Inertia and couple‐stress effects on squeeze‐film characteristics with reference to biological bearings

Abstract

Couple stresses affect lubrication when additives are used or the lubricant contains long‐chain molecules. Such couple stresses may have a considerable effect on the behaviour of bearings in practice. The influence of couple stresses and lubricant inertia on the mechanical parameters of a curvilinear thrust bearing with a squeeze film is considered in this paper. Simulation of the squeeze‐film behaviour of a human joint modelled as a spherical bearing is discussed as an example.

Sensitivity study of the morphometric fitting on the pressure field inside ankle joints

“…SF is considered as a mixture of two incompressible fluids: Viscous (hyaluronic acid-protein macromolecular complex) and ideal (water and small solutes). The long chain of polysaccharide hyaluronic acid molecules present in the synovial fluid works as polar additives and gives the motivation for assuming the synovial fluid as a stokes couple-stress fluid [9,20]. Making the usual assumptions of hydrodynamic lubrication applicable to thin films, and in the case of mono-dimensional pressure in the x direction, the modified Reynolds equation in non-dimensional form is [7]:…”

“…These have included a wide range of lubrication concepts, for example hydrodynamic, boundary and mixed-regime. Therefore, the understanding of the influence of the geometric configuration in the joint behaviour is important to study the ankle joint behaviour as a mechanical system which stands the external load (human body weight) under a hydrodynamic regime of lubrication in the synovial capsule during the first moments of the gait cycle [7][8][9]. We present the data processing chain under different methodology and system simulation results.…”

Deep Investigation on Natural Convection Flow of a Couple Stress Fluid with Nanoparticles in an MHD Vertical Porous Channel with Convective Boundary Conditions

“…He proposed the micron-continuum theory with polar effects and defined the rotation field in terms of velocity field to establish the constitutive relationship between stress and strain rate. Synthetic fluids, polymers, animal blood, thickened oils, synovial fluid in synovial joints and suspension fluids are the fields of application of the couple-stress fluids [8][9][10][11][12][13][14][15].…”

Effect of Surface Roughness on the Squeeze Film Lubrication of Finite Poroelastic Partial Journal Bearings with Couple Stress Fluids: A Special Reference to Hip Joint Lubrication

“…Bujurke et al [8] have studied the effect of couple stresses in squeeze film poroelastic bearings with special reference to synovial joints on the basis of Stokes [9] couple stress fluid theory. Walicki and Walicka [10] studied the inertia and couple stress effects on squeeze film characteristics with reference to biological bearings. Bujurke and Kudenatti [11] have presented the analysis of rough poroelastic bearings with reference to lubrication mechanism of synovial joints.…”