Influence of material properties and operating conditions on the predicted performance of poroelastic faced bearings

Abstract

A new lubrication model of poroelastic lubrication of materials with low Young’s modulus and permeability is presented based on Darcy’s law and linear elastic solid mechanics and a contact model. A rotating bearing surface moving against a flat surface is considered and the effect of material parameters and operating conditions is analyzed. The results show that the material parameters (permeability ( k), Young’s modulus ( E), and viscosity ( μ)) and operating conditions (angular velocity ( ω) and material deformation ( δ)) have significant effects on the lubrication performance of the poroelastic bio-inspired materials. It is also observed that the load ratio (the ratio of pressure-borne load to the applied load along the contact boundary) increases as k and E decrease, and as μ, ω, and δ increase. Conversely maximum solid stress decreases with decreasing of E, μ, ω, δ and with increasing of k. The relationship of the load ratio, contact stress, and deformation relative to E and k has been illustrated in this paper.

Influence of magnetic fluids’ cohesion force and squeeze dynamic effect on the lubrication performance of journal bearing

“…As a result, equation 8reduces to the magnetic Newtonian fluids case. 17,18 Equation 8is a modified Reynolds equation, which can be given in dimensionless form of equation 10using…”

An investigation into the contact between soft elastic and poroelastic bodies rotating under load

“…Experiments have identified the benefit of such flows in cartilage which boost the lubrication performance, recently this has been referred to as tribological rehydration [9][10][11]. This model indicates the potential means by which this is facilitated, in which flow across the contacting interface would be permitted and lubrication theory used to govern fluid flow outside the contact [18]. …”

“…By implementing an Eulerian frame of reference is subsequently given by Eq. (8) [18,19], where for each body the centres of rotation are x y R and x y R . Additionally, under linear elastic assumptions the volumetric strain is defined as the divergence of the deformation field .…”

“…At the contacting interface this latter condition can be interpreted as no leakage between the bodies as they are compressed and as such mass is conserved. Models have been developed to explore the potential of a lubricating region along the contacting boundary in which flow in and out of the poroelastic material is permitted [18], however in this model no lubrication is assumed and fluid does not leave the contacting bodies.…”

“…Findings from the development of the biphasic theory have demonstrated that a significant fluid pressure can be maintained so long as the contact moves to hydrated regions faster than the rate of leakage [15,16]. Modelling the poroelastic lubrication mechanisms has been a considerable challenge, with the large deformation of the cartilage and changing permeability with compression, as well as numerical problems in obtained computational solutions being some of the challenges [17][18][19].…”