An investigation of convection effects in complete and almost complete contact problems

The problem of a rigid, square-ended and an almost square-ended rigid punch sliding with both plane and anti-plane velocity components is studied. It is shown that, for a truly complete contact, if the contacting body is incompressible, convection effects are absent. Introducing either: (a) local rounding or (b) finite compressibility of the contacting body into the problem introduces convection, and hence an inconsistency into the bulk/pointwise application of the orthogonal friction law.