An Intersonic Slip Pulse at a Frictional Interface Between Dissimilar Materials

Two homogeneous and isotropic elastic half-spaces are acted upon by remote normal and shear tractions. The applied shear stress is less than that which is required to produce overall sliding of the two bodies. The possible existence of a slip pulse is investigated, i.e., a finite-width region, on the interface, of altered normal and shear stress which satisfies the Amontons-Coulomb law of friction. Pulses which travel at a speed which is greater than the minimum shear wave speed and less than the maximum dilatational wave of the two bodies, are of interest in this investigation. Such pulses are shown to exist for sufficient friction and for modest mismatches in material combinations. The pulse is weakly singular at the leading edge and bounded at the trailing edge. Furthermore it travels at speeds just below the lesser dilatational wave speed and in the opposite direction of sliding of the lower wave-speed material. In addition, a pair of equations are given which relate the interfacial normal and shear stress to the interfacial slip velocity. These relations are analogous to the subsonic results of Weertman, but are valid for an arbitrary speed range.