THREE DIMENSIONAL ELASTIC-PLASTIC CONTACT OF NOMINALLY FLAT ROUGH SURFACES BASED ON FEA-BASED CONSTITUTIVE ASPERITY CONTACT RELATIONS AND INCLUDING ASPERITY SHOULDER CONTACT

Three dimensional elastic-plastic contact of two nominally flat rough surfaces is considered. Equations governing the shoulder-shoulder contact of asperities are derived based on the asperity-asperity constitutive relations from a finite element model of their elastic-plastic interaction proposed by Kogut and Etsion [12]. Shoulder-shoulder asperity contact yields a slanted contact force consisting of both tangential (parallel to mean plane) and normal components. An analytical fusion technique is developed to combine the piecewise asperity level constitutive relations. This is shown to yield upon statistical summation the cumulative effect resulting in the contact force between two rough surfaces with two components, one in the normal direction and a half-plane tangential component.