AN INVESTIGATION INTO THE CONSTANT FRICTION FACTOR WITH THE UPPER-BOUND FLOW FUNCTION ELEMENTAL TECHNIQUE

An upper-bound flow function elemental technique is proposed to investigate the constant friction factor from the ring-compression test. In this investigation, the condition of constant shear stress on the friction interface is caused to be satisfied by the constrained technique. The calibration curves for constant friction factors established by this method are compared with those of other methods and with experimental results. It is shown that the results are in good agreement with both those from the rigid-plastic finite-element solution and with experimental results. Furthermore, a numerical interpolating method called the friction-area-divided method is recommended for the evaluation of the friction factors of lubricants from a set of calculated calibration curves and may provide a useful tool for industrial applications.