Seminar of Dr. Rosario Capozza, November 24th
© 2011 EPFL
LSMS is happy to invite you to a Conference presented by Dr. Rosario Capozza from Tel Aviv University, Israel
“Onset and stabilization of frictional motion”, November 24th, 2011 at 11h,
Room GC A1 416
Recent experiments show that the onset of frictional motion and the associated stick-slip are ruled by the complex rupture processes of microscopic contacts forming the interface of two contacting bodies.
Two examples of this complexity are the stochasticity associated to the stick-slip motion (e.g. irregularity in the intervals between slip events) and the variability of static friction coefficient that, in contrast to the common belief, is not a material constant.
In the first case, applying small-amplitude oscillations to the shear force, we show, experimentally and theoretically, that the stick-slip periods synchronize. We further show that this phase locking is related to the inhibition of slow rupture modes which forces a transition to fast rupture, providing a possible mechanism for observed remote triggering of earthquakes.
In the second case we provide a theoretical framework for understanding how and why for the same material the measured values of static friction coefficient can vary within wide limits. More specifically, we show:
- What are the maximal and minimal values of static friction for the same material and normal load.
- What is a relation between the measured value of static friction and the state of the slider and how to characterize this state.
- What is the effect of loading configuration on static friction.