The effect of slip on critical contact pressure causing wear mode transition based on Burwell-Strang's concept - Analysis by slip line field theory

This paper describes the effect of slip on rough surface contact. The conta ct is regarded as 2D and is assumed as that between rough surface and plane to apply the slip line field theory. Individual summit of asperity on the rough surface is modeled by blunt rigid wedge, while counter plane is treat ed as pure plastic material with no work hardening. From the above approxim ation, the relation between the size of yielding region under contacting su rface and load of each contact is calculated using the results of the slip line field analysis for wedge indentation with and without tracking motion. These results are applied to the contact analysis for random rough surface s using stochastic method, and the effects of some parameters on this relat ion are calculated. From these calculations, the following conclusions are derived. 1) The size of the yielding region increases as the semi wedge ang le of asperity decreases. For real surfaces with more than 80 degrees in se mi wedge angle, the size of yielding region in slip condition is smaller th an that in condition without slip. 2) As shear stress of contact boundary i ncreases, the size of yielding region increases. The shear of contact surfa ce decreases the size of the yielding region for low shear stress of contac t boundary. Therefore, this shear makes the condition of load mild in lubri cated contact.