Multi-scale analysis of high-speed dynamic friction

Friction occurring at the interface between dissimilar metallic components as a result of high velocity impact or explosive loading can have a profound effect on the subsequent motion. A comprehensive understanding of the involved processes across a wide range of initial conditions remains outstanding. Dry sliding of single crystal silver on copper at high pressure is investigated for a range of sliding speeds using a multi-scale modelling method based upon the domain decomposition approach (molecular dynamics in the near interface region and continuum mechanics elsewhere). The transient solutions reveal detailed observations of the processes that lead to phenomena such as the growth of epitaxial layers of the softer material, shifting of the sliding interface due to formation of shear-bands, development of amorphous structures, and ultimately the resultant motion of the components. Analysis of the results also links these processes to the changes in the state of the material through growth of dislocations and thermal effects.