Physically based modeling of reciprocating lip seal friction

Lip seal friction under constant speed sliding is modeled as the sum of thr ee physically based components: (1) viscous shear loss in the lubricant; (2 ) hysteresis losses due to roughness-imposed deformation of the seal materi al, and (3) hysteresis losses due to deformation caused by varying intermol ecular forces at the sliding interface. Increasingly thick hydrodynamic fil ms progressively reduce contributions of the roughness and intermolecular c omponents. Peaks in friction expected from these two components are smaller , occurring at lower sliding speed, than in ''dry" rubber friction. Model s imulations capture friction trends with temperature, hydraulic pressure, se al material, lubricant viscosity and shaft roughness.