giuda Department of Industrial Engineering, University of Salerno, Fisciano (SA), Italy doi:10.4203/ccp.100.78 purchase the full-text of this paper Full Bibliographic Reference for this paper F. Abate, V. D'Agostino, R. Di Giuda, "A Numerical Approach to the Effect of Surface Texturing on Parallel Thrust Bearings", in B.H.V. Topping, (Editor), "Proceedings of the Eighth International Conference on Engineering Computational Technology", Civil-Comp Press, Stirlingshire, UK, Paper 78, 2012. doi:10.4203/ccp.100.78 Keywords: parallel thrust bearing, surface texturing, friction coefficient. Summary The aim of the work described in this paper is to provide an effective numerical tool to examine through a parametric analysis how texture might influence tribological characteristics in a mixed lubrication regime. A simplified geometrical model of a single pad in the form of a rectangular parallel slider is considered in this paper. It is well known, in fact, that each pad, when properly textured, develops the same hydrodynamic force. Hence, in order to evaluate the load carrying capacity of the complete parallel thrust bearing it is sufficient to determine the hydrodynamic pressure distribution over a single pad. The Reynolds equation in two-dimensional form, that governs the problem studied is applied to problems in finite geometry, does not permit exact analyticalsolution but requires a resolution of the numerical type. Moreover, obtaining the solution is further complicated by the equation of balance of the loads arising from both the fluid and the multi asperity contacts. Furthermore, the discretization with a fixed grid has led to large numbers of nodes, in order to reconstruct with accuracy the pressure distribution inside the cavities. Therefore a numerical study of a thrust bearing with a series of dimples created on the stationary surface was carried out in order to evaluate the influence of the texture parameters. Simulations were performed varying the parameters of, width, depth and density of the dimples. The results obtained are presented in terms of pressure distribution, friction coefficient, minimum film thickness and load carrying capacity. The main conclusions that can be drawn are: the partial laser texturing seems to be much more suitable than the full laser texturing to the formation of a pressure that can support external loads the existence of dimples on the steel surface was observed to reduce the friction coefficient substantially, when compared with un-textured surfaces the positive effect of the dimples does not depend linearly by their number; the dimple influence is affected by working conditions and the width of the dimples one of the key parameters appears to be the aspect ratio, it is not possible to uniquely identify an optimum value as this depends on the mutual distance between the dimples purchase the full-text of this paper (price £20) go to the previous paper go to the next paper return to the table of contents return to the book description purchase this book (price £50 +P&P)
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