A classical contact mechanics problem was considered: that is, the indentation of a ductile half-plane by a rigid flat punch (in plane strain), and it was re-visited using the dislocation mechanics approach. The dislocation nucleation and dislocation interaction beneath the indenter were examined. The threshold load for dislocation nucleation and the dislocation emission angle were obtained in analytical form. Moreover, based upon the consideration of dislocation interaction, the mechanism of contact load evolution (hardening) was explored. A triangular so-called dead-zone beneath the indenter, which could not be thus far accurately explained by traditional continuum models, was predicted; in good agreement with the results of careful experiments reported in the literature. The proposed model was likely to be useful for the analysis of contacts at both the micro- and macro-scales.

Dislocation Model of Localized Plastic Deformation Initiated with a Flat Punch. L.Ma, A.M.Korsunsky, M.Wiercigroch: International Journal of Solids and Structures, 2010, 47[7-8], 1082-9