Influence of tilt angle and grinding angle of the plate on friction and transfer layer formation
In the present investigation, unidirectional grinding marks were attained on the steel plates. Experiments were then conducted using pins of high purity Al, pure Mg and Al-Mg alloys against the prepared steel plates using an inclined pin-on-plate sliding tester. The inclination angle of the plate was varied in the tests and for each inclination angle, the pins were slid both perpendicular and parallel to the unidirectional grinding marks direction under both dry and lubricated conditions. Results showed that the friction, transfer layer formation, and the presence of stick-slip motion significantly depend on the grinding marks direction and tilt angle of the hard surfaces under both dry and lubricated conditions for all the three materials investigated.
Effect of Surface Topography on Friction and Transfer Layer during Sliding
Surface topography influences friction and transfer layer formation during sliding. In the present investigation, various kinds of surface topography were produced on steel plates. Pins made of metals (pure Al, Cu and Pb) and alloys (Al-4Mg and Al-8Mg) were then slid against prepared steel plates using inclined pin-on-plate sliding tester to understand the role of surface topography of harder surface and load on friction and transfer layer formation under both dry and lubricated conditions. It was observed that the transfer layer formation and coefficient of friction along with its two components, namely adhesion and plowing, are strongly dependent on surface topography and independent of surface roughness (Ra). The plowing component of friction was highest for the surface that promotes plane strain conditions and lowest for the surface that promotes plane stress conditions near the surface.
Mathematical Modeling of Scour and Deposition
Electronic computers are opening up the field of sedimentation engineering by permitting the analysis of problems which heretofore have required too much time and effort. Movable stream bed profiles are being calculated in addition to water surface profiles. The initial gradation of sediment material in the stream bed may be prescribed to facilitate the calculation of an armor layer. This gradation is continually changed by the computer program in response to sediment particles being deposited on the stream bed and material on the stream bed being removed to satisfy transport capacity. Hydraulic sorting of sediment by grain size is accomodated. The stream bed does not have to be represented by a single grain size. Retardance of motion because of armor layer is calculated.