BOUNDARY AND MIXED FRICTION IN THE PRESENCE OF DYNAMIC NORMAL LOADS .2. FRICTION TRANSIENTS

The normal dynamic model of the sliding system developed in Part I of this paper is combined with a friction model, obtained separately from the same apparatus, to provide estimates of the friction under dynami c loading conditions. The Two-dimensional friction model, developed fr om measurements at constant normal load and slowly varying sliding spe eds, includes the normal approach of the sliding bodies as a key varia ble. From the combined model, estimates of friction under harmonic loa ding and of friction transients associated with short duration impacts are compared with measurements. The very good agreement between estim ates and measurements indicates that, while a good friction model is r equired, the crucial and most variable aspect of the modeling of dynam ic friction is the representation of the normal dynamics of the slidin g system.