Characterization and modeling of friction and wear: an overview

Abstract

In this age of virtual design, high-performance machines, and precise motion control, the abilityto characterize friction and wear processes and then to model and simulate them, becomes a pertinentissue. This communication gives a condensed overview of the generic characteristics of friction, thereafter,generic models, developed at KULeuven, PMA, are presented and discussed.with Leuven Air Bearings N.V. since Sept. 2010In regard to friction, both sliding and rolling are considered. The characterization concerns (i) therelationship between the friction (traction) force and the state of sliding of the system (displacement,velocity,…), at a given normal load; (ii) the relationship between the coefficient of friction and the normalload.As regards frictional behaviour in function of sliding (rolling) state, the main features are: (i) pre-sliding (prerolling) hysteresis and (ii) gross-sliding (rolling) dynamics. Models are presented that capture those featuresand relate them to the contact characteristics. Comparison with experimental results is also presented forthe main features. Secondly, the dependence of the coefficient of friction on the normal load is identifiedand modelled.Finally, regarding wear simulation, the generic friction model is extended to cater for an asperity populationthat changes during the lifetime of sliding. Based on fatigue considerations, asperities get broken after acertain number of contact cycles, and are replaced by smaller ones. With the aid of this model, we try tocorrelate energy dissipation with wear evolution, and support that by experimental observation.