Proceedings of SerbiaTrib '13

Table 1: Nomenclature of Symbols.Terms Definition Value Terms Definition ValueF h and M hF fh andM fhF MBHydrodynamic Force andmomentfrictional force andmoment due to lubricantfilmInertial force due toprimary bodyCalculated byintegratinghydrodynamic pressuresCalculated byintegrating the ShearstressCalculated by Equation(3)M MBF MB andF FınF G Gas Force or Thrust Force Pre-defined term aYF FinInertial force due to FinCalculated by Equation(4)I BMoment due to massof primary bodyReciprocatinginertial forcesAcceleration of thebodyCalculated byEquation (5)Calculated byEquation (7)Calculated byEquation (8)Calculated byEquation (9)Angular moment of Inertia about thebody’s center of massxPerpendicular distance from point of application ofF MB to the center of gravity of FinC Constantη p Viscosity at Pressure ‘p’ p Concerned pressureη 0Viscosity at atmosphericpressuren Constantαpressure viscosity coefficientThe slope of this graph is α[16]Obtained throughexperimental dataApproximately 16Calculated by plotting the natural algorithm of dynamic viscosity versus pressure.For the case of boundary lubrication nohydrodynamic film is sustained. The coefficient offriction is very high and friction is proportional tothe applied load for a certain range of slidingvelocity and temperature.Fluid film lubrication is further classified ashydrodynamic and Elastohydrodynamiclubrication, based on the fact that the surfacesunder consideration show remarkable elasticdeformation or not. As evident from abovediscussion the selection of lubrication regime isvery important and is completely dependent on thecircumstances under which the surfaces come incontact.The present research is focussed on thelubrication solution for problem under the regimeof elastohydrodynamic lubrication. The presentresearch is devided into 7 sections. Section 2focusses on the literature studied and benchmarkedfor the present research. The problem underconsideration is explained in the section 3.The constraints explained in the senction 3 laiddown the basics for developement of amethodology for the solution, the same isexplained in the section 4. Section 5 explains theresults obtained on the basis of methodology ofsection 4. Section 6 concludes the work bydrawing the conclusions based on discussions ofsection 5.2. LITERATURE SURVEY:The studies in the field of tribology initiated in19 th century with the experiment of BeauchampTower when he noticed that the oil film providedin between the surfaces of a journal bearing tries topump out of a hole provided on top of the bearing.He conculded that the pumping phenomenon canbe explained with the generation of hydrodynamicpressure between the bearing surfaces.Reynolds in 1886 [2] provided themathematical solution for the generation of abovementioned pressure. The theory presented byReynolds provided the long waited analytical proofof the hydrodynamic pressure generated betweenthe surfaces. This hydrodynamic pressure helpskeep the surfaces apart and thus avoiding themetal-metal contact which inturn avoid themechanical wear.After Reynolds, many scholars tried to predictthe lubricant film thickness based on his work, forproblem related to different types of bearingsincluding thrust bearing, journal bearing and sliderbearing etc. The most notable work in this reagrdwas done in the field of automobiles to predict thelubrication solution for piston-liner assembly.G.M. Hamilton in 1972 [3] predicted the filmthickness solution for piston-liner problem whileconsidering the regime of hydrodynamiclubrication. Further in 1977 Hamrok and Dowson[4] formulated the empirical formulae for filmthickness calculation.252 13 th International Conference on Tribology – Serbiatrib’13