Incremental versus continuous load-lubrication procedure in the determination of friction conditions by the ring compression test

This work presents the differences found when using two types of methodology (continuous and incremental) in the application of load-lubricant during ring compression tests. Friction calibration maps have been obtained by conducting ring compression tests to flat rings of aluminium alloy UNS A97075-T6 with molybdenum disulphide (MoS2) as lubricant. Accordingly, in order to determine the particular values of the Coulomb friction coefficient, the problem was simulated using an elasto-plastic model with the finite element code Abaqus/Standard. A friction coefficients map from experiments and finite element simulation is drawn to compare the friction coefficient values derived from the continuous and incremental procedure. A comparison with experiments done with graphite powder as lubricant is also presented. Results of this investigation show that friction curves are affected by the methodology of load-lubricant application, and some guidelines about the use of these maps depending on the actual process cond...