Fluid dynamic bearings have very quickly replaced ball bearings of the HDD spindle motor. Main of the reasons is that they provide better dynamics and stability conditions, because fluid lubricant prohibits the solid contact between cooperating surfaces i.e. between the rotating and stationary parts and provides the damping effects and stiffness. The HDD spindle system is supported by two journal and two thrust bearings with herringbone or spiral grooves They have contribu...
układ kostny człowieka
The lubrication parameters of rough and used cartilage surface in human hip joint changes suddenly after its injury.Stochastic changes of the roughness of the surfaces of the head of bone and stochastic changes of the load imply the random changes of the gap height.Hence the pressure distribution and capacity as well as friction forces coefficiend radically decrease or increase in several microseconds after trauma.These changes are very diddicult to measure,hence an approp...
numerical differential equations
This paper shows numerical calculations of the friction forces in spherical coordinates for hydrodynamic steady and unsteady unsymmetrical synovial non-Newtonian fluid flow with variable viscosity and for random changes of human hip joint gap