An investigation of the applicability of contact models to the normal load-deformation behaviour of artificially shaped granite

Abstract

The validity of different available contact models is tested against experimental data for contact normal loading of artificially shaped granite stones. Three elastic models and two plastic models were tested with different combinations of contact shape (spherical, conical and flat) and roughnesses. It was found that the deviation from the Hertz model increased with surface roughness with a generally better representation of the data achieved by using models which consider surface roughness and the fractality of the surface. The validity of all these models seems to be limited to before excessive plastic deformations start taking place, after which the contact seems to deform under constant stiffness.