Wear rate and debris are key problems to implanted metal-on-metal hip joints. Surface texture on bearing surfaces is reported to increase tribological performances. Research on the translation of this technology to metal-on-metal hip joint for reduction of friction, wear rate and debris generation is limited. The aim of this study was to investigate, by theoretical predictions and experimental ...

Overcoming friction while generating useful torque is a challenge for micro engines. Here we report the development of microscale engine that utilizes transition boiling as mode propulsion and Leidenfrost effect friction-less bearing. The shows significantly improved performance compared to engine, which uses vapor entrainment mechanism (up 3 orders magnitude higher efficiency). We characterize...

To date most of the MEMS devices are been based on Silicon. This is due to the technological know-how accumulated on manipulating, machining, manufacturing of Silicon. However, only very few devices involve moving parts. This is because of the rapid wear arising from high friction in these Silicon based systems. Recent tribometric experiments carried out by Gardos on Silicon and polycrystalline...

This paper introduces an improved friction model accounting for elastoplastic behavior of interacting asperities along contiguous rough surfaces for a line contact solution. It is based on Greenwood and Tripp’s original boundary friction model and specifically tailored for a boundary regime of lubrication. The numerical solution of Reynolds’ equation is achieved by implementing Elrod’s cavitati...

The article is devoted to the analysis of a mathematical model lubricant mootion in working gap radial sliding bearing with support profile having fluoroplast-containing composite polymer coating groove on surface, which has micro-polar properties. New models describing motion material groove, micropolar rheological properties laminar mode motion, approximation for “thin layer”, are proposed. A...

Surface texturing has been shown to be an effective modification approach for improving tribological performance. This study examined the friction reduction effect generated by square dimples of different sizes and geometries. Dimples were fabricated on the surface of ASP2023 steel plates using femtosecond laser-assisted surface texturing techniques, and reciprocating sliding line contact tests...

Osteoarthritis is a complex disease involving the mechanical breakdown of articular cartilage in the presence of altered joint mechanics and chondrocyte death, but the connection between these factors is not well established. Lubricin, a mucinous glycoprotein encoded by the PRG4 gene, provides boundary lubrication in articular joints. Joint friction is elevated and accompanied by accelerated ca...

The diarthrodial, knee joint is a remarkably efficient bearing system; articulating cartilage surfaces provide nearly frictionless performance with minimal wear. The low friction properties of the cartilage surfaces are due in part to the boundary lubricant, superficial zone protein (SZP); also known as lubricin or proteoglycan 4 (PRG4). In previous work, SZP localization and cartilage friction...

We study the rise dynamics of a large particle in a granular bed under vertical vibration using molecular dynamics simulations. Systematic variation of the particle properties and external wall friction in the simulations shows that the large particle rising is very sensitive to external wall friction. The dynamical response of the granular bed with wall friction is shown to include an expansio...

The bearing capacity of strip footings on unsaturated soils is studied using slip line theory. The suction profiles considered are non-uniform with depth and correspond to vertical flow of water by infiltration or evaporation. The slip line theory assumes a plastic equilibrium state of a Mohr-Coulomb soil in which suction influences are included using the effective stress concept. This paper sh...