RHEOLOGICAL MODEL OF SOLID LAYER IN ROLLING-CONTACT

The rheological behaviour of interfacial layers forming a third body i n rolling-sliding contact (such as a locomotive wheel and rail) and co nsisting of wear debris and contaminants, is an important factor affec ting rolling-sliding contact traction characteristics. The shear stres s : properties of individual components of the contaminant layer, such as oxidized wear debris, sand, clay and molybdenum disulfide, were me asured for different slip distances using a specially designed rheolog y apparatus. Based on experimental results, the following elastic-plas tic rheological model for compressed layers is suggested: [GRAPHICS] T his model establishes a relationship between three rheological paramet ers: the shear moduli of elasticity (G) and plasticity (k) and the cri tical shear stress (tau(c)). Based on this relationship, a frictional model for rolling-sliding contacts separated by an interfacial layer i s presented in this paper. It shows that the friction is affected by t he third-body rheology, slip distance and the load, with the shear str ess versus slip distance relationship of the interfacial layer exhibit ing the dominant influence.