A QUANTITATIVE INVESTIGATION OF DISPLACEMENT ACCOMMODATION IN 3RD-BODY CONTACT

Recently, the ''velocity accommodation'' concept was introduced in tri bology. In third-body contacts, velocity accommodation can occur in fi ve sites and according to four modes, giving rise to 20 possible combi nations, i.e. 20 velocity accommodation mechanisms. The present paper addresses the role of third and first bodies in elastic and/or plastic deformations in velocity accommodation. For this, a simplified model is first proposed to represent third-body contacts separated by wear d ebris or solid lubricants. Then, by using the finite element method, t he relative movement between first bodies in contact under different t ypes of loading is simulated and the deformation of the model as well as the stress and strain field in the third body is determined numeric ally. Results quantify the role of the third and first bodies in eithe r elastic or plastic deformation. When only relative tangential displa cement is imposed, a simple analytical formula based upon a model of t wo compliances in series is suggested in order to estimate the displac ement accommodation of third and first bodies.