Energy-based modelling of adhesive wear in the mixed lubrication regime

Abstract

Adhesive wear in dry contacts is often described using the Archard or Fleischer model. Both provide equations for the determination of a wear volume, taking the load, the sliding path and a set of material parameters into account. While the Fleischer model is based on energetic approaches, the Archard formulation uses an empirical factor-the wear coefficient-describing the intensity of wear. Today, a numerical determination of the wear coefficient is already possible and both approaches can be deduced to a local accumulation of friction energy. The aim of this work is to enhance existing energy-based wear models into the mixed lubrication regime. Therefore, the pressure distribution within the contact area will be determined numerically taking real surface topographies into account. The emerging contact area will be divided into one part of solid and a second part of elastohydrodynamically lubricated (EHL) contacts. Based on the resulting pressure and shear stress distribution, the formation of micro cracks within the loaded volume will be described. Determining a critical number of load cycles for each asperity, a locally resolved wear coefficient will be derived and the local wear depth calculated.