Abstract
Frictional resistance to slip, , is determined by the real area of contact, , and the shear strength of the contacts forming the frictional interface. We perform simultaneous high-speed local measurements of and at the tail of propagating rupture fronts. Rate dependence is investigated over 2 orders of magnitude of local slip velocities which reach up to . A critical slip velocity is observed that signifies a transition in the frictional behavior: enhanced velocity weakening of and . These measurements enable us to infer the contact shear strength, an otherwise elusive quantity, and show that the contact shear strength persistently increases with slip rate. This, surprisingly, contrasts with expected contact softening at the high temperatures induced by rapid sliding.
- Received 15 March 2017
DOI:https://doi.org/10.1103/PhysRevLett.118.234301
© 2017 American Physical Society