nan Jamari

New Material Development for Surface Layer and Surface Technology in Tribology Science to Improve Energy Efficiency

This paper reviews the development of new material and surface technology in tribology and its contribution to energy efficiency. Two examples of the economic benefits, resulted from the optimum tribology in the transportation sector and the manufacturing industry are discussed. The new materials are proposed to modify the surface property by laminating the bulk material with thin layer/coating. Under a suitable condition, the thin layer on a surface can provide a combination of good wear, a low friction and corrosion resistance for the mechanical components. The innovation in layer technology results molybdenum disulfide (MoS2), diamond like carbon (DLC), cubic boron nitride (CBN) and diamond which perform satisfactory outcome. The application of the metallic coatings to carbon fibre reinforced polymer matrix composites (CFRP) has the capacity to provide considerable weight and power savings for many engineering components. The green material for lubricant and additives such as the use of sunflower oil w...

Two‐Dimensional Finite Element Analysis on Running‐in of Elastic‐Plastic Rolling Contact

The running‐in of rolling contact between a rigid cylinder against a deformable rough surface is simulated by finite element method in this paper. Two‐dimensional model of rough surface is employed in the simulation by considering the elastic‐plastic material with strain hardening behavior. The topographical changes of the rough surface due to running‐in of rolling contact are observed for the applied load or interferences. A relatively high load is applied so that it operates in the elastic‐plastic deformation regime. The running‐in phase, indicated by the high asperity truncation, is found within the first two cycle of the rolling contact. After the third cycle, the steady state deformation occurs. A comparison between the running‐in of rolling contact and the repeated static contact for the same model and is also presented.

Tribological characteristic enhancement effects by polymer thickened oil in lubricated sliding contacts

Polymer thickened oils are the most preferred materials for modern lubrication applications due to their high shear. The present paper explores a lubrication mechanism in sliding contact lubricated with polymer thickened oil considering cavitation. Investigations are carried out by using a numerical method based on commercial CFD (computational fluid dynamic) software ANSYS for fluid flow phenomenon (Fluent) to assess the tribological characteristic (i.e. hydrodynamic pressure distribution) of lubricated sliding contact. The Zwart-Gerber-Belamri model for cavitation is adopted in this simulation to predict the extent of the full film region. The polymer thickened oil is characterized as non-Newtonian power-law fluid. The simulation results show that the cavitation lead lower pressure profile compared to that without cavitation. In addition, it is concluded that the characteristic of the lubrication performance with polymer thickened oil is strongly dependent on the Power-law index of lubricant.