A constitutive model for interface friction

A new adhering-slipping rate constitutive model for interface friction is formulated. The model is fully three-dimensional in nature, but rate-independent, isothermal and isotropic in character. The conditions imposed by the requirement that the interface constitutive model be independent of an observer are carefully examined, and the new consititute model is objective or invariant under a change in observer. An incrementally objective, implicit time-integration procedure for the model is also developed. Although idealized, the model should be useful for a first-order accounting of frictional behavior at dry, unlubricated contacting interfaces in quasistatic deformation processing operations of metallic workpieces with rigid tools.