Theoretical analysis of a rolling-sliding elastohydrodynamic lubrication line contact with a subsurface inclusion

Abstract

This work investigates the transient effects of a single subsurface inclusion over the pressure, film thickness, and von Mises stress in a line elastohydrodynamic lubrication contact. Results are obtained with a fully-coupled finite element model for either a stiff or a soft inclusion moving at the speed of the surface. Two cases analyzed consider the inclusion moving either at the same speed as the mean velocity of the lubricant or moving slower. Two additional cases investigate reducing either the size of the inclusion or its stiffness differential with respect to the matrix. It is shown that the well-known two-wave elastohydrodynamic lubrication mechanism induced by surface features is also applicable to the inclusions. Also, that the effects of the inclusion become weaker both when its size is reduced and when its stiffness approaches that of the matrix. A direct comparison with predictions by the semi-analytical model of Morales-Espejel et al. ( Proc IMechE, Part J: J Engineering Tribology 2017; 231) shows reasonable qualitative agreement. Quantitatively some differences are observed which, after accounting for the semi-analytical model's simplicity, physical agreement, and computational efficiency, may then be considered as reasonable for engineering applications.

Fretting Wear and Lubrication Characteristics of the Steel Ring of a Metal Belt-Type Continuously Variable Transmission

“…Furthermore, the heat transfer along the film thickness direction is negligible. The required energy equation can be expressed as (25) where p c is the equal-pressure specific heat capacity of the lubricating oil; T is the lubricating oil temperature; and J is the thermal power equivalent.…”

“…The lubrication state of mechanical systems and the corresponding service life has aroused widespread attention in the scientific research field, and scholars have increasingly studied the characteristics of lubricating oil films [25][26][27]. Wang [28][29] comprehensively studied the lubrication-dynamic contact oil film stiffness of point-contact spiral bevel gears under periodically fluctuating loads and speeds and found a competitive relationship between dynamic load and contact area.…”

Rapid analysis of the effects of surface and sub-surface defects in elastohydrodynamic contacts

“…In order to check the accuracy of the analysis the results were compared with results presented in Quinonez and Morales-Espejel. 15 These appear to be the only available results for non-stationary defects under both rolling and sliding conditions. The conditions examined in Quinonez and Morales-Espejel 15 are somewhat artificial and considered transverse, cylindrical inclusions in one surface.…”

“…15 These appear to be the only available results for non-stationary defects under both rolling and sliding conditions. The conditions examined in Quinonez and Morales-Espejel 15 are somewhat artificial and considered transverse, cylindrical inclusions in one surface. The mating surface was assumed rigid.…”

“…Surface and sub-surface defects such as cracks and inclusions tend to reduce the life of elastohydrodynamic components and may lead to catastrophic failure. The effect of inclusions has received considerable attention in recent years, see for example, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] but detailed analysis is hampered by the complexity of the problem. Behaviour of surface defects, typically cracks, is perhaps even more complex with crack propagation being influenced by the presence of fluid inside the defect itself.…”