Elastohydrodynamic solution for concentrated elliptical point contact of machine elements under combined entraining and squeeze-film motion

Abstract

• Abstract: This paper presents numerical solution of isothermal elastohydrodynamic conjunction for concentrated contact of elastic bodies under the elliptical point contact condition. The solution includes the effect of squeeze-film motion that occurs under transient conditions due to the application of cyclic loads and/or oscillating motions in machine elements. It is shown that this time-dependent behaviour increases the load-carrying capacity of the contact which is largely responsible as a mechanism of lubricant film formation when the low speeds of entraining motion yield a low film thickness. An extrapolated oil-film thickness formula is also presented that can be employed under dynamic conditions.

Cavitation induced starvation for piston-ring/liner tribological conjunction

“…The model has at the base the approach proposed by Vijayaraghavan and Keith [15] for Elrod's cavitation algorithm. To account for localised contact deflection, which could have significant consequences for the cavitation development, the finite difference scheme suggested by Jalali et al [14] for an elastohydrodynamic contact was carefully adapted for the current conditions.…”

“…Equation (17) is solved using the finite difference scheme suggested by Jalali et al [14]. The Poiseuille term is discretized using central differences.…”

“…The pressure loop uses the iterative approach proposed by Jalali et al [14] for integrating Reynolds equation as a starting point. However, here the convergence is focused on θ and the lubricant pressure is computed after the convergence is achieved.…”

“…The classic formulation of the Reynolds equation does not account for the negative pressure in the diverging part of the contact [13]. One possible solution is limiting the outlet pressures to the atmospheric pressure [14] or to the cavitation pressure [15]. Although this is a very fast method, mass conservation of the fluid flow in the cavitation region is not fulfilled.…”

“…However, localised contact deflection (especially in the vicinity of the dead centers) could have significant consequences for the cavitation development (this will be discussed in figure 11). To account for it, the finite difference scheme suggested by Jalali et al [14] for an elastohydrodynamic contact was carefully adapted for the current conditions. The resulted integrated approach is referred to as Modified Elrod (Mod.…”