Abstract
Byline: A. H. Elkholy, M. O. Othman, A. Assar, M. M. El-Refaee, A. Khadrawi A contact concept is proposed to explain the tribology of unlubricated metal-to-metal sliding at high speeds. It is aimed at studying the relationship between relative surface speeds, contact temperature and friction coefficient during oscillatory motion under dry conditions. An experimental set-up was designed and built where two cylindrical rods of crossed axes are used to simulate the contacting oscillating bodies. Four frequencies of 4, 6, 8 and 10 Hz, a constant amplitude of 1.25 mm, and three static contacting loads of 6, 8 and 10 Newtons were tested. Temperatures at four different locations along the surface of contact of one of the rods were measured. An analytical model based upon heat flow equations and friction energy is developed to determine the gradients of both the contact temperature and friction coefficient within the vicinity of contact. The heat flow equations are solved numerically using the Finite Difference Technique. Good correlation between experimental and analytical results was obtained with a maximum deviation of no more than 15%.