Grant IDEI 912 financed by CNCSIS (National Council for Academic Research).

During the last 10 years a new lubrication mechanism applicable to highly compressible porous layers imbibated with a fluid/lubricant has been developed. This lubrication process was observed and analyzed independently by prof. Pascovici from University POLITEHNICA of Bucharest (UPB) and prof. Weinbaum from City University of New York. This type of lubrication is strongly dependent on porosity variation and consequently, on permeability; therefore, prof. Pascovici proposed the name of ex-poro-hydrodynamic (XPHD) lubrication.

The applications foreseen until present referred to: viscosity pumps, thrust bearings, red cells lubrication in narrow capillary, squeeze effects in the case of natural or artificial human joints, skiing on fresh powder snow and even high-speed trains. Basically, XPHD lubrication implies flow in a porous medium whose solid phase, represented by fibers, induces negligible compression compared to the hydrodynamic pressure generated within the porous layer. The main objective of the project is to study, theoretically (analytically and numerically) and experimentally, the XPHD lubrication, in order to develop innovative dampers using the squeeze effect under impact load. An exploratory study, with promising results, has recently taken place at UPB, for a plane circular configuration. The geometrical configurations proposed to be investigated are: plane-circular, mono- and multi-layer, spherical and cylindrical aligned. XPHD shock dampers would compete with electrorheological or colloidal shock dampers. The XPHD solution has the advantage of simplicity compared to the aforementioned solutions. The fluid used by the XPHD shock absorber could be water or mineral/natural/synthetic oil, unlike the other alternatives which require special fluids. A new collaboration with LMS from University of Poitiers is possible in order to apply this method to high performance sports equipment.

  • Hydrodynamic Lubrication
  • Thin Layers
  • Porous Media
  • Compliant Media
  • Impact Loading