On the Stiffness and Damping Characteristics of Line Contacts under Transient Elastohydrodynamic Lubrication

Abstract

The elastohydrodynamic lubrication (EHL) oil film between contact interfaces acts as a spring or damper to reduce wear and vibration for frictional pairs. To analyze the dynamic behaviors of friction pairs in mechanical systems both effectively and accurately, the stiffness and damping parameters under EHL contact states are essential. The presented work develops a numerical model to investigate the EHL stiffness and damping characteristics based on the transient EHL system and elastic contact theory of line contact, in which the stiffness force is separated according to the relationship with approach distance of the contact body established in the steady process, and then the damping can be obtained. The results show that the stiffness force plays an increasingly important role over the applied load conditions while the damping effects is gradually weakened. EHL stiffness is obviously smaller than dry contact stiffness, but the discrepancy is decreasing with the increasing load. Moreover, the higher entrainment velocity, lubricant viscosity and larger curvature radii leads to smaller stiffness and damping. The elastic modulus generates little effect on dynamic characteristics when the load is light while dominates the maximum level of the contact stiffness.

Dynamical model of fatigue pitting fault helical gear pair considering lubricating oil film influence: Theoretical analysis and experimental verification

“…Total damping and stiffness of the j th slice of the i th LOA at the moment t can be computed by inserting the parameters into Eqs. (19)(20)(21)(22)(23)(24)(25)(26)(27).…”

“…The thickness of the oil film is reduced. The viscosity effect of the lubricant during extrusion decreased, resulting in a reduction of damping [21]. As the LOA passes through the pitting area, the contact force on the LOA located in the pitting area is drastically reduced, and the reduced contact force is carried by the LOA located in the non-pitting area.…”

“…They studied the engagement characteristics and dynamic model of the helical gear system. Fang et al [21] developed a numerical model to analyze the EHL line contact stiffness and damping. The calculation methods of stiffness and damping parameters of the oil film have been associated to a lesser extent with gear pitting fault.…”

Performance Analysis of Thermal and Surface Roughness Effect of Slider Bearings with Unsteady Fluid Film Lubricant Using Finite Element Method

“…Theoretical and numerical analyses were used to investigate the static properties of aerostatic porous journal bearings by Gu et al [26]. Fang et al [27] discussed transient elastohydrodynamic lubrication under line contact stiffness and damping behaviors. Jamshed et al [28] used a single-phase optimized entropy analysis to illustrate the thermal efficiency improvement of solar aircraft employing unsteady hybrid nanofluids.…”

Static and Dynamic Characteristics of Rough Porous Rayleigh Step Bearing Lubricated with Couple Stress Fluid

“…Yandong Gu et al [35] determined the static characteristics of aerostatic porous journal bearings theoretically and numerically. Fang et al [36] discussed line contact stiffness and damping behaviors under transient elastohydrodynamic lubrication.…”